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Chong J, Benchohra A, Besnard C, Guénée L, Rosspeintner A, Cruz CM, Jiménez JR, Piguet C. Taming 2,2'-biimidazole ligands in trivalent chromium complexes. Dalton Trans 2024. [PMID: 39011611 DOI: 10.1039/d4dt01608d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
Complete or partial replacement of well-known five-membered chelating 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen) ligands with analogous didentate 2,2'-biimidazole (H2biim) provides novel perspectives for exploiting the latter pH-tuneable bridging unit for connecting inert trivalent chromium with cationic partners. The most simple homoleptic complex [Cr(H2biim)3]3+ and its stepwise deprotonated analogues are only poorly soluble in most solvents and their characterization is limited to some solid-state structures, in which the pseudo-octahedral [CrN6] units are found to be intermolecularly connected via peripheral N-H⋯X hydrogen bonds. Moreover, the associated high-energy stretching N-H vibrations drastically quench the targeted near infrared (NIR) CrIII-based phosphorescence, which makes these homoleptic building blocks incompatible with the design of molecular-based luminescent assemblies. Restricting the number of bound 2,2'-biimidazole ligands to a single unit in the challenging heteroleptic [Cr(phen)2(Hxbiim)](1+x)+ (x = 2-0) complexes overcomes the latter limitations and allows (i) the synthesis and characterization of these [CrN6] chromophores in the solid state and in solution, (ii) the stepwise and controlled deprotonation of the bound 2,2'-biimidazole ligand and (iii) the implementation of Cr-centered phosphorescence with energies, lifetimes and quantum yields adapted for using the latter chromophores as sensitizers in promising 'complex-as-ligand' strategies.
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Affiliation(s)
- Julien Chong
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
| | - Amina Benchohra
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
- Laboratoire CEMCA UMR, CNRS 6521, UFR Sciences and Techniques, 6, avenue Victor Le Gorgeu, 29238 Brest Cedex 3, France
| | - Céline Besnard
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Laure Guénée
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Arnulf Rosspeintner
- Department of Physical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Carlos M Cruz
- Department of Organic Chemistry, Unidad de Excelencia de Química (UEQ), University of Granada, Avda. Fuente Nueva s/n, 18071 Granada, Spain
| | - Juan-Ramón Jiménez
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada and Unidad de Excelencia en Quımica (UEQ), Avda. Fuente Nueva s/n, 18071 Granada, Spain
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
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2
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Doeven EH, Connell TU, Sinha N, Wenger OS, Francis PS. Electrochemiluminescence of a First-Row d 6 Transition Metal Complex. Angew Chem Int Ed Engl 2024; 63:e202319047. [PMID: 38519420 DOI: 10.1002/anie.202319047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/12/2024] [Accepted: 03/22/2024] [Indexed: 03/24/2024]
Abstract
We report the electrochemiluminescence (ECL) of a 3d6 Cr(0) complex ([Cr(LMes)3]; λem=735 nm) with comparable photophysical properties to those of ECL-active complexes of 4d6 or 5d6 precious metal ions. The electrochemical potentials of [Cr(LMes)3] are more negative than those of [Ir(ppy)3] and render the [Cr(LMes)3]* excited state inaccessible through conventional co-reactant ECL with tri-n-propylamine or oxalate. ECL can be obtained, however, through the annihilation route in which potentials sufficient to oxidise and reduce the luminophore are alternately applied. When combined with [Ir(ppy)3] (λem=520 nm), the annihilation ECL of [Cr(LMes)3] was greatly enhanced whereas that of [Ir(ppy)3] was diminished. Under appropriate conditions, the relative intensities of the two spectrally distinct emissions can be controlled through the applied potentials. From this starting point for ECL with 3d6 metal complexes, we discuss some directions for future development.
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Affiliation(s)
- Egan H Doeven
- Centre for Sustainable Bioproducts, Faculty of Science, Engineering and Built Environment, Deakin University Waurn Ponds, Victoria, 3216, Australia
| | - Timothy U Connell
- Centre for Sustainable Bioproducts, Faculty of Science, Engineering and Built Environment, Deakin University Waurn Ponds, Victoria, 3216, Australia
| | - Narayan Sinha
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
- School of Chemical Sciences, Indian Institute of Technology (IIT) Mandi Kamand, Mandi, 175075, Himachal Pradesh, India
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Paul S Francis
- Centre for Sustainable Bioproducts, Faculty of Science, Engineering and Built Environment, Deakin University Waurn Ponds, Victoria, 3216, Australia
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3
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Ajayi T, Lough AJ, Morris RH. Mechanochemical Synthesis of Chromium(III) Complexes Containing Bidentate PN and Tridentate P-NH-P and P-NH-P' Ligands. ACS OMEGA 2024; 9:19690-19699. [PMID: 38708235 PMCID: PMC11064035 DOI: 10.1021/acsomega.4c02076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 04/02/2024] [Accepted: 04/05/2024] [Indexed: 05/07/2024]
Abstract
Chromium(III) complexes bearing bidentate {NH2(CH2)2PPh2: PN, (S,S)-[NH2(CHPh)2PPh2]: P'N} and tridentate [Ph2P(CH2)2N(H)(CH2)2PPh2: P-NH-P, (S,S)-(iPr)2PCH2CH2N(H)CH(Ph)CH(Ph)PPh2: P-NH-P'] ligands have been synthesized using a mechanochemical approach. The complexes {cis-[Cr(PN)Cl2]Cl (1), cis-[Cr(P'N)Cl2]Cl (2), mer-Cr(P-NH-P)Cl3 (3), and mer-Cr(P-NH-P')Cl3 (4)} were obtained in high yield (95-97%) via the grinding of the respective ligands andthe solid Cr(III) ion precursor [CrCl3(THF)3] with the aid of a pestle and mortar, followed by recrystallization in acetonitrile. The isolated complexes are high spin. A single-crystal X-ray diffraction study of 2 revealed a cationic chromium complex with two P'N ligands in a cis configuration with P' trans to P' with chloride as the counteranion. The X-ray study of 4 shows a neutral Cr(III) complex with the P-NH-P' ligand in a mer configuration. The difference in molecular structures and bulkiness of the ligands influence the electronic, magnetic, and electrochemical properties of the complexes as exhibited by the bathochromic shifts in the electronic absorption peaks of the complexes and the relative increase in the magnetic moment of 3 (4.19 μβ) and 4 (4.15 μβ) above the spin only value (3.88 μβ) for a d3 electronic configuration. Complexes 1-4 were found to be inactive in the hydrogenation of an aldimine [(E)-1-(4-fluorophenyl)-N-phenylmethanimine] under a variety of activating conditions. The addition of magnesium and trimethylsilyl chloride in THF did cause hydrogenation at room temperature, but this occurred even in the absence of the chromium complex. The hydrogen in the amine product came from the THF solvent in this novel reaction, as determined by deuterium incorporation into the product when deuterated THF was used.
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Affiliation(s)
- Tomilola
J. Ajayi
- Department of Chemistry, University
of Toronto, 80 Saint George Street, Toronto M5S3H6, Ontario, Canada
| | - Alan J. Lough
- Department of Chemistry, University
of Toronto, 80 Saint George Street, Toronto M5S3H6, Ontario, Canada
| | - Robert H. Morris
- Department of Chemistry, University
of Toronto, 80 Saint George Street, Toronto M5S3H6, Ontario, Canada
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4
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Benchohra A, Chong J, Cruz CM, Besnard C, Guénée L, Rosspeintner A, Piguet C. Additional Insights into the Design of Cr(III) Phosphorescent Emitters Using 6-Membered Chelate Ring Bis(imidazolyl) Didentate Ligands. Inorg Chem 2024; 63:3617-3629. [PMID: 38206181 DOI: 10.1021/acs.inorgchem.3c03422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
The interest in Cr(III) complexes has been renewed over the past decades for building practical guidelines in the design of efficient earth-abundant phosphorescent near-infrared emitters. In that context, we report the first family of homoleptic tri(didentate) Cr(III) complexes [CrL3]3+ based on polyaromatic ligands inducing 6-membered chelate rings, namely, the bis(1-methylimidazol-2-yl)ketone (L = bik), bis(1-methylimidazol-2-yl)methane (L = bim), and bis(1-methylimidazol-2-yl)ethane (L = bie) ligands. The programmed close-to-perfect octahedral microsymmetry of {CrIIIN6} chromophores found in [Cr(bik)3](OTf)3 (1), [Cr(bim)3](OTf)3 (2), and [Cr(bie)3](BF4)3 (3) ensures a ligand-field strength large enough to induce intense and long-lived Cr-based phosphorescence. Impressive excited-state lifetimes (5.0-8.2 ms) were obtained at low temperatures for the [Cr(L)3]3+ series. Additionally, the photoluminescent quantum yield climbs to 0.8% for compound 1 in deaerated solutions. Moreover, the photophysical features of the three homoleptic complexes are barely influenced by the presence of dioxygen presumably because of the poor overlap between the Cr-based phosphorescence spectra (ca. 14100 cm-1) and the 1Σg+ ← 3Σg- transition in the absorption spectrum of dioxygen (13100 cm-1). The multiredox electrochemical pattern of 1 is evidenced by cyclic voltammetry as well as its strong photooxidant behavior. The pH sensitivity of 2 and 3 luminescence is discussed, along with the reactivity of their β-diketiminate derivatives.
