1
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Halcrow MA, Vasili HB, Pask CM, Kulak AN, Cespedes O. Activating a high-spin iron(II) complex to thermal spin-crossover with an inert non-isomorphous molecular dopant. Dalton Trans 2024; 53:6983-6992. [PMID: 38563124 DOI: 10.1039/d4dt00443d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
[Fe(bpp)2][ClO4]2 (bpp = 2,6-bis{pyrazol-1-yl}pyridine; monoclinic, C2/c) is high-spin between 5-300 K, and crystallises with a highly distorted molecular geometry that lies along the octahedral-trigonal prismatic distortion pathway. In contrast, [Ni(bpp)2][ClO4]2 (monoclinic, P21) adopts a more regular, near-octahedral coordination geometry. Gas phase DFT minimisations (ω-B97X-D/6-311G**) of [M(bpp)2]2+ complexes show the energy penalty associated with that coordination geometry distortion runs as M2+ = Fe2+ (HS) ≈ Mn2+ (HS) < Zn2+ ≈ Co2+ (HS) ≲ Cu2+ ≪ Ni2+ ≪ Ru2+ (LS; HS = high-spin, LS = low-spin). Slowly crystallised solid solutions [FexNi1-x(bpp)2][ClO4]2 with x = 0.53 (1a) and 0.74 (2a) adopt the P21 lattice, while x = 0.87 (3a) and 0.94 (4a) are mixed-phase materials with the high-spin C2/c phase as the major component. These materials exhibit thermal spin-transitions at T½ = 250 ± 1 K which occurs gradually in 1a, and abruptly and with narrow thermal hysteresis in 2a-4a. The transition proceeds to 100% completeness in 1a and 2a; that is, the 26% Ni doping in 2a is enough to convert high-spin [Fe(bpp)2][ClO4]2 into a cooperative, fully SCO-active material. These results were confirmed crystallographically for 1a and 2a, which revealed similarities and differences between these materials and the previously published [FexNi1-x(bpp)2][BF4]2 series. Rapidly precipitated powders with the same compositions (1b-4b) mostly resemble 1a-4a, except that 2b is a mixed-phase material; 2b-4b also contain a fraction of amorphous solid in addition to the two crystal phases. The largest iron fraction that can be accommodated by the P21 phase in this system is 0.7 ± 0.1.
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Affiliation(s)
- Malcolm A Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
| | - Hari Babu Vasili
- School of Physics and Astronomy, University of Leeds, W. H. Bragg Building, Leeds, LS2 9JT, UK
| | - Christopher M Pask
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
| | - Alexander N Kulak
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
| | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, W. H. Bragg Building, Leeds, LS2 9JT, UK
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2
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Capel Berdiell I, Michaels E, Munro OQ, Halcrow MA. A Survey of the Angular Distortion Landscape in the Coordination Geometries of High-Spin Iron(II) 2,6-Bis(pyrazolyl)pyridine Complexes. Inorg Chem 2024; 63:2732-2744. [PMID: 38258555 PMCID: PMC10848207 DOI: 10.1021/acs.inorgchem.3c04138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/04/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024]
Abstract
Reaction of 2,4,6-trifluoropyridine with sodium 3,4-dimethoxybenzenethiolate and 2 equiv of sodium pyrazolate in tetrahydrofuran at room temperature affords 4-(3,4-dimethoxyphenylsulfanyl)-2,6-di(pyrazol-1-yl)pyridine (L), in 30% yield. The iron(II) complexes [FeL2][BF4]2 (1a) and [FeL2][ClO4]2 (1b) are high-spin with a highly distorted six-coordinate geometry. This structural deviation from ideal D2d symmetry is common in high-spin [Fe(bpp)2]2+ (bpp = di{pyrazol-1-yl}pyridine) derivatives, which are important in spin-crossover materials research. The magnitude of the distortion in 1a and 1b is the largest yet discovered for a mononuclear complex. Gas-phase DFT calculations at the ω-B97X-D/6-311G** level of theory identified four minimum or local minimum structural pathways across the distortion landscape, all of which are observed experimentally in different complexes. Small distortions from D2d symmetry are energetically favorable in complexes with electron-donating ligand substituents, including sulfanyl groups, which also have smaller energy penalties associated with the lowest energy distortion pathway. Natural population analysis showed that these differences reflect greater changes to the Fe-N{pyridyl} σ-bonding as the distortion proceeds, in the presence of more electron-rich pyridyl donors. The results imply that [Fe(bpp)2]2+ derivatives with electron-donating pyridyl substituents are more likely to undergo cooperative spin transitions in the solid state. The high-spin salt [Fe(bpp)2][CF3SO3]2, which also has a strong angular distortion, is also briefly described and included in the analysis.
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Affiliation(s)
| | - Evridiki Michaels
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Orde Q. Munro
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Malcolm A. Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
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Suhr S, Schröter N, Kleoff M, Neuman N, Hunger D, Walter R, Lücke C, Stein F, Demeshko S, Liu H, Reissig HU, van Slageren J, Sarkar B. Spin State in Homoleptic Iron(II) Terpyridine Complexes Influences Mixed Valency and Electrocatalytic CO 2 Reduction. Inorg Chem 2023; 62:6375-6386. [PMID: 37043797 DOI: 10.1021/acs.inorgchem.3c00253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Two homoleptic Fe(II) complexes in different spin states bearing superbasic terpyridine derivatives as ligands are investigated to determine the relationship between spin state and electrochemical/spectroscopic behavior. Antiferromagnetic coupling between a ligand-centered radical and the high-spin metal center leads to an anodic shift of the first reduction potential and results in a species that shows mixed valency with a moderately intense intervalence-charge-transfer band. The differences afforded by the different spin states extend to the electrochemical reactivity of the complexes: while the low-spin species is a precatalyst for electrocatalytic CO2 reduction and leads to the preferential formation of CO with a Faradaic efficiency of 37%, the high-spin species only catalyzes proton reduction at a modest Faradaic efficiency of approximately 20%.
