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Valerio L, Hakey BM, Leary DC, Stockdale E, Brennessel WW, Milsmann C, Matson EM. Synthesis and Characterization of Isostructural Th(IV) and U(IV) Pyridine Dipyrrolide Complexes. Inorg Chem 2024; 63:9610-9623. [PMID: 38377955 PMCID: PMC11134498 DOI: 10.1021/acs.inorgchem.3c04391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 01/24/2024] [Accepted: 01/24/2024] [Indexed: 02/22/2024]
Abstract
A series of pyridine dipyrrolide actinide(IV) complexes, (MesPDPPh)AnCl2(THF) and An(MesPDPPh)2 (An = U, Th, where (MesPDPPh) is the doubly deprotonated form of 2,6-bis(5-(2,4,6-trimethylphenyl)-3-phenyl-1H-pyrrol-2-yl)pyridine), have been prepared. Characterization of all four complexes has been performed through a combination of solid- and solution-state methods, including elemental analysis, single crystal X-ray diffraction, and electronic absorption and nuclear magnetic resonance spectroscopies. Collectively, these data confirm the formation of the mono- and bis-ligated species. Time-dependent density functional theory has been performed on all four An(IV) complexes, providing insight into the nature of electronic transitions that are observed in the electronic absorption spectra of these compounds. Room temperature, solution-state luminescence of the actinide complexes is presented. Both Th(IV) derivatives exhibit strong photoluminescence; in contrast, the U(IV) species are nonemissive.
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Affiliation(s)
- Leyla
R. Valerio
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Brett M. Hakey
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Dylan C. Leary
- C.
Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Erin Stockdale
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - William W. Brennessel
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Carsten Milsmann
- C.
Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Ellen M. Matson
- Department
of Chemistry, University of Rochester, Rochester, New York 14627, United States
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2
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Landaeta VR, Horsley Downie TM, Wolf R. Low-Valent Transition Metalate Anions in Synthesis, Small Molecule Activation, and Catalysis. Chem Rev 2024; 124:1323-1463. [PMID: 38354371 PMCID: PMC10906008 DOI: 10.1021/acs.chemrev.3c00121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 02/16/2024]
Abstract
This review surveys the synthesis and reactivity of low-oxidation state metalate anions of the d-block elements, with an emphasis on contributions reported between 2006 and 2022. Although the field has a long and rich history, the chemistry of transition metalate anions has been greatly enhanced in the last 15 years by the application of advanced concepts in complex synthesis and ligand design. In recent years, the potential of highly reactive metalate complexes in the fields of small molecule activation and homogeneous catalysis has become increasingly evident. Consequently, exciting applications in small molecule activation have been developed, including in catalytic transformations. This article intends to guide the reader through the fascinating world of low-valent transition metalates. The first part of the review describes the synthesis and reactivity of d-block metalates stabilized by an assortment of ligand frameworks, including carbonyls, isocyanides, alkenes and polyarenes, phosphines and phosphorus heterocycles, amides, and redox-active nitrogen-based ligands. Thereby, the reader will be familiarized with the impact of different ligand types on the physical and chemical properties of metalates. In addition, ion-pairing interactions and metal-metal bonding may have a dramatic influence on metalate structures and reactivities. The complex ramifications of these effects are examined in a separate section. The second part of the review is devoted to the reactivity of the metalates toward small inorganic molecules such as H2, N2, CO, CO2, P4 and related species. It is shown that the use of highly electron-rich and reactive metalates in small molecule activation translates into impressive catalytic properties in the hydrogenation of organic molecules and the reduction of N2, CO, and CO2. The results discussed in this review illustrate that the potential of transition metalate anions is increasingly being tapped for challenging catalytic processes with relevance to organic synthesis and energy conversion. Therefore, it is hoped that this review will serve as a useful resource to inspire further developments in this dynamic research field.
