Electron transfer (ET) from donor to acceptor is often mediated by nuclear-electronic (vibronic) interactions in molecular bridges. Using an ultrafast electronic-vibrational-vibrational pulse-sequence, we demonstrate how the outcome of light-induced ET can be radically altered by mode-specific infrared (IR) excitation of vibrations that are coupled to the ET pathway. Picosecond narrow-band IR excitation of high-frequency bridge vibrations in an electronically excited covalent trans -acetylide platinum(II) donor-bridge-acceptor system in solution alters both the dynamics and the yields of competing ET pathways, completely switching a charge separation pathway off. These results offer a step toward quantum control of chemical reactivity by IR excitation.

Complexes containing the humble 1,2,3-triazole ring moiety have enabled access to highly tunable with efficient phosphorescence but have also in facilitated access to novel photoreactive excited states yielding highly unusual photochemical reactivity.

The series of osmium(ii) complexes [Os(bpy)_3−n(btz)_n][PF₆]₂(bpy = 2,2′-bipyridyl, btz = 1,1′-dibenzyl-4,4′-bi-1,2,3-triazolyl,1 n= 0,2 n= 1,3 n= 2,4 n= 3), have been prepared, characterised and used as phosphors within light-emitting electrochemical cells.