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Affiliation(s)
- Simon Suhr
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Nicolai Schröter
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Merlin Kleoff
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195 Berlin, Germany
| | - Nicolas Neuman
- Instituto de Desarrollo Tecnológico para la Industria Química - INTEC, UNL-CONICET, CCT-CONICET Santa Fe, S3000ZAA Santa Fe, Santa Fe, Argentina
| | - David Hunger
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Robert Walter
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Clemens Lücke
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Felix Stein
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Serhiy Demeshko
- Institut für Anorganische Chemie, Georg-August Universität Göttingen, Tammannstraße 4, 37077 Göttingen, Germany
| | - Hang Liu
- Institut für Technische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Hans-Ulrich Reissig
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195 Berlin, Germany
| | - Joris van Slageren
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Biprajit Sarkar
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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Shahid N, Burrows KE, Pask CM, Cespedes O, Howard MJ, McGowan PC, Halcrow MA. Heteroleptic iron( ii) complexes of chiral 2,6-bis(oxazolin-2-yl)-pyridine (PyBox) and 2,6-bis(thiazolin-2-yl)pyridine ligands – the interplay of two different ligands on the metal ion spin sate. Dalton Trans 2022; 51:4262-4274. [DOI: 10.1039/d2dt00393g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The spin-crossover properties of [Fe(LR)L][ClO4]2 (LR = a chiral PyBox {L1R} or ThioPyBox {L2R} derivative) show subtle differences depending on the tridentate ‘L’ co-ligand.
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Affiliation(s)
- Namrah Shahid
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT
| | - Kay E. Burrows
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT
| | | | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, WH Bragg Building, Leeds, UK LS2 9JT
| | - Mark J. Howard
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT
| | - Patrick C. McGowan
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT
| | - Malcolm A. Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT
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5
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Ma C, Besson C. Precise control of the degree and regioselectivity of functionalization in nitro- and amino-functionalized di(trispyrazolylborato)iron(II) spin crossover complexes. Dalton Trans 2021; 50:18077-18088. [PMID: 34846411 DOI: 10.1039/d1dt03445f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Di(trispyrazolylborato)iron(II) ([Tp2Fe]) complexes represent one of the most robust classes of spin-crossover complexes. Their stability renders them particularly suitable for integration in nanoscale devices, e.g. as sensors or information storage units. While prior studies of the functionalization of those derivatives have been focused on the electronic and steric effects of alkyl and -CF3 groups in position 3, a pyrazole exchange reaction between nitropyrazole and either trispyrazolylborate or its iron complex allows the regioselective installation of nitro substituents in positions 3, 4 and 5 of the [Tp2Fe] complexes. The degree of substitution can be varied from 1 to 4 functionalized pyrazoles per complex. The amine-functionalized analogues are accessed by reduction of the nitro analogues under hydrogen transfer conditions. With the exception of di- and tetra-3-NO2 substituted complexes, all derivatives display spin crossover properties in the solid state, with transition temperatures ranging from 180 to 380 K and showing different degrees of abruptness but no hysteresis. The Slichter-Drickamer model was used to extract the empirical thermodynamic transition parameters, allowing a systematic investigation of the influence of stoichiometry, position, and electronic nature of the substitution on the magnetic properties of the complexes. The steric effects dominate for substitution in position 3 but the electronic effects are significant for the other positions.
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Affiliation(s)
- Chenyang Ma
- Department of Chemistry, The George Washington University, 800 22nd Street NW, Washington, D.C. 20052, USA.
| | - Claire Besson
- Department of Chemistry, The George Washington University, 800 22nd Street NW, Washington, D.C. 20052, USA.
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Oulmidi A, Radi S, Idir A, Zyad A, Kabach I, Nhiri M, Robeyns K, Rotaru A, Garcia Y. Synthesis and cytotoxicity against tumor cells of pincer N-heterocyclic ligands and their transition metal complexes. RSC Adv 2021; 11:34742-34753. [PMID: 35494785 PMCID: PMC9042687 DOI: 10.1039/d1ra05918a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/20/2021] [Indexed: 12/15/2022] Open
Abstract
The complexes: [CoL2](ClO4)2 (1), [FeL2](ClO4)2 (2), [NiL2](ClO4)2 (3) and [MnLCl2] (4), with L = diethyl-1,1′-(pyridine-2,6-diyl)bis(5-methyl-1H-pyrazole-3-carboxylate), were synthesized and fully characterized. Structural analysis revealed two distinct patterns influenced by the counter ions where L acts as a tridentate chelating ligand. The in vitro antitumor activity of L and L′ (diethyl 2,2′-(pyridine-2,6-diylbis(5-methyl-1H-pyrazole-3,1-diyl)) diacetate) as well as their metal complexes, was tested by the measurement of their cytostatic and cytotoxic properties towards the blood cancer mastocytoma cell line P815. We have also investigated their interactions with the antioxidant enzyme system. As a result, [MnL′Cl2] (1′) exhibited the strongest activity compared to reference cis-platin with no cytotoxicity towards normal cells PBMCs (Peripheral Blood Mononuclear Cells). On the other hand, the antioxidant enzyme activity showed that the efficiency of metal complex 1′ against P815 tumor cells was via the rise in the SOD activity and inhibition of CAT enzyme activity. This proof of concept study allows disclosure of a new class of molecules in cancer therapeutics. The complexes: [CoL2](ClO4)2 (1), [FeL2](ClO4)2 (2), [NiL2](ClO4)2 (3) and [MnLCl2] (4), with L = diethyl-1,1′-(pyridine-2,6-diyl)bis(5-methyl-1H-pyrazole-3-carboxylate), were synthesized and fully characterized.![]()
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Affiliation(s)
- Afaf Oulmidi
- LCAE, Department of Chemistry, Faculty of Sciences, University Mohamed I BP 524 60 000 Oujda Morocco +212-10472330.,Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université catholique de Louvain Belgium
| | - Smaail Radi
- LCAE, Department of Chemistry, Faculty of Sciences, University Mohamed I BP 524 60 000 Oujda Morocco +212-10472330
| | - Abderrazak Idir
- Team of Experimental Oncology and Natural Substances, Cellular and Molecular Immunopharmacology, Faculty of Sciences and Techniques, Sultan Moulay Slimane University Mailbox 523 23000 Beni Mellal Morocco
| | - Abdelmajid Zyad
- Team of Experimental Oncology and Natural Substances, Cellular and Molecular Immunopharmacology, Faculty of Sciences and Techniques, Sultan Moulay Slimane University Mailbox 523 23000 Beni Mellal Morocco
| | - Imad Kabach
- Laboratory of Biochemistry and Molecular Genetics, Faculty of Sciences and Technology Tangier Morocco
| | - Mohamed Nhiri
- Laboratory of Biochemistry and Molecular Genetics, Faculty of Sciences and Technology Tangier Morocco
| | - Koen Robeyns
- Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université catholique de Louvain Belgium
| | - Aurelian Rotaru
- Department of Electrical Engineering and Computer Science, MANSiD Research Center, "Stefan cel Mare" University University Street, 13 Suceava 720229 Romania
| | - Yann Garcia
- Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université catholique de Louvain Belgium
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7
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Spin-Crossover in Iron(II) Complexes of N,N′-Disubstituted 2,6-Bis(Pyrazol-3-yl)Pyridines: An Effect of a Distal Substituent in the 2,6-Dibromophenyl Group. CRYSTALS 2021. [DOI: 10.3390/cryst11080922] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A series of new bis(pyrazol-3-yl)pyridines (LR) N,N′-disubstituted by 4-functionalized 2,6-dibromophenyl groups have been synthesized to study the effect of a distal substituent on the spin-crossover (SCO) behaviour of the iron(II) complexes [Fe(LR)2](ClO4)2 by variable-temperature magnetometry, NMR spectroscopy, and X-ray diffraction. The SCO-assisting tendency of the substituents with different electronic and steric properties (i.e., the bromine atom and the methyl group) in the para-position of the 2,6-dibromophenyl group is discussed. Together with earlier reported SCO-active iron(II) complexes with N,N′-disubstituted bis(pyrazol-3-yl)pyridines, these new complexes open the way for this family of SCO compounds to emerge as an effective ‘tool’ in revealing structure–function relations, a prerequisite for successful molecular design of switchable materials for future breakthrough applications in sensing, switching, and memory devices.
