1
|
Mo BR, Wu JY, Yang JD, Cheng JP. Metal-Carbon Bond Heterolysis Energy Scale for Model Palladium Catalysts. Inorg Chem 2024. [PMID: 39327997 DOI: 10.1021/acs.inorgchem.4c03225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2024]
Abstract
Thermodynamic studies of transition-metal intermediates are crucial for understanding of metal-catalyzed transformations. Herein, a series of arylpalladium cyanomethanides were synthesized and characterized. Their palladium-carbon bond heterolysis energies (ΔGhet(Pd-C)) were determined in DMSO for the first time by equilibrium methods. ΔGhet(Pd-C) values of 7.9-19.1 kcal/mol, located between the ΔGhet(Pd-O) and ΔGhet(Pd-N) scales previously established, are much smaller than the corresponding ΔGhet(C-H)s of phenylacetonitrile (30.0 kcal/mol). Linear free energy relationship (LEFR) analysis reveals insights into the structure-property relationship and the factor dictating the thermodynamics of metalation. These ΔGhet(Pd-X)s in combination with ΔGhet(X-H)s are successfully used to diagnose the reaction feasibility and selectivity of X-H bond activation.
Collapse
Affiliation(s)
- Bin-Rui Mo
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jun-Yan Wu
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jin-Dong Yang
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jin-Pei Cheng
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, China
| |
Collapse
|
2
|
Marques HM. The inorganic chemistry of the cobalt corrinoids - an update. J Inorg Biochem 2023; 242:112154. [PMID: 36871417 DOI: 10.1016/j.jinorgbio.2023.112154] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 01/23/2023] [Accepted: 01/26/2023] [Indexed: 02/05/2023]
Abstract
The inorganic chemistry of the cobalt corrinoids, derivatives of vitamin B12, is reviewed, with particular emphasis on equilibrium constants for, and kinetics of, their axial ligand substitution reactions. The role the corrin ligand plays in controlling and modifying the properties of the metal ion is emphasised. Other aspects of the chemistry of these compounds, including their structure, corrinoid complexes with metals other than cobalt, the redox chemistry of the cobalt corrinoids and their chemical redox reactions, and their photochemistry are discussed. Their role as catalysts in non-biological reactions and aspects of their organometallic chemistry are briefly mentioned. Particular mention is made of the role that computational methods - and especially DFT calculations - have played in developing our understanding of the inorganic chemistry of these compounds. A brief overview of the biological chemistry of the B12-dependent enzymes is also given for the reader's convenience.
Collapse
Affiliation(s)
- Helder M Marques
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa.
| |
Collapse
|
3
|
Toda MJ, Lodowski P, Mamun AA, Kozlowski PM. Electronic and photolytic properties of hydridocobalamin. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2021; 224:112295. [PMID: 34548209 DOI: 10.1016/j.jphotobiol.2021.112295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/06/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Hydridocobalamin (HCbl), is a known member of the B12 family of molecules (cobalamins, Cbls) yet unlike other well-studied Cbls, little is known of the electronic and photolytic properties of this species. Interest in HCbl has increased significantly in recent years when at least three experimentally proposed mechanisms implicate HCbl as an intermediary in the photoreaction of coenzyme B12-dependent photoreceptor CarH. Specifically, cleavage of the Co-C5' bond of coenzyme B12 could lead to a β-hydride or β‑hydrogen elimination reaction to form HCbl. HCbl is known to be a transient species where the oxidation state of the Co is variable; Co(I)-H+ ↔ Co(II)-H ↔ Co(III)-H-. Further, HCbl is a very unstable with a pKa of ~1. This complicates experimental studies and to the best of our knowledge there are no available crystal structures of HCbl - either for the isolated molecule or bound to an enzyme. In this study, the electronic structure, photolytic properties, and reactivity of HCbl were explored to determine the preferred oxidation state as well as its potential role in the formation of the photoproduct in CarH. Natural bond orbital (NBO) analysis was performed to determine the oxidation state of Co in isolated HCbl. Based on the NBO analysis of HCbl, Co clearly had excess negative charge, which is in stark contrast to other alkylCbls where the Co ion is marked by significant positive charge. In sum, NBO results indicate that the CoH bond is strongly polarized and almost ionic. It can be described as protonated Co(I). In addition, DFT was used to explore the bond dissociation energy of HCbl based on homolytic cleavage of the CoH bond. TD-DFT calculations were used to compare computed electronic transitions to the experimentally determined absorption spectrum. The photoreaction of CarH was explored using an isolated model system and a pathway for hydrogen transfer was found. Finally, quantum mechanics/molecular mechanics (QM/MM) calculations were employed to investigate the formation of HCbl in CarH.