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Affiliation(s)
| | | | - Robert Wolf
- University of Regensburg, Institute
of Inorganic Chemistry, 93040 Regensburg, Germany
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3
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Zars E, Pick L, Swain A, Bhunia M, Carroll PJ, Munz D, Meyer K, Mindiola DJ. Iron-Catalyzed Intermolecular C-H Amination Assisted by an Isolated Iron-Imido Radical Intermediate. Angew Chem Int Ed Engl 2023:e202311749. [PMID: 37815099 DOI: 10.1002/anie.202311749] [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: 08/12/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 10/11/2023]
Abstract
Here we report the use of a base metal complex [(tBu pyrpyrr2 )Fe(OEt2 )] (1-OEt2 ) (tBu pyrpyrr2 2- =3,5-tBu2 -bis(pyrrolyl)pyridine) as a catalyst for intermolecular amination of Csp3 -H bonds of 9,10-dihydroanthracene (2 a) using 2,4,6-trimethyl phenyl azide (3 a) as the nitrene source. The reaction is complete within one hour at 80 °C using as low as 2 mol % 1-OEt2 with control in selectivity for single C-H amination versus double C-H amination. Catalytic C-H amination reactions can be extended to other substrates such as cyclohexadiene and xanthene derivatives and can tolerate a variety of aryl azides having methyl groups in both ortho positions. Under stoichiometric conditions the imido radical species [(tBu pyrpyrr2 )Fe{=N(2,6-Me2 -4-tBu-C6 H2 )] (1-imido) can be isolated in 56 % yield, and spectroscopic, magnetometric, and computational studies confirmed it to be an S = 1 FeIV complex. Complex 1-imido reacts with 2 a to produce the ferrous aniline adduct [(tBu pyrpyrr2 )Fe{NH(2,6-Me2 -4-tBu-C6 H2 )(C14 H11 )}] (1-aniline) in 45 % yield. Lastly, it was found that complexes 1-imido and 1-aniline are both competent intermediates in catalytic intermolecular C-H amination.
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Affiliation(s)
- Ethan Zars
- Department of Chemistry, University of Pennsylvania, 231 S 34th St, Philadelphia, PA-19104, USA
| | - Lisa Pick
- Department of Chemistry & Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen - Nürnberg (FAU), 91058, Erlangen, Germany
| | - Abinash Swain
- Inorganic Chemistry: Coordination Chemistry, Saarland University, Campus C4 1, 66123, Saarbrücken, Germany
| | - Mrinal Bhunia
- Department of Chemistry, University of Pennsylvania, 231 S 34th St, Philadelphia, PA-19104, USA
| | - Patrick J Carroll
- Department of Chemistry, University of Pennsylvania, 231 S 34th St, Philadelphia, PA-19104, USA
| | - Dominik Munz
- Inorganic Chemistry: Coordination Chemistry, Saarland University, Campus C4 1, 66123, Saarbrücken, Germany
| | - Karsten Meyer
- Department of Chemistry & Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen - Nürnberg (FAU), 91058, Erlangen, Germany
| | - Daniel J Mindiola
- Department of Chemistry, University of Pennsylvania, 231 S 34th St, Philadelphia, PA-19104, USA
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4
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Palluccio TD, Germain ME, Marazzi M, Temprado M, Silvia JS, Müller P, Cummins CC, Davis JV, Serafim LF, Captain B, Hoff CD, Rybak-Akimova EV. Binding of Nitriles and Isonitriles to V(III) and Mo(III) Complexes: Ligand vs Metal Controlled Mechanism. Inorg Chem 2023. [PMID: 37377337 DOI: 10.1021/acs.inorgchem.3c00595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
The synthesis and structures of nitrile complexes of V(N[tBu]Ar)3, 2 (Ar = 3,5-Me2C6H3), are described. Thermochemical and kinetic data for their formation were determined by variable temperature Fourier transform infrared (FTIR), calorimetry, and stopped-flow techniques. The extent of back-bonding from metal to coordinated nitrile indicates that electron donation from the metal to the nitrile plays a less prominent role for 2 than for the related complex Mo(N[tBu]Ar)3, 1. Kinetic studies reveal similar rate constants for nitrile binding to 2, but the activation parameters depend critically on the nature of R in RCN. Activation enthalpies range from 2.9 to 7.2 kcal·mol-1, and activation entropies from -9 to -28 cal·mol-1·K-1 in an opposing manner. Density functional theory (DFT) calculations provide a plausible explanation supporting the formation of a π-stacking interaction between a pendant arene of the metal anilide of 2 and the arene substituent on the incoming nitrile in favorable cases. Data for ligand binding to 1 do not exhibit this range of activation parameters and are clustered in a small area centered at ΔH‡ = 5.0 kcal·mol-1 and ΔS‡ = -26 cal·mol-1·K-1. Computational studies are in agreement with the experimental data and indicate a stronger dependence on electronic factors associated with the change in spin state upon ligand binding to 1.