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Nikovskii IA, Polezhaev AV, Aleshin DY, Mel’nikova EK, Nelyubina YV. Synthesis and Spin State of the Iron(II) Complex with the N,N'-Disubstituted 2,6-Bis(pyrazol-3-yl)pyridine Ligand. RUSS J COORD CHEM+ 2020. [DOI: 10.1134/s107032842006007x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Pankratova Y, Aleshin D, Nikovskiy I, Novikov V, Nelyubina Y. In Situ NMR Search for Spin-Crossover in Heteroleptic Cobalt(II) Complexes. Inorg Chem 2020; 59:7700-7709. [PMID: 32383584 DOI: 10.1021/acs.inorgchem.0c00716] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Here we report the first successful attempt to identify spin-crossover compounds in solutions of metal complexes produced by mixing different ligands and an appropriate metal salt by variable-temperature nuclear magnetic resonance (NMR) spectroscopy. Screening the spin state of a cobalt(II) ion in a series of thus obtained homoleptic and heteroleptic compounds of terpyridines (terpy) and 2,6-bis(pyrazol-3-yl)pyridines (3-bpp) by using this NMR-based approach, which only relies on the temperature behavior of chemical shifts, revealed the first cobalt(II) complexes with a 3-bpp ligand to undergo a thermally induced spin-crossover. A simple analysis of NMR spectra collected from mixtures of different compounds without their isolation or purification required by the current method of choice, the Evans technique, thus emerges as a powerful tool in a search for new spin-crossover compounds and their molecular design boosted by wide possibilities for chemical modifications in heteroleptic complexes.
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Affiliation(s)
- Yanina Pankratova
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia.,Moscow State University, Leninskie gory, 1, 119991 Moscow, Russia
| | - Dmitry Aleshin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia.,Mendeleev University of Chemical Technology of Russia, Miusskaya pl., 9, 125047 Moscow, Russia
| | - Igor Nikovskiy
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
| | - Valentin Novikov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny 141700, Moscow Region, Russia
| | - Yulia Nelyubina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991 Moscow, Russia
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10
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Nikovskii IA, Polezhaev AV, Aleshin DY, Mel’nikova EK, Dorovatovskii PV, Nelyubina YV. Iron(II) and Cobalt(II) Complexes with 2,6-Bis(1,4-Diphenyl-5-Hydroxy-1H-Pyrazol-3-yl)pyridine: Synthesis, Structures, and Spin States. RUSS J COORD CHEM+ 2020. [DOI: 10.1134/s1070328420050048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Nikovskiy I, Polezhaev A, Novikov V, Aleshin D, Pavlov A, Saffiulina E, Aysin R, Dorovatovskii P, Nodaraki L, Tuna F, Nelyubina Y. Towards the Molecular Design of Spin-Crossover Complexes of 2,6-Bis(pyrazol-3-yl)pyridines. Chemistry 2020; 26:5629-5638. [PMID: 31967374 DOI: 10.1002/chem.202000047] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Indexed: 01/27/2023]
Abstract
The molecular design of spin-crossover complexes relies on controlling the spin state of a transition metal ion by proper chemical modifications of the ligands. Herein, the first N,N'-disubstituted 2,6-bis(pyrazol-3-yl)pyridines (3-bpp) are reported that, against the common wisdom, induce a spin-crossover in otherwise high-spin iron(II) complexes by increasing the steric demand of a bulky substituent, an ortho-functionalized phenyl group. As N,N'-disubstituted 3-bpp complexes have no pendant NH groups that make their spin state extremely sensitive to the environment, the proposed ligand design, which may be applicable to isomeric 1-bpp or other families of popular bi-, tri- and higher denticity ligands, opens the way for their molecular design as spin-crossover compounds for future breakthrough applications.
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Affiliation(s)
- Igor Nikovskiy
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia
| | - Alexander Polezhaev
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Bauman Moscow State Technical University, 2nd Baumanskaya Str. 5, 105005, Moscow, Russia
| | - Valentin Novikov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, 141700, Moscow Region, Russia
| | - Dmitry Aleshin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Mendeleev University of Chemical Technology of Russia, Miusskaya pl., 9, 125047, Moscow, Russia
| | - Alexander Pavlov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, 141700, Moscow Region, Russia
| | - Elnara Saffiulina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Mendeleev University of Chemical Technology of Russia, Miusskaya pl., 9, 125047, Moscow, Russia
| | - Rinat Aysin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, 141700, Moscow Region, Russia
| | - Pavel Dorovatovskii
- National Research Centre "Kurchatov Institute", Akademika Kurchatova pl., 1, 123182, Moscow, Russia
| | - Lydia Nodaraki
- University of Manchester, Oxford Rd., Manchester, M13 9PL, UK
| | - Floriana Tuna
- University of Manchester, Oxford Rd., Manchester, M13 9PL, UK
| | - Yulia Nelyubina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str., 28, 119991, Moscow, Russia.,Bauman Moscow State Technical University, 2nd Baumanskaya Str. 5, 105005, Moscow, Russia
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12
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Attwood M, Akutsu H, Martin L, Cruickshank D, Turner SS. Above room temperature spin crossover in thioamide-functionalised 2,6-bis(pyrazol-1-yl)pyridine iron(ii) complexes. Dalton Trans 2018; 48:90-98. [PMID: 30456406 DOI: 10.1039/c8dt03240h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This work describes the synthesis of two novel functionalised 2,6-bis(pyrazol-1-yl)pyridine (bpp) ligands, namely 2,6-bis(pyrazol-1-yl)pyridine-4-carbothioamide (bppCSNH2) and N-methyl-2,6-bis(pyrazol-1-yl)pyridine-4-carbothioamide (bppCSNHMe). The corresponding solvated or non-solvated Fe(ii) salts, [Fe(bppCSNH2)2]X2 and [Fe(bppCSNHMe)2]X2 (X = BF4- or ClO4-) were synthesised and their properties measured by SQUID magnetometry, Evans NMR, differential scanning calorimetry and single crystal X-ray diffraction. In the solid state [Fe(bppCSNH2)2]2+ salts persist in the low spin state below 350 K. The structure of [Fe(bppCSNH2)2](BF4)2·2MeNO2 shows a network of intermolecular interactions responsible for the low spin state stabilisation, relative to the prototypical [Fe(bpp)2]2+ spin crossover (SCO) salts. By contrast the complexes of bppCSNHMe both display abrupt SCO above 300 K. [Fe(bppCSNHMe)2](BF4)2·MeNO2 requires solvent loss before SCO can be observed centred at 332 K. The non-solvated [Fe(bppCSNHMe)2](ClO4)2 shows SCO centred at 325 K. Analysis of solvated and non-solvated crystal structures suggests that cooperativity is facilitated by thioamide-group interactions with neighbouring pyrazolyl and pyridyl moieties.