Collapse
Affiliation(s)
- Megan J Toda
- Department of Chemistry, University of Louisville, Louisville, KY 40292, United States
| | - Piotr Lodowski
- Institute of Chemistry, University of Silesia in Katowice, Szkolna 9, PL-40 006 Katowice, Poland
| | - Abdullah Al Mamun
- Department of Chemistry, University of Louisville, Louisville, KY 40292, United States
| | - Pawel M Kozlowski
- Department of Chemistry, University of Louisville, Louisville, KY 40292, United States.
| |
Collapse
|
4
|
Tsybizova A, Brenig C, Kieninger C, Kräutler B, Chen P. Surprising Homolytic Gas Phase Co-C Bond Dissociation Energies of Organometallic Aryl-Cobinamides Reveal Notable Non-Bonded Intramolecular Interactions. Chemistry 2021; 27:7252-7264. [PMID: 33560580 PMCID: PMC8251903 DOI: 10.1002/chem.202004589] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Indexed: 01/12/2023]
Abstract
Aryl-cobalamins are a new class of organometallic structural mimics of vitamin B12 designed as potential 'antivitamins B12 '. Here, the first cationic aryl-cobinamides are described, which were synthesized using the newly developed diaryl-iodonium method. The aryl-cobinamides were obtained as pairs of organometallic coordination isomers, the stereo-structure of which was unambiguously assigned based on homo- and heteronuclear NMR spectra. The availability of isomers with axial attachment of the aryl group, either at the 'beta' or at the 'alpha' face of the cobalt-center allowed for an unprecedented comparison of the organometallic reactivity of such pairs. The homolytic gas-phase bond dissociation energies (BDEs) of the coordination-isomeric phenyl- and 4-ethylphenyl-cobinamides were determined by ESI-MS threshold CID experiments, furnishing (Co-Csp 2 )-BDEs of 38.4 and 40.6 kcal mol-1 , respectively, for the two β-isomers, and the larger BDEs of 46.6 and 43.8 kcal mol-1 for the corresponding α-isomers. Surprisingly, the observed (Co-Csp 2 )-BDEs of the Coβ -aryl-cobinamides were smaller than the (Co-Csp 3 )-BDE of Coβ -methyl-cobinamide. DFT studies and the magnitudes of the experimental (Co-Csp 2 )-BDEs revealed relevant contributions of non-bonded interactions in aryl-cobinamides, notably steric strain between the aryl and the cobalt-corrin moieties and non-bonded interactions with and among the peripheral sidechains.
Collapse
Affiliation(s)
- Alexandra Tsybizova
- Laboratorium für Organische ChemieDepartment of Chemistry and Applied BiosciencesETH ZürichZürichSwitzerland
| | - Christopher Brenig
- Institute of Organic Chemistry & Center of Molecular BiosciencesUniversity of InnsbruckInnsbruckAustria
| | - Christoph Kieninger
- Institute of Organic Chemistry & Center of Molecular BiosciencesUniversity of InnsbruckInnsbruckAustria
| | - Bernhard Kräutler
- Institute of Organic Chemistry & Center of Molecular BiosciencesUniversity of InnsbruckInnsbruckAustria
| | - Peter Chen
- Laboratorium für Organische ChemieDepartment of Chemistry and Applied BiosciencesETH ZürichZürichSwitzerland
| |
Collapse
|
5
|
Sitek P, Chmielowska A, Jaworska M, Lodowski P, Szczepańska M. Theoretical study of cobalt and nickel complexes involved in methyl transfer reactions: structures, redox potentials and methyl binding energies. Struct Chem 2019. [DOI: 10.1007/s11224-019-01384-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
6
|
Demarteau J, Debuigne A, Detrembleur C. Organocobalt Complexes as Sources of Carbon-Centered Radicals for Organic and Polymer Chemistries. Chem Rev 2019; 119:6906-6955. [DOI: 10.1021/acs.chemrev.8b00715] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Jérémy Demarteau
- Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liège, Allée du 6 Août, Building B6A, Agora Square, 4000 Liège, Belgium
| | - Antoine Debuigne
- Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liège, Allée du 6 Août, Building B6A, Agora Square, 4000 Liège, Belgium
| | - Christophe Detrembleur
- Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, University of Liège, Allée du 6 Août, Building B6A, Agora Square, 4000 Liège, Belgium
| |
Collapse
|
7
|
Padmanabhan S, Jost M, Drennan CL, Elías-Arnanz M. A New Facet of Vitamin B 12: Gene Regulation by Cobalamin-Based Photoreceptors. Annu Rev Biochem 2017; 86:485-514. [PMID: 28654327 PMCID: PMC7153952 DOI: 10.1146/annurev-biochem-061516-044500] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Living organisms sense and respond to light, a crucial environmental factor, using photoreceptors, which rely on bound chromophores such as retinal, flavins, or linear tetrapyrroles for light sensing. The discovery of photoreceptors that sense light using 5'-deoxyadenosylcobalamin, a form of vitamin B12 that is best known as an enzyme cofactor, has expanded the number of known photoreceptor families and unveiled a new biological role of this vitamin. The prototype of these B12-dependent photoreceptors, the transcriptional repressor CarH, is widespread in bacteria and mediates light-dependent gene regulation in a photoprotective cellular response. CarH activity as a transcription factor relies on the modulation of its oligomeric state by 5'-deoxyadenosylcobalamin and light. This review surveys current knowledge about these B12-dependent photoreceptors, their distribution and mode of action, and the structural and photochemical basis of how they orchestrate signal transduction and control gene expression.
