A rare doubly nitrato and phenoxido bridged trimetallic CuIIcomplex: EPR, antiferromagnetic coupling and theoretical rationalization

A rare trimetallic CuII complex, [Cu3(L)2(NO3)2] (1) has been afforded incorporating a [CuL] metalloligand, [where H2L = N,N'-bis(salicylidene)-1,3-propanediamine]. In 1, in addition to the double phenoxido bridge, the two terminal CuII atoms are linked to the central CuII by means of syn–anti bridging nitrate anions giving rise to a linear arrangement. Complex 1 exhibits strong antiferromagnetic coupling and shows an cMT value of 0.703 cm3 mol–1 K at 300 K. DFT computational studies reveal that there is a clear magneto-structural correlation between the Cu–O–Cu angle and the JCu–Cu values, which is in accordance with the experimental evidence. The biological effect of 1 on the viability of different human carcinoma cells was evaluated using MTT assay and the results indicate that this complex induces a decrease in cell-population growth of human colorectal carcinoma cells (COLO 205) with apoptosis.