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Affiliation(s)
- Max Attwood
- Department of Chemistry, University of Surrey, Guildford, GU2 7XH, UK.
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13
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Synthesis and electron paramagnetic resonance studies of seven coordinated Mn(II) complexes with tridentate N-donor ligands. Polyhedron 2018. [DOI: 10.1016/j.poly.2018.08.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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Intramolecular Spin State Locking in Iron(II) 2,6-Di(pyrazol-3-yl)pyridine Complexes by Phenyl Groups: An Experimental Study. MAGNETOCHEMISTRY 2018. [DOI: 10.3390/magnetochemistry4040046] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Here we report a series of 1-phenyl-5-substituted 2,6-di(pyrazol-3-yl)pyridine complexes with iron(II) ion found in a high spin state in solids (according to magnetochemistry) and in solution (according to NMR spectroscopy), providing experimental evidence for it being an intramolecular effect induced by the phenyl groups. According to X-ray diffraction, the high spin locking of the metal ion is a result of its highly distorted coordination environment (with a very low ‘twist’ angle atypical of 2,6-di(pyrazol-3-yl)pyridine complexes), which remains this way in complexes with different substituents and counterions, in a diamagnetic zinc(II) analogue and in their solutions. Three possible reasons behind it, including additional coordination with the phenyl group, energy penalty incurred by its rotation or intramolecular stacking interactions, are addressed experimentally.
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15
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Rusbridge EK, Peng Y, Powell AK, Robinson D, Fitzpatrick AJ. An octahedral tetrachlorido Fe(ii) complex with aminopyrazinium ligands from a serendipitous redox synthesis exhibiting magnetic exchange through non-covalent 3-D architectures. Dalton Trans 2018; 47:7644-7648. [PMID: 29796507 DOI: 10.1039/c8dt01401a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An air stable, neutral Fe(ii) complex with four equatorial chlorido ligands has been stabilised through a serendipitous redox process and in situ ligand protonation. A three-dimensional non-covalent network composed of halogen bonding and π-π stacking promotes magnetic exchange interactions though the lattice. The electronic structure has been investigated using DFT.
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Affiliation(s)
- Elizabeth K Rusbridge
- School of Science and Technology, Nottingham Trent University, NG11 8NS, Nottingham, UK.
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16
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Capel Berdiell I, Kulmaczewski R, Cespedes O, Halcrow MA. An Incomplete Spin Transition Associated with a Z'=1→Z'=24 Crystallographic Symmetry Breaking. Chemistry 2018; 24:5055-5059. [PMID: 29111607 PMCID: PMC5972820 DOI: 10.1002/chem.201704896] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Indexed: 12/31/2022]
Abstract
Crystalline [FeL2 ][BF4 ]2 ⋅Me2 CO (L=N-[2,6-di{pyrazol-1-yl}pyrid-4-yl]acetamide) is high-spin at room temperature, and undergoes an abrupt, hysteretic spin-crossover at T1/2 =137 K (ΔT1/2 =14 K) that proceeds to about 50 % completeness. This is associated with a crystallographic phase transition, from phase 1 (P21 /c, Z=4) to phase 2 (P21 , Z=48). The cations associate into chains in the crystal through weak intermolecular π⋅⋅⋅π interactions. Phase 2 contains a mixture of high-spin and low-spin molecules, which are grouped into triads along these chains. The perchlorate salt [FeL2 ][ClO4 ]2 ⋅Me2 CO also adopts phase 1 at room temperature but undergoes a different phase transition near 135 K to phase 3 (P21 /c, Z=8) without a change in spin state.
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Affiliation(s)
- Izar Capel Berdiell
- School of ChemistryUniversity of LeedsWoodhouse LaneLeedsLS2 9JTUnited Kingdom
| | - Rafal Kulmaczewski
- School of ChemistryUniversity of LeedsWoodhouse LaneLeedsLS2 9JTUnited Kingdom
| | - Oscar Cespedes
- School of Physics and AstronomyUniversity of LeedsE.C. Stoner BuildingLeedsLS2 9JTUnited Kingdom
| | - Malcolm A. Halcrow
- School of ChemistryUniversity of LeedsWoodhouse LaneLeedsLS2 9JTUnited Kingdom
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17
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Bridonneau N, Rigamonti L, Poneti G, Pinkowicz D, Forni A, Cornia A. Evidence of crystal packing effects in stabilizing high or low spin states of iron(ii) complexes with functionalized 2,6-bis(pyrazol-1-yl)pyridine ligands. Dalton Trans 2018; 46:4075-4085. [PMID: 28272635 DOI: 10.1039/c7dt00248c] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The molecular structures and magnetic properties of homoleptic iron(ii) compounds [Fe(bpp-COOMe)2](ClO4)2 (1) and [Fe(bpp-triolH3)2](ClO4)2 (2) have been investigated to ascertain their spin crossover (SCO) behaviour. In these hexacoordinated complexes, the bpp (2,6-bis(pyrazol-1-yl)pyridine) ligands adopt a mer-mer coordination mode and carry COOMe or C(O)NHC(CH2OH)3para substituents, respectively, on the central pyridyl ring. In spite of the almost equal donor power of the ligands to the iron(ii) centre, the two compounds feature different spin state configurations at room temperature. Compound 1 displays a highly-distorted octahedral environment around the iron(ii) centre, which adopts a high spin (HS) state at all temperatures, even under an external applied pressure up to 1.0 GPa. By contrast, 2 is characterized by a more regular octahedral coordination around the metal ion and exhibits a low spin (LS) configuration at or below room temperature. However, it shows a thermally-induced SCO behaviour at T > 400 K, along with Light-Induced Excited Spin State Trapping (LIESST) at low temperature, with TLIESST = 38 K. Since DFT (U)M06/6-311+G(d) geometry optimizations in vacuo indicate that both complexes should adopt a HS state and a highly-distorted coordination geometry, the stabilization of a LS configuration in 2 is ultimately ascribed to the effect of intermolecular hydrogen bonds, which align the [Fe(bpp-triolH3)2]2+ cations in 1D chains and impart profound differences in the geometric arrangement of the ligands.