Collapse
Affiliation(s)
- S Padmanabhan
- Instituto de Química Física Rocasolano, Consejo Superior de Investigaciones Científicas, 28006 Madrid, Spain;
| | - Marco Jost
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158-2140;
| | - Catherine L Drennan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Department of Biology and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139;
| | - Montserrat Elías-Arnanz
- Departamento de Genética y Microbiología, Área de Genética, Unidad Asociada al Instituto de Química Física Rocasolano, Consejo Superior de Investigaciones Científicas, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain;
| |
Collapse
|
8
|
Kozlowski PM, Garabato BD, Lodowski P, Jaworska M. Photolytic properties of cobalamins: a theoretical perspective. Dalton Trans 2016; 45:4457-70. [PMID: 26865262 DOI: 10.1039/c5dt04286k] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This Perspective Article highlights recent theoretical developments, and summarizes the current understanding of the photolytic properties of cobalamins from a computational point of view. The primary focus is on two alkyl cobalamins, methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl), as well as two non-alkyl cobalamins, cyanocobalamin (CNCbl) and hydroxocobalamin (HOCbl). Photolysis of alkyl cobalamins involves low-lying singlet excited states where photodissociation of the Co-C bond leads to formation of singlet-born alkyl/cob(ii)alamin radical pairs (RPs). Potential energy surfaces (PESs) associated with cobalamin low-lying excited states as functions of both axial bonds, provide the most reliable tool for initial analysis of their photochemical and photophysical properties. Due to the complexity, and size limitations associated with the cobalamins, the primary method for calculating ground state properties is density functional theory (DFT), while time-dependent DFT (TD-DFT) is used for electronically excited states. For alkyl cobalamins, energy pathways on the lowest singlet surface, connecting metal-to-ligand charge transfer (MLCT) and ligand field (LF) minima, can be associated with photo-homolysis of the Co-C bond observed experimentally. Additionally, energy pathways between minima and seams associated with crossing of S1/S0 surfaces, are the most efficient for internal conversion (IC) to the ground state. Depending on the specific cobalamin, such IC may involve simultaneous elongation of both axial bonds (CNCbl), or detachment of axial base followed by corrin ring distortion (MeCbl). The possibility of intersystem crossing, and the formation of triplet RPs is also discussed based on Landau-Zener theory.
Collapse
Affiliation(s)
- Pawel M Kozlowski
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA.
| | | | | | | |
Collapse
|
9
|
Rodgers ZL, Shell TA, Brugh AM, Nowotarski HL, Forbes MDE, Lawrence DS. Fluorophore Assisted Photolysis of Thiolato-Cob(III)alamins. Inorg Chem 2016; 55:1962-9. [PMID: 26848595 DOI: 10.1021/acs.inorgchem.5b02036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cobalamins are known to react with thiols to yield stable β-axial Co(III)-S bonded thiolato-cobalamin complexes. However, in stark contrast to the Co-C bond in alkylcobalamins, the photolability of the Co-S bond in thiolato-cobalamins remains undetermined. We have investigated the photolysis of N-acetylcysteinyl cob(III)alamin at several wavelengths within the ultraviolet and visible spectrum. To aid in photolysis, we show that attaching fluorophore "antennae" to the cobalamin scaffold can improve photolytic efficiency by up to an order of magnitude. Additionally, electron paramagnetic resonance confirms previous conjectures that the photolysis of thiolato-cobalamins at wavelengths as long as 546 nm produces thiyl radicals.
Collapse
Affiliation(s)
- Zachary L Rodgers
- Department of Chemistry, ‡Division of Chemical Biology and Medicinal Chemistry, and §Department of Pharmacology, University of North Carolina , Chapel Hill, North Carolina 27599, United States
| | - Thomas A Shell
- Department of Chemistry, ‡Division of Chemical Biology and Medicinal Chemistry, and §Department of Pharmacology, University of North Carolina , Chapel Hill, North Carolina 27599, United States
| | - Alexander M Brugh
- Department of Chemistry, ‡Division of Chemical Biology and Medicinal Chemistry, and §Department of Pharmacology, University of North Carolina , Chapel Hill, North Carolina 27599, United States
| | - Hannah L Nowotarski
- Department of Chemistry, ‡Division of Chemical Biology and Medicinal Chemistry, and §Department of Pharmacology, University of North Carolina , Chapel Hill, North Carolina 27599, United States
| | - Malcolm D E Forbes
- Department of Chemistry, ‡Division of Chemical Biology and Medicinal Chemistry, and §Department of Pharmacology, University of North Carolina , Chapel Hill, North Carolina 27599, United States
| | - David S Lawrence
- Department of Chemistry, ‡Division of Chemical Biology and Medicinal Chemistry, and §Department of Pharmacology, University of North Carolina , Chapel Hill, North Carolina 27599, United States
| |
Collapse
|
10
|
Brown JE, Diaz L, Christoff-Tempesta T, Nesbitt KM, Reed-Betts J, Sanchez J, Davies KW. Characterization of Nitrazine Yellow as a Photoacoustically Active pH Reporter Molecule. Anal Chem 2015; 87:3623-30. [DOI: 10.1021/ac503515k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jordan E. Brown
- Department of Chemistry and
Physics, Florida Gulf Coast University, 10501 FGCU Boulevard South, Fort Myers, Florida 33965-6565, United States
| | - Lilibet Diaz
- Department of Chemistry and
Physics, Florida Gulf Coast University, 10501 FGCU Boulevard South, Fort Myers, Florida 33965-6565, United States
| | - Ty Christoff-Tempesta
- Department of Chemistry and
