Synthesis, spectroscopic characterizations, DFT calculations, antimicrobial studies and pesticidal activity of heterobimetallic complexes of Ni(II) with main group metals/transition metal dichlorides

The newly designed trinuclear heterobimetallic complexes [Ni(L)2(M)2R4Cl2] were synthesized by using methanolic solution of mononuclear Ni(II) complex and various organometallic dichlorides (where L = o-phenylenediamine (C6H8N2), M = Sn(IV), Si(IV), Ti(IV) and Zr(IV) and R = Ph, Me, C5H5 etc.). The synthesized complexes were characterized on the basis of physico-chemical and spectral (FTIR, UV-visible, Mass, 1H NMR) studies. IR spectroscopy confirmed the coordination of -NH2 group to the metal center. PXRD patterns shown the crystalline nature of all the synthesized complexes. Density Functional Theory study help to correlate the quantum chemical parameters like electronegativity, bond length, bond angles, dipole moment, electrophilicity, hardness, softness and to calculate the energy gap of HOMO and LUMO of the mononuclear metal complex as well as trinuclear heterobimetallic complexes. The frequency computation was done using the hybrid B3LYP functional level of theory. Among the synthesized complexes, mononuclear metal complex adopted square planar geometry while trinuclear heterobimetallic complexes adopted distorted octahedral geometry. The results of PXRD and DFT study exhibited a good correlation. The in-vitro antimicrobial potency of these resulting complexes has been scrutinized and promising results were attained. Moreover, the pesticidal activity of the synthesized complexes was also evaluated against nymph and adult species of Chrotogonus trachypterus by taking into consideration their mortality rate.