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Affiliation(s)
- Nathalie Bridonneau
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia and INSTM RU of Modena and Reggio Emilia, via G. Campi 103, 41125 Modena, Italy.
| | - Luca Rigamonti
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia and INSTM RU of Modena and Reggio Emilia, via G. Campi 103, 41125 Modena, Italy.
| | - Giordano Poneti
- Laboratory of Molecular Magnetism (LAMM), Dipartimento di Chimica 'Ugo Schiff', Università degli Studi di Firenze and INSTM RU of Firenze, via della Lastruccia 3-13, 50019 Sesto Fiorentino (FI), Italy
| | - Dawid Pinkowicz
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland
| | - Alessandra Forni
- Consiglio Nazionale delle Ricerche (CNR), Istituto di Scienze e Tecnologie Molecolari (ISTM), Università degli Studi di Milano and INSTM RU of Milan, via C. Golgi 19, 20133 Milano, Italy
| | - Andrea Cornia
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia and INSTM RU of Modena and Reggio Emilia, via G. Campi 103, 41125 Modena, Italy.
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18
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Deeth RJ, Halcrow MA, Kershaw Cook LJ, Raithby PR. Ab Initio Ligand Field Molecular Mechanics and the Nature of Metal-Ligand π-Bonding in Fe(II) 2,6-di(pyrazol-1-yl)pyridine Spin Crossover Complexes. Chemistry 2017; 24:5204-5212. [DOI: 10.1002/chem.201704558] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Robert J. Deeth
- Department of Chemistry; University of Warwick; Coventry CV4 7AL UK
- Department of Chemistry; University of Bath; Claverton Down Bath BA2 7AY UK
| | | | | | - Paul R. Raithby
- Department of Chemistry; University of Bath; Claverton Down Bath BA2 7AY UK
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19
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Attwood M, Turner SS. Back to back 2,6-bis(pyrazol-1-yl)pyridine and 2,2′:6′,2″-terpyridine ligands: Untapped potential for spin crossover research and beyond. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2017.09.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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20
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Bushuev MB, Vinogradova KA, Gatilov YV, Korolkov IV, Nikolaenkova EB, Krivopalov VP. Spin crossover in iron(II) hexafluorophosphate complexes with 2-(pyridin-2-yl)-4-(3,5-di-R-1H-pyrazol-1-yl)-6-methylpyrimidines. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2017.08.006] [Citation(s) in RCA: 4] [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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21
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Capel Berdiell I, Kulmaczewski R, Halcrow MA. Iron(II) Complexes of 2,4-Dipyrazolyl-1,3,5-triazine Derivatives-The Influence of Ligand Geometry on Metal Ion Spin State. Inorg Chem 2017; 56:8817-8828. [PMID: 28699741 DOI: 10.1021/acs.inorgchem.7b00699] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Seven [FeL2][BF4]2 complex salts were prepared, where L is a 6-substituted 2,4-di(pyrazol-1-yl)-1,3,5-triazine (bpt) derivative. The complexes are all crystallographically high-spin, and exhibit significant distortions from an ideal D2d-symmetric coordination geometry. In one case, an unusual type of metal ion disorder was observed among a cubic array of ligands in the crystal lattice. The complexes are also high-spin between 3 and 300 K in the solid state and, where measured, between 239 and 333 K in CD3CN solution. This result is unexpected, since homoleptic iron(II) complexes of related 2,6-di(pyrazol-1-yl)pyridine, 2,6-di(pyrazol-1-yl)pyrazine, and 2,6-di(pyrazol-1-yl)pyrimidine derivatives often exhibit thermal spin-crossover behavior. Gas-phase density functional theory calculations confirm the high-spin form of [Fe(bpt)2]2+ and its derivatives is stabilized relative to iron(II) complexes of the other ligand types. This reflects a weaker Fe/pyrazolyl σ-bonding interaction, which we attribute to a small narrowing of the chelate ligand bite angle associated with the geometry of the 1,3,5-triazinyl ring. Hence, the high-spin state of [Fe(bpt)2]2+ centers does not reflect the electronic properties of its heterocyclic ligand donors but is imposed by the bpt ligand conformation. A high-spin homoleptic iron(III) complex of one of the bpt derivatives was also synthesized.
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Affiliation(s)
- Izar Capel Berdiell
- School of Chemistry, University of Leeds , Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Rafal Kulmaczewski
- School of Chemistry, University of Leeds , Woodhouse Lane, Leeds LS2 9JT, U.K
| | - Malcolm A Halcrow
- School of Chemistry, University of Leeds , Woodhouse Lane, Leeds LS2 9JT, U.K
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22
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Sánchez-Sánchez C, Desplanches C, Clemente-Juan JM, Clemente-León M, Coronado E. Photomagnetic properties of an Fe(ii) spin-crossover complex of 6-(3,5-diamino-2,4,6-triazinyl)-2,2′-bipyridine and its insertion into 2D and 3D bimetallic oxalate-based networks. Dalton Trans 2017; 46:2680-2689. [DOI: 10.1039/c6dt04900a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Fe(ii) complex of 6-diaminotriazyl-2,2′-bipyridine shows the LIESST effect and has been used as a countercation of two oxalate-based ferromagnets.
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Affiliation(s)
- C. Sánchez-Sánchez
- Instituto de Ciencia Molecular (ICMol)
- Universidad de Valencia
- 46980 Paterna
- Spain
| | | | - J. M. Clemente-Juan
- Instituto de Ciencia Molecular (ICMol)
- Universidad de Valencia
- 46980 Paterna
- Spain
| | - M. Clemente-León
- Instituto de Ciencia Molecular (ICMol)
- Universidad de Valencia
- 46980 Paterna
- Spain
| | - E. Coronado
- Instituto de Ciencia Molecular (ICMol)
- Universidad de Valencia
- 46980 Paterna
- Spain
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23
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Bartual-Murgui C, Vela S, Darawsheh M, Diego R, Teat SJ, Roubeau O, Aromí G. A probe of steric ligand substituent effects on the spin crossover of Fe(ii) complexes. Inorg Chem Front 2017. [DOI: 10.1039/c7qi00347a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ligand substituents modulate the SCO temperature of Fe(ii) complexes through intramolecular non-covalent interactions.