Physics, Florida Gulf Coast University, 10501 FGCU Boulevard South, Fort Myers, Florida 33965-6565, United States
| | - Kathryn M. Nesbitt
- Department of Chemistry and
Physics, Florida Gulf Coast University, 10501 FGCU Boulevard South, Fort Myers, Florida 33965-6565, United States
| | - Julia Reed-Betts
- Department of Chemistry and
Physics, Florida Gulf Coast University, 10501 FGCU Boulevard South, Fort Myers, Florida 33965-6565, United States
| | - John Sanchez
- Department of Chemistry and
Physics, Florida Gulf Coast University, 10501 FGCU Boulevard South, Fort Myers, Florida 33965-6565, United States
| | - Kevin W. Davies
- Department of Chemistry and
Physics, Florida Gulf Coast University, 10501 FGCU Boulevard South, Fort Myers, Florida 33965-6565, United States
| |
Collapse
|
11
|
Qu ZW, Hansen A, Grimme S. Co–C Bond Dissociation Energies in Cobalamin Derivatives and Dispersion Effects: Anomaly or Just Challenging? J Chem Theory Comput 2015; 11:1037-45. [DOI: 10.1021/acs.jctc.5b00007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Zheng-wang Qu
- Mulliken
Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie der Universität Bonn, Beringstraße
4, 53115 Bonn, North Rhine-Westphalia, Germany
| | - Andreas Hansen
- Mulliken
Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie der Universität Bonn, Beringstraße
4, 53115 Bonn, North Rhine-Westphalia, Germany
| | - Stefan Grimme
- Mulliken
Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie der Universität Bonn, Beringstraße
4, 53115 Bonn, North Rhine-Westphalia, Germany
| |
Collapse
|
12
|
Lodowski P, Jaworska M, Andruniów T, Garabato BD, Kozlowski PM. Mechanism of Co–C Bond Photolysis in the Base-On Form of Methylcobalamin. J Phys Chem A 2014; 118:11718-34. [DOI: 10.1021/jp508513p] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Piotr Lodowski
- Department
of Theoretical Chemistry, Institute of Chemistry, University of Silesia, Szkolna 9, PL-40 006 Katowice, Poland
| | - Maria Jaworska
- Department
of Theoretical Chemistry, Institute of Chemistry, University of Silesia, Szkolna 9, PL-40 006 Katowice, Poland
| | - Tadeusz Andruniów
- Institute
of Physical and Theoretical Chemistry, Department of Chemistry, Wroclaw University of Technology, 50-370 Wroclaw, Poland
| | - Brady D. Garabato
- Department
of Chemistry, University of Louisville, Louisville, Kentucky 40292, United States
| | - Pawel M. Kozlowski
- Department
of Chemistry, University of Louisville, Louisville, Kentucky 40292, United States
| |
Collapse
|
13
|
Kobylianskii IJ, Widner FJ, Kräutler B, Chen P. Co-C bond energies in adenosylcobinamide and methylcobinamide in the gas phase and in silico. J Am Chem Soc 2013; 135:13648-51. [PMID: 24007238 DOI: 10.1021/ja406676p] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Essential to biological activity of adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl) is the Co-C bond cleavage step. Hence, we report an accurate determination of the homolytic gas-phase Co-C bond dissociation energies in the related adenosyl- and methylcobinamides (41.5 ± 1.2 and 44.6 ± 0.8 kcal/mol, respectively) utilizing an energy-resolved threshold collision-induced dissociation technique. This approach allows for benchmarking of electronic structure methods separate from (often ill-defined) solvent effects. Adequacy of various density functional theory methods has been tested with respect to the experimentally obtained values.
Collapse
|
14
|
Bushnell EAC, Gherib R, Gauld JW. Insights into the Catalytic Mechanism of Coral Allene Oxide Synthase: A Dispersion Corrected Density Functional Theory Study. J Phys Chem B 2013; 117:6701-10. [DOI: 10.1021/jp403405b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Eric A. C. Bushnell
- Department of Chemistry and Biochemistry,
University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - Rami Gherib
- Department of Chemistry and Biochemistry,
University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - James W. Gauld
- Department of Chemistry and Biochemistry,
University of Windsor, Windsor, Ontario N9B 3P4, Canada
| |
Collapse
|
15
|
Kumar N, Kuta J, Galezowski W, Kozlowski PM. Electronic Structure of One-Electron-Oxidized Form of the Methylcobalamin Cofactor: Spin Density Distribution and Pseudo-Jahn–Teller Effect. Inorg Chem 2013; 52:1762-71. [DOI: 10.1021/ic3013443] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Neeraj Kumar
- Department of Chemistry, University of Louisville,
Louisville, Kentucky 40292, United States
| | - Jadwiga Kuta
- Department of Chemistry, University of Louisville,
Louisville, Kentucky 40292, United States
| | - Wlodzimierz Galezowski
- Department of Chemistry, A. Mickiewicz University,
Umultowska 89b, 61-614 Poznan, Poland
| | - Pawel M. Kozlowski
- Department of Chemistry, University of Louisville,
Louisville, Kentucky 40292, United States
| |
Collapse
|
16
|
Kozlowski PM, Kumar M, Piecuch P, Li W, Bauman NP, Hansen JA, Lodowski P, Jaworska M. The Cobalt–Methyl Bond Dissociation in Methylcobalamin: New Benchmark Analysis Based on Density Functional Theory and Completely Renormalized Coupled-Cluster Calculations. J Chem Theory Comput 2012; 8:1870-94. [DOI: 10.1021/ct300170y] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pawel M. Kozlowski
- Department of Chemistry, University
of Louisville,
2320 South Brook St., Louisville, Kentucky 40292, United States
| | - Manoj Kumar
- Department of Chemistry, University
of Louisville,
2320 South Brook St., Louisville, Kentucky 40292, United States
| | - Piotr Piecuch
- Department of Chemistry, Michigan State University,
578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Wei Li
- Department of Chemistry, Michigan State University,
578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Nicholas P. Bauman
- Department of Chemistry, Michigan State University,
