Synthesis, crystal structure and Hirshfeld surface analysis of the complex compound bis(o-phenylenediamine-N,N')-bis(2,4-dihydroxybenzoato-O)-cadmium(II)

Abstract

In this paper, the synthesis, crystal structure, Hirshfeld surface analysis, and intermolecular interaction energies of a new complex compound [Cd(OPD)2(2,4-DBA)2] involving Cd(II), o-phenylenediamine (OPD), and 2,4-dihydroxybenzoic acid (2,4-DBA) were studied. The resulting complex compound has a symmetrical structure and forms an octahedral shape in space. Its syngony is monoclinic and the space group is P21/n. In the crystal structure of the molecule, the unit cell parameters are: a = 5.4981(1) Å, b = 19.3609(5) Å, and c = 11.5687(2) Å. Two molecules of OPD are bound to the central atom in a chelate state by donor-acceptor bonds. Two molecules of 2,4-DBA are bound to the central atom in a monodentate state by ionic bonds. The length of the donor-acceptor bonds bound to the central atom in the molecule is 2.36Å. The crystal structure of the molecule contains intra- and intermolecular hydrogen bonds of the N−H•••O and O−H•••O types. The processes of interaction of particles in the molecule were studied based on Hirshfeld surface analysis. Based on the 2D fingerprint di and de functions, it was determined that the interaction of H…H, H…O/O…H and H…C/C…H pairs of atoms occupies the main share in the structure of the molecule. The O−H•••π interactions and intermolecular interaction energies of the molecule were also determined. The total interaction energy of the molecule is -320.1 kJ. The vibrational frequencies of the bonds and functional groups in the resulting complex compound were determined based on Raman spectroscopic analysis.