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Affiliation(s)
- Amina Benchohra
- Department of Inorganic Analytical and Applied Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Julien Chong
- Department of Inorganic Analytical and Applied Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Carlos M Cruz
- Department of Organic Chemistry, Unidad de Excelencia de Química (UEQ) University of Granada, Avenida Fuente Nueva, ES-18071 Granada, Spain
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Céline Besnard
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Laure Guénée
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Arnulf Rosspeintner
- Department of Physical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Claude Piguet
- Department of Inorganic Analytical and Applied Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
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5
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Alazaly AM, Clarkson GJ, Ward MD, Abdel-Shafi AA. Mechanism of Oxygen Quenching of the Excited States of Heteroleptic Chromium(III) Phenanthroline Derivatives. Inorg Chem 2023; 62:16101-16113. [PMID: 37721399 PMCID: PMC10548418 DOI: 10.1021/acs.inorgchem.3c02343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Indexed: 09/19/2023]
Abstract
In this study, we report the synthesis and characterization of some heteroleptic Cr(III) complexes of the form [Cr(Phen)2L](OTf)3, where Phen = 1,10-phenanthroline and L is either 2,2'-bipyridine (bpy) or its derivatives, such as 4,4'-dimethyl-2,2'-bipyridine (4,4'-DMB), 4,4'-dimethoxy-2,2'-bipyridine (4,4'-DMOB), 4,4'-ditert-butyl-2,2'-bipyridine (4,4'-dtbpy), 5,5'-dimethyl-2,2'-bipyridine (5,5'-DMB), 4,4'-dimethoxycarbonyl-2,2'-bipyridine (4,4'-dmcbpy) or 1,10-phenanthroline derivatives, such as 5-methyl-1,10-phenanthroline (5-Me-Phen) and 4,7-dimethyl-1,10-phenanthroline (4,7-DMP). Heteroleptic complexes were prepared in two stages via the intermediate [Cr(Phen)2(CF3SO3)2](CF3SO3) and five examples have been crystallographically characterized. Steady-state absorption and luminescence emission characteristics of these complexes were measured in 1 M HCl solutions. The luminescence quantum yield of these complexes was found to be the lowest for [Cr(Phen)2(4,4'-dmcbpy)](OTf)3 and the highest for [Cr(Phen)2(4,4'-DMB)](OTf)3 with values of 0.31 × 10-2 and 1.48 × 10-2, respectively. The calculated excited state energy, E0-0, was found to vary within the narrow range of 163.1-165.0 kJ mol-1 across the series. Transient absorption spectra in degassed, air-equilibrated, and oxygen-saturated 1 M HCl aqueous solutions were also measured at different time decays and demonstrated no significant differences, indicating the absence of any ion-separated species in the excited state. Excited-state decay traces at the wavelength of maximum absorption were used to calculate oxygen quenching rate constants, kq, which were found to be in the range 3.26-5.27 × 107 M-1 s-1. Singlet oxygen luminescence photosensitized by these complexes was observed in D2O, and its luminescence intensity at 1270 nm was used for the determination of singlet oxygen quantum yields for these complexes, which were in the range of 0.20-0.44, while the fraction of the excited 2E state quenched by oxygen was in the range of 0.22-0.68, and the efficiency of singlet oxygen production was in the range of 0.44-0.90. The mechanism by which the excited 2E state is quenched by oxygen is explained by a spin statistical model that predicts the balance between charge transfer and noncharge transfer deactivation pathways, which was represented by the parameter pCT that was found to vary from 0.35 to 0.68 for this series of Cr(III) complexes.
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Affiliation(s)
- Ahmed
M. M. Alazaly
- Department
of Chemistry, Faculty of Science, Ain Shams
University, Abbassia, Cairo 11566, Egypt
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.
| | - Guy J. Clarkson
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.
| | - Michael D. Ward
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.
| | - Ayman A. Abdel-Shafi
- Department
of Chemistry, Faculty of Science, Ain Shams
University, Abbassia, Cairo 11566, Egypt
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6
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Jones RW, Auty AJ, Wu G, Persson P, Appleby MV, Chekulaev D, Rice CR, Weinstein JA, Elliott PIP, Scattergood PA. Direct Determination of the Rate of Intersystem Crossing in a Near-IR Luminescent Cr(III) Triazolyl Complex. J Am Chem Soc 2023. [PMID: 37224437 DOI: 10.1021/jacs.3c01543] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A detailed understanding of the dynamics of photoinduced processes occurring in the electronic excited state is essential in informing the rational design of photoactive transition-metal complexes. Here, the rate of intersystem crossing in a Cr(III)-centered spin-flip emitter is directly determined through the use of ultrafast broadband fluorescence upconversion spectroscopy (FLUPS). In this contribution, we combine 1,2,3-triazole-based ligands with a Cr(III) center and report the solution-stable complex [Cr(btmp)2]3+ (btmp = 2,6-bis(4-phenyl-1,2,3-triazol-1-yl-methyl)pyridine) (13+), which displays near-infrared (NIR) luminescence at 760 nm (τ = 13.7 μs, ϕ = 0.1%) in fluid solution. The excited-state properties of 13+ are probed in detail through a combination of ultrafast transient absorption (TA) and femtosecond-to-picosecond FLUPS. Although TA spectroscopy allows us to observe the evolution of phosphorescent excited states within the doublet manifold, more significantly and for the first time for a complex of Cr(III), we utilize FLUPS to capture the short-lived fluorescence from initially populated quartet excited states immediately prior to the intersystem crossing process. The decay of fluorescence from the low-lying 4MC state therefore allows us to assign a value of (823 fs)-1 to the rate of intersystem crossing. Importantly, the sensitivity of FLUPS to only luminescent states allows us to disentangle the rate of intersystem crossing from other closely associated excited-state events, something which has not been possible in the spectroscopic studies previously reported for luminescent Cr(III) systems.
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Affiliation(s)
- Robert W Jones
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Alexander J Auty
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
| | - Guanzhi Wu
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
| | - Petter Persson
- Division of Theoretical Chemistry, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Martin V Appleby
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
| | - Dimitri Chekulaev
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
| | - Craig R Rice
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Julia A Weinstein
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
| | - Paul I P Elliott
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Paul A Scattergood
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
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7
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Nikovskiy I, Aleshin DY, Novikov VV, Polezhaev AV, Khakina EA, Melnikova EK, Nelyubina YV. Selective Pathway toward Heteroleptic Spin-Crossover Iron(II) Complexes with Pyridine-Based N-Donor Ligands. Inorg Chem 2022; 61:20866-20877. [PMID: 36511893 DOI: 10.1021/acs.inorgchem.2c03270] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A new synthetic pathway is devised to selectively produce previously elusive heteroleptic iron(II) complexes of terpyridine and N,N'-disubstituted bis(pyrazol-3-yl)pyridines that stabilize the opposite spin states of the metal ion. Such a combination of the ligands in a series of the heteroleptic complexes induces the spin-crossover (SCO) not experienced by the homoleptic complexes of these ligands or shifts it to lower/higher temperatures respective to the SCO-active homoleptic complex. The midpoint temperatures of the resulting SCO span from ca. 200 K to the ambient temperature and beyond the highest temperature accessible by NMR spectroscopy and SQUID magnetometry. The proposed "one-pot" approach is applicable to other N-donor ligands to selectively produce heteroleptic complexes─including those inaccessible by alternative synthetic pathways─with highly tunable SCO behaviors for practical applications in sensing, switching, and multifunctional devices.