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Affiliation(s)
- C. Bartual-Murgui
- Departament de Química Inorgànica i Orgànica and IN2UB
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| | - S. Vela
- Laboratoire de Chimie Quantique
- UMR 7177
- CNRS-Université de Strasbourg
- F-67000 Strasbourg
- France
| | - M. Darawsheh
- Departament de Química Inorgànica i Orgànica and IN2UB
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| | - R. Diego
- Departament de Química Inorgànica i Orgànica and IN2UB
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| | - S. J. Teat
- Advanced Light Source
- Berkeley Laboratory
- Berkeley
- USA
| | - O. Roubeau
- Instituto de Ciencia de Materiales de Aragón (ICMA)
- CSIC and Universidad de Zaragoza
- 50009 Zaragoza
- Spain
| | - G. Aromí
- Departament de Química Inorgànica i Orgànica and IN2UB
- Universitat de Barcelona
- 08028 Barcelona
- Spain
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24
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The Effect of Ligand Design on Metal Ion Spin State—Lessons from Spin Crossover Complexes. CRYSTALS 2016. [DOI: 10.3390/cryst6050058] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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25
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Kershaw Cook LJ, Kulmaczewski R, Mohammed R, Dudley S, Barrett SA, Little MA, Deeth RJ, Halcrow MA. A Unified Treatment of the Relationship Between Ligand Substituents and Spin State in a Family of Iron(II) Complexes. Angew Chem Int Ed Engl 2016; 55:4327-31. [PMID: 26929084 PMCID: PMC4804750 DOI: 10.1002/anie.201600165] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Indexed: 11/10/2022]
Abstract
The influence of ligands on the spin state of a metal ion is of central importance for bioinorganic chemistry, and the production of base-metal catalysts for synthesis applications. Complexes derived from [Fe(bpp)2 ](2+) (bpp=2,6-di{pyrazol-1-yl}pyridine) can be high-spin, low-spin, or spin-crossover (SCO) active depending on the ligand substituents. Plots of the SCO midpoint temperature (T1/2 ) in solution vs. the relevant Hammett parameter show that the low-spin state of the complex is stabilized by electron-withdrawing pyridyl ("X") substituents, but also by electron-donating pyrazolyl ("Y") substituents. Moreover, when a subset of complexes with halogeno X or Y substituents is considered, the two sets of compounds instead show identical trends of a small reduction in T1/2 for increasing substituent electronegativity. DFT calculations reproduce these disparate trends, which arise from competing influences of pyridyl and pyrazolyl ligand substituents on Fe-L σ and π bonding.
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Affiliation(s)
- Laurence J Kershaw Cook
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | | | | | - Stephen Dudley
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
| | - Simon A Barrett
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
| | - Marc A Little
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK
| | - Robert J Deeth
- Inorganic Computational Chemistry Group, Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK.
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26
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Kershaw Cook LJ, Kulmaczewski R, Mohammed R, Dudley S, Barrett SA, Little MA, Deeth RJ, Halcrow MA. A Unified Treatment of the Relationship Between Ligand Substituents and Spin State in a Family of Iron(II) Complexes. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201600165] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Laurence J. Kershaw Cook
- School of Chemistry; University of Leeds; Leeds LS2 9JT UK
- Department of Chemistry; University of Bath, Claverton Down; Bath BA2 7AY UK
| | | | | | - Stephen Dudley
- School of Chemistry; University of Leeds; Leeds LS2 9JT UK
| | | | - Marc A. Little
- School of Chemistry; University of Leeds; Leeds LS2 9JT UK
- Department of Chemistry; University of Liverpool; Crown Street Liverpool L69 7ZD UK
| | - Robert J. Deeth
- Inorganic Computational Chemistry Group; Department of Chemistry; University of Warwick; Coventry CV4 7AL UK
- School of Chemistry; University of Edinburgh; Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
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Bartual-Murgui C, Vela S, Roubeau O, Aromí G. Designed intramolecular blocking of the spin crossover of an Fe(ii) complex. Dalton Trans 2016; 45:14058-14062. [DOI: 10.1039/c6dt03047e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ligand intramolecular interactions trap an Fe(ii) complex in the high spin state, in a case of thermodynamic trapping rather than kinetic.
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Affiliation(s)
- C. Bartual-Murgui
- Departament de Química Inorgànica i Orgànica and IN2UB
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| | - S. Vela
- Laboratoire de Chimie Quantique
- Université de Strasbourg
- F-67000 Strasbourg
- France
| | - O. Roubeau
- Instituto de Ciencia de Materiales de Aragón (ICMA)
- CSIC and Universidad de Zaragoza
- 50009 Zaragoza
- Spain
| | - G. Aromí
- Departament de Química Inorgànica i Orgànica and IN2UB
- Universitat de Barcelona
- 08028 Barcelona
- Spain
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Zadrozny JM, Greer SM, Hill S, Freedman DE. A flexible iron(ii) complex in which zero-field splitting is resistant to structural variation. Chem Sci 2015; 7:416-423. [PMID: 29861991 PMCID: PMC5952318 DOI: 10.1039/c5sc02477c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/02/2015] [Indexed: 01/19/2023] Open
Abstract
The zero-field splitting parameters D and E in the iron(ii) complex [Fe(C3S5)2]2– are shown to be remarkably resistant to a twist of the inter-ligand dihedral angle (θd) from 90 to 70°.
The relationship between electronic structure and zero-field splitting dictates key design parameters for magnetic molecules. In particular, to enable the directed synthesis of new electronic spin based qubits, developing complexes where zero-field splitting energies are invariant to structural changes is a critical challenge. Toward those ends, we report three salts of a new compound, a four-coordinate iron(ii) complex [Fe(C3S5)2]2– ([(18-crown-6)K]+ (1), Ph4P+ (2), Bu4N+ (3)) with a continuous structural variation in a single parameter, the dihedral angle (θd) between the two C3S52– ligands, as a function of counterion (θd = 89.98(4)° for 1 to 72.41(2)° for 3). Electron paramagnetic resonance data for 1–3 reveal zero-field splitting parameters that are unusually robust to the structural variation. Mössbauer spectroscopic measurements indicate that the structural variation in θd primarily affects the highest-energy 3d-orbitals (dxz and dyz) of the iron(ii) ion. These orbitals have the smallest impact on the zero-field splitting parameters, thus the distortion has a minor effect on D and E. These results represent the first part of a directed effort to understand how spin state energies may be fortified against structural distortions for future applications of qubits in non-crystalline environments.
