[Bis(picolinate-κ2N:O)Copper(II)] di(benzene1,3,5- tricarboxylic acid): Hydrothermal synthesis, structural characterization, magnetic properties and DFT study

A new metal-organic hybrid complex [Bis(picolinate-κ2N:O)Copper(II)] di(benzene-1,3,5- tricarboxylic acid) was synthesized hydrothermally. Physico-chemical characterization of the complex was perfomed with FTIR spectroscopy, single crystal X-ray diffraction, TGA, EPR, SQUID and FESEM. Single crystal X-ray diffraction study revealed that the complex crystallizes in a monoclinic form with space group P1 21/c 1. The unit cell dimensions are a = 4.9853 (4), b = 13.1082 (5), c = 21.6616 (8) Å; the axial angles are α = 90°, β = 91.230° (6) and γ = 90°. The asymmetric unit of the title complex is composed of a Cu(II) ion and two 2-picolinic acid anions. The Cu(II) ion occupies the centre of symmetry coordinated through two pyridine nitrogen atoms and two oxygen atoms of the carboxyl group giving rise to a slightly distorted square planar coordination environment. EPR and SQUID studies revealed it to be a stable paramagnetic material. The stability of the complex was well justified by thermogravimetric and DFT studies.