Synthesis?structures And Properties Of Silver Complexs Based On Photochromic Ligands Containning Cyanide Groups

Dithienylethene is recognized as the most likely practical optical storage material because of the excellent photochromic properties,characteristic thermal stability,sensitive response and good fatigue resistance.From the crystal engineering,when the metal ions are coordinated to dithienylethene compounds,complexes can possess new photophysical and photochemical properties maintaining the original photochromic properties.This new method opened up a new thought for the practical application of organic photochromic materials.In this paper,three kinds of photochromic dithienylethene compounds were synthesized or chosen as ligand,namely cis-1,2-Dicyano-1,2-bis-(2,4,5-trimethyl-3-thienyl)ethene(abbreviation:cis-dbe);1,2-bis-[2-methy-5-(3-cyanophenyl)-3-thiehyl]perfluorocyolopentene(ab breviation:BM-3-CP-3-TP);1,2-bis-[2-methy-5-(4-cyanophenyl)-3-thiehyl]perfluorocyolopente ne(abbreviation:BM-4-CP-3-TP).Self-assembly of these ligands with AgX(X = CF3COO-or BF4-)had gave rise to three new photochromic complexes 1,2 and 3.The crystal structures of BM-3-CP-3-TP and 1 had been investigated by X-ray crystallographic analysis.The structures of Complexes 2 and 3 had been investigated by infrared spectra.The photochromic properties of these complexes were studied by ultraviolet-visible spectrometry in solid phase,solution and PMMA film,respectively.And their fatigue resistances were studied in PMMA film.The main conclusions are concluded as follows:(1)X-ray single crystal diffraction analysis results show complexl is a monodentate binuclear complex.The BF4-anion is not coordinating to Ag+,but as counter-ions trapped in the sides of the cationic framework.The coordination of silver ion is five-coordinated trigonal bipyramid geometry.The ligand is fixed in the cis configuration because of silver ions coordination.The reaction of carbon distance is 3.46A,and the two thiophene rings is antiparallel configuration.(2)The position of cyano in photochromic compounds has an important influence to form photochromic metal complexes.Para-substituted cyano is easier to form complexes than meta-substituted cyano.(3)The X-ray single crystal diffraction analysis results show that the reaction of carbon distance is 3.56 A and the configuration of two thiophene rings is antiparallel in BM-3-CP-3-TP.The 1HNMR shows that the closed form of BM-3-CP-3-TP is primary in static state.This implies that the quantity rate of BM-3-CP-3-TP is close to 1 in liquid.(4)The ultraviolet-visible spectra show that the cmplex1,2 and 3 have reversible photochromic properties in solution and PMMA film,and may have favorable fatigue resistance in PMMA film.This imply that the introduction of metal ions don't suppress or inhibit the photochromic properties of lignands.