title: Synthesis, structure and photophysical properties of a flavin-based platinum(II) complex.
abstract: 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 PtS(2)N(2) planar 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 (1)π-π* emission state.
authors.affiliation: Division of Chemistry, Faculty of Science, Hokkaido University, North-10 West-8, Sapporo 060-0810, Japan. akoba@sci.hokudai.ac.jp
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Korin
authors.initials: K
authors.lastname: Ohbayashi
authors.forename: Rie
authors.initials: R
authors.lastname: Aoki
authors.forename: Ho-Chol
authors.initials: HC
authors.lastname: Chang
authors.forename: Masako
authors.initials: M
authors.lastname: Kato
mesh_terms: D000042:Absorption; D018360:Crystallography, X-Ray; D005415:Flavins / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D009944:Organoplatinum Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014961:X-Ray Diffraction
chemical_list: C559360:2-(2-(3,4-dihydro-7,8-dimethyl-2,4-dioxobenzo(g)pteridin-10(2H)-yl)ethylidene)-hydrazinecarbothioamide Pt(II); D005415:Flavins; D008024:Ligands; D009944:Organoplatinum Compounds