Investigation of structure-directing interactions within copper(i) thiocyanate complexes through X-ray analyses and non-covalent interaction (NCI) theoretical approach

Abstract

Herein, we reported the synthesis of copper(I) thiocyanate complexes with ortho-pyridinyl carbohydrazones containing a thiophene (L₁) or a furyl ring (L₂) as a mixture of two different crystals for each compound, linkage isomers of C_1N, [Cu(NCS)(L₁)PPh₃] and C_1S, [Cu(SCN)(L₁)PPh₃], for L₁, whereas monomeric and polymeric structures C_2N, [Cu(NCS)(L₂)PPh₃], and C_2P, [–(NCS)Cu(L₂)–]_n, for L₂. Crystallographic information and theoretical calculations, mainly noncovalent interaction reduced density gradient (NCI-RDG) analyses, were pursued to generate a profound understanding of the structure-directing interactions in these complexes. The supramolecular assemblies are first driven by cooperative π⋯π interactions and hydrogen bonds followed by CH⋯π, S⋯S and S⋯π linkages. In the case of the linkage isomers, intermolecular interactions may have a significant role in the formation of the less stable S-bound isomer C_1S.