578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Jared A. Hansen
- Department of Chemistry, Michigan State University,
578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Piotr Lodowski
- Institute
of Chemistry, University of Silesia, Szkolna
9, PL-40 006 Katowice, Poland
| | - Maria Jaworska
- Institute
of Chemistry, University of Silesia, Szkolna
9, PL-40 006 Katowice, Poland
| |
Collapse
|
17
|
Kozlowski PM, Kamachi T, Kumar M, Yoshizawa K. Reductive elimination pathway for homocysteine to methionine conversion in cobalamin-dependent methionine synthase. J Biol Inorg Chem 2012; 17:611-9. [DOI: 10.1007/s00775-012-0881-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 02/02/2012] [Indexed: 12/20/2022]
|
18
|
Hirao H. Which DFT Functional Performs Well in the Calculation of Methylcobalamin? Comparison of the B3LYP and BP86 Functionals and Evaluation of the Impact of Empirical Dispersion Correction. J Phys Chem A 2011; 115:9308-13. [DOI: 10.1021/jp2052807] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Hajime Hirao
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| |
Collapse
|
19
|
Peng J, Tang KC, McLoughlin K, Yang Y, Forgach D, Sension RJ. Ultrafast Excited-State Dynamics and Photolysis in Base-Off B12 Coenzymes and Analogues: Absence of the trans-Nitrogenous Ligand Opens a Channel for Rapid Nonradiative Decay. J Phys Chem B 2010; 114:12398-405. [DOI: 10.1021/jp104641u] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Jian Peng
- Department of Chemistry and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Kuo-Chun Tang
- Department of Chemistry and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Kaitlin McLoughlin
- Department of Chemistry and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Yang Yang
- Department of Chemistry and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Danika Forgach
- Department of Chemistry and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Roseanne J. Sension
- Department of Chemistry and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1055
| |
Collapse
|
20
|
Mebs S, Henn J, Dittrich B, Paulmann C, Luger P. Electron Densities of Three B12 Vitamins. J Phys Chem A 2009; 113:8366-78. [DOI: 10.1021/jp902433x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stefan Mebs
- Institut für Chemie und Biochemie/Kristallographie, Freie Universität Berlin, Fabeckstrasse 36a, 14195 Berlin, Germany, Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany, Mineralogisch-Petrographisches Institut, Universität Hamburg, Grindelallee 48, 20146 Hamburg, Germany
| | - Julian Henn
- Institut für Chemie und Biochemie/Kristallographie, Freie Universität Berlin, Fabeckstrasse 36a, 14195 Berlin, Germany, Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany, Mineralogisch-Petrographisches Institut, Universität Hamburg, Grindelallee 48, 20146 Hamburg, Germany
| | - Birger Dittrich
- Institut für Chemie und Biochemie/Kristallographie, Freie Universität Berlin, Fabeckstrasse 36a, 14195 Berlin, Germany, Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany, Mineralogisch-Petrographisches Institut, Universität Hamburg, Grindelallee 48, 20146 Hamburg, Germany
| | - Carsten Paulmann
- Institut für Chemie und Biochemie/Kristallographie, Freie Universität Berlin, Fabeckstrasse 36a, 14195 Berlin, Germany, Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany, Mineralogisch-Petrographisches Institut, Universität Hamburg, Grindelallee 48, 20146 Hamburg, Germany
| | - Peter Luger
- Institut für Chemie und Biochemie/Kristallographie, Freie Universität Berlin, Fabeckstrasse 36a, 14195 Berlin, Germany, Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany, Mineralogisch-Petrographisches Institut, Universität Hamburg, Grindelallee 48, 20146 Hamburg, Germany
| |
Collapse
|
21
|
Ooms KJ, Bernard GM, Kadziola A, Kofod P, Wasylishen RE. Solid-state 13C and 59Co NMR spectroscopy of 13C-methylcobalt(iii) complexes with amine ligands. Phys Chem Chem Phys 2009; 11:2690-9. [PMID: 19421527 DOI: 10.1039/b820753d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Five octahedral Co(iii) cations, [trans-Co(en)(2)(X)((13)CH(3))](n+) where en = ethylenediamine, X = CN(-), N(3)(-), NH(3), NO(2)(-) or H(2)O and n = 1 or 2, as well as [Co(NH(3))(5)(13)CH(3)](2+), have been investigated by solid-state (13)C and (59)Co NMR spectroscopy. We show that the determination of the (59)Co nuclear quadrupolar parameters both directly via(59)Co NMR and indirectly via(13)C NMR provide complementary information that is unavailable if one investigates only one nucleus. Specifically, (1)J((59)Co,(13)C) and the orientation of the largest component of the EFG were determined via(13)C NMR spectroscopy, which also established the negative sign of C(Q)((59)Co). Cobalt-59 NMR spectroscopy was used to characterize the cobalt magnetic shielding tensor, to verify the magnitudes of C(Q)((59)Co) and to establish the value of eta(Q), which is difficult to determine indirectly. The measurements show that the EFG tensors are either axially symmetric or close to being so, but there is a wide range of C(Q) values, from -40 MHz for the complex with X = H(2)O to -105 MHz with X = CN(-). The Co chemical shift tensors are approximately axially symmetric with the spans, delta(11)-delta(33), ranging from 3700 to 5600 ppm for X = H(2)O and CN(-), respectively. The latter measurements also established the relative orientations of the Co EFG and chemical shift tensors. Density functional theory calculations of the (59)Co EFG and magnetic shielding tensors as well as of (1)J((59)Co,(13)C) for the NO(2)(-) and N(3)(-) complexes were undertaken. These calculations confirm the experimental observation that the sign of C(Q) is negative and that the largest component of the EFG is along the Co-methyl-carbon bond.
