Synthesis, structural characterization and DFT calculations of a diphenyl-2-pyridylphosphine complex of copper(II)

Abstract

The reaction of Cu(NO₃)₂·3H₂O with a potentially bidentate P,N-donor ligand, diphenyl-2-pyridylphosphine (PPh₂Py), in 1:2 molar ratio resulted in formation of a κ²N,O-chelated complex, [Cu(κ²N,O-P(O)Ph₂Py)₂(NO₃)₂] (1). A single-crystal X-ray study confirmed the formation of a five-membered κ²N, O-chelate involving pyridyl nitrogen and phosphine oxide oxygen donor sites. A DFT study was carried out on 1 to understand the chelate ring expansion process upon oxidation with PPh₂Py. DFT analysis revealed that 1 contains a relatively strong M-N bond compared to its M-P bond, facilitating the oxidation of the P atom followed by chelate ring expansion.

KEYWORDS:

• Phosphine ligand
• chelate ring expansion
• DFT study

Acknowledgement

BJS thanks Phil Liebing, Friedrich-Schiller-Universität Jena, Germany for measuring single crystal X-ray data. Assam Science and Technology University [ASTU/TEQIP-III/Collaborative Research/2019/548/10258], [ASTU/TEQIP-III/Collaborative Research/2019/2569] and University Grant Commission [Grant No. F.42-326/2013 (SR)] are gratefully acknowledged for providing partial financial grants.

Disclosure statement

No potential conflict of interest was reported by the authors.