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Affiliation(s)
- Igor Nikovskiy
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia.,Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia
| | - Dmitry Yu Aleshin
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia
| | - Valentin V Novikov
- Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, 141700Dolgoprudny, Russia
| | - Alexander V Polezhaev
- Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia
| | - Ekaterina A Khakina
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia.,HSE University, Miasnitskaya Str., 20, 101000Moscow, Russia
| | - Elizaveta K Melnikova
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia
| | - Yulia V Nelyubina
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991Moscow, Russia.,Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, 105005Moscow, Russia
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8
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Wu Z, Yang J, Wei Z, Su Q, Yuan S, Wang X, Long S, Liu S, Zhang G. Novel Fe2+ responsive nanofibrous membrane for corrosion detection and adsorption. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.124817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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Sittel S, Naumann R, Heinze K. Molecular Rubies in Photoredox Catalysis. Front Chem 2022; 10:887439. [PMID: 35464204 PMCID: PMC9021569 DOI: 10.3389/fchem.2022.887439] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 03/17/2022] [Indexed: 01/22/2023] Open
Abstract
The molecular ruby [Cr(tpe) 2 ] 3+ and the tris(bipyridine) chromium(III) complex [Cr(dmcbpy) 3 ] 3+ as well as the tris(bipyrazine)ruthenium(II) complex [Ru(bpz) 3 ] 2+ were employed in the visible light-induced radical cation [4+2] cycloaddition (tpe = 1,1,1-tris(pyrid-2-yl)ethane, dmcbpy = 4,4'-dimethoxycarbonyl-2,2'-bipyridine, bpz = 2,2'-bipyrazine), while [Cr(ddpd) 2 ] 3+ serves as a control system (ddpd = N,N'-dimethyl-N,N'-dipyridin-2-ylpyridine-2,6-diamine). Along with an updated mechanistic proposal for the CrIII driven catalytic cycle based on redox chemistry, Stern-Volmer analyses, UV/Vis/NIR spectroscopic and nanosecond laser flash photolysis studies, we demonstrate that the very weakly absorbing photocatalyst [Cr(tpe) 2 ] 3+ outcompetes [Cr(dmcbpy) 3 ] 3+ and even [Ru(bpz) 3 ] 2+ in particular at low catalyst loadings, which appears contradictory at first sight. The high photostability, the reversible redoxchemistry and the very long excited state lifetime account for the exceptional performance and even reusability of [Cr(tpe) 2 ] 3+ in this photoredox catalytic system.
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Affiliation(s)
- Steven Sittel
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Robert Naumann
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Katja Heinze
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
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10
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Joyce JP, Portillo RI, Rappé AK, Shores MP. Doublet Ground State in a Vanadium(II) Complex: Redox and Coordinative Noninnocence of Tripodal Ligand Architecture. Inorg Chem 2022; 61:6376-6391. [DOI: 10.1021/acs.inorgchem.1c03418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Justin P. Joyce
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Romeo I. Portillo
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Anthony K. Rappé
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Matthew P. Shores
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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11
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Stein L, Boden P, Naumann R, Förster C, Niedner-Schatteburg G, Heinze K. The overlooked NIR luminescence of Cr(ppy) 3. Chem Commun (Camb) 2022; 58:3701-3704. [PMID: 35226026 DOI: 10.1039/d2cc00680d] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cr(ppy)3, a structural analog of the green phosphorescent Ir(ppy)3, emits even in solution at room temperature from a weakly distorted spin-flip state at 910 nm (Hppy = 2-phenylpyridine). The low energy arises from an enhanced covalence of the Cr-C bonds as compared to Cr-N bonds. Lower temperature reduces thermally activated decay increasing the emission intensity.
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Affiliation(s)
- Laura Stein
- Johannes Gutenberg-University, Department of Chemistry, Duesbergweg 10-14, Mainz, Germany.
| | - Pit Boden
- Department of Chemistry and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern, Germany
| | - Robert Naumann
- Johannes Gutenberg-University, Department of Chemistry, Duesbergweg 10-14, Mainz, Germany.
| | - Christoph Förster
- Johannes Gutenberg-University, Department of Chemistry, Duesbergweg 10-14, Mainz, Germany.
| | - Gereon Niedner-Schatteburg
- Department of Chemistry and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern, Germany
| | - Katja Heinze
- Johannes Gutenberg-University, Department of Chemistry, Duesbergweg 10-14, Mainz, Germany.
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12
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Abstract
In molecular photochemistry, charge-transfer emission is well understood and widely exploited. In contrast, luminescent metal-centered transitions only came into focus in recent years. This gave rise to strongly phosphorescent CrIII complexes with a d3 electronic configuration featuring luminescent metal-centered excited states which are characterized by the flip of a single spin. These so-called spin-flip emitters possess unique properties and require different design strategies than traditional charge-transfer phosphors. In this review, we give a brief introduction to ligand field theory as a framework to understand this phenomenon and outline prerequisites for efficient spin-flip emission including ligand field strength, symmetry, intersystem crossing and common deactivation pathways using CrIII complexes as instructive examples. The recent progress and associated challenges of tuning the energies of emissive excited states and of emerging applications of the unique photophysical properties of spin-flip emitters are discussed. Finally, we summarize the current state-of-the-art and challenges of spin-flip emitters beyond CrIII with d2, d3, d4 and d8 electronic configuration, where we mainly cover pseudooctahedral molecular complexes of V, Mo, W, Mn, Re and Ni, and highlight possible future research opportunities.
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13
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Stein L, Wang C, Förster C, Resch-Genger U, Heinze K. Bulky ligands protect molecular ruby from oxygen quenching. Dalton Trans 2022; 51:17664-17670. [DOI: 10.1039/d2dt02950b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Steric protection strongly reduces phosphorescence quenching of excited molecular rubies by oxygen. The most bulky ligand enables photoluminescence quantum yields up to 5.1% and lifetimes up to 518 µs in air-saturated acetonitrile.
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Affiliation(s)
- Laura Stein
- Department of Chemistry, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Cui Wang
- Division Biophotonics, Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Christoph Förster
- Department of Chemistry, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Ute Resch-Genger
- Division Biophotonics, Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Katja Heinze
- Department of Chemistry, Johannes Gutenberg University of Mainz, Mainz, Germany
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14
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Baptista FA, Krizsan D, Stitch M, Sazanovich IV, Clark IP, Towrie M, Long C, Martinez-Fernandez L, Improta R, Kane-Maguire NAP, Kelly JM, Quinn SJ. Adenine Radical Cation Formation by a Ligand-Centered Excited State of an Intercalated Chromium Polypyridyl Complex Leads to Enhanced DNA Photo-oxidation. J Am Chem Soc 2021; 143:14766-14779. [PMID: 34464120 PMCID: PMC8447253 DOI: 10.1021/jacs.1c06658] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
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Assessment of the
DNA photo-oxidation and synthetic photocatalytic
activity of chromium polypyridyl complexes is dominated by consideration
of their long-lived metal-centered excited states. Here we report
the participation of the excited states of [Cr(TMP)2dppz]3+ (1) (TMP = 3,4,7,8-tetramethyl-1,10-phenanthroline;
dppz = dipyrido[3,2-a:2′,3′-c]phenazine) in DNA photoreactions. The interactions of
enantiomers of 1 with natural DNA or with oligodeoxynucleotides
with varying AT content (0–100%) have been studied by steady
state UV/visible absorption and luminescence spectroscopic methods,
and the emission of 1 is found to be quenched in all
systems. The time-resolved infrared (TRIR) and visible absorption
spectra (TA) of 1 following excitation in the region
between 350 to 400 nm reveal the presence of relatively long-lived
dppz-centered states which eventually yield the emissive metal-centered
state. The dppz-localized states are fully quenched when bound by
GC base pairs and partially so in the presence of an AT base-pair
system to generate purine radical cations. The sensitized formation
of the adenine radical cation species (A•+T) is identified by assigning the TRIR spectra with help of
DFT calculations. In natural DNA and oligodeoxynucleotides containing
a mixture of AT and GC of base pairs, the observed time-resolved spectra
are consistent with eventual photo-oxidation occurring predominantly
at guanine through hole migration between base pairs. The combined
targeting of purines leads to enhanced photo-oxidation of guanine.
These results show that DNA photo-oxidation by the intercalated 1, which locates the dppz in contact with the target purines,
is dominated by the LC centered excited state. This work has implications
for future phototherapeutics and photocatalysis.
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Affiliation(s)
| | - Dorottya Krizsan
- School of Chemistry, University College Dublin, Dublin 4, Ireland
| | - Mark Stitch
- School of Chemistry, University College Dublin, Dublin 4, Ireland
| | - Igor V Sazanovich
- STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, U.K
| | - Ian P Clark
- STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, U.K
| | - Michael Towrie
- STFC Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX, U.K
| | - Conor Long
- The School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
| | - Lara Martinez-Fernandez
- Departamento de Química, Facultad de Ciencias and Institute for Advanced Research in Chemistry(IADCHEM) Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049 Madrid, Spain
| | - Roberto Improta
- Consiglio Nazionale delle Ricerche, Istituto di Biostrutture e Bioimmagini, 80136 Naples, Italy
| | - Noel A P Kane-Maguire
- Department of Chemistry, Furman University, 3300 Poinsett Highway, Greenville, South Carolina 29613-1120, United States
| | - John M Kelly
- School of Chemistry, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
| | - Susan J Quinn
- School of Chemistry, University College Dublin, Dublin 4, Ireland
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15
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Joyce JP, Portillo RI, Nite CM, Nite JM, Nguyen MP, Rappé AK, Shores MP. Electronic Structures of Cr(III) and V(II) Polypyridyl Systems: Undertones in an Isoelectronic Analogy. Inorg Chem 2021; 60:12823-12834. [PMID: 34382400 DOI: 10.1021/acs.inorgchem.1c01129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A recently reported description of the photophysical properties of V2+ polypyridyl systems has highlighted several distinctions between isoelectronic, d3, Cr3+, and V2+ tris-homoleptic polypyridyl complexes of 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen). Here, we combine theory and experimental data to elucidate the differences in electronic structures. We provide the first crystallographic structures of the V2+ complexes [V(bpy)3](BPh4)2 (V-1B) and [V(phen)3](OTf)2 (V2) and observe pronounced trigonal distortion relative to analogous Cr3+ complexes. We use electronic absorption spectroscopy in tandem with TD-DFT computations to assign metal-ligand charge transfer (MLCT) properties of V-1B and V2 that are unique from the intraligand transitions, 4(3IL), solely observed in Cr3+ analogues. Our newly developed natural transition spin density (NTρα,β) plots characterize both the Cr3+ and V2+ absorbance properties. A multideterminant approach to DFT assigns the energy of the 2E state of V-1B as stabilized through electron delocalization. We find that the profound differences in excited state lifetimes for Cr3+ and V2+ polypyridyls arise from differences in the characters of their lowest doublet states and pathways for intersystem crossing, both of which stem from trigonal structural distortion and metal-ligand π-covalency.