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Affiliation(s)
- Joseph M Zadrozny
- Department of Chemistry , Northwestern University , Evanston , IL 60208 , USA .
| | - Samuel M Greer
- Department of Chemistry and Biochemistry , Florida State University , Tallahassee , FL 32306 , USA.,National High Magnetic Field Laboratory , Tallahassee , FL 32310 , USA
| | - Stephen Hill
- National High Magnetic Field Laboratory , Tallahassee , FL 32310 , USA.,Department of Physics , Florida State University , Tallahassee , FL 32306 , USA
| | - Danna E Freedman
- Department of Chemistry , Northwestern University , Evanston , IL 60208 , USA .
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29
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Kershaw Cook LJ, Thorp-Greenwood FL, Comyn TP, Cespedes O, Chastanet G, Halcrow MA. Unexpected Spin-Crossover and a Low-Pressure Phase Change in an Iron(II)/Dipyrazolylpyridine Complex Exhibiting a High-Spin Jahn–Teller Distortion. Inorg Chem 2015; 54:6319-30. [DOI: 10.1021/acs.inorgchem.5b00614] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Tim P. Comyn
- Institute
for Materials Research, School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, E. C. Stoner Building, Leeds LS2 9JT, United Kingdom
| | | | - Malcolm A. Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, United Kingdom
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30
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Spin state behavior of iron(II)/dipyrazolylpyridine complexes. New insights from crystallographic and solution measurements. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2014.08.006] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Kershaw Cook LJ, Shepherd HJ, Comyn TP, Baldé C, Cespedes O, Chastanet G, Halcrow MA. Decoupled Spin Crossover and Structural Phase Transition in a Molecular Iron(II) Complex. Chemistry 2015; 21:4805-16. [DOI: 10.1002/chem.201406307] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Indexed: 11/05/2022]
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32
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Kershaw Cook LJ, Kulmaczewski R, Barrett SA, Halcrow MA. Iron(ii) complexes of 4-sulfanyl-, 4-sulfinyl- and 4-sulfonyl-2,6-dipyrazolylpyridine ligands. A subtle interplay between spin-crossover and crystallographic phase changes. Inorg Chem Front 2015. [DOI: 10.1039/c5qi00083a] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The compound shown exhibits an abrupt thermal spin-transition, with an accompanying crystallographic phase change at slightly lower temperature which is visible as a shoulder on the susceptibility curve.
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Masárová P, Zoufalý P, Moncol J, Nemec I, Pavlik J, Gembický M, Trávníček Z, Boča R, Šalitroš I. Spin crossover and high spin electroneutral mononuclear iron(iii) Schiff base complexes involving terminal pseudohalido ligands. NEW J CHEM 2015. [DOI: 10.1039/c4nj01363h] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Six new Schiff-base complexes (1–6) with pseudohalido terminal ligands exhibits spin crossover or high spin state behaviour.
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Affiliation(s)
- Petra Masárová
- Institute of Inorganic Chemistry
- FCHPT
- Slovak University of Technology
- 812 37 Bratislava
- Slovakia
| | - Pavel Zoufalý
- Regional Centre of Advanced Technologies and Materials
- Department of Inorganic Chemistry
- Faculty of Science
- Palacký University
- 771 46 Olomouc
| | - Ján Moncol
- Institute of Inorganic Chemistry
- FCHPT
- Slovak University of Technology
- 812 37 Bratislava
- Slovakia
| | - Ivan Nemec
- Regional Centre of Advanced Technologies and Materials
- Department of Inorganic Chemistry
- Faculty of Science
- Palacký University
- 771 46 Olomouc
| | - Ján Pavlik
- Institute of Inorganic Chemistry
- FCHPT
- Slovak University of Technology
- 812 37 Bratislava
- Slovakia
| | | | - Zdeněk Trávníček
- Regional Centre of Advanced Technologies and Materials
- Department of Inorganic Chemistry
- Faculty of Science
- Palacký University
- 771 46 Olomouc
| | - Roman Boča
- Department of Chemistry
- FPV
- University of SS Cyril and Methodius
- 917 01 Trnava
- Slovakia
| | - Ivan Šalitroš
- Institute of Inorganic Chemistry
- FCHPT
- Slovak University of Technology
- 812 37 Bratislava
- Slovakia
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Vela S, Novoa JJ, Ribas-Arino J. Insights into the crystal-packing effects on the spin crossover of [FeII(1-bpp)]2+-based materials. Phys Chem Chem Phys 2014; 16:27012-24. [DOI: 10.1039/c4cp03971h] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Davidson RJ, Ainscough EW, Brodie AM, Waterland MR, Allcock HR, Hindenlang MD, Moubaraki B, Murray KS, Gordon KC, Horvath R, Jameson GN. A behavioural difference between an iron(II) grafted polyphosphazene and its small molecule cyclophosphazene analogue. INORG CHEM COMMUN 2013. [DOI: 10.1016/j.inoche.2013.09.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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36
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Iron(II) complexes of 2,6-di(1-alkylpyrazol-3-yl)pyridine derivatives – The influence of distal substituents on the spin state of the iron centre. Polyhedron 2013. [DOI: 10.1016/j.poly.2013.01.057] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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37
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Šalitroš I, Fuhr O, Kruk R, Pavlik J, Pogány L, Schäfer B, Tatarko M, Boča R, Linert W, Ruben M. Thermal and Photoinduced Spin Crossover in a Mononuclear Iron(II) Complex with a Bis(pyrazolyl)pyridine Type of Ligand. Eur J Inorg Chem 2013. [DOI: 10.1002/ejic.201201123] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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38
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Mohammed R, Chastanet G, Tuna F, Malkin TL, Barrett SA, Kilner CA, Létard JF, Halcrow MA. Synthesis of 2,6-Di(pyrazol-1-yl)pyrazine Derivatives and the Spin-State Behavior of Their Iron(II) Complexes. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201201100] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Pápai M, Vankó G, de Graaf C, Rozgonyi T. Theoretical Investigation of the Electronic Structure of Fe(II) Complexes at Spin-State Transitions. J Chem Theory Comput 2012; 9:509-519. [PMID: 25821416 PMCID: PMC4358629 DOI: 10.1021/ct300932n] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Indexed: 01/30/2023]
Abstract
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The electronic structure relevant to low spin (LS)↔high
spin (HS) transitions in Fe(II) coordination compounds with a FeN6 core are studied. The selected [Fe(tz)6]2+ (1) (tz = 1H-tetrazole), [Fe(bipy)3]2+ (2) (bipy = 2,2′-bipyridine), and [Fe(terpy)2]2+ (3) (terpy = 2,2′:6′,2″-terpyridine)
complexes have been actively studied experimentally, and with their
respective mono-, bi-, and tridentate ligands, they constitute a comprehensive
set for theoretical case studies. The methods in this work include
density functional theory (DFT), time-dependent DFT (TD-DFT), and
multiconfigurational second order perturbation theory (CASPT2). We
determine the structural parameters as well as the energy splitting
of the LS–HS states (ΔEHL) applying the above methods and comparing their performance. We
also determine the potential energy curves representing the ground
and low-energy excited singlet, triplet, and quintet d6 states along the mode(s) that connect the LS and HS states. The
results indicate that while DFT is well suited for the prediction
of structural parameters, an accurate multiconfigurational approach
is essential for the quantitative determination of ΔEHL. In addition, a good qualitative agreement
is found between the TD-DFT and CASPT2 potential energy curves. Although
the TD-DFT results might differ in some respect (in our case, we found
a discrepancy at the triplet states), our results suggest that this
approach, with due care, is very promising as an alternative for the
very expensive CASPT2 method. Finally, the two-dimensional (2D) potential
energy surfaces above the plane spanned by the two relevant configuration
coordinates in [Fe(terpy)2]2+ were computed
at both the DFT and CASPT2 levels. These 2D surfaces indicate that
the singlet–triplet and triplet–quintet states are separated
along different coordinates, i.e., different vibration modes. Our
results confirm that in contrast to the case of complexes with mono-
and bidentate ligands, the singlet–quintet transitions in [Fe(terpy)2]2+ cannot be described using a single configuration
coordinate.
