Hirshfeld Surface Analysis, Interaction Energy Calculations of Metal (II) 4-Cyanobenzoate with Nicotinamide / N,N'-Diethylnicotinamide Complexes

Abstract

Hirshfeld surface analysis, a suitable tool for investigating intermolecular interactions, has been widely used in crystallography in recent years. A breakdown of related fingerprint graphics is presented as a color chart, allowing a quantitative analysis of intermolecular interaction types. In this study, the intermolecular interactions of diaqua-bis(4-cyanobenzoato-κO)bis(nicotinamide-κN 1 )cobalt(II) (I), diaquabis(4-cyanobenzoato-κO)bis(nicotinamide-κN 1 )copper(II) (II), diaquabis(4-cyanobenzoatoκO)bis(nicotinamide-κN 1 )nickel(II) (III), triaqua(4-cyanobenzoato-κ 2O,O')(nicotinamide-κN)zinc(II) 4- cyanobenzoate (IV), diaquabis(4-cyanobenzoato-κO)bis(N,N’-diethylnicotinamide-κN)cadmium(II) (V), diaquabis(4-cyanobenzoato-κO)bis(N,N’-diethylnicotinamide-κN)zinc(II) (VI) and catena-poly[[aquabis(4- cyanobenzoato-κO)copper(II)]-μ-N,N’-diethylnicotinamide-κ 2N 1 :O] (VII) complexes, crystal structures were previously determined and investigated by using Hirshfeld surface analysis via CrystalExplorer Program Version 17.5. In addition, the intermolecular interaction energies of the complexes were calculated using CEHF/3-21G and CE-B3LYP/6-31G (d,p) energy models that involved in CrystalExplorer (CE) software. Related to the obtained Hirshfeld surface analysis results, H…H, H…C/C…H, H…O/O…H, H…N/N…H, C…C, C…N/N…C and C… O/O…C constitute the intermolecular interactions of the complexes. Additionally, N…O/O…N and N…N interactions only in I, II, III, IV and VII complexes, H...Cu/Cu...H, O...Cu/Cu...O only in complexes II and VII and O ...O interactions only in complexes II, V and VI were also found. The most significant interactions of all of the complexes were found as the H…H interactions. These results support the existence of π-π interactions between benzene and pyridine rings and medium strength hydrogen bonds which contribute to the stability of the crystal packing of the complexes that are determined by single crystal X-ray diffraction method. Depending on the intermolecular interactions and the energy-framework analysis the O-H...O and N-H...O hydrogen bonds, and π···π stacking and C−H···π interaction energies are the most significant forces in the crystal packaging. The estimation of the intermolecular interactions and electrostatic energy values of the complexes are very important for the classification of them for their electrical, magnetic and optical properties.