Synthesis, structures and photoluminescence behavior of some group 10 metal alkynyl complexes derived from 3-(N-carbazolyl)-1-propyne

A new class of luminescent and thermally stable mononuclear group 10 platinum(II) and palladium(II) acetylides trans-[Pt(PR3)2(L)2] (R = Bu, Et) and trans-[Pd(PBu3)2(L)2] (LH = 3-(N-carbazolyl)-1-propyne) have been successfully synthesized and characterized. The structural properties of these discrete metal complexes have been studied by X-ray crystallography. We report their optical absorption and photoluminescence spectra and interpret the results in terms of the nature of the metal center and the type of phosphines used. Our investigations indicate that they display heavy metal-enhanced phosphorescence bands at 77 K and we find that the platinum complexes afford more intense triplet emission than that for the palladium congener, consistent with the stronger heavy-atom effect of the third row element than the second row neighbor of the same group.