A new chromium (III) complex containing N-(2-pyridylmethyl)-2-pyrazinecarboxamide, (NPyPzCa): Synthesis, molecular and crystal structure and theoretical electron density analysis

摘要

The chromium (III) complex [Cr(NPyPzCa)Cl2(H_2O)].(CH_3)2O (1) (NPyPzCa stands for N-(2-pyr-idylrnethyl)-2-pyrazinecarboxamide) has been synthesized and characterized by single crystal X-ray diffraction. The Cr(III) atom exhibits an octahedral geometry due to the coordination of three donor atoms from carboxamide ligand, two chlorine atoms and one water molecule. There is O-H-O hydrogen bonds and also n-n interactions between adjacent pyridine and pyrazine rings that seem to be effective in the stabilization of the crystal packing. The topological and energetic properties of the electron density distribution of all the metal-ligand bonding interactions in this complex have also been calculated and studied at several DFT levels. According to the results, metal-ligand bonding interactions belong (from the topological and energetic point of view) to new interactions that represent a mix of closed-shell (ionic) and shared (covalent) characters.