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Affiliation(s)
- Justin P Joyce
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Romeo I Portillo
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Collette M Nite
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Jacob M Nite
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Michael P Nguyen
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Anthony K Rappé
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Matthew P Shores
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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16
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Jiménez JR, Doistau B, Poncet M, Piguet C. Heteroleptic trivalent chromium in coordination chemistry: Novel building blocks for addressing old challenges in multimetallic luminescent complexes. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2020.213750] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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17
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Teets TS, Wu Y, Kim D. Photophysical Properties and Redox Potentials of Photosensitizers for Organic Photoredox Transformations. Synlett 2021. [DOI: 10.1055/a-1390-9065] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AbstractPhotoredox catalysis has proven to be a powerful tool in synthetic organic chemistry. The rational design of photosensitizers with improved photocatalytic performance constitutes a major advancement in photoredox organic transformations. This review summarizes the fundamental ground-state and excited-state photophysical and electrochemical attributes of molecular photosensitizers, which are important determinants of their photocatalytic reactivity.
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18
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Dill RD, Portillo RI, Shepard SG, Shores MP, Rappé AK, Damrauer NH. Long-Lived Mixed 2MLCT/MC States in Antiferromagnetically Coupled d 3 Vanadium(II) Bipyridine and Phenanthroline Complexes. Inorg Chem 2020; 59:14706-14715. [PMID: 32886504 DOI: 10.1021/acs.inorgchem.0c01950] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Exploration of [V(bpy)3]2+ and [V(phen)3]2+ (bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline) using electronic spectroscopy reveals an ultrafast excited-state decay process and implicates a pair of low-lying doublets with mixed metal-to-ligand charge-transfer (MLCT) and metal-centered (MC) character. Transient absorption (TA) studies of the vanadium(II) species probing in the visible and near-IR, in combination with spectroelectrochemical techniques and computational chemistry, lead to the conclusion that after excitation into the intense and broad visible 4MLCT ← 4GS (ground-state) absorption band (ε400-700 nm = 900-8000 M-1 cm-1), the 4MLCT state rapidly (τisc < 200 fs) relaxes to the upper of two doublet states with mixed MLCT/MC character. Electronic interconversion (τ ∼ 2.5-3 ps) to the long-lived excited state follows, which we attribute to formation of the lower mixed state. Following these initial dynamics, GS recovery ensues with τ = 430 ps and 1.6 ns for [V(bpy)3]2+ and [V(phen)3]2+, respectively. This stands in stark contrast with isoelectronic [Cr(bpy)3]3+, which rapidly forms a long-lived doublet metal-centered (2MC) state following photoexcitation and lacks strong visible GS absorption character. 2MLCT character in the long-lived states of the vanadium(II) species produces geometric distortion and energetic stabilization, both of which accelerate nonradiative decay to the GS compared to [Cr(bpy)3]3+, where the GS and 2MC are well nested. These conclusions are significant because (i) long-lived states with MLCT character are rare in first-row transition-metal complexes and (ii) the presence of a 2MLCT state at lower energy than the 4MLCT state has not been previously considered. The spin assignment of charge-transfer states in open-shell transition-metal complexes is not trivial; when metal-ligand interaction is strong, low-spin states must be carefully considered when assessing reactivity and decay from electronic excited states.
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Affiliation(s)
- Ryan D Dill
- Department of Chemistry and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
| | - Romeo I Portillo
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Samuel G Shepard
- Department of Chemistry and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
| | - Matthew P Shores
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Anthony K Rappé
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Niels H Damrauer
- Department of Chemistry and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
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19
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Doistau B, Jiménez JR, Guerra S, Besnard C, Piguet C. Key Strategy for the Rational Incorporation of Long-Lived NIR Emissive Cr(III) Chromophores into Polymetallic Architectures. Inorg Chem 2020; 59:1424-1435. [PMID: 31909978 DOI: 10.1021/acs.inorgchem.9b03163] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The CrIIIN6 chromophores are particularly appealing for low-energy sensitization via energy transfer processes since they show extremely long excited state lifetimes reaching the millisecond range in the technologically crucial near-infrared domain. However, their properties were barely harnessed in multimetallic structures because of the lack of both monitoring methods and accessible synthetic pathways. We herein report a remedy to monitor and control the formation of CrIII-containing assemblies in solution via the design of a CrIIIN6 inert "complex-as-ligand" that can be included into polymetallic architectures. As a proof of concept, these CrN6 building blocks were reacted in solution with ZnII or FeII to give extended trinuclear linear Cr-M-Cr assemblies, the structure of which could be addressed by NMR spectroscopy despite the presence of two slowly relaxing CrIII paramagnetic centers. In addition to long CrIII excited state lifetimes and weak sensitivity to oxygen quenching, these polymetallic assemblies display controlled CrIII to MII energy transfers, which pave the way for use of the "complex-as-ligand" strategy for introducing photophysically active CrIII probes into light-converting polymetallic devices.
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Affiliation(s)
- Benjamin Doistau
- Department of Inorganic and Analytical Chemistry , University of Geneva , 30 quai Ernest Ansermet , CH-1211 Geneva 4 , Switzerland
| | - Juan-Ramón Jiménez
- Department of Inorganic and Analytical Chemistry , University of Geneva , 30 quai Ernest Ansermet , CH-1211 Geneva 4 , Switzerland
| | - Sebastiano Guerra
- Department of Inorganic and Analytical Chemistry , University of Geneva , 30 quai Ernest Ansermet , CH-1211 Geneva 4 , Switzerland
| | - Céline Besnard
- Laboratory of Crystallography , University of Geneva , 24 quai Ernest Ansermet , CH-1211 Geneva 4 , Switzerland
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry , University of Geneva , 30 quai Ernest Ansermet , CH-1211 Geneva 4 , Switzerland
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20
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Jiménez JR, Poncet M, Doistau B, Besnard C, Piguet C. Luminescent polypyridyl heteroleptic Cr III complexes with high quantum yields and long excited state lifetimes. Dalton Trans 2020; 49:13528-13532. [PMID: 32968750 DOI: 10.1039/d0dt02872j] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Implementing high quantum yields and long-lived excited state lifetimes within heteroleptic luminescent CrIII complexes is a keystone for the design of supramolecular energy-converting devices exploiting this cheap metal. In this contribution, we discuss the stepwise and rational optimization of these two limiting factors within a series of heteroleptic CrIII complexes.
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Affiliation(s)
- Juan-Ramón Jiménez
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
| | - Maxime Poncet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
| | - Benjamin Doistau
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
| | - Céline Besnard
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland.
