Bimetallic bis(diphenylphosphino)acetylene bridged copper(I) complexes with 1,10-phenanthroline derivatives: synthesis, crystal structure, and spectroscopic characterization

Abstract

A new series of bimetallic bis(diphenylphosphino)acetylene-bridged copper(I) 1,10-phenanthroline complexes, [Cu₂(dppa)₂(L)₂](BF₄)₂; L = 1,10-phenanthroline (1); 4-methyl-1,10-phenanthroline (2); 4,7-dimethyl-1,10-phenanthroline (3); and 2,9-dimethyl-1,10-phenanthroline (4), have been prepared and characterized by spectroscopic methods. The X-ray structures of 1 and 4 were determined. The structures consist of centrosymmetric bimetallic 10-membered chair-like dimetallacycles. In 1, intermolecular C–H⋯π interactions result in bending of the phenanthroline ligand and sterically induced lengthening of one Cu–P bond. In 1–4, the ³¹P NMR downfield coordination shift, relative to the free ligand, correlates with the basic strength of the 1,10-phenanthroline ligands.

Graphical Abstract

Keywords:

• Binuclear Cu(I) complexes
• Bis(diphenylphosphino)acetylene
• 1,10-phenanthroline derivatives
• X-ray structure
• ³¹P NMR

Acknowledgements

The authors acknowledge the support of King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, Saudi Arabia, and express their appreciation to the support from the Ministry of Higher Education, Saudi Arabia, in establishment of the Center of Research Excellence in Petroleum Refining and Petrochemicals at KFUPM.

Notes

This work is dedicated to the parents of Dr. Atif Fazal.