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Affiliation(s)
- Taryn D Palluccio
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Meaghan E Germain
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Marco Marazzi
- Departamento de Química Analítica, Química Física e Ingeniería Química, Grupo de Reactividad y Estructura Molecular (RESMOL), Universidad de Alcalá, Alcalá de Henares, Madrid 28805, Spain
- Instituto de Investigación Química 'Andrés M. del Río'' (IQAR), Universidad de Alcalá, Alcalá de Henares, Madrid 28805, Spain
| | - Manuel Temprado
- Departamento de Química Analítica, Química Física e Ingeniería Química, Grupo de Reactividad y Estructura Molecular (RESMOL), Universidad de Alcalá, Alcalá de Henares, Madrid 28805, Spain
- Instituto de Investigación Química 'Andrés M. del Río'' (IQAR), Universidad de Alcalá, Alcalá de Henares, Madrid 28805, Spain
| | - Jared S Silvia
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Peter Müller
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Christopher C Cummins
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jack V Davis
- Department of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Leonardo F Serafim
- Department of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Burjor Captain
- Department of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Carl D Hoff
- Department of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Elena V Rybak-Akimova
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
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5
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Zars E, Gravogl L, Gau MR, Carroll PJ, Meyer K, Mindiola DJ. Isostructural bridging diferrous chalcogenide cores [Fe II(μ-E)Fe II] (E = O, S, Se, Te) with decreasing antiferromagnetic coupling down the chalcogenide series. Chem Sci 2023; 14:6770-6779. [PMID: 37350823 PMCID: PMC10283490 DOI: 10.1039/d3sc01094e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/24/2023] [Indexed: 06/24/2023] Open
Abstract
Iron compounds containing a bridging oxo or sulfido moiety are ubiquitous in biological systems, but substitution with the heavier chalcogenides selenium and tellurium, however, is much rarer, with only a few examples reported to date. Here we show that treatment of the ferrous starting material [(tBupyrpyrr2)Fe(OEt2)] (1-OEt2) (tBupyrpyrr2 = 3,5-tBu2-bis(pyrrolyl)pyridine) with phosphine chalcogenide reagents E = PR3 results in the neutral phosphine chalcogenide adduct series [(tBupyrpyrr2)Fe(EPR3)] (E = O, S, Se; R = Ph; E = Te; R = tBu) (1-E) without any electron transfer, whereas treatment of the anionic starting material [K]2[(tBupyrpyrr2)Fe2(μ-N2)] (2-N2) with the appropriate chalcogenide transfer source yields cleanly the isostructural ferrous bridging mono-chalcogenide ate complexes [K]2[(tBupyrpyrr2)Fe2(μ-E)] (2-E) (E = O, S, Se, and Te) having significant deviation in the Fe-E-Fe bridge from linear in the case of E = O to more acute for the heaviest chalcogenide. All bridging chalcogenide complexes were analyzed using a variety of spectroscopic techniques, including 1H NMR, UV-Vis electronic absorbtion, and 57Fe Mössbauer. The spin-state and degree of communication between the two ferrous ions were probed via SQUID magnetometry, where it was found that all iron centers were high-spin (S = 2) FeII, with magnetic exchange coupling between the FeII ions. Magnetic studies established that antiferromagnetic coupling between the ferrous ions decreases as the identity of the chalcogen is tuned from O to the heaviest congener Te.
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Affiliation(s)
- Ethan Zars
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Lisa Gravogl
- Department of Chemistry & Pharmacy, Friedrich-Alexander-Universität Erlangen - Nürnberg (FAU) Egerlandstr. 1 91058 Erlangen Bavaria Germany
| | - Michael R Gau
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Patrick J Carroll
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Karsten Meyer
- Department of Chemistry & Pharmacy, Friedrich-Alexander-Universität Erlangen - Nürnberg (FAU) Egerlandstr. 1 91058 Erlangen Bavaria Germany
| | - Daniel J Mindiola
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
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6
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Regenauer NI, Wadepohl H, Roşca D. Terminal N 2 Dissociation in [(PNN)Fe(N 2 )] 2 (μ-N 2 ) Leads to Local Spin-State Changes and Augmented Bridging N 2 Activation. Chemistry 2022; 28:e202202172. [PMID: 35916757 PMCID: PMC9804668 DOI: 10.1002/chem.202202172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Indexed: 01/09/2023]
Abstract
Nitrogen fixation at iron centres is a fundamental catalytic step for N2 utilisation, relevant to biological (nitrogenase) and industrial (Haber-Bosch) processes. This step is coupled with important electronic structure changes which are currently poorly understood. We show here for the first time that terminal dinitrogen dissociation from iron complexes that coordinate N2 in a terminal and bridging fashion leaves the Fe-N2 -Fe unit intact but significantly enhances the degree of N2 activation (Δν≈180 cm-1 , Raman spectroscopy) through charge redistribution. The transformation proceeds with local spin state change at the iron centre (S= 1 / 2 ${{ 1/2 }}$ →S=3 /2 ). Further dissociation of the bridging N2 can be induced under thermolytic conditions, triggering a disproportionation reaction, from which the tetrahedral (PNN)2 Fe could be isolated. This work shows that dinitrogen activation can be induced in the absence of external chemical stimuli such as reducing agents or Lewis acids.
