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Mascarenhas EJ, Fondell M, Büchner R, Eckert S, Vaz da Cruz V, Föhlisch A. Photo-Induced Ligand Substitution of Cr(CO) 6 in 1-Pentanol Probed by Time Resolved X-Ray Absorption Spectroscopy. Phys Chem Chem Phys 2022; 24:17979-17985. [PMID: 35737440 PMCID: PMC9348521 DOI: 10.1039/d1cp05834g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cr(CO)6 was investigated by X-ray absorption spectroscopy. The spectral signature at the metal edge provides information about the back-bonding of the metal in this class of complexes. Among the processes it participates in is ligand substitution in which a carbonyl ligand is ejected through excitation to a metal to ligand charge transfer (MLCT) band. The unsaturated carbonyl Cr(CO)5 is stabilized by solution media in square pyramidal geometry and further reacts with the solvent. Multi-site-specific probing after photoexcitation was used to investigate the ligand substitution photoreaction process which is a common first step in catalytic processes involving metal carbonyls. The data were analysed with the aid of TD-DFT computations for different models of photoproducts and signatures for ligand rearrangement after substitution were found. The rearrangement was found to occur in about 790 ps in agreement with former studies of the photoreaction. The photo-induced ligand substitution reaction of Cr(CO)6 in 1-pentanol was investigated using time-resolved X-ray absorption spectroscopy. The results point to ligand rearrangement after photoexcitation.![]()
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Affiliation(s)
- Eric J Mascarenhas
- Universität Potsdam, Institut für Physik und Astronomie, 14476 Potsdam, Germany.
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
| | - Mattis Fondell
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
| | - Robby Büchner
- Universität Potsdam, Institut für Physik und Astronomie, 14476 Potsdam, Germany.
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
| | - Sebastian Eckert
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
| | - Vinícius Vaz da Cruz
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
| | - Alexander Föhlisch
- Universität Potsdam, Institut für Physik und Astronomie, 14476 Potsdam, Germany.
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Methods and Instrumentation for Synchrotron Radiation Research, 12489 Berlin, Germany
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Thapa Magar R, Breen DJ, Schrage BR, Ziegler CJ, Rack JJ. Slow 3MLCT Formation Prior to Isomerization in Ruthenium Carbene Sulfoxide Complexes. Inorg Chem 2021; 60:16120-16127. [PMID: 34672621 DOI: 10.1021/acs.inorgchem.1c01558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of photochromic complexes with general formulas of [Ru(bpy)2(NHC-SR)]2+ and [Ru(bpy)2(NHC-S(O)R)]2+ were prepared and investigated by X-ray crystallography, electrochemistry, and ultrafast transient absorption spectroscopy {where bpy is 2,2'-bipyridine and NHC-SR and NHC-S(O)R are chelating thioether (-SR) and chelating sulfoxide [-S(O)R] N-heterocyclic carbene (NHC) ligands}. The only differences between these complexes are the nature of the R group on the sulfur (Me vs Ph), the identity of the carbene (imidazole vs benzimidazole), and the number of linker atoms in the chelate (CH2 vs C2H4). A total of 13 structures are presented {four [Ru(bpy)2(NHC-SR)]2+ complexes, four [Ru(bpy)2(NHC-S(O)R)]2+ complexes, and five uncomplexed ligands}, and these reveal the expected coordination geometry as predicted from other spectroscopy data. The data do not provide insight into the photochemical reactivity of these compounds. These carbene ligands do impart stability with respect to ground state and excited state ligand substitution reactions. Bulk photolysis reveals that these complexes undergo efficient S → O isomerization, with quantum yields ranging from 0.24 to 0.87. The excited state reaction occurs with a time constant ranging from 570 ps to 1.9 ns. Electrochemical studies reveal an electron transfer-triggered isomerization, and voltammograms are consistent with an ECEC (electrochemical-chemical electrochemical-chemical) reaction mechanism. The carbene facilitates an unusually slow S → O isomerization and an unusally fast O → S isomerization. Temperature studies reveal a small and negative entropy of activation for the O → S isomerization, suggesting an associative transition state in which the sulfoxide simply slides along the S-O bond during isomerization. Ultrafast studies provide evidence of an active role of the carbene in the excited state dynamics of these complexes.
