Open AccessEnergy Dispersive XAFS: Characterization of Electronically Excited States of Copper(I) Complexes
Author(s) -
Moniek Tromp,
Andrew J. Dent,
Jon Headspith,
Timothy L. Easun,
Xue-Zhong Sun,
Michael W. George,
Olivier Mathon,
Grigory Smolentsev,
Michelle Hamilton,
John Evans
Publication year - 2013
Publication title -
the journal of physical chemistry. b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 392
eISSN - 1520-6106
pISSN - 1520-5207
DOI - 10.1021/jp4020355
Subject(s) - excited state , diimine , x ray absorption spectroscopy , x ray absorption fine structure , chemistry , copper , dihedral angle , spectroscopy , phenanthroline , absorption spectroscopy , crystallography , atomic physics , molecule , optics , physics , hydrogen bond , catalysis , biochemistry , organic chemistry , quantum mechanics
Energy dispersive X-ray absorption spectroscopy (ED-XAS), in which the whole XAS spectrum is acquired simultaneously, has been applied to reduce the real-time for acquisition of spectra of photoinduced excited states by using a germanium microstrip detector gated around one X-ray bunch of the ESRF (100 ps). Cu K-edge XAS was used to investigate the MLCT states of [Cu(dmp)2](+) (dmp =2,9-dimethyl-1,10-phenanthroline) and [Cu(dbtmp)2](+) (dbtmp =2,9-di-n-butyl-3,4,7,8-tetramethyl-1,10-phenanthroline) with the excited states created by excitation at 450 nm (10 Hz). The decay of the longer lived complex with bulky ligands, was monitored for up to 100 ns. DFT calculations of the longer lived MLCT excited state of [Cu(dbp)2](+) (dbp =2,9-di-n-butyl-1,10-phenanthroline) with the bulkier diimine ligands, indicated that the excited state behaves as a Jahn-Teller distorted Cu(II) site, with the interligand dihedral angle changing from 83 to 60° as the tetrahedral coordination geometry flattens and a reduction in the Cu-N distance of 0.03 Å.