Synthesis, NMR spectral and structural studies on mixed ligand complexes of Pd(II) dithiocarbamates: First structural report on palladium(II) dithiocarbamate with SCN−ligand

• Three new mixed ligand complexes with PdS3P and PdS2PCl chromophores were synthesized.
• First structural report on Pd(II) dithiocarbamate with PdS3P chromophore.
• Steric and electronic influences of dithiocarbamate, SCN− and Cl−.

Three new mixed ligand complexes of palladium(II) dithiocarbamates; [Pd(4-dpmpzdtc)(PPh3)(SCN)] (1), [Pd(4-dpmpzdtc)(PPh3)Cl] (2) and [Pd(bzbudtc)(PPh3)Cl] (3), (where, 4-dpmpzdtc = 4-(diphenylmethyl)piperazinecarbodithioato anion, bzbudtc = N-benzyl-N-butyldithiocarbamato anion and PPh3 = triphenylphosphine) have been synthesized from their respective parent dithiocarbamates by ligand exchange reactions and characterized by IR and NMR (1H, 13C and 31P) spectroscopy. IR and NMR spectral data support the isobidentate coordination of the dithiocarbamate ligands in all complexes (1–3) in solid and in solution, respectively. Single crystal diffraction analysis of complexes 1–3 evidences that all three complexes are exhibiting distorted square planar geometry. The Pd–S distances in 1–3 vary in accordance with the differences in trans influences of PPh3, SCN− and Cl− and it is in the order of PPh3 > SCN− > and Cl−. Interchange of the anionic auxiliary ligand (SCN− to Cl−) induces asymmetry to the dithiocarbamate-metal bonds. Thioureide C–N bond distances are short in 1–3, supporting a contribution of thioureide form to the structures. The observed distortions in the square planar geometry for 1–3, are in the order of 1 > 2 > 3.

Three new palladium(II) dithiocarbamates have been prepared and structurally characterized by IR, NMR and single crystal XRD. This is the first structural report on palladium(II) dithiocarbamate with SCN– ligand. C–H···chelate interactions in the packing due to metalloaromatic character of the chelate is evidenced.Figure optionsDownload as PowerPoint slide