Collapse
Affiliation(s)
- Kristopher J Ooms
- Gunning-Lemieux Chemistry Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, CanadaT6G 2G2
| | | | | | | | | |
Collapse
|
22
|
Lodowski P, Jaworska M, Andruniów T, Kumar M, Kozlowski PM. Photodissociation of Co−C Bond in Methyl- and Ethylcobalamin: An Insight from TD-DFT Calculations. J Phys Chem B 2009; 113:6898-909. [DOI: 10.1021/jp810223h] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Piotr Lodowski
- Department of Theoretical Chemistry, Institute of Chemistry, University of Silesia, Szkolna 9, PL-40 006 Katowice, Poland; Institute of Physical and Theoretical Chemistry, Department of Chemistry, Wroclaw University of Technology, 50-370 Wroclaw, Poland; and Department of Chemistry, University of Louisville, Louisville, Kentucky 40292
| | - Maria Jaworska
- Department of Theoretical Chemistry, Institute of Chemistry, University of Silesia, Szkolna 9, PL-40 006 Katowice, Poland; Institute of Physical and Theoretical Chemistry, Department of Chemistry, Wroclaw University of Technology, 50-370 Wroclaw, Poland; and Department of Chemistry, University of Louisville, Louisville, Kentucky 40292
| | - Tadeusz Andruniów
- Department of Theoretical Chemistry, Institute of Chemistry, University of Silesia, Szkolna 9, PL-40 006 Katowice, Poland; Institute of Physical and Theoretical Chemistry, Department of Chemistry, Wroclaw University of Technology, 50-370 Wroclaw, Poland; and Department of Chemistry, University of Louisville, Louisville, Kentucky 40292
| | - Manoj Kumar
- Department of Theoretical Chemistry, Institute of Chemistry, University of Silesia, Szkolna 9, PL-40 006 Katowice, Poland; Institute of Physical and Theoretical Chemistry, Department of Chemistry, Wroclaw University of Technology, 50-370 Wroclaw, Poland; and Department of Chemistry, University of Louisville, Louisville, Kentucky 40292
| | - Pawel M. Kozlowski
- Department of Theoretical Chemistry, Institute of Chemistry, University of Silesia, Szkolna 9, PL-40 006 Katowice, Poland; Institute of Physical and Theoretical Chemistry, Department of Chemistry, Wroclaw University of Technology, 50-370 Wroclaw, Poland; and Department of Chemistry, University of Louisville, Louisville, Kentucky 40292
| |
Collapse
|
23
|
Langlotz B, Lloret Fillol J, Gross J, Wadepohl H, Gade L. Living Radical Polymerization of Acrylates Mediated by 1,3-Bis(2-pyridylimino)isoindolatocobalt(II) Complexes: Monitoring the Chain Growth at the Metal. Chemistry 2008; 14:10267-79. [DOI: 10.1002/chem.200801373] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
24
|
Davies KW, Maivald D, Grabowski JJ. A photoacoustic calorimetric characterization of the reaction enthalpy and volume for the preparation of a reactive intermediate from CpMn(CO)3. J Photochem Photobiol A Chem 2008. [DOI: 10.1016/j.jphotochem.2008.01.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
25
|
Qi XJ, Li Z, Fu Y, Guo QX, Liu L. anti-Spin-Delocalization Effect in Co−C Bond Dissociation Enthalpies. Organometallics 2008. [DOI: 10.1021/om701135c] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Xiu-Juan Qi
- Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Zhe Li
- Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yao Fu
- Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Qing-Xiang Guo
- Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Lei Liu
- Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China, and Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| |
Collapse
|
26
|
Kuta J, Patchkovskii S, Zgierski MZ, Kozlowski PM. Performance of DFT in modeling electronic and structural properties of cobalamins. J Comput Chem 2007; 27:1429-37. [PMID: 16807975 DOI: 10.1002/jcc.20454] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Computational modeling of the enzymatic activity of B12-dependent enzymes requires a detailed understanding of the factors that influence the strength of the Co--C bond and the limits associated with a particular level of theory. To address this issue, a systematic analysis of the electronic and structural properties of coenzyme B12 models has been performed to establish the performance of three different functionals including B3LYP, BP86, and revPBE. In particular the cobalt-carbon bond dissociation energies, axial bond lengths, and selected stretching frequencies have been analyzed in detail. Current analysis shows that widely used B3LYP functional significantly underestimates the strength of the Co--C bond while the nonhybrid BP86 functional produces very consistent results in comparison to experimental data. To explain such different performance of these functionals molecular orbital analysis associated with axial bonds has been performed to show differences in axial bonding provided by hybrid and nonhybrid functionals.
