The photochemical and photophysical properties of the [[M3(dppm)3(CO)]] 2+ clusters (M = Pd, Pt)

This title clusters were first reported by Puddephatt and his group over 30 years ago, and their reactivity was thoroughly investigated, namely including the oxidative additions of inorganic and organic substrates and host-guest associations. Then, Mugnier and Harvey, scrutinized in large detail the rich electrochemical behaviour of the [[Pd-3(dppm)(3)(CO)]](2+) cluster, [Pd-3(2+)], namely of the reduced paramagnetic species [Pd-3(center dot+)] during the 1997-2010 period. Concurrently, Harvey and his group conducted an in depth study, starting about 2008 until now, of the rather equally rich photophysical properties of both [M-3(2+) thorn] (M = Pd, Pt) clusters. This mini-review of 39 references focusses on these properties, which have never been reviewed before. Their excited state properties such as the presence of higher and lower energy triplet excited states, triplet-triplet energy transfers in assemblies and upconversion, as well as the strong electron acceptor behaviour of [Pd-3(2+)] are discussed. Impressive ultrafast rates of electron transfer (<85 fs) between electron donors such as porphyrin and tetrabenzoporphyrin derivatives and this cluster have been reported. (C) 2018 Elsevier B.V. All rights reserved.