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Affiliation(s)
- Nicolas I. Regenauer
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 276Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 276Germany
| | - Dragoş‐Adrian Roşca
- Anorganisch-Chemisches InstitutUniversität HeidelbergIm Neuenheimer Feld 276Germany
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7
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Torres JF, Oi CH, Moseley IP, El‐Sakkout N, Knight BJ, Shearer J, García‐Serres R, Zadrozny JM, Murray LJ. Dinitrogen Coordination to a High‐Spin Diiron(I/II) Species. Angew Chem Int Ed Engl 2022; 61:e202202329. [DOI: 10.1002/anie.202202329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Juan F. Torres
- Center for Catalysis and Florida Center for Heterocyclic Chemistry Department of Chemistry University of Florida Gainesville FL 32611 USA
| | - Collin H. Oi
- Center for Catalysis and Florida Center for Heterocyclic Chemistry Department of Chemistry University of Florida Gainesville FL 32611 USA
| | - Ian P. Moseley
- Department of Chemistry Colorado State University Fort Collins CO 80523 USA
| | - Nabila El‐Sakkout
- Univ. Grenoble Alpes CNRS CEA IRIG Laboratoire de Chimie et Biologie des Métaux 17 rue des Martyrs 38000 Grenoble France
| | - Brian J. Knight
- Center for Catalysis and Florida Center for Heterocyclic Chemistry Department of Chemistry University of Florida Gainesville FL 32611 USA
| | - Jason Shearer
- Department of Chemistry Trinity University San Antonio TX 78212 USA
| | - Ricardo García‐Serres
- Univ. Grenoble Alpes CNRS CEA IRIG Laboratoire de Chimie et Biologie des Métaux 17 rue des Martyrs 38000 Grenoble France
| | - Joseph M. Zadrozny
- Department of Chemistry Colorado State University Fort Collins CO 80523 USA
| | - Leslie J. Murray
- Center for Catalysis and Florida Center for Heterocyclic Chemistry Department of Chemistry University of Florida Gainesville FL 32611 USA
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8
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Regenauer NI, Wadepohl H, Roşca DA. Metal-Ligand Cooperativity in Iron Dinitrogen Complexes: Proton-Coupled Electron Transfer Disproportionation and an Anionic Fe(0)N 2 Hydride. Inorg Chem 2022; 61:7426-7435. [PMID: 35508073 DOI: 10.1021/acs.inorgchem.2c00459] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metal-ligand cooperativity and redox-active ligands enable the use of open-shell first-row transition metals in catalysis. However, the fleeting nature of the reactive intermediates prevents direct inspection of the relevant catalytic species. By employing phosphine α-iminopyridine (PNN)-based complexes, we show that chemical and redox metal-ligand cooperativity can be combined in the coordination sphere of iron dinitrogen complexes. These systems show dual activation modes either through deprotonation, which triggers reversible core dearomatization, or through reversibly accepting one electron by reducing the imine functionality. (PNN)Fe(N2) fragments can be obtained under mildly reducing conditions. Deprotonation of such complexes induces dearomatization of the pyridine core while retaining a terminally coordinated N2 ligand. This species is nevertheless stable in solution only below -30 °C and undergoes unusual ligand-assisted redox disproportionation through proton-coupled electron transfer at room temperature. The origin of this phenomenon is the significant lability of the α-imine C-H bonds in the dearomatized species, where the calculated bond dissociation free energy is 48.7 kcal mol-1. The dispropotionation reaction yields an overreduced iron compound, demonstrating that the formation of such species can be triggered by mild bases, and does not require harsh reducing agents. Reaction of the dearomatized species with dihydrogen yields a rare anionic Fe hydride that binds dinitrogen and features a rearomatized core.