Collapse
Affiliation(s)
- Jadwiga Kuta
- Department of Chemistry, University of Louisville, 2320 S. Brook Street, Louisville, Kentucky 40292, USA
| | | | | | | |
Collapse
|
27
|
Galezowski W, Kubicki M. X-ray Structures and Homolysis of Some Alkylcobalt(III) Phthalocyanine Complexes. Inorg Chem 2005; 44:9902-13. [PMID: 16363861 DOI: 10.1021/ic051078p] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The first crystallographic data for sigma-bonded alkylcobalt(III) phthalocyanine complexes are reported. A single-crystal X-ray structure of CH(3)CH(2)Co(III)Pc (Pc = dianion of phthalocyanine) reveals that the solid consists of centrosymmetric face-to-face dimers in which the CH(3)CH(2)Co(III)Pc units retain their square pyramidal geometry. The structure appears to be the first one reported for a five-coordinate RCo(III)(chelate) complex with an electron-deficient equatorial system. The Co-C bond in CH(3)CH(2)Co(III)Pc (2.031(5) A) is the longest found in five-coordinate RCo(III)(chel) complexes (R = simple primary alkyl group). Another X-ray study demonstrates that CH(3)Co(III)Pc(py) has a distorted octahedral geometry with axial bonds of very similar length to those in methylcobalamin. The axial bonds are shorter than those in its octaethylporphyrin analogue, in accordance with a weaker trans axial influence in six-coordinate complexes containing an electron-deficient phthalocyanine equatorial ligand. A different trend has been observed for five-coordinate RCo(III)(chel) complexes: electron-rich equatorial systems seem to make the Co-C axial bond shorter. Kinetic data for the homolysis of RCo(III)Pc complexes (R = Me, Et) in dimethylacetamide are also reported. Homolysis of ethyl derivatives is faster. The Co-C bond dissociation energies (BDEs) for the pyridine adducts of the methyl and the ethyl derivative are 30 +/- 1 and 29 +/- 1 kcal/mol, respectively. The BDE for CH(3)CoPc(py) is considerably lower than that for MeCbl despite the very similar lengths of the axial bonds in the two complexes. The results of this work do not support any correlation between the Co-C bond length and the bond strength as defined by BDE.
Collapse
Affiliation(s)
- Wlodzimierz Galezowski
- Department of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland.
| | | |
Collapse
|
28
|
Affiliation(s)
- Kenneth L Brown
- Department of Chemistry and Biochemistry, Ohio University, Athens, 45701, USA.
| |
Collapse
|
29
|
Dölker N, Morreale A, Maseras F. Computational study on the difference between the Co–C bond dissociation energy in methylcobalamin and adenosylcobalamin. J Biol Inorg Chem 2005; 10:509-17. [PMID: 15986217 DOI: 10.1007/s00775-005-0662-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2004] [Accepted: 05/16/2005] [Indexed: 10/25/2022]
Abstract
The bond dissociation energies of the Co-C bonds in the cobalamin cofactors methylcobalamin and adenosylcobalamin were calculated using the hybrid quantum mechanics/molecular mechanics method IMOMM (integrated molecular orbital and molecular mechanics). Calculations were performed on models of differing complexities as well as on the full systems. We investigated the origin of the different experimental values for the Co-C bond dissociation energies in methylcobalamin and adenosylcobalamin, and have provided an explanation for the difficulties encountered when we attempt to reproduce this difference in quantum chemistry. Additional calculations have been performed using the Miertus-Scrocco-Tomasi method in order to estimate the influence of solvent effects on the homolytic Co-C bond cleavage. Introduction of these solvation effects is shown to be necessary for the correct reproduction of experimental trends in bond dissociation energies in solution, which consequently have no direct correlation with dissociation processes in the enzyme.
Collapse
Affiliation(s)
- Nicole Dölker
- Unitat de Química Física, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain.
