Chromic triboluminescence of self-assembled platinum(II) complexes.

A series of Pt(II) complexes bearing N-heterocyclic carbenes, [Pt(CN)(Rim-Mepy)] (Rim-MepyH = 3-alkyl-1-(4-methyl-(2-pyridinyl))-1-imidazolium, R = Me, Et, Pr, or Bu), exhibits triboluminescence in the visible range from blue to red, as well as the corresponding intense photoluminescence. Remarkably, among the complexes, the Pr-substituted one exhibits chromic triboluminescence behaviour during the process of rubbing and also vapour exposure.