Jian-Xin Shi

Synthesis, redox and optical properties of low-bandgap platinum(II) polyynes with 9-dicyanomethylene-substituted fluorene acceptors

In view of the strong electron-with-drawing nature of the cyano substituent, a blue donor/acceptor-type organometallic polymer (trans-[-Pt(PBu 3 ) 2 =C≡C-R-C≡C-] n (R = 9-dicyanomethylenefluorene-2,7-diyl)) was prepared in good yield by CuI-catalyzed polymerization involving the dehydrohalogenating coupling of trans-[-Pt(PBu 3 ) 2 Cl 2 ] and H-C≡C-R-C≡C-H. The thermal, redox and photoconducting properties of the polymer are reported. Electronic absorption studies indicate that it has a bandgap of 1.58 eV which is the lowest among any of the metal polyyne polymers reported in the literature. The derivatization of the polymer backbone with electron deficient dicyano-substituted electron acceptor in the side chain is found to be effective to tune the bandgap of this class of materials while maintaining their solubility and processability.

Oligo(fluorenyleneethynylenegermylene)s and their metallopolymers

Oligo(fluorenyleneethynylenegermylene)s and their polyplatinynes are synthesized and photophysically characterized; inclusion of heavy germylene bridges greatly boosts the phosphorescence decay rate in metallopolymers.

Synthesis, structures and optical spectroscopy of photoluminescent platinum-linked poly(silylacetylenes)

Synthetic routes to a series of novel oligomeric and polymeric platinum(II)-containing silylacetylenes have been developed. The CuI-catalyzed reaction of trans-[Pt(PEt3)2PhCl] with the alkynylsilane Ph2Si(CCH)2, in a basic medium, afforded the mononuclear trans-[Ph(Et3P)2PtCCSiPh2CCH] (1) and the dinuclear trans-[Ph(Et3P)2PtCCSiPh2CCPt(PEt3)2Ph] (2). Complex 1 can be utilized as a key starting material for access to the triplatinum(II) system trans-[Ph(Et3P)2PtCCSiPh2CCPt(PBu3)2CCSiPh2CCPt(PEt3)2Ph] (3). Attempted oxidative coupling of 1 only led to the isolation of the triacetylenic species trans-[Ph(Et3P)2PtCCCCCCPt(PEt3)2Ph] (5), involving cleavage of Si–C(alkyne) bonds. Soluble and thermally stable platinum(II) poly-yne silane polymer trans-[–Pt(PBu3)2CCSiPh2CC–]n (4) was prepared in good yield by CuI-catalyzed polymerization of trans-[Pt(PBu3)2Cl2] and Ph2Si(CCH)2. The single-crystal X-ray structural analyses and DFT calculations were performed on 1, 2 and 5. We report the optical absorption and photoluminescence spectra of these new metal-based oligomeric and polymeric silylacetylenes and the results are compared with platinum(II) poly-ynes with purely acetylenic and (hetero)aromatic conjugated units.