Yang F, Zhao J, Wang J. Two-Dimensional Infrared Study of (13)C-Natural Abundant Vibrational Transition Reveals Intramolecular Vibrational Redistribution Rather than Fluxional Exchange in Mn(CO)5Br.
J Phys Chem B 2016;
120:1304-11. [PMID:
26836759 DOI:
10.1021/acs.jpcb.5b11310]
[Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this work, molecular-symmetry enhanced (13)CO natural abundant isotopic infrared transition was identified in Mn(CO)5Br dissolved in CCl4 by FTIR spectroscopy. Diagonal and associated off-diagonal two-dimensional IR (2D IR) peaks of the (13)CO-species were found to be spectrally separated from the all-(12)CO species, allowing a direct probe of the (13)C natural abundant ensemble. Temperature-dependent FTIR experiment showed no evidence of ligand exchange in the metal carbonyl complex. Intramolecular vibrational redistribution dynamics among the CO stretching vibrational states were extracted using population-time dependent 2D IR diagonal and off-diagonal peaks for both radial mono-(13)CO and all-(12)CO isotopomers. This work demonstrates the potential use of natural abundant isotopic molecular species as a probe for revealing equilibrium and nonequilibrium structural dynamics in condensed-phase molecular systems.
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