UV-visible spectroscopy of macrocyclic alkyl, nitrosyl and halide complexes of cobalt and rhodium. Experiment and calculation

作者：Hull Emily A; West Aaron C; Pestovsky Oleg; Kristian Kathleen E; Ellern Arkady; Dunne James F; Carraher Jack M; Bakac Andreja^*; Windus Theresa L

来源：Dalton Transactions, 2015, 44(8): 3811-3816.

DOI：10.1039/c4dt03143a

Transition metal complexes (NH3)(5)CoX2+ (X = CH3, Cl) and L(H2O)MX2+, where M = Rh or Co, X = CH3, NO, or Cl, and L is a macrocyclic N-4 ligand are examined by both experiment and computation to better understand their electronic spectra and associated photochemistry. Specifically, irradiation into weak visible bands of nitrosyl and alkyl complexes (NH3)(5)CoCH32+ and L(H2O)(MX2+)-X-III (X = CH3 or NO) leads to photohomolysis that generates the divalent metal complex and (CH3)-C-center dot or (NO)-N-center dot, respectively. On the other hand, when X = halide or NO2, visible light photolysis leads to dissociation of X-and/or cis/trans isomerization. Computations show that visible bands for alkyl and nitrosyl complexes involve transitions from M-X bonding orbitals and/or metal d orbitals to M-X antibonding orbitals. In contrast, complexes with X = Cl or NO2 exhibit only d-d bands in the visible, so that homolytic cleavage of the M-X bond requires UV photolysis. UV-Vis spectra are not significantly dependent on the structure of the equatorial ligands, as shown by similar spectral features for (NH3)(5)CoCH32+ and L-1(H2O)CoCH32+.

• 出版日期2015