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Affiliation(s)
- Nicolas I Regenauer
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Hubert Wadepohl
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
| | - Dragoş-Adrian Roşca
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
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9
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Hakey BM, Leary DC, Lopez LM, Valerio LR, Brennessel WW, Milsmann C, Matson EM. Synthesis and Characterization of Pyridine Dipyrrolide Uranyl Complexes. Inorg Chem 2022; 61:6182-6192. [PMID: 35420825 PMCID: PMC9044449 DOI: 10.1021/acs.inorgchem.2c00348] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The first actinide complexes of the pyridine dipyrrolide (PDP) ligand class, (MesPDPPh)UO2(THF) and (Cl2PhPDPPh)UO2(THF), are reported as the UVI uranyl adducts of the bulky aryl substituted pincers (MesPDPPh)2- and (Cl2PhPDPPh)2- (derived from 2,6-bis(5-(2,4,6-trimethylphenyl)-3-phenyl-1H-pyrrol-2-yl)pyridine (H2MesPDPPh, Mes = 2,4,6-trimethylphenyl), and 2,6-bis(5-(2,6-dichlorophenyl)-3-phenyl-1H-pyrrol-2-yl)pyridine (H2Cl2PhPDPPh, Cl2Ph = 2,6-dichlorophenyl), respectively). Following the in situ deprotonation of the proligand with lithium hexamethyldisilazide to generate the corresponding dilithium salts (e.g., Li2ArPDPPh, Ar = Mes of Cl2Ph), salt metathesis with [UO2Cl2(THF)2]2 afforded both compounds in moderate yields. The characterization of each species has been undertaken by a combination of solid- and solution-state methods, including combustion analysis, infrared, electronic absorption, and NMR spectroscopies. In both complexes, single-crystal X-ray diffraction has revealed a distorted octahedral geometry in the solid state, enforced by the bite angle of the rigid meridional (ArPDPPh)2- pincer ligand. The electrochemical analysis of both compounds by cyclic voltammetry in tetrahydrofuran (THF) reveals rich redox profiles, including events assigned as UVI/UV redox couples. A time-dependent density functional theory study has been performed on (MesPDPPh)UO2(THF) and provides insight into the nature of the transitions that comprise its electronic absorption spectrum.
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Affiliation(s)
- Brett M Hakey
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Dylan C Leary
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Lauren M Lopez
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Leyla R Valerio
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - William W Brennessel
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Carsten Milsmann
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Ellen M Matson
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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10
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Torres JF, Oi CH, Moseley I, El-Sakkout N, Knight BJ, Shearer J, García-Serres R, Zadrozny JM, Murray LJ. Dinitrogen Coordination to a High Spin Diiron(I/II) Species. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | | | - Ian Moseley
- Colorado State University Chemistry UNITED STATES
| | - Nabila El-Sakkout
- Université Grenoble Alpes: Universite Grenoble Alpes Chemistry UNITED STATES
| | | | | | | | | | - Leslie Justin Murray
- University of Florida Department of Chemistry P.O. Box 117200 32611-7200 Gainesville UNITED STATES
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11
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Zars E, Gravogl L, Gau M, Carroll PJ, Meyer K, Mindiola DJ. Iron(II) Mediated Deazotation of Benzyl Azide: Trapping and Subsequent Transformations of the Benzaldimine Fragment. Inorg Chem 2022; 61:1079-1090. [PMID: 34978453 DOI: 10.1021/acs.inorgchem.1c03243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mono-benzaldimine (HN═CHPh) complex [(tBupyrpyrr2)Fe(HN═CHPh)] (1-HN═CHPh) has been prepared by reaction of [(tBupyrpyrr2)Fe(OEt2)] (1-OEt2) (tBupyrpyrr2 = 2,6-bis(3,5-di-tert-butyl-pyrrolyl)pyridine) with one equivalent of benzyl azide. Compound 1-HN═CHPh retains the cis-divacant octahedral coordination geometry akin to 1, as established by single crystal X-ray diffraction study. A bis-HN═CHPh complex [(tBupyrpyrr2)Fe(HN═CHPh)2] (2) was also prepared by the addition of two equivalents of benzyl azide to 1, and its molecular structure exhibits the two HN═CHPh ligands coordinated trans to each other, thereby forming a square pyramidal coordination geometry at the FeII center. Reaction of 1 with excess benzyl azide yields [(tBupyrpyrr2)Fe(HN═CHPh)2·PhCHNCH(NH2)Ph] (2-PhCHNCH(NH2)Ph), which contains an unstable benzylideneamino phenyl methanamine fragment, effectively hydrogen bonded to 2. Thermolysis of 2 or 2-PhCHNCH(NH2)Ph releases the HN═CHPh self-coupling products hydrobenzamide (A), N-benzylidine benzylamine (B), and benzonitrile (C). Under catalytic conditions, free HN═CHPh (cis/trans-HN═CHPh mixture) is produced using 2.5 mol % of 1 in 90% spectroscopic yield. These studies provide a clearer understanding for the conversion of the HN═CHPh in 2 or 2-PhCHNCH(NH2)Ph to the C-C and C-N coupled products. Reduction of 1-HN═CHPh with KC8 yields the reductively coupled benzylamide complex [K(OEt2)]2[(tBupyrpyrr2)2Fe2(μ2-NHCHPhCHPhNH)] (3) as the result of a new C-C bond formed between two radical benzylamide fragments.
