Synthesis, structure and photophysical properties of a flavin-based platinum(ii) complexElectronic supplementary information (ESI) available: Emission lifetime decay profiles, cyclic voltamograms and the shapes of the HOMO-1 of Fl-(H)TSC and [Pt(Fl–TSC)2]. CCDC reference numbers 790484–790485. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c0dt01139h

We synthesized a thiosemicarbazone-functionalized flavin (Fl-(H)TSC: 2-[2-(3,4-dihydro-7,8-dimethyl-2,4-dioxobenzo[g]pteridin-10(2H)-yl)ethylidene]-hydrazinecarbothioamide) and its Pt(ii) complex [Pt(Fl-TSC)2], and characterized it using X-ray diffraction, UV–visible absorption and luminescence spectroscopy. X-ray structural analysis for [Pt(Fl-TSC)2] revealed that the structure of the isoalloxazine part was almost the same as that in lumiflavin (7,8,10-trimethylisoalloxazine), and the thiosemicarbazone moiety acted as a bidentate ligand to form a PtS2N2planar conformation. UV–visible absorption and luminescence spectra of these compounds were very similar to those of riboflavin, but the emission intensity and the lifetime decreased considerably. Theoretical calculations suggested that the charge-separated state (Fl−-TSC+) contributed to the faster quenching from the 1π–π* emission state. [ABSTRACT FROM AUTHOR]