Synthesis, spectral, structural, and DFT studies on nickel(II) complexes with pyrrole based dithiocarbamate and triphenylphosphine ligands

GRAPHICAL ABSTRACT

ABSTRACT

Bis(N-(pyrrol-2-ylmethyl)-N-isopropyldithiocarbamato-S,S′)nickel(II) (1) and (N-(pyrrol-2-ylmethyl)-N-isopropyldithiocarbamato-S,S′)(thiocyanato-N)(triphenylphosphine)nickel(II) (2) have been prepared and characterized by elemental analysis, IR, ¹H, and¹³C NMR and UV-visible absorption spectra. In addition, the structures of 2 and (N-(pyrrol-2-ylmethyl)-N-butyldithiocarbamato-S,S′)(thiocyanato-N)(triphenylphosphine)nickel(II) (3) have been elucidated by X-ray crystallography. UV-vis spectral data are consistent with the formation of square planar complexes. The crystal structures of 2 and 3 reveal S₂NP square-planar configuration around the Ni atom. A rare C–H···Ni short contact interaction was observed in complex 3 involving ortho-hydrogen atom of one of the phenyl ring of the triphenylphosphine. DFT calculations on complexes 2 and 3are in close agreement with the crystallographic results. The energy gap between HOMO and LUMO for 2 and 3 is 2.7167 and 2.6936 eV, respectively. Molecular electrostatic potential analysis of 2 and 3 support the partial double character of thioureide C–N bond.

KEYWORDS:

• Ni(II) dithiocarbamate complexes
• trans effect
• DFT studies
• anagostic interaction

Acknowledgment

The authors are thankful to SAIF, Indian Institute of Technology-Madras for the single crystal X-ray structural analysis.

Funding

Dr. S. Thirumaran is thankful to University Grants Commission (UGC), India (F. No. 42-341/2013 (SR)) for providing funds for this research study.