| | | | | |
Collapse
|
30
|
Kozlowski PM, Zgierski MZ. Electronic and Steric Influence of Trans Axial Base on the Stereoelectronic Properties of Cobalamins. J Phys Chem B 2004. [DOI: 10.1021/jp040373c] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pawel M. Kozlowski
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, and Steacie Institute for Molecular Science, National Research Council of Canada, Ottawa, Ontario, Canada K1A OR6
| | - Marek Z. Zgierski
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, and Steacie Institute for Molecular Science, National Research Council of Canada, Ottawa, Ontario, Canada K1A OR6
| |
Collapse
|
31
|
Ren X, Alleyne BD, Djurovich PI, Adachi C, Tsyba I, Bau R, Thompson ME. Organometallic Complexes as Hole-Transporting Materials in Organic Light-Emitting Diodes. Inorg Chem 2004; 43:1697-707. [PMID: 14989662 DOI: 10.1021/ic035183f] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The use of metal complexes fac-tris(1-phenylpyrazolato-N,C(2)('))cobalt(III) [fac-Co(ppz)(3)], fac-tris(2-phenylpyridinato-N,C(2)(') cobalt(III) [fac-Co(ppy)(3)], and [tris[2-((pyrrole-2-ylmethylidene)amino)ethyl]amine]gallium(III) [Ga(pma)] as materials for hole-transporting layers (HTL) in organic light-emitting diodes (OLEDs) is reported. Co(ppz)(3) and Co(ppy)(3) were prepared by following literature procedures and isolated as mixtures of facial (fac) and meridional (mer) isomers. The more stable fac isomers were separated from the unstable mer forms via column chromatography and thermal gradient sublimation. Crystals of fac-Co(ppz)(3) are monoclinic, space group P2(1)/c, with a = 13.6121(12) A, b = 15.5600(12) A, c = 22.9603(17) A, beta = 100.5 degrees, V = 4781.3(7) A(3), and Z = 8. [Tris[2-((pyrrol-2-ylmethylidene)amino)ethyl]amine]gallium [Ga(pma)] was prepared by the reaction of gallium(III) nitrate with the pmaH(3) ligand precursor in methanol. Ga(pma) crystallizes in the cubic space group I3d with cell parameters a = 20.2377(4) A, b = 20.2377(4) A, c = 20.2377(4) A, beta = 90.0 degrees, V = 8288.6(3) A(3), and Z = 16. These cobalt and gallium complexes are pale colored to colorless solids, with optical energy gaps ranging 2.6-3.36 eV. A two-layer HTL/ETL (ETL = electron-transporting layer) device structure using fac-Co(ppz)(3) and fac-Co(ppy)(3) as the HTL does not give efficient electroluminescence. However, the introduction of a thin layer of a hole-transporting material (N,N'-bis(1-naphthyl)-N,N'-diphenylbenzidine, NPD) as an energy "stair-step" and electron/exciton-blocker dramatically improves the device performance. Both fac-Co(ppz)(3) and fac-Co(ppy)(3) devices give external quantum efficiencies higher than 1.0%, with brightness 5000 and 7000 Cd/m(2) at 10 V, respectively. Ga(pma) also functions as an efficient interface layer, giving device performances very similar to those of analogous devices using NPD as the interface layer. Stability tests have been carried out for Co(ppz)(3)/NPD/Alq(3) and Co(ppy)(3)/NPD/Alq(3) devices. While fac-Co(ppy)(3) gave stable OLEDs, the fac-Co(ppz)(3)-based devices had very short lifetimes. On the basis of the experimental results of chemical oxidation of fac-Co(ppz)(3), the major cause for the fast decay of the fac-Co(ppz)(3) device is proposed to be the decomposition of fac-Co(ppz)(3)(+) in the HTL layer during the device operation.
Collapse
Affiliation(s)
- Xiaofan Ren
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | | | | | | | | | | | | |
Collapse
|
32
|
Churio MS, Brusa MA, Grela MA. Application of photoacoustic calorimetry to the determination of volume changes in reactions involving radical anions in aqueous solutions. Photochem Photobiol Sci 2003; 2:754-8. [PMID: 12911223 DOI: 10.1039/b301838e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The particular features of the application of photoacoustic calorimetry to the determination of volume changes in reactions involving radical anions in aqueous solutions are addressed. Analysis of recent literature data on volume changes of redox pairs, including our previous results on the couples NO2(-)/NO2 and SO4(2-)/(SO4)*-, together with known values of molal volume changes for ionization reactions, allow us to derive an empirical correlation for these categories of reactions. Finally, the pertinence of describing the volume changes of complex processes as a simple sum of separable terms is critically examined.
Collapse
Affiliation(s)
- María S Churio
- Departamento de Química, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 624 (7600) Mar del Plata, Argentina.
| | | | | |
Collapse
|
33
|
Dölker N, Maseras F, Lledós A. Density Functional Study on the Effect of the trans Axial Ligand of B12 Cofactors on the Heterolytic Cleavage of the Co−C Bond. J Phys Chem B 2002. [DOI: 10.1021/jp026233p] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicole Dölker
- Unitat de Química Física, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain
| | - Feliu Maseras
- Unitat de Química Física, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain
| | - Agustí Lledós
- Unitat de Química Física, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain
| |
Collapse
|
34
|
Dölker N, Maseras F, Lledós A. A Density Functional Study on the Effect of the Trans Axial Ligand of Cobalamin on the Homolytic Cleavage of the Co−C Bond. J Phys Chem B 2001. [DOI: 10.1021/jp010144f] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Nicole Dölker
- Unitat de Química Física, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain
| | - Feliu Maseras
- Unitat de Química Física, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain
| | - Agustí Lledós
- Unitat de Química Física, Edifici C.n, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain
| |
Collapse
|
35
|
Metzler DE, Metzler CM, Sauke DJ. Light and Life. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50026-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
36
|
The Gomberg century: Free radicals 1900–2000. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2001. [DOI: 10.1016/s0065-3160(01)36002-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|
37
|
Syntheses and monolayer properties of vitamin B12 derivatives with seven alkyl chains. Colloids Surf A Physicochem Eng Asp 2000. [DOI: 10.1016/s0927-7757(00)00416-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|