Coordination Compounds of Transition Metals With 3-Arylidene-1-pyrrolines: Synthesis and Structural Features

Within the scope of the work, series of new coordination compounds with derivatives of 3-aryliden-1-pyrroline as N-donor ligands have been obtained. The crystal structure of the obtained complexes has been analyzed, showing the dependence of the molecular structure and packing of molecules in crystals on