Open AccessElectron delocalization in the S 1 and T 1 metal-to-ligand charge transfer states of trans -substituted metal quadruply bonded complexes
Author(s) -
Brian G. Alberding,
Malcolm H. Chisholm,
Judith C. Gallucci,
Yagnaseni Ghosh,
Terry L. Gustafson
Publication year - 2011
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.1103082108
Subject(s) - delocalized electron , singlet state , chemistry , ligand (biochemistry) , metal , crystallography , charge (physics) , spectroscopy , photochemistry , atomic physics , excited state , physics , biochemistry , receptor , organic chemistry , quantum mechanics
The singletS 1 and tripletT 1 photoexcited states of the compounds containing MM quadruple bondstrans -M2 (Ti PB)2 (O2 CC6 H4 -4-CN)2 , where Ti PB = 2,4,6-triisopropylbenzoate and M = Mo (I ) or M = W (I ′ ), andtrans -M2 (O2 CMe)2 ((N[i Pr ])2 CC ≡ CC6 H5 )2 , where M = Mo (II ) and M = W (II ′ ), have been investigated by a variety of spectroscopic techniques including femtosecond time-resolved infrared spectroscopy. The singlet states are shown to be delocalized metal-to-ligand charge transfer (MLCT) states forI andI ′ but localized forII andII ′ involving the cyanobenzoate or amidinate ligands, respectively. The triplet states are MoMoδδ * for bothI andII but delocalized3 MLCT forI ′ and localized3 MLCT forII ′ . These differences arise from consideration of the relative orbital energies of the M2 δ or M2 δ * and the ligandπ ∗ as well as the magnitudes of orbital overlap.