Interaction of copper(II) complexes with bis(p-nitrophenyl)phosphate: Structural and spectral studies

Abstract When the complexes [Cu(L1)(H 2 O)](ClO 4 ) 2 1 , where L1 = 4-methyl-1-(pyrid-2-ylmethyl)-1,4-diazacycloheptane, and [Cu(L2)Cl 2 ] 2 , where L2 = 4-methyl-1-(quinol-2-ylmethyl)-1,4-diazacycloheptane are interacted with one/two equivalents of bis( p -nitrophenylphosphate, ( p -NO 2 Ph) 2 PO 2 , BNP), no hydrolysis of BNP is observed. From the solution the adducts of copper(II) complexes [Cu 2 (L1) 2 (( p -NO 2 Ph) 2 PO 2 ) 2 ]-(ClO 4 ) 2 3 and [Cu(L2)(( p -NO 2 Ph) 2 PO 2 ) 2 ]·H 2 O 4 have been isolated and structurally characterised. The X-ray crystal structure of 3 contains two Cu(L1) units bridged by two BNP molecules. The Cu···Cu distance (5.1 A) reveals no Cu–Cu interaction. On the other hand, the complex 4 is mononuclear with Cu(II) coordinated to the 3N ligand as well as BNP molecules through phosphate oxygen. The trigonality index ( τ , 0.37) observed for 4 is high suggesting the presence of significant trigonal distortion in the coordination geometry around copper(II). The complexes are further characterized by spectral and electrochemical studies.