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Studies the temperature dependence of both emission spectrum and crystal structure of a liner-chain platinum complex. Correlation of the luminescence emission spectrum and the Pt---Pt distance for the platinum(II) complex; Behavior the platinum complex crystal; Pi-pi interactions of the complex.

Reports on the preparation of three platinum(II) complexes and their x-ray crystal structures and luminescence properties. Synthesis; Solution and refinement of structures; Physical measurements; Structural description; Emission and absorption properties.

We synthesized a novel Pt(II)--diimine complex with a typical ambidentate thiocyanato ligand, [Pt(thiocyanato)2(H2dcbpy)] (1j H2dcbpy =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 [PtCl2(H2dcbpy)] and KSCN in aqueous solution at 0 °C enabled successful isolation of an isomer with the S-coordinated thiocyanato ligand, [Pt(SCN)2(H2dcbpy)] (1SS·H2O), as a nonluminescent orange solid, Interestingly, 1SS·H2O was isomerized completely to one isomer with the N-coordinated isothiocyanato ligand, [Pt(NCS)2(H2dcbpy)] (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)(H2dcbpy)] (1SN), was obtained as a nonluminescent yellow solid simply by exposure of 1SS·H2O to acetone vapor at room temperature, and about 80% of 1SS&niddot;H2O was found to be converted to ISN. In the solution state, each isomer changed gradually to an isomeric mixture, but pure 1SS was regenerated by UV light irradiation (λirr = 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 H2dcbpy 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 abihty among the carboxyl groups of the H2dcbpy 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 sTvitching function driven by vapor molecules. [ABSTRACT FROM AUTHOR]

The neutral square-planar complexes [Pt(RN)2)2(NHCOtBu)2] (R = H, 1; Et, 2) and [Pt(DACH)(NHCOtBu)2] (DACH = 1,2-diaminocyclohexane, 3) act as metalloligands and make bonds to closed-shell Tl(l) ions to afford one- and two-dimensional platinum-thallium oligomers or polymers based on heterobimetallic backbones. A series of heteronuclear platinum(II)-thallium(l) complexes have been synthesized and structurally characterized. The structures of the Pt-TI compounds resulted from [Pt(RN)2)2(NHCOtBu)2] and TIX [X = NO3-, ClO4-, PF6-, and Cp2Fe(Co2)22-] are dependent on both counteranions and the amine substituents. The compounds [Pt(NH3)2(NHCOtBu)2TI]+ (X = NO3, 8; ClO4-, 9) adopt one-dimensional zigzag chain structures consisting of repeatedly stacked [Pt(NH3)2-(NHCOtBu)2TI]+ units, whereas [{Pt(NH3)2(NHCOtBu)2}2TI2]X2 (X = PF6-, 10) consists of a helical chain. Compound 3 reacts with TI+ to give [{Pt(DACH)(NHCOtBu)2}2TI](NO3)-[Pt(DACH)(NHCOtBu)2]·3H2O (14) and one-dimensional polymeric [{Pt(DACH)(NHCOtBu)2}2TI2]X2 (X = ClO4-, 15; PF6-, 16). Reactions of [Pt(DACH)(NHCOCH3)2) with TI+ ions afford one-dimensional coordination polymers [{Pt(DACH)(NHCOCH3)2}2TI2]X2 (X = NO3-, 17; ClO4-, 18; PF6-, 19). The polymeric [{Pt(DACH)(NHCO′)2}TI2]2+ (R = CH3, tBu) complexes adopt helical structures, which are generated around the crystallographic 2 screw axis. The distance between the coils corresponds to the unit cell length, which ranges from 22.58 to 22.68 Å. The platinum-thallium bond distances fall in a narrow range around 3.0 Å. The complexes derived from [Pt(NH3)2(NHCOtBu)2] are luminescent at 77 K. The trinuclear complexes [{Pt(RN)2)(NHCOtBu)2}2TI]+ do not emit at room temperature but are emissive at 77 K, whereas the polymeric platinum-thallium complexes containing 1 ,2-diaminocyclohexane are intensively luminescent at both room temperature and 77 K. The color variations are interesting; 15 exhibits intense yellow-green, 16 exhibits green, and 17-19 exhibit blue luminescence. The presence of bonding between platinum and thallium is supported by the short metal-metal separations and the strong low-energy luminescence of these compounds in their solid states. [ABSTRACT FROM AUTHOR]