| Title: | Vapor-controlled linkage isomerization of a vapochromic bis(thiocyanato)platinum(II) complex: new external stimuli to control isomerization behavior |
| Author(s): | Kobayashi A; Fukuzawa Y; Chang HC; Kato M; |
| Address: | "Division of Chemistry, Faculty of Science, Hokkaido University, North-10 West-8, Kita-ku, Sapporo 060-0810, Japan. akoba@sci.hokudai.ac.jp" |
| ISSN/ISBN: | 1520-510X (Electronic) 0020-1669 (Linking) |
| Abstract: | "We synthesized a novel Pt(II)-diimine complex with a typical ambidentate thiocyanato ligand, [Pt(thiocyanato)(2)(H(2)dcbpy)] (1; H(2)dcbpy =4,4'-dicarboxy-2,2'-bipyridine), and found that the complex 1 exhibits unique linkage isomerizations with drastic color and luminescence changes driven by exposure to volatile organic chemical (VOC) vapors in the solid state. Reaction between [PtCl(2)(H(2)dcbpy)] and KSCN in aqueous solution at 0 degrees C enabled successful isolation of an isomer with the S-coordinated thiocyanato ligand, [Pt(SCN)(2)(H(2)dcbpy)] (1SS.H(2)O), as a nonluminescent orange solid. Interestingly, 1SS.H(2)O was isomerized completely to one isomer with the N-coordinated isothiocyanato ligand, [Pt(NCS)(2)(H(2)dcbpy)] (1NN.3DMF) by exposure to DMF vapor, and this isomerization was accompanied by significant color and luminescence changes from nonluminescent orange to luminescent red. IR spectroscopy and thermogravimetric analysis revealed that adsorption of the DMF vapor and transformation of the hydrogen-bonded structure both played important roles in this vapor-induced linkage isomerization. Another isomer containing both S- and N-coordinated thiocyanato ligands, [Pt(SCN)(NCS)(H(2)dcbpy)] (1SN), was obtained as a nonluminescent yellow solid simply by exposure of 1SS.H(2)O to acetone vapor at room temperature, and about 80% of 1SS.H(2)O was found to be converted to 1SN. In the solution state, each isomer changed gradually to an isomeric mixture, but pure 1SS was regenerated by UV light irradiation (lambda(irr.) = 300 nm) of an MeOH solution of the mixture. In the crystal structure of 1SN, the complex molecules were hydrogen-bonded to each other through the carboxyl groups of the H(2)dcbpy ligand and the N site of the thiocyanato ligand, whereas the 1NN molecules in the 1NN.4DMF crystal were hydrogen-bonded to the solvated DMF molecules. Competition of the hydrogen-bonding ability among the carboxyl groups of the H(2)dcbpy ligand, N and S atoms of the thiocyanato ligand, and the vapor molecule was found to be one of the most important factors controlling linkage isomerization behavior in the solid state. This unique linkage isomerization controlled by vapor can provide an outstanding vapochromic system as well as a new molecular switching function driven by vapor molecules" |
| Keywords: | "Crystallography, X-Ray Ligands Models, Molecular Molecular Structure Organoplatinum Compounds/chemical synthesis/*chemistry Stereoisomerism Thiocyanates/*chemistry Volatilization;" |
| Notes: | "MedlineKobayashi, Atsushi Fukuzawa, Yuki Chang, Ho-Chol Kato, Masako eng Research Support, Non-U.S. Gov't 2012/06/28 Inorg Chem. 2012 Jul 16; 51(14):7508-19. doi: 10.1021/ic202734f. Epub 2012 Jun 26" |
