Synthesis, spectroscopic characterization, thermal and luminescent properties of new organosulfur-functionalized platinum(II) bis(alkenylarylalkynyl) complexes

Abstract

A series of organosulfur-functionalized trans-platinum(II) bis(alkenylarylalkynyl) complexes, having one tolylthio moiety in each alkenyl backbone with general formula trans-[(PEt3)2Pt{CC-Ar-CHCH(SC6H4CH3)}2], (2a–2d), (where, Ar = phenylene, biphenylene, 2,5-dimethylphenylene, and 2,5-dimethoxyphenylene) were synthesized in good to excellent yields with good regioselectivity. As compared to the absorption band of trans-platinum(II) bis(alkynylarylalkynyl) complexes, we found that the position of the lowest energy absorption bands in the trans-platinum(II) bis(alkenylarylalkynyl) complexes were red-shifted, after the functionalization of the trans-platinum(II) bis(alkynylarylalkynyl) complexes with arylthiol. For all trans-platinum(II) complexes, the lowest energy absorption bands in the UV/Vis spectra, in chloroform solution, at room temperature, were observed in the range 362–394 nm, and under excitation at the wavelength of the absorption maximum exhibited the emission peak maximum at room temperature in the range 401–426 nm. The newly synthesized complexes are not exhibited phosphorescence at room temperature but are exhibited at low temperature, 77 K. All the new platinum(II) complexes have been fully characterized by spectroscopic analysis as well as elemental analysis, and the trans square-planar arrangement at the platinum centre has been confirmed by single-crystal X-ray diffraction study of complex 2a.