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Affiliation(s)
- Ethan Zars
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Lisa Gravogl
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Chemistry and Pharmacy, Inorganic Chemistry, Egerlandstr. 1, Erlangen 91058, Germany
| | - Michael Gau
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Patrick J Carroll
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Karsten Meyer
- Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Department of Chemistry and Pharmacy, Inorganic Chemistry, Egerlandstr. 1, Erlangen 91058, Germany
| | - Daniel J Mindiola
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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12
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Bae DY, Lee G, Lee E. Fixation of Dinitrogen at an Asymmetric Binuclear Titanium Complex. Inorg Chem 2021; 60:12813-12822. [PMID: 34492761 DOI: 10.1021/acs.inorgchem.1c01050] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A new type of dititanium dinitrogen complex supported by a triphenolamine (TPA) ligand is reported. Analysis by single-crystal X-ray diffraction and Raman and NMR spectroscopy reveals different coordination geometries for the two titanium centers. Hence, coordination of TPA and a nitrogen ligand results in trigonal-bipyramidal geometry, while an octahedral titanium center is obtained upon additional coordination of an ethoxide generated upon C-O bond cleavage in a diethyl ether solvent molecule. The titanium complex successfully generates ammonia in the presence of an excess amount of PCy3HI and KC8 in 154% yield (per titanium atom). A titanium complex with a bulkier TPA does not form a dinitrogen complex, and mononuclear titanium dinitrogen complexes were not accessible, presumably because of the high tendency of early transition metals to form binuclear dinitrogen complexes.
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Affiliation(s)
- Dae Young Bae
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Gunhee Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
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Aguilar-Calderón JR, Fehn D, Sorsche D, Miehlich M, Carroll PJ, Zars E, Meyer K, Mindiola DJ. Redox-Controlled and Reversible N-N Bond Forming and Splitting with an Iron IV Terminal Imido Ligand. Inorg Chem 2021; 60:13091-13100. [PMID: 34375089 DOI: 10.1021/acs.inorgchem.1c01509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidation of the low-spin FeIV imido complex [{(tBupyrr)2py}Fe═NAd] (1) ((tBupyrr)2py2- = 2,6-bis(3,5-di-tert-butyl-pyrrolyl)pyridine, Ad = 1-adamantyl) with AgOAc or AgNO3 promotes reductive N-N bond coupling of the former imido nitrogen with a pyrrole nitrogen to form the respective ferric hydrazido-like pincer complexes [{(tBupyrrNAd)(tBupyrr)py}Fe(κ2-X)] (X = OAc-, 2OAc; NO3-, 2NO3). Reduction of 2OAc with KC8 cleaves the N-N bond to reform the FeIV imido ligand in 1, whereas acid-mediated demetalation of 2OAc or 2NO3 yields the free hydrazine ligand [(tBupyrrNHAd)(tBupyrrH)py] (3), the latter of which can be used as a direct entry to the iron imido complex when treated with [Fe{N(SiMe3)2}2]. In addition to characterizing these Fe systems, we show how this nitrene transfer strategy can be expanded to Co for the one-step synthesis of Co{(tBu-NHAdpyrr)(tBupyrr)py}] (4) ((tBu-NHAdpyrr)(tBupyrr)py2- = 2-(3-tBu-5-(1-adamantylmethyl-2-methylpropane-2-yl)-pyrrol-2-yl)-6-(3,5-tBu2-pyrrol-2-yl)-pyridine).
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Affiliation(s)
| | - Dominik Fehn
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Dieter Sorsche
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Matthias Miehlich
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Patrick J Carroll
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Ethan Zars
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Karsten Meyer
- Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Daniel J Mindiola
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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Yamout LS, Ataya M, Hasanayn F, Holland PL, Miller AJM, Goldman AS. Understanding Terminal versus Bridging End-on N 2 Coordination in Transition Metal Complexes. J Am Chem Soc 2021; 143:9744-9757. [PMID: 34180663 DOI: 10.1021/jacs.1c01146] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Terminal and bridging end-on coordination of N2 to transition metal complexes offer possibilities for distinct pathways in ammonia synthesis and N2 functionalization. Here we elucidate the fundamental factors controlling the two binding modes and determining which is favored for a given metal-ligand system, using both quantitative density functional theory (DFT) and qualitative molecular orbital (MO) analyses. The Gibbs free energy for converting two terminal MN2 complexes into a bridging MNNM complex and a free N2 molecule (2ΔGeq°) is examined through systematic variations of the metal and ligands; values of ΔGeq° range between +9.1 and -24.0 kcal/mol per M-N2 bond. We propose a model that accounts for these broad variations by assigning a fixed π-bond order (BOπ) to the triatomic terminal MNN moiety that is equal to that of the free N2 molecule, and a variable BOπ to the bridging complexes based on the character (bonding or antibonding) and occupancy of the π-MOs in the tetratomic MNNM core. When the conversion from terminal to bridging coordination and free N2 is associated with an increase in the number of π-bonds (ΔBOeqπ > 0), the bridging mode is greatly favored; this condition is satisfied when each metal provides 1, 2, or 3 electrons to the π-MOs of the MNNM core. When each metal in the bridging complex provides 4 electrons to the MNNM π-MOs, ΔBOeqπ = 0; the equilibrium in this case is approximately ergoneutral and the direction can be shifted by dispersion interactions.
