Mono- and binuclear Cu (II) 3,5-diiodosalicylates: Structures and features of non-covalent interactions in crystalline state

Abstract Reactions of CuCl2•2H2O or Cu(NO3)2•6H2O with 3,5-diiodosalicylic acid (DISA) in presence of trialkylamines result in structurally diverse products. Depending on the ratio of reagents and Cu source, there were isolated either mononuclear complexes (R3NH)2[Cu(DISA)2] (R = Et (1), n-Pr (2) and n-Bu (3)) where fully deprotonated DISA forms 5-membered chelate rings, or binuclear paddlewheel-type (R3NH)2[Cu2(DISA)4Cl2] (r = n-Pr (4)). General feature of these complexes is their ability to form halogen bonding (XB) in solid state; the energies of XBs were estimated based on the QTAIM analysis results (DFT calculations were used to get electron density, and then the topological analysis was used to estimate the energies via empirical correlations between the interaction energy and the potential or kinetic energy density of electrons at the bond critical points (3, –1)).