Synthesis, Characterization and Photophysical Properties of Metallopolyynes and Metallodiynes of Platinum(II) with Dibenzothiophene Derivatives

Soluble, thermally stable, and easily processable platinum(II) polyyne polymers of the form trans -[–Pt(PBu 3 ) 2 C≡CRC≡C–] n (R = 2,8-disubstituted dibenzothiophene, 2,8-disubstituted and 3,7-disubstituted dibenzothiophene- S , S -dioxide units) have been prepared in good yields by CuI-catalyzed polymerization involving the dehydrohalogenating coupling of trans -[PtCl 2 (PBu 3 ) 2 ] and HC≡CRC≡CH. We report their optical absorption and photoluminescence spectra and compare the results with the monomeric model complexes trans -[Pt(Ph)(PEt 3 ) 2 C≡CRC≡CPt(Ph)(PEt 3 ) 2 ]. The different electronic properties and linkage geometry of the central R group lead to new organometallic materials with distinct photophysical traits. The polymer with more conjugated 3,7-disubstituted dibenzothiophene- S , S -dioxide mainly displays fluorescence band, while its isomer with less conjugated 2,8-disubstituted spacer effectively enhances the intersystem crossing rate and strong phosphorescence emission can be detected even at room temperature.