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Affiliation(s)
- Lynn S Yamout
- Department of Chemistry, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Mohamad Ataya
- Department of Chemistry, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Faraj Hasanayn
- Department of Chemistry, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Patrick L Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Alexander J M Miller
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Alan S Goldman
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, United States
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Hakey BM, Leary DC, Rodriguez JG, Martinez JC, Vaughan NB, Darmon JM, Akhmedov NG, Petersen JL, Dolinar BS, Milsmann C. Effects of 2,6‐Dichlorophenyl Substituents on the Coordination Chemistry of Pyridine Dipyrrolide Iron Complexes. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202100117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Brett M. Hakey
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Dylan C. Leary
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Jose G. Rodriguez
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Jordan C. Martinez
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Nicholas B. Vaughan
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | | | - Novruz G. Akhmedov
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Jeffrey L. Petersen
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Brian S. Dolinar
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
| | - Carsten Milsmann
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown, West Virginia USA
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Eaton MC, Catalano VJ, Shearer J, Murray LJ. Dinitrogen Insertion and Cleavage by a Metal-Metal Bonded Tricobalt(I) Cluster. J Am Chem Soc 2021; 143:5649-5653. [PMID: 33830763 DOI: 10.1021/jacs.1c01840] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Reduction of a tricobalt(II) tri(bromide) cluster supported by a tris(β-diketiminate) cyclophane results in halide loss, ligand compression, and metal-metal bond formation to yield a 48-electron CoI3 cluster, Co3LEt/Me (2). Upon reaction of 2 with dinitrogen, all metal-metal bonds are broken, steric conflicts are relaxed, and dinitrogen is incorporated within the internal cavity to yield a formally (μ3-η1:η2:η1-dinitrogen)tricobalt(I) complex, 3. Broken symmetry DFT calculations (PBE0/def2-tzvp/D3) support an N-N bond order of 2.1 in the bound N2 with the calculated N-N stretching frequency (1743 cm-1) comparable to the experimental value (1752 cm-1). Reduction of 3 under Ar in the presence of Me3SiBr results in N2 scission with tris(trimethylsilyl)amine afforded in good yield.
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Affiliation(s)
- Mary C Eaton
- Center for Catalysis and Florida Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Vincent J Catalano
- Department of Chemistry, University of Nevada, Reno, Nevada 89557, United States
| | - Jason Shearer
- Department of Chemistry, Trinity University, San Antonio, Texas 78212, United States
| | - Leslie J Murray
- Center for Catalysis and Florida Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States
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Wang Q, Brooks SH, Liu T, Tomson NC. Tuning metal-metal interactions for cooperative small molecule activation. Chem Commun (Camb) 2021; 57:2839-2853. [PMID: 33624638 PMCID: PMC8274379 DOI: 10.1039/d0cc07721f] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cluster complexes have attracted interest for decades due to their promise of drawing analogies to metallic surfaces and metalloenzyme active sites, but only recently have chemists started to develop ligand scaffolds that are specifically designed to support multinuclear transition metal cores. Such ligands not only hold multiple metal centers in close proximity but also allow for fine-tuning of their electronic structures and surrounding steric environments. This Feature Article highlights ligand designs that allow for cooperative small molecule activation at cluster complexes, with a particular focus on complexes that contain metal-metal bonds. Two useful ligand-design elements have emerged from this work: a degree of geometric flexibility, which allows for novel small molecule activation modes, and the use of redox-active ligands to provide electronic flexibility to the cluster core. The authors have incorporated these factors into a unique class of dinucleating macrocycles (nPDI2). Redox-active fragments in nPDI2 mimic the weak-overlap covalent bonding that is characteristic of M-M interactions, and aliphatic linkers in the ligand backbone provide geometric flexibility, allowing for interconversion between a range of geometries as the dinuclear core responds to the requirements of various small molecule substrates. The union of these design elements appears to be a powerful combination for analogizing critical aspects of heterogeneous and metalloenzyme catalysts.
