Synthesis, characterization, luminescence and non-linear optical properties of diimine platinum(II) complexes with arylacetylene ligands

A series of platinum(II) complexes (diimine)Pt(CCR)2, where diimine is 2,2′-bipyridine (bpy) or 4,4′-bis(tert-butyl)-2,2′-bipyridine (dtbpy) and alkynyl ligand is biphenylacetylide or terphenylacetylide, were synthesized and their photophysical and non-linear optical properties were investigated. All compounds (1–3) were characterized using NMR spectroscopy, ESI mass-spectrometry and elemental analysis. X-Ray crystal structure of the complex containing 4,4′-bis(tert-butyl)-2,2′-bipyridine and terphenylacetylide ligands is reported. The electronic absorption and emission spectra of the complexes have been studied. Room temperature phosphorescence was observed for the complexes in solution with the luminescence quantum yield in the 7.5–11% range and excited state lifetimes in microsecond time domain. All complexes under study exhibit two-photon luminescence and their double quantum absorption cross-section was found to be in the 9–22 GM range.