Synthesis and characterization of 3d and 4f metal complexes of Schiff base ligands

Abstract

Square planar complexes of monomeric [Cu(L1)2] (1) and [Ni(L1)2] (2) (where L1 is C20H24NO2) are isolated through the use of Schiff base ligands and characterized by X-ray diffraction, UV–Vis, electron paramagnetic resonance (EPR) and DFT calculations. Effects of coordinating and non-coordinating solvent for 1 and 2 (UV–Vis) were studied in detail. The EPR spectra recorded for 1, confirms the rhombic nature of Cu(II) ion of 1 in the solid state, g = [2.185, 2.086, 2.036], and frozen fluid with the spin Hamiltonian parameters, g = [2.207, 2.079, 2.040]. The slight deviation in the g-tensor of 1 from its powder to frozen solution is attributed to the loss of intermolecular hydrogen bonding in fluid solution. UV–Vis (for 1 and 2) and EPR (for 1) parameters obtained from DFT calculations are consistent with the experimental data, and further confirms that the solid state structures of 1 and 2 are maintained in solution. Crystal structures of praseodymium and lanthanum monomeric complexes obtained with HL2 (C14H11NO2) are also reported. The X-ray crystal structure of the praseodymium complex solved in an orthorhombic crystal system with molecular formula [Pr(HL2)2(NO3)3] (3), whereas lanthanum in a triclinic system with molecular formula [La(HL2)3(NO3)3] (4) with multiple intermolecular hydrogen bonds. Complexes 3 and 4 are found to be in distorted bicapped square anti-prism and Icosahedron geometries respectively.