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Affiliation(s)
- Rajani Thapa Magar
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87111, United States
| | - Douglas J Breen
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87111, United States
| | - Briana R Schrage
- Knight Chemical Laboratory, Department of Chemistry, University of Akron, Akron, Ohio 44312-3601, United States
| | - Christopher J Ziegler
- Knight Chemical Laboratory, Department of Chemistry, University of Akron, Akron, Ohio 44312-3601, United States
| | - Jeffrey J Rack
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87111, United States
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Intramolecular exchange of coordinated and dangling phosphines in pentacarbonyl group 6 complexes of 1,1,2-tris(diphenylphosphino)ethane. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2010.08.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Shagal A, Schultz RH. Steric and Electronic Effects in Linkage Isomerization Reactions of M(CO)5(L) (M = Cr, Mo, W; L = 2-methyl-2,3-dihydrofuran, 2,3-dihydropyran). Organometallics 2007. [DOI: 10.1021/om700456x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Shagal
- Department of Chemistry, Bar-Ilan University, 52900 Ramat-Gan, Israel
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Butler JM, George MW, Schoonover JR, Dattelbaum DM, Meyer TJ. Application of transient infrared and near infrared spectroscopy to transition metal complex excited states and intermediates. Coord Chem Rev 2007. [DOI: 10.1016/j.ccr.2006.12.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Biber L, Reuvenov D, Revzin T, Sinai T, Zahavi A, Schultz RH. Reactions of the transient species Cr(CO)5(cyclohexane) with C4HnE (n = 4, 8; E = O, NH, S) studied by time-resolved IR absorption spectroscopy. Dalton Trans 2007:41-51. [PMID: 17160173 DOI: 10.1039/b612902a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved IR absorption spectroscopy is used to investigate substitution of the cyclohexane (CyH) molecule of the photolytically generated alkane-solvated transient intermediate Cr(CO)5(CyH) by heterocyclic ligands C4HnE (n=4, 8; E=O, NH, S). From the concentration and temperature dependences of the pseudo-first order rate constants, we obtain activation parameters for the reactions, and find that they are consistent with an associative (A) or interchange (I) mechanism. As was the case with ligand substitution reactions at W(CO)5(CyH), a ligand's reactivity depends both on its electron-donating ability and on its polarizability. We also find that for a reaction with a given DeltaH, the activation entropy is higher for reaction of Cr(CO)5(CyH) than it is for reaction of W(CO)5(CyH). Comparison of the present results with ligand substitution reactions of W(CO)5(CyH), CpMn(CO)2(CyH), and Cr(CO)5(n-heptane) indicates that for ligand substitution reactions at alkane-solvated transition-metal intermediates, the solvent's effect upon the reaction rate is primarily entropic.
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Affiliation(s)
- Lena Biber
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 52900, Israel
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Shanoski JE, Glascoe EA, Harris CB. Ligand Rearrangement Reactions of Cr(CO)6 in Alcohol Solutions: Experiment and Theory. J Phys Chem B 2005; 110:996-1005. [PMID: 16471634 DOI: 10.1021/jp055636x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ligand rearrangement reaction of Cr(CO)6 is studied in a series of alcohol solutions using ultrafast infrared spectroscopy and Brownian dynamics simulations. Excitation with 266 nm light gives Cr(CO)5 which is quickly solvated by a ligand from the bath. In alcohol solutions, solvation by an alkyl or hydroxyl site can occur; all alkyl bound complexes eventually rearrange to hydroxyl bound complexes. This rearrangement has been described using both an intermolecular (stochastic) and intramolecular (chainwalk) mechanism. Experiments alone do not allow for characterization of the mechanism, and therefore, theoretical calculations were carried out for the first time by modeling the ligand rearrangement as a diffusive walk along a potential defined by the different interaction possibilities. Experiments and simulations were carried out for Cr(CO)6 in 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 2-methylbutanol, and 3-methylbutanol. The trends in the theoretical and experimental rearrangement times are similar for all simulations carried out indicating that the two mechanisms have very similar ensemble behavior when bath effects are taken into account. The nature of the mechanism responsible for motion along the alcohol chain is not of primary importance in isolating the kinetic behavior because of the highly diffusive nature of the reaction. Future experimental and theoretical work will be directed at identifying a definitive assignment of the reaction mechanism.
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Affiliation(s)
- Jennifer E Shanoski
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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Snively CM, Pellerin C, Rabolt JF, Chase DB. Acquisition of mid-infrared spectra from nonrepeatable events with sub-100-micros temporal resolution using planar array infrared spectroscopy. Anal Chem 2005; 76:1811-6. [PMID: 15053637 DOI: 10.1021/ac0499118] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel method is presented that is capable of collecting time-resolved vibrational spectroscopic information with sub-100-micros temporal resolution. Unlike previous step scan FT-IR approaches, the phenomena under study do not necessarily need to be repeatable. The methodology described herein is based on the planar array infrared (PA-IR) technique, which utilizes a spectrograph for wavelength dispersion and a mid-infrared focal plane array (FPA) detector for simultaneous detection of multiple wavelengths. Unlike previous PA-IR approaches, a rolling mode FPA is employed. This unique data readout mode, where data are read out of the array two rows at a time, is exploited to generate increased temporal resolution. The capabilities of this technique are demonstrated using the example of the electric field-induced Freedericksz transition of a nematic liquid crystal. It is shown that the orientational dynamics of a single transition can be tracked over a spectral range of 154 cm(-)(1) with a temporal resolution of 99.17 micros while requiring a total experimental time of less than 1 s.
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Affiliation(s)
- Christopher M Snively
- Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA.
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Schultz RH. Reactions of the Transient Species W(CO)5(Cyclohexane) with Thiophene and Tetrahydrothiophene Studied by Time-Resolved Infrared Absorption Spectroscopy. Organometallics 2004. [DOI: 10.1021/om049588z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lugovskoy A, Shagal A, Lugovskoy S, Huppert I, Schultz RH. Reaction of the Transient Species W(CO)5(Cyclohexane) with Pyrrolidine and with Pyrrole. Organometallics 2003. [DOI: 10.1021/om0300530] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alex Lugovskoy
- Department of Chemistry, Bar-Ilan University, 52900 Ramat-Gan, Israel
| | - A. Shagal
- Department of Chemistry, Bar-Ilan University, 52900 Ramat-Gan, Israel
| | - S. Lugovskoy
- Department of Chemistry, Bar-Ilan University, 52900 Ramat-Gan, Israel
| | - Ilan Huppert
- Department of Chemistry, Bar-Ilan University, 52900 Ramat-Gan, Israel
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