Synthesis, structure, spectroscopic properties and DFT studies on some 7-hydroxy-4-methyl-8-(arylazo)-2H-1-benzopyran-2-one and their complexes with some divalent transition metal ions

A novel 7-hydroxy-4-methyl-8-(p-tolylazo)-2H-1-benzopyran-2-one (coumarin) (L1) and 7-hydroxy-4methy1-8-(p-anisylazo)-2H-1-benzopyran-2-one (coumarin) (12) and their metal complexes with Mn(II), Co(II), Ni(II) Cu(II) and Zn(II) have been prepared and characterized by elemental analysis, infrared (IR), proton nuclear magnetic resonance (H-1 NMR) and mass spectra. The solid complexes have been also characterized by thermal analyses (TG and DTA), magnetic measurements, electronic transition, molar conductance; mass spectra, and electron spin resonance (ESR). The molecular orbital calculations of the complexes have been performed using the density functional theory (DFT) method and the basis sets 6-31G* and 6-311G**. The computational results revealed that the proposed geometrical structures for the investigated metal complexes suggest trigonal bipyramid for 1:1 and tetrahedral geometry for 1:2 complexes. The 1:1 complexes contain coordinated and lattice held water molecules whereas 1:2 complexes contain only lattice water molecules. The complexes behave as non -electrolytes in dimethyl formamide (DMF). (C) 2016 Elsevier B.V. All rights reserved.