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21
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The first tris-heteroleptic copper cage, ligated by germsesquioxanes, 2,2′-bipyridines and 3,5-dimethylpyrazolates. Synthesis, structure and unique catalytic activity in oxidation of alkanes and alcohols with peroxides. J Organomet Chem 2019. [DOI: 10.1016/j.jorganchem.2019.120911] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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22
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Jiménez JR, Doistau B, Cruz CM, Besnard C, Cuerva JM, Campaña AG, Piguet C. Chiral Molecular Ruby [Cr(dqp)2]3+ with Long-Lived Circularly Polarized Luminescence. J Am Chem Soc 2019; 141:13244-13252. [DOI: 10.1021/jacs.9b06524] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Juan-Ramón Jiménez
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 Quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Benjamin Doistau
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 Quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Carlos M. Cruz
- Departamento de Quı́mica Orgánica, Unidad de Excelencia de Quı́mica Aplicada a Biomedicina y Medioambiente, Universidad de Granada, Avda. Fuentenueva, E-18071 Granada, España
| | - Céline Besnard
- Laboratory of Crystallography, University of Geneva, 24 Quai E. Ansermet, CH-1211 Geneva 4, Switzerland
| | - Juan M. Cuerva
- Departamento de Quı́mica Orgánica, Unidad de Excelencia de Quı́mica Aplicada a Biomedicina y Medioambiente, Universidad de Granada, Avda. Fuentenueva, E-18071 Granada, España
| | - Araceli G. Campaña
- Departamento de Quı́mica Orgánica, Unidad de Excelencia de Quı́mica Aplicada a Biomedicina y Medioambiente, Universidad de Granada, Avda. Fuentenueva, E-18071 Granada, España
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 Quai E. Ansermet, CH-1211 Geneva 4, Switzerland
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23
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Katari M, Carmichael D, Jacquemin D, Frison G. Structure of Electronically Reduced N-Donor Bidentate Ligands and Their Heteroleptic Four-Coordinate Zinc Complexes: A Survey of Density Functional Theory Results. Inorg Chem 2019; 58:7169-7179. [PMID: 31117621 DOI: 10.1021/acs.inorgchem.8b03549] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of Hartree-Fock exchange in describing the structural changes occurring upon reduction of bipyridine-based ligands and their complexes is investigated within the framework of density functional theory (DFT) calculations. A set of four free ligands in their neutral and radical anionic forms, and two of their zinc complexes in their dicationic and monocationic radical forms, is used to compare a large panel of pure, conventional, and long-range corrected hybrid DFT functionals; coupled cluster single and double calculations are used alongside experimental results as benchmarks. Particular attention has been devoted to the magnitude of the change, upon reduction, of the Δ-parameter, which measures the difference between the Cpy-Cpy and the C-N bond lengths in bipyridine ligand and is known to experimentally correlate with the charge of the ligands. Our results indicate that the structural changes significantly depend on the amount of exact exchange included in the functional. A progressive evolution is observed for the free ligands, whereas two distinct sets of results are obtained for the complexes. Functionals with a small degree of HF exchange, e.g., B3LYP, do not adequately describe geometric changes for the considered species, and, quite surprisingly, the same holds for the CC2 method. The best agreement to experimental and CCSD values is obtained with functionals that include a significant but not excessive part of exact exchange, e.g., CAM-B3LYP, M06-2X, and ωB97X-D. The calculated localization of the added electron after reduction, which depends on the self-interaction error, is used to rationalize these outcomes. Static correlation is also shown to play a role in the accurate description of the electronic structure.
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Affiliation(s)
| | - Duncan Carmichael
- LCM, CNRS, Ecole Polytechnique , IP Paris , F-91128 Palaiseau , France
| | - Denis Jacquemin
- University of Nantes , CNRS, CEISAM (UMR 6230), 2 chemin de la Houssinière , 44322 Nantes , Cedex 03 , France
| | - Gilles Frison
- LCM, CNRS, Ecole Polytechnique , IP Paris , F-91128 Palaiseau , France
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24
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Al-Riyahee AA, Horton PN, Coles SJ, Amoroso AJ, Pope SJ. Syntheses, X-ray structures and characterisation of luminescent chromium(III) complexes incorporating 8-quinolinato ligands. Polyhedron 2019. [DOI: 10.1016/j.poly.2018.10.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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25
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Doistau B, Collet G, Bolomey EA, Sadat-Noorbakhsh V, Besnard C, Piguet C. Heteroleptic Ter–Bidentate Cr(III) Complexes as Tunable Optical Sensitizers. Inorg Chem 2018; 57:14362-14373. [PMID: 30376321 DOI: 10.1021/acs.inorgchem.8b02530] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Benjamin Doistau
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Guillaume Collet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Emilio Acuña Bolomey
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Vida Sadat-Noorbakhsh
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Céline Besnard
- Laboratory of Crystallography, University of Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
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26
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Abstract
In this invited Perspective, recent developments and possible future directions of research on photoactive coordination compounds made from nonprecious transition metal elements will be discussed. The focus is on conceptually new, structurally well-characterized complexes with excited-state lifetimes between 10 ps and 1 ms in fluid solution for possible applications in photosensitizing, light-harvesting, luminescence and catalysis. The key metal elements considered herein are Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, W and Ce in various oxidation states equipped with diverse ligands, giving access to long-lived excited states via a range of fundamentally different types of electronic transitions. Research performed in this area over the past five years demonstrated that a much broader spectrum of metal complexes than what was long considered relevant exhibits useful photophysics and photochemistry.
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Affiliation(s)
- Oliver S Wenger
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland
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27
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Higgins RF, Fatur SM, Damrauer NH, Ferreira EM, Rappé AK, Shores MP. Detection of an Energy-Transfer Pathway in Cr-Photoredox Catalysis. ACS Catal 2018. [DOI: 10.1021/acscatal.8b03013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert F. Higgins
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Steven M. Fatur
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Niels H. Damrauer
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Eric M. Ferreira
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Anthony K. Rappé
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Matthew P. Shores
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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28
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Zhang Y, Lee TS, Petersen JL, Milsmann C. A Zirconium Photosensitizer with a Long-Lived Excited State: Mechanistic Insight into Photoinduced Single-Electron Transfer. J Am Chem Soc 2018; 140:5934-5947. [PMID: 29671586 DOI: 10.1021/jacs.8b00742] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Time-resolved emission spectroscopy for the luminescent zirconium complex Zr(MePDP)2 (MePDP = 2,6-bis(5-methyl-3-phenyl-1 H-pyrrol-2-yl)pyridine) revealed a long-lived excited state with a lifetime τ = 325 ± 10 μs. Computational studies using time-dependent density functional theory were conducted to identify the nature of the luminescent excited state as a mixed triplet intraligand/ligand-to-metal charge-transfer state. Stern-Volmer experiments showed a strong dependence of the quenching rate on the redox potential of the quencher indicating photoinduced single-electron transfer (SET) as the quenching pathway. Mechanistic investigations of the photocatalytic homocoupling of benzyl bromide allowed the detection of organic radical intermediates during turnover and provided further evidence for SET mediated by Zr(MePDP)2. Isolation of the one-electron-reduced form of the photosensitizer, [Zr(MePDP)2]-, enabled studies of its electronic structure by a combination of experimental and computational techniques and confirmed its role as a strong reductant. Additionally, the role of the benzimidazolium hydride derivatives as two-electron sacrificial reductants during photoredox catalysis was investigated. In combination, the results presented in this report establish a detailed mechanistic picture of a photoredox catalytic reaction promoted by an earth-abundant early transition metal photosensitizer.
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Affiliation(s)
- Yu Zhang
- C. Eugene Bennett Department of Chemistry , West Virginia University , Morgantown , West Virginia 26506 , United States
| | - Tia S Lee
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Jeffrey L Petersen
- C. Eugene Bennett Department of Chemistry , West Virginia University , Morgantown , West Virginia 26506 , United States
| | - Carsten Milsmann
- C. Eugene Bennett Department of Chemistry , West Virginia University , Morgantown , West Virginia 26506 , United States
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29
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Three oxidation states of the bis(3,5-di-tert-butyl-2-phenolato)azanido pincer ligand on chromium(III). Polyhedron 2018. [DOI: 10.1016/j.poly.2017.08.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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30
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Cadranel A, Oviedo PS, Alborés P, Baraldo LM, Guldi DM, Hodak JH. Electronic Energy Transduction from {Ru(py) 4} Chromophores to Cr(III) Luminophores. Inorg Chem 2018; 57:3042-3053. [PMID: 29473740 DOI: 10.1021/acs.inorgchem.7b02799] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Despite the large body of work on {Ru(bpy)2} sensitizer fragments, the same attention has not been devoted to their {Ru(py)4} analogues. In this context, we explored the donor-acceptor trans-[Ru(L)4{(μ-NC)Cr(CN)5}2]4-, where L = pyridine, 4-methoxypyridine, 4-dimethylaminopyridine. We report on the synthesis and the crystal structure as well as the electrochemical, spectroscopical, and photophysical properties of these trimetallic complexes, including transient absorption measurements. We observed emission from chromium-centered d-d states upon illuminating into either MLCT or MM'CT absorptions of {Ru(L)4} or {Ru-Cr}, respectively. The underlying energy transfer is as fast as 600 fs with quantum efficiencies ranging from 10% to 100%. These results document that {Ru(py)4} sensitizer fragments are as efficient as {Ru(bpy)2} in short-range energy transfer scenarios.