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Affiliation(s)
- Qiuran Wang
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, USA.
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Zhu H, Aarons J, Peng Q. High spin polarized Fe2 cluster combined with vicinal nonmetallic sites for catalytic ammonia synthesis from a theoretical perspective. Inorg Chem Front 2021. [DOI: 10.1039/d1qi01083b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Compared to other Fen (n > 2) clusters, Fe2 cluster catalysts combined with vicinal nonmetallic sites are expected to be an ideal catalyst for ammonia synthesis with a lower N–H formation (0.47 eV) and N–N dissociation (0.50 eV) energy barrier at the same time.
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Affiliation(s)
- Hongdan Zhu
- State Key Laboratory and Institute of Elemento-Organic Chemistry and Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Jolyon Aarons
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Qian Peng
- State Key Laboratory and Institute of Elemento-Organic Chemistry and Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
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Dias HVR, Pramanik A. Nickel(II) carbonyl, ammonia, and aceto-nitrile complexes supported by a pyridine dipyrrolide pincer ligand. Acta Crystallogr E Crystallogr Commun 2020; 76:1741-1747. [PMID: 33209345 PMCID: PMC7643235 DOI: 10.1107/s2056989020013341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 10/05/2020] [Indexed: 01/12/2023]
Abstract
The synthesis, isolation and crystal structures of nickel(II) carbonyl, aceto-nitrile and ammonia complexes supported by a dianionic, pyridine dipyrrolide pincer ligand [pyrr2py]2-, namely, carbonyl[2,2'-(pyridine-2,6-di-yl)bis-(3,5-di-p-tolyl-pyrrolido-κN)]-nickel(II), [Ni(C41H33N3)(CO)], ammine[2,2'-(pyridine-2,6-di-yl)bis-(3,5-di-p-tolyl-pyrrolido-κN)]nickel(II), [Ni(C41H33N3)(NH3)], and (aceto-nitrile-κN)[2,2'-(pyridine-2,6-di-yl)bis-(3,5-di-p-tolyl-pyrrolido-κN)]nickel(II), [Ni(C41H33N3)(CH3CN)], as well as the free ligand 2,6-bis-(3,5-di-p-tolyl-pyrrol-2-yl)pyridine, C41H35N3 or [pyrr2py]H2 are reported. The nickel complexes are four-coordinate and adopt a square-planar geometry. The CO stretch of the nickel-bound carbon monoxide ligand of [pyrr2py]Ni(CO) has been observed at 2101 cm-1. The ammonia and aceto-nitrile complexes, [pyrr2py]Ni(NH3) and [pyrr2py]Ni(NCMe) feature all-nitro-gen coordination spheres around nickel consisting of different N-donor ligand types.
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Affiliation(s)
- H. V. Rasika Dias
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, USA
| | - Abhijit Pramanik
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, USA
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Abstract
Activation of dinitrogen plays an important role in daily anthropogenic life, and the processes by which this fixation occurs have been a longstanding and significant research focus within the community. One of the major fields of dinitrogen activation research is the use of multimetallic compounds to reduce and/or activate N2 into a more useful nitrogen-atom source, such as ammonia. Here we report a comprehensive review of multimetallic-dinitrogen complexes and their utility toward N2 activation, beginning with the d-block metals from Group 4 to Group 11, then extending to Group 13 (which is exclusively populated by B complexes), and finally the rare-earth and actinide species. The review considers all polynuclear metal aggregates containing two or more metal centers in which dinitrogen is coordinated or activated (i.e., partial or complete cleavage of the N2 triple bond in the observed product). Our survey includes complexes in which mononuclear N2 complexes are used as building blocks to generate homo- or heteromultimetallic dinitrogen species, which allow one to evaluate the potential of heterometallic species for dinitrogen activation. We highlight some of the common trends throughout the periodic table, such as the differences between coordination modes as it relates to N2 activation and potential functionalization and the effect of polarizing the bridging N2 ligand by employing different metal ions of differing Lewis acidities. By providing this comprehensive treatment of polynuclear metal dinitrogen species, this Review aims to outline the past and provide potential future directions for continued research in this area.
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Affiliation(s)
- Devender Singh
- Center for Catalysis, and Florida Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA
| | - William R. Buratto
- Center for Catalysis, and Florida Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA
| | - Juan F. Torres
- Center for Catalysis, and Florida Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA
| | - Leslie J. Murray
- Center for Catalysis, and Florida Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA
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