A New phenoxido/trifluoroacetato bridged heterometallic Ni II2 –Cu II derivative: Structure, EPR interpretation and DFT computation

The trinuclear heterometallic Ni 2II −Cu II complex, [Ni 2 (L) 2 (CF 3 COO) 2 Cu] (1) is afforded incorporating a tetradentate Schiff base precursor, H 2 L [where H 2 L = N,N′-bis(salicylidene)-1,3-propanediamine]. In 1, the two terminal Ni II atoms are linked to the central Cu II by a syn-anti bridging trifluroacetate and a double phenoxido bridge, giving rise to a linear structure. The EPR spectra show that the trinuclear structure remains unchanged in non-coordinating solvents, whereas in DMF and DMSO the resonances of mononuclear Cu II species with an axial symmetry and a well-resolved hyperfine structure are observed. DFT calculations reveal that the spin Hamiltonian parameters are g z 2.22 and A z 176.4 × 10 −4 cm −1 , which are in good agreement with the experimental values. The biological outcome of complex 1 on the viability of different human carcinoma cells are analyzed by MTT assay and the results suggest that it induces a decrease in cell-population growth with apoptosis.