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Affiliation(s)
- Alejandro Cadranel
- Departamento de Química Analítica, Inorgánica y Química Física & INQUIMAE, Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires , Pabellón 2 , Ciudad Universitaria, C1428EHA Buenos Aires , Argentina.,Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM) , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 1-3 , 91058 Erlangen , Germany
| | - Paola S Oviedo
- Departamento de Química Analítica, Inorgánica y Química Física & INQUIMAE, Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires , Pabellón 2 , Ciudad Universitaria, C1428EHA Buenos Aires , Argentina
| | - Pablo Alborés
- Departamento de Química Analítica, Inorgánica y Química Física & INQUIMAE, Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires , Pabellón 2 , Ciudad Universitaria, C1428EHA Buenos Aires , Argentina
| | - Luis M Baraldo
- Departamento de Química Analítica, Inorgánica y Química Física & INQUIMAE, Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires , Pabellón 2 , Ciudad Universitaria, C1428EHA Buenos Aires , Argentina
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM) , Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 1-3 , 91058 Erlangen , Germany
| | - José H Hodak
- Departamento de Química Analítica, Inorgánica y Química Física & INQUIMAE, Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires , Pabellón 2 , Ciudad Universitaria, C1428EHA Buenos Aires , Argentina
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31
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Olafsen BE, Crescenzo GV, Moisey LP, Patrick BO, Smith KM. Photolytic Reactivity of Organometallic Chromium Bipyridine Complexes. Inorg Chem 2018; 57:9611-9621. [PMID: 29461816 DOI: 10.1021/acs.inorgchem.7b03195] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Known stable [Cr(bpy)2(Ph)2](BPh4) complexes undergo reductive elimination of biphenyl with visible-light photolysis using household incandescent or compact fluorescent light bulbs. A series of [Cr(R-bpy)2(Ar)2](X) complexes (R = H or CMe3; Ar = Ph, C6H4-CMe3, or C6H4-OMe; X = I, BPh4, or PF6) were prepared, and the effect of varying the bipyridine and aryl ligands on the UV-visible spectra and electrochemistry of the chromium(III) complexes was investigated. Photolysis of a mixture of two different bis(aryl) complexes gave only the homocoupled biaryl products by 1H NMR and gas chromatography/mass spectrometry analysis. The initial product of photoinduced reductive elimination of [Cr(bpy)2(Ar)2](PF6) was trapped with bipyridine to generate [Cr(bpy)3](PF6) and with benzoyl peroxide to form [Cr(bpy)2(O2CPh)2](PF6). The latter chromium(III) bis(benzoate) complex was also synthesized by the addition of bipyridine and PhCO2H to Cp2Cr, followed by air oxidation. The neutral Cr(bpy)(S2CNMe2)Ph2 complex also generated biphenyl upon visible-light photolysis. While the treatment of Cr(tBu-bpy)(dpm)Cl2 [dpm = (OCtBu)2CH] with AgO2CPh gave trans-Cr(tBu-bpy)(dpm)(O2CPh)2, reaction of the dichloro precursor with PhMgCl produced anionic [Cr(tBu-bpy)Ph3]- with [Mg(dpm)(THF)4]+ as the countercation, with both complexes characterized by single-crystal X-ray diffraction. Protonolysis of Cr(bpy)Ph3(THF) with 8-hydroxyquinoline produced Cr(bpy)(quin)Ph2, which generated biphenyl under visible-light photolysis, and the initial product of reductive elimination was trapped by bipyridine or benzoyl peroxide. A related Cr(bpy)(quin)2 complex was synthesized by protonolysis of Cr(bpy)[N(SiMe3)2]2 and characterized by single-crystal X-ray diffraction.
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Affiliation(s)
- Benjamin E Olafsen
- Department of Chemistry , University of British Columbia, Okanagan , 3247 University Way , Kelowna , British Columbia V1V 1V7 , Canada
| | - Giuseppe V Crescenzo
- Department of Chemistry , University of British Columbia, Okanagan , 3247 University Way , Kelowna , British Columbia V1V 1V7 , Canada
| | - Luke P Moisey
- Department of Chemistry , University of British Columbia, Okanagan , 3247 University Way , Kelowna , British Columbia V1V 1V7 , Canada
| | - Brian O Patrick
- Department of Chemistry , University of British Columbia, Vancouver , Vancouver , British Columbia V6T 1Z21 , Canada
| | - Kevin M Smith
- Department of Chemistry , University of British Columbia, Okanagan , 3247 University Way , Kelowna , British Columbia V1V 1V7 , Canada
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32
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Jiménez JR, Doistau B, Besnard C, Piguet C. Versatile heteroleptic bis-terdentate Cr(iii) chromophores displaying room temperature millisecond excited state lifetimes. Chem Commun (Camb) 2018; 54:13228-13231. [DOI: 10.1039/c8cc07671e] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cr–Br bonds can be specifically labilized for producing phosphorescent and tuneable heteroleptic bis-terdentate Cr(iii) long-lived sensitizers.
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Affiliation(s)
- Juan-Ramón Jiménez
- Department of Inorganic and Analytical Chemistry, University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Benjamin Doistau
- Department of Inorganic and Analytical Chemistry, University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Céline Besnard
- Laboratory of Cristallography, University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry, University of Geneva
- CH-1211 Geneva 4
- Switzerland
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33
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Büldt LA, Wenger OS. Chromium complexes for luminescence, solar cells, photoredox catalysis, upconversion, and phototriggered NO release. Chem Sci 2017; 8:7359-7367. [PMID: 29163886 PMCID: PMC5672834 DOI: 10.1039/c7sc03372a] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/04/2017] [Indexed: 12/15/2022] Open
Abstract
Cr(iii) and Cr(0) complexes are earth-abundant alternatives to photosensitizers that are commonly made from precious metals.
Some complexes of Cr(iii) and Cr(0) have long been known to exhibit interesting photophysical and photochemical properties, but in the past few years important conceptual progress was made. This Perspective focuses on the recent developments of Cr(iii) complexes as luminophores and dyes for solar cells, their application in photoredox catalysis, their use as sensitizers in upconversion processes, and their performance as photochemical nitric oxide sources. The example of a luminescent Cr(0) isocyanide complex illustrates the possibility of obtaining photoactive analogues of d6 metal complexes that are commonly made from precious metals such as Ru(ii) or Ir(iii). The studies highlighted herein illustrate the favorable excited-state properties of robust first-row transition metal complexes with broad application potential.
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Affiliation(s)
- Laura A Büldt
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland .
| | - Oliver S Wenger
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland .
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34
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Androš Dubraja L, Jurić M, Torić F, Pajić D. The influence of metal centres on the exchange interaction in heterometallic complexes with oxalate-bridged cations. Dalton Trans 2017; 46:11748-11756. [PMID: 28828439 DOI: 10.1039/c7dt02522j] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of bis(phenanthroline)metal(ii) cations (M = Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) with bis(oxalato)chromium(iii) anions in a water/ethanol solution gives rise to a series of compounds with oxalate-bridged cations, [{M(phen)2}2(μ-C2O4)][Cr(phen)(C2O4)2]2·4H2O [Mn2Cr2 (1), Co2Cr2 (2), Ni2Cr2 (3), Cu2Cr2 (4) and Zn2Cr2 (5)]. Their structural analysis reveals that all the prepared compounds crystallize in the triclinic system, space group P1[combining macron], having similar unit cell parameters, molecular structures and crystal packing features. All metal centres in 1-5 are octahedrally coordinated: M2+ in homodinuclear cations are coordinated with two phen molecules and one bridging oxalate ligand; Cr3+ in anions is coordinated with one phen ligand and two bidentate oxalate groups. The copper atom in Cu2Cr2 (4) exhibits a Jahn-Teller-distorted octahedral coordination. Owing to the considerable number of pyridyl groups present in 1-5 (from phen ligands) the crystal packing of cations and anions is driven by stacking interactions appearing in offset-face-to-face (OFF) and edge-to-face (EF) orientations. The hydrogen bonds between the anions and water molecules of crystallization form 1D ladder-like motifs. In addition to the single crystal X-ray diffraction studies, the characterization of the new complexes was accomplished by means of IR and UV/Vis spectroscopy and magnetization measurements on a SQUID magnetometer. The temperature dependence of magnetic susceptibility reveals different magnetic super exchange interactions taking place in homodinuclear oxalate-bridged cations depending on the transition metal centre (Mn2+, Co2+, Ni2+ and Cu2+). Oxalate ligands mediate the ferromagnetic coupling of Cu2+ metal cations in Cu2Cr2 (4), whereas in Mn2Cr2 (1), Co2Cr2 (2) and Ni2Cr2 (3), antiferromagnetic interactions are observed between Mn2+, Co2+ and Ni2+ cations, respectively. Also, relatively large zero-field splitting parameters for Cr3+ ions (from mononuclear anions), D ≈ 1 cm-1, were observed.
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35
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Arai N, Ohkuma T. Photochemically Promoted Aza-Diels-Alder-Type Reaction: High Catalytic Activity of the Cr(III)/Bipyridine Complex Enhanced by Visible Light Irradiation. J Org Chem 2017; 82:7628-7636. [PMID: 28653840 DOI: 10.1021/acs.joc.7b00838] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Aza-Diels-Alder-type cycloaddition reactions between a range of N-arylimines and functionalized alkenes were effectively catalyzed by the Cr(III)/bipyridine complex under irradiation of blue light, to give the corresponding 1,2,3,4-tetrahydroquinoline derivatives in high yields with excellent diastereoselectivity. Typically, the reaction of benzylideneaniline with 1-vinyl-2-pyrrolidinone proceeded smoothly with a substrate-to-catalyst molar ratio (S/C) of 1000 and completed within 4 h at room temperature (20-25 °C), affording the cycloaddition product in 97% yield.
