Role of imidazole edge to edge supramolecular interaction in the crystal packing of Cu(II)(SCN−)2(imidazole)2 complex: A novel variety of supramolecular interaction revealed by CCDC database analysis and explored through DFT computational studies

Abstract

Crystalline molecular solids are self-assembled entities in which molecular components are packed by various intermolecular forces. A novel edge to edge supramolecular interaction between the imidazole molecules has been observed in the crystal packing of the coordination complexes Cu(II)(SCN−)2(imidazole)2. In this edge to edge interaction, one of the C-N bonds of an imidazole molecule exhibit non-bonded interaction with the complementary C-N bond of another imidazole molecule with no facial overlap between the imidazole molecules. This edge-to-edge interaction of imidazole molecules along with NH···S, CH···S interaction governs the packing of molecular complexes in the solid state. Basis set superposition error corrected interaction energy of this edge to edge supramolecular interaction of imidazole has been estimated to be -2.59 kcal/mole. The electronic nature of this novel intermolecular interaction has been computed through DFT methodology. A CCDC database search has revealed that, a sizable number of crystals containing imidazole moiety shows this type of edge to edge supramolecular interaction. Hirshfeld surface analysis shows that this edge to edge interaction play cooperative role along with other intermolecular forces in the crystal packing of the present complex.