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Mechanism of Formation of Copper(II) Chloro Complexes Revealed by Transient Absorption Spectroscopy and DFT/TDDFT Calculationsстатья
- Авторы: Mereshchenko Andrey S., Olshin Pavel K., Karabaeva Kanykey E., Panov Maxim S., Wilson R.Marshall, Kochemirovsky Vladimir A., Skripkin Mikhail Yu, Tveryanovich Yury S., Tarnovsky Alexander N.
- Журнал: Journal of Physical Chemistry B
- Том: 119
- Номер: 28
- Год издания: 2015
- Издательство: American Chemical Society
- Местоположение издательства: United States
- Первая страница: 8754
- Последняя страница: 8763
- DOI: 10.1021/acs.jpcb.5b03889
- Аннотация: Copper(II) complexes are extremely labile with typical ligand exchange rate constants on the order of 106-109 M-1 s-1. As a result, it is often difficult to identify the actual formation mechanism of these complexes. In this work, using UV-vis transient absorption when probing in a broad time range (20 ps to 8 μs) in conjunction with DFT/TDDFT calculations, we studied the dynamics and underlying reaction mechanisms of the formation of extremely labile copper(II) CuCl42- chloro complexes from copper(II) CuCl3- trichloro complexes and chloride ions. These two species, produced via photochemical dissociation of CuCl42- upon 420 nm excitation into the ligand-to-metal-charge-transfer electronic state, are found to recombine into parent complexes with bimolecular rate constants of (9.0 ± 0.1) × 107 and (5.3 ± 0.4) × 108 M-1 s-1 in acetonitrile and dichloromethane, respectively. In dichloromethane, recombination occurs via a simple one-step addition. In acetonitrile, where [CuCl3]- reacts with the solvent to form a [CuCl3CH3CN]- complex in less than 20 ps, recombination takes place via ligand exchange described by the associative interchange mechanism that involves a [CuCl4CH3CN]2- intermediate. In both solvents, the recombination reaction is potential energy controlled.
- Добавил в систему: Кочемировский Владимир Алексеевич