Abstract

The crystal arrangement of molecules is necessary to determine what kind of supramolecular structures (2- or 3-dimensional framework) are formed as a result of intermolecular interactions, furthermore, it depends on the physicochemical properties of the crystal, for example, melting temperature, solubility, stability, activity and etc.. However, such qualitative analysis can be replaced by quantitative analyzes based on quantum-chemical approaches. One of them is based on the calculation of a surface with the same electron charge density, called the Hirshfeld surface. In our case, the main contribution of intermolecular interactions of mixed-ligand metal complex [Cu(PHBA)2(MEA)2] by Hirshfeld surface analysis and quantum chemical DFT calculations has shown that that they correspond to strong H‧‧‧O/O‧‧‧H bonds. Using DFT calculations, it was calculated that an odd electron MO (doublet state) arises when a complex is formed due to an odd d (d9) orbital in the Cu2+ ion of the compound [Cu(PHBA)2(MEA)2]. By the molecular docking studies the investigated complex compound [Cu(PHBA)2](MEA)2] recorded stronger binding energies than auxins taken as a control. The compound [Cu(PHBA)2](MEA)2], which showed the strongest performance, had a result 6% higher than the highest performing natural auxin. Quant-chemical calculation results are tested by agrochemical investigations on the mungbean plant