Neutral mononuclear luminescent Pd(II) complexes with heterocyclic thiolate ligands and chelating phosphines. Structural and photophysical assignments

Two heterocyclic thiolate ligands, namely pymt and py2S (pymt = pyrimidine2-thiolate and py2S = pyridine-2-thiolate) and the diphosphines bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), were used in the synthesis of three neutral Pd(II) complexes (cis-[Pd(dppm)(pymt)2] (1), cis-[Pd(dppe)(pymt)2] (2) and cis-[Pd(dppp)(pyrt)2] (3)). Crystallographic analysis of the isolated complexes reveals their square planar arrangement and the coordination of the thiolate moieties through their exocyclic sulfur atom. The complexes absorb in the visible part of the spectrum through charge transfer transitions while after photoexcitation at 385 nm they appear to emit with a broad band located at 465 nm.

The present study comprises the synthesis and photophysical investigation of three new square planar palladium(II) compounds, each bearing two thiolate units and a chelating diphosphine. DFT calculations are performed in order to rationalize their spectroscopic behavior in solution.Figure optionsDownload as PowerPoint slide