Photoluminescence of Tetranuclear Mercury(II) Complexes

The complexes [Hg4(SPh)6(PPh3)4]2+ and [Hg(2-pyridylphenyl)Cl]4 show an intense low-temperature (77 K) phosphorescence at λmax=690 and 500 nm. This emission is assumed to originate from a metal-centered ds excited state which contains considerable ligand-to-metal charge transfer character

Photolysis of methylcobalamin. Nature of the reactive excited state

Photolysis of methylcobalamin (Co(III)corrin(CH3)L + H2O + O2 �> Co(III)(H2O)L + H2CO + OH-) shows a pronounced wave-length dependence. It is suggested that the reactive excited state is of the ligand-to-ligand charge transfer (LLCT) type and involves the promotion of an electron from the Co-C sigma-bond to a pi*(corrin) orbital. This LLCT transition mixes with the pipi*(corrin) transitions. Owing to this LLCT contribution, the pipi*-absorption bands are also photoactive but with reduced efficiency

Photochemistry of Coordination Compounds of the Main Group Metals

A general concept is developed which relates characteristics excited states of main group metal complexes to typical photoreactions. With regard to their electronic spectra and photochemistry the main group metals are classified according to their ground state electron configuration nsxnpy. The photochemistry is generally dominated by the reactivity of metal-centered sp and ligand to metal charge transfer excited states which in most cases initiate inter- and intramolecular photoredox processes

Electronic Spectra and Photochemistry of Coordinated Astaxanthin

Astaxanthin (AXT) is a natural carotenoid which provides colorations to numerous living species such as salmon. Owing to its chelate function deprotonated astaxanthin (axt − ) should be easily attached to metal ions. The complex Rh III (phpy) 2 (axt) with phpy − = deprotonated 2-phenylpyridine was prepared, and its electronic spectra and photochemistry were examined and compared to that of free AXT. Although different in detail, the spectra and photochemistry of AXT and R