Synthesis and crystal structure determination of the pesudopolymoph nickel complex incorporating macrocyclic Schiff base ligand, [NiLCl]Cl•H2O, at low temperature and calculation of the polarizability and hyperpolarizability by halogen altering

The structure of [NiLCl]Cl•H2O (2), which synthesized by condensation reaction of 2-(3-(2-formylphenoxy)-2-hydroxypropoxy)benzaldehyde and 1,3-diamino-2-propanol in the presence of NiCl2•6H2O at methanol, has been determined by single-crystal X-ray diffraction. Distorted octahedral coordination environment around Ni(II) ion is constructed by two imine nitrogen atoms, two ether oxygen atoms, one alcohol oxygen atom, and one chloride anion. The complex (2) is pesudopolymorph for the previously reported [NiLCl]Cl•0.75H2O (1) complex [1]. There are two formula units [NiLCl]Cl per asymmetric unit of both complexes. Each asymmetric unit of (1) and (2) includes two water molecules of crystallization, although one of the two water molecules in (1) has half-site occupancy. The optimized structure of (2) and similar compounds by Cl replacement with Br and I in DFT/B3LYP level of theory using LANL2DZ (for nickel and halogen) and 6-31G(d,p) (for the other elements) basis sets illustrate good agreement with experimental ones. Based on optimized structures of three compounds, their polarizability and hyperpolarizability were calculated at the same level to predict their nonlinear optical(NLO) properties. The calculated NLO values of the compounds are much greater than the corresponding value of urea.