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Affiliation(s)
- Mátyás Pápai
- Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary
| | - György Vankó
- Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary
| | - Coen de Graaf
- Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007 Tarragona, Spain ; Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, 08010, Barcelona, Spain
| | - Tamás Rozgonyi
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, H-1025 Budapest, Pusztaszeri út 59-67, Hungary
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40
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Craig GA, Costa JS, Roubeau O, Teat SJ, Aromí G. Local Coordination Geometry and Spin State in Novel FeIIComplexes with 2,6-Bis(pyrazol-3-yl)pyridine-Type Ligands as Controlled by Packing Forces: Structural Correlations. Chemistry 2012; 18:11703-15. [DOI: 10.1002/chem.201200820] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Indexed: 11/10/2022]
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41
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Bushuev MB, Krivopalov VP, Nikolaenkova EB, Daletsky VA, Berezovskii GA, Sheludyakova LA, Varnek VA. Spin crossover complex [](ClO4)2·H2O (L1 = 4-methyl-2,6-bis(1H-pyrazol-1-yl)pyrimidine): Synthesis and properties. Polyhedron 2012. [DOI: 10.1016/j.poly.2012.05.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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42
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Šalitroš I, Fuhr O, Eichhöfer A, Kruk R, Pavlik J, Dlháň L, Boča R, Ruben M. The interplay of iron(ii) spin transition and polymorphism. Dalton Trans 2012; 41:5163-71. [DOI: 10.1039/c2dt11906d] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Halcrow MA. Structure:function relationships in molecular spin-crossover complexes. Chem Soc Rev 2011; 40:4119-42. [PMID: 21483934 DOI: 10.1039/c1cs15046d] [Citation(s) in RCA: 642] [Impact Index Per Article: 49.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spin-crossover compounds are becoming increasingly popular for device and sensor applications, and in soft materials, that make use of their switchable colour, paramagnetism and conductivity. The de novo design of new solid spin-crossover compounds with pre-defined switching properties is desirable for application purposes. This challenging problem of crystal engineering requires an understanding of how the temperature and cooperativity of a spin-transition are influenced by the structure of the bulk material. Towards that end, this critical review presents a survey of molecular spin-crossover compounds with good availability of crystallographic data. A picture is emerging that changes in molecular shape between the high- and low-spin states, and the ability of a lattice to accommodate such changes, can play an important role in determining the existence and the cooperativity of a thermal spin-transition in the solid state (198 references).
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Affiliation(s)
- Malcolm A Halcrow
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, UK LS2 9JT. m.a.halcrow@ leeds.ac.uk
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44
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Ostermeier M, Berlin MA, Meudtner R, Demeshko S, Meyer F, Limberg C, Hecht S. Complexes of Click-Derived Bistriazolylpyridines: Remarkable Electronic Influence of Remote Substituents on Thermodynamic Stability as well as Electronic and Magnetic Properties. Chemistry 2010; 16:10202-13. [DOI: 10.1002/chem.201000721] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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45
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Bao X, Leng JD, Meng ZS, Lin Z, Tong ML, Nihei M, Oshio H. Tuning the Spin States of Two Apical Iron(II) Ions in the Trigonal-Bipyramidal [{FeII(μ-bpt)3}2FeII3(μ3-O)]2+ Cations Through the Choice of Anions. Chemistry 2010; 16:6169-74. [DOI: 10.1002/chem.201000526] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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46
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Tovee CA, Kilner CA, Barrett SA, Thomas JA, Halcrow MA. A Back-to-Back Ligand with Dipyrazolylpyridine and Dipicolylamine Metal-Binding Domains. Eur J Inorg Chem 2010. [DOI: 10.1002/ejic.200901107] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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47
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Quiñonero D, Deyà PM, Carranza MP, Rodríguez AM, Jalón FA, Manzano BR. Experimental and computational study of the interplay between C–H/π and anion–π interactions. Dalton Trans 2010; 39:794-806. [PMID: 20066224 DOI: 10.1039/b915794h] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- David Quiñonero
- Departament de Química, Universitat de les Illes Balears, Crta. Valldemossa km 7.5, 07122 Palma de Mallorca, Spain.
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48
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Iron(II) complexes of 2,6-di(pyrazol-1-yl)pyridines—A versatile system for spin-crossover research. Coord Chem Rev 2009. [DOI: 10.1016/j.ccr.2009.07.009] [Citation(s) in RCA: 284] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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49
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Liu GF, Li LL, Ren ZG, Li HX, Cheng ZP, Zhu J, Zhu XL, Lang JP. Two Cationic Copper(I) Catalysts with N-Donor Ligands for the Polymerization of Methyl Methacrylate. MACROMOL CHEM PHYS 2009. [DOI: 10.1002/macp.200900216] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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50
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Pritchard R, Kilner CA, Barrett SA, Halcrow MA. Two new 4′,4′′-disubstituted dipyrazolylpyridine derivatives, and the structures and spin states of their iron(II) complexes. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2009.01.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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