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Affiliation(s)
- Noriyoshi Arai
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University , Sapporo, Hokkaido 060-8628, Japan
| | - Takeshi Ohkuma
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University , Sapporo, Hokkaido 060-8628, Japan.,Frontier Chemistry Center, Faculty of Engineering, Hokkaido University , Sapporo, Hokkaido 060-8628, Japan
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36
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Barbour JC, Kim AJI, deVries E, Shaner SE, Lovaasen BM. Chromium(III) Bis-Arylterpyridyl Complexes with Enhanced Visible Absorption via Incorporation of Intraligand Charge-Transfer Transitions. Inorg Chem 2017; 56:8212-8222. [PMID: 28665604 DOI: 10.1021/acs.inorgchem.7b00953] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A series of chromium(III) bis-arylterpyridyl complexes containing intraligand charge-transfer (ILCT) excited states were prepared and characterized. These complexes show significant absorption in the visible region due to the ILCT bands. The ILCT bands are tunable across the UV and visible spectrum via incorporation of electron-withdrawing and electron-donating groups on the aryl ring. The absorption of Cr(4'-(4-methoxyphenyl)-2,2':6',2″-terpyridine)23+ (4) in particular is much stronger in the visible region (ε = 11 900 M-1 cm-1 at 450 nm and ε = 5090 M-1 cm-1 at 500 nm) than that of the parent complex Cr(tpy)23+ (tpy = 2,2':6',2″-terpyridine; ε = 2160 M-1 cm-1 at 450 nm, and ε = 170 M-1 cm-1 at 500 nm). Emission experiments on this series reveal Cr(III)-based phosphorescence with lifetimes from 140 to 600 ns upon excitation into the ILCT bands, which indicates funneling of the excitation energy from ligand-localized excited states to Cr(III)-based excited states. Cyclic voltammograms exhibit at least three reversible ligand-based reductions. The first reduction shows shifts of up to -160 mV compared to Cr(tpy)23+. The excited-state reduction potential of these complexes ranges from +0.95 to +1.04 V vs the ferrocene/ferrocenium couple, making them potent photooxidants.
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Affiliation(s)
- Johanna C Barbour
- Department of Chemistry, Wheaton College , 501 College Avenue, Wheaton, Illinois 60187, United States
| | - Amy J I Kim
- Department of Chemistry, Wheaton College , 501 College Avenue, Wheaton, Illinois 60187, United States
| | - Elsemarie deVries
- Department of Chemistry, Wheaton College , 501 College Avenue, Wheaton, Illinois 60187, United States
| | - Sarah E Shaner
- Department of Chemistry, Benedictine University , 5700 College Road, Lisle, Illinois 60532, United States
| | - Benjamin M Lovaasen
- Department of Chemistry, Wheaton College , 501 College Avenue, Wheaton, Illinois 60187, United States
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37
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Jurić M, Androš Dubraja L, Pajić D, Torić F, Zorko A, Ozarowski A, Despoja V, Lafargue-Dit-Hauret W, Rocquefelte X. Experimental and Theoretical Investigation of the Anti-Ferromagnetic Coupling of Cr III Ions through Diamagnetic -O-Nb V-O- Bridges. Inorg Chem 2017; 56:6879-6889. [PMID: 28586215 DOI: 10.1021/acs.inorgchem.7b00181] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis and properties of a novel hetero-tetranuclear compound [Cr2(bpy)4(μ-O)4Nb2(C2O4)4]·3H2O (1; bpy = 2,2'-bipyridine), investigated by single-crystal X-ray diffraction, magnetization measurements, IR, UV/visible spectroscopy, electron paramagnetic resonance (EPR; X- and Q-bands and high-field), and density functional theory (DFT) calculations, are reported. Crystal structure of 1 (orthorhombic Pcab space group) consists of a square-shaped macrocyclic {Cr2(μ-O)4Nb2} core in which CrIII and NbV ions are alternately bridged by oxo ions and three uncoordinated water molecules. The intramolecular CrIII···CrIII distances through the -O-NbV-O- bridges are 7.410(2) and 7.419(2) Å, while diagonal separation is 5.406(2) Å. The temperature dependence of magnetization M(T) evidences an anti-ferromagnetic ground state, which originates from a magnetic interaction between two CrIII ions of spin 3/2 through two triatomic -O-NbV-O- diamagnetic bridges. A spin Hamiltonian appropriate for polynuclear isolated magnetic units was used. The best-fitting curve for this model is obtained with the parameters gCr = 1.992(3), J = -12.77(5) cm-1, and |D| = 0.17(4) cm-1. The CrIII···CrIII dimer model is confirmed by EPR spectra, which exhibit a pronounced change of their shape around the temperature corresponding to the intradimer coupling J. The EPR spectra simulations and DFT calculations reveal the presence of a single-ion anisotropy that is close to being uniaxial, D = -0.31 cm-1 and E = 0.024 cm-1.
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Affiliation(s)
- Marijana Jurić
- Ruđer Bošković Institute , Bijenička cesta 54, 10000 Zagreb, Croatia
| | | | - Damir Pajić
- Department of Physics, Faculty of Science, University of Zagreb , Bijenička cesta 32, 10000 Zagreb, Croatia
| | - Filip Torić
- Department of Physics, Faculty of Science, University of Zagreb , Bijenička cesta 32, 10000 Zagreb, Croatia
| | - Andrej Zorko
- Jožef Stefan Institute , Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University , Tallahassee, Florida 32310, United States
| | - Vito Despoja
- Department of Physics, Faculty of Science, University of Zagreb , Bijenička cesta 32, 10000 Zagreb, Croatia
| | | | - Xavier Rocquefelte
- Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS, Université de Rennes 1 , Rennes, France
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38
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Yang Y, Liu Q, Zhang L, Yu H, Dang Z. Mechanistic Investigation on Oxygen-Mediated Photoredox Diels–Alder Reactions with Chromium Catalysts. Organometallics 2017. [DOI: 10.1021/acs.organomet.6b00886] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yimeng Yang
- Department
of Polymer Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
- Department
of Chemistry and Center for Atomic Engineering of Advanced Materials, Anhui University, Hefei 230601, People’s Republic of China
| | - Qian Liu
- Department
of Chemistry and Center for Atomic Engineering of Advanced Materials, Anhui University, Hefei 230601, People’s Republic of China
| | - Liang Zhang
- Department
of Polymer Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
| | - Haizhu Yu
- Department
of Chemistry and Center for Atomic Engineering of Advanced Materials, Anhui University, Hefei 230601, People’s Republic of China
| | - Zhimin Dang
- Department
of Polymer Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
- State
Key Laboratory of Power System and Department of Electrical Engineering, Tsinghua University, Beijing 100084, People’s Republic of China
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39
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Büldt LA, Guo X, Vogel R, Prescimone A, Wenger OS. A Tris(diisocyanide)chromium(0) Complex Is a Luminescent Analog of Fe(2,2'-Bipyridine) 32. J Am Chem Soc 2017; 139:985-992. [PMID: 28054486 DOI: 10.1021/jacs.6b11803] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A meta-terphenyl unit was substituted with an isocyanide group on each of its two terminal aryls to afford a bidentate chelating ligand (CNtBuAr3NC) that is able to stabilize chromium in its zerovalent oxidation state. The homoleptic Cr(CNtBuAr3NC)3 complex luminesces in solution at room temperature, and its excited-state lifetime (2.2 ns in deaerated THF at 20 °C) is nearly 2 orders of magnitude longer than the current record lifetime for isoelectronic Fe(II) complexes, which are of significant interest as earth-abundant sensitizers in dye-sensitized solar cells. Due to its chelating ligands, Cr(CNtBuAr3NC)3 is more robust than Cr(0) complexes with carbonyl or monodentate isocyanides, manifesting in comparatively slow photodegradation. In the presence of excess anthracene in solution, efficient energy transfer and subsequent triplet-triplet annihilation upconversion is observed. With an excited-state oxidation potential of -2.43 V vs Fc+/Fc, the Cr(0) complex is a very strong photoreductant. The findings presented herein are relevant for replacement of precious metals in dye-sensitized solar cells and in luminescent devices by earth-abundant elements.
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Affiliation(s)
- Laura A Büldt
- Department of Chemistry, University of Basel , St. Johanns-Ring 19 and Spitalstrasse 51, 4056 Basel, Switzerland
| | - Xingwei Guo
- Department of Chemistry, University of Basel , St. Johanns-Ring 19 and Spitalstrasse 51, 4056 Basel, Switzerland
| | - Raphael Vogel
- Department of Chemistry, University of Basel , St. Johanns-Ring 19 and Spitalstrasse 51, 4056 Basel, Switzerland
| | - Alessandro Prescimone
- Department of Chemistry, University of Basel , St. Johanns-Ring 19 and Spitalstrasse 51, 4056 Basel, Switzerland
| | - Oliver S Wenger
- Department of Chemistry, University of Basel , St. Johanns-Ring 19 and Spitalstrasse 51, 4056 Basel, Switzerland
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40
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Zare D, Doistau B, Nozary H, Besnard C, Guénée L, Suffren Y, Pelé AL, Hauser A, Piguet C. CrIII as an alternative to RuII in metallo-supramolecular chemistry. Dalton Trans 2017; 46:8992-9009. [DOI: 10.1039/c7dt01747b] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Semi-labile [Cr(tpy)(CF3SO3)3] precursors can be exploited for building rod-like dinuclear dyads, in which paramagnetic and luminescent trivalent CrIII replace diamagnetic RuII for unravelling intermetallic communication in supramolecular architectures.
