A phenoxo–azido assorted Schiff base copper(II) bridged dimer in trace level fluorescence sensing of a pesticide: a DFT supported phenomenon

Abstract

A binuclear phenoxo- and azido-bridged copper(II) Schiff base complex has been synthesized along with its mononuclear copper-Schiff base analog. The compounds have been characterized by IR spectroscopy and CHN elemental analysis. The single-crystal structure and variable temperature magnetic properties of the binuclear compound have been studied from the X-ray crystallographic data and superconducting quantum interference device magnetometry, respectively. The synthesized crystalline binuclear complex has interesting spectral features that allow it to act as a spectral sensor toward an organophosphorus pesticide which is a potential environmental toxicant coming to the environment as agricultural waste. Although both the mononuclear and binuclear complexes are suitable as sensors for the organophosphorus, the binuclear complex being crystalline is suitable for attaining structural and mechanistic details of the interaction. Density functional theory calculations and ESI MS analysis of the interactions with the binuclear complex suggest that the binding of organophosphorus substrate with 2 occurs through one copper center.

Keywords:

• Mixed bridged
• Schiff base
• copper(II)
• organophosphorus
• sensing
• DFT study

Acknowledgments

S. S. thankfully acknowledges UGC and DST, New Delhi for funding of the total work done in the Dept. of Chemistry, A. P. C. College. S. S. also acknowledges DST-FIST for funding of Instruments. K. S. acknowledges UGC (Sanction no. 41-248/2012 (SR)) and UGC CAS V for funding.