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Affiliation(s)
- Davood Zare
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Benjamin Doistau
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Homayoun Nozary
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Céline Besnard
- Laboratory of Crystallography
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Laure Guénée
- Laboratory of Crystallography
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Yan Suffren
- Department of Physical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Anne-Laure Pelé
- Department of Physical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Andreas Hauser
- Department of Physical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
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41
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Stevenson SM, Higgins RF, Shores MP, Ferreira EM. Chromium photocatalysis: accessing structural complements to Diels-Alder adducts with electron-deficient dienophiles. Chem Sci 2017; 8:654-660. [PMID: 28451213 PMCID: PMC5297334 DOI: 10.1039/c6sc03303b] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/11/2016] [Indexed: 12/29/2022] Open
Abstract
A chromium-catalyzed, visible light-activated net [4 + 2] cycloaddition between dienes and electron-deficient alkenes is described. Gathered evidence, via control experiments, isolated intermediates, and measured redox potentials, points to several converging reaction pathways that afford the cyclohexene adducts, including a photochemical [2 + 2] cycloaddition/vinylcyclobutane rearrangement cascade and a substrate excitation/oxidation sequence to a radical cation intermediate. Notably, the accompanying mechanistic stipulations result in a process that yields regioisomeric compounds from those generated by traditional Diels-Alder cycloadditions.
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Affiliation(s)
- Susan M Stevenson
- Department of Chemistry , University of Georgia , Athens , GA 30602 , USA .
| | - Robert F Higgins
- Department of Chemistry , Colorado State University , Fort Collins , CO 80523 , USA
| | - Matthew P Shores
- Department of Chemistry , Colorado State University , Fort Collins , CO 80523 , USA
| | - Eric M Ferreira
- Department of Chemistry , University of Georgia , Athens , GA 30602 , USA .
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42
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Zendehdel M, Nia NY, Nasr-Esfahani M, Farahani P, Karbaschi MR. A combined computational and experimental study on the hydrogen bonding with chloride ion in a crab-claw like site of a new chromium Schiff base complex. Inorganica Chim Acta 2016. [DOI: 10.1016/j.ica.2016.03.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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43
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Higgins RF, Fatur SM, Shepard SG, Stevenson SM, Boston DJ, Ferreira EM, Damrauer NH, Rappé AK, Shores MP. Uncovering the Roles of Oxygen in Cr(III) Photoredox Catalysis. J Am Chem Soc 2016; 138:5451-64. [DOI: 10.1021/jacs.6b02723] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Robert F. Higgins
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Steven M. Fatur
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Samuel G. Shepard
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Susan M. Stevenson
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - David J. Boston
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Eric M. Ferreira
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Niels H. Damrauer
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Anthony K. Rappé
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Matthew P. Shores
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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Goforth SK, Gill TW, Weisbruch AE, Kane-Maguire KA, Helsel ME, Sun KW, Rodgers HD, Stanley FE, Goudy SR, Wheeler SK, Wheeler JF, Kane-Maguire NAP. Synthesis of cis-[Cr(diimine)2(1-methylimidazole)2](3+) Complexes and an Investigation of Their Interaction with Mononucleotides and Polynucleotides. Inorg Chem 2016; 55:1516-26. [PMID: 26836266 DOI: 10.1021/acs.inorgchem.5b02323] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
A protocol is presented for the synthesis of chromium(III) complexes of the type cis-[Cr(diimine)2(1-methylimidazole)2](3+). These compounds exhibit large excited-state oxidizing powers and strong luminescence in solution. Emission is quenched by added guanine, yielding rate constants that track the driving force for guanine oxidation. The cis-[Cr(TMP)(DPPZ)(1-MeImid)2](3+) species binds strongly to duplex DNA with a preference for AT base sites in the minor groove and may serve as a precursor for photoactivated DNA covalent adduct formation.
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Affiliation(s)
- Sarah K Goforth
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Thomas W Gill
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - April E Weisbruch
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | | | - Marian E Helsel
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Katherine W Sun
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Hillary D Rodgers
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Floyd E Stanley
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Samuel R Goudy
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Sandra K Wheeler
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - John F Wheeler
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
| | - Noel A P Kane-Maguire
- Department of Chemistry, Furman University , Greenville, South Carolina 29613, United States
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de Ruiter G, Thompson NB, Lionetti D, Agapie T. Nitric oxide activation by distal redox modulation in tetranuclear iron nitrosyl complexes. J Am Chem Soc 2015; 137:14094-106. [PMID: 26390375 DOI: 10.1021/jacs.5b07397] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A series of tetranuclear iron complexes displaying a site-differentiated metal center was synthesized. Three of the metal centers are coordinated to our previously reported ligand, based on a 1,3,5-triarylbenzene motif with nitrogen and oxygen donors. The fourth (apical) iron center is coordinatively unsaturated and appended to the trinuclear core through three bridging pyrazolates and an interstitial μ4-oxide moiety. Electrochemical studies of complex [LFe3(PhPz)3OFe][OTf]2 revealed three reversible redox events assigned to the Fe(II)4/Fe(II)3Fe(III) (-1.733 V), Fe(II)3Fe(III)/Fe(II)2Fe(III)2 (-0.727 V), and Fe(II)2Fe(III)2/Fe(II)Fe(III)3 (0.018 V) redox couples. Combined Mössbauer and crystallographic studies indicate that the change in oxidation state is exclusively localized at the triiron core, without changing the oxidation state of the apical metal center. This phenomenon is assigned to differences in the coordination environment of the two metal sites and provides a strategy for storing electron and hole equivalents without affecting the oxidation state of the coordinatively unsaturated metal. The presence of a ligand-binding site allowed the effect of redox modulation on nitric oxide activation by an Fe(II) metal center to be studied. Treatment of the clusters with nitric oxide resulted in binding of NO to the apical iron center, generating a {FeNO}(7) moiety. As with the NO-free precursors, the three reversible redox events are localized at the iron centers distal from the NO ligand. Altering the redox state of the triiron core resulted in significant change in the NO stretching frequency, by as much as 100 cm(-1). The increased activation of NO is attributed to structural changes within the clusters, in particular, those related to the interaction of the metal centers with the interstitial atom. The differences in NO activation were further shown to lead to differential reactivity, with NO disproportionation and N2O formation performed by the more electron-rich cluster.
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Affiliation(s)
- Graham de Ruiter
- Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - Niklas B Thompson
- Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - Davide Lionetti
- Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
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Cabrera PJ, Yang X, Suttil JA, Brooner REM, Thompson LT, Sanford MS. Evaluation of Tris-Bipyridine Chromium Complexes for Flow Battery Applications: Impact of Bipyridine Ligand Structure on Solubility and Electrochemistry. Inorg Chem 2015; 54:10214-23. [DOI: 10.1021/acs.inorgchem.5b01328] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pablo J. Cabrera
- Department of Chemistry, University of Michigan, 930 North University
Avenue, Ann Arbor, Michigan 48109, United States
- Joint Center for Energy
Storage Research (JCESR), Argonne, Illinois, United States
| | - Xingyi Yang
- Department
of Chemical Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, United States
- Joint Center for Energy
Storage Research (JCESR), Argonne, Illinois, United States
| | - James A. Suttil
- Department of Chemistry, University of Michigan, 930 North University
Avenue, Ann Arbor, Michigan 48109, United States
- Joint Center for Energy
Storage Research (JCESR), Argonne, Illinois, United States
| | - Rachel E. M. Brooner
- Department of Chemistry, University of Michigan, 930 North University
Avenue, Ann Arbor, Michigan 48109, United States
- Joint Center for Energy
Storage Research (JCESR), Argonne, Illinois, United States
| | - Levi T. Thompson
- Department
of Chemical Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, Michigan 48109, United States
- Joint Center for Energy
Storage Research (JCESR), Argonne, Illinois, United States
| | - Melanie S. Sanford
- Department of Chemistry, University of Michigan, 930 North University
Avenue, Ann Arbor, Michigan 48109, United States
- Joint Center for Energy
Storage Research (JCESR), Argonne, Illinois, United States
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Stevenson SM, Shores MP, Ferreira EM. Photooxidizing Chromium Catalysts for Promoting Radical Cation Cycloadditions. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201501220] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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48
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Stevenson SM, Shores MP, Ferreira EM. Photooxidizing Chromium Catalysts for Promoting Radical Cation Cycloadditions. Angew Chem Int Ed Engl 2015; 54:6506-10. [DOI: 10.1002/anie.201501220] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Indexed: 11/08/2022]
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Li Z, Leed NA, Dickson-Karn NM, Dunbar KR, Turro C. Directional charge transfer and highly reducing and oxidizing excited states of new dirhodium(ii,ii) complexes: potential applications in solar energy conversion. Chem Sci 2014. [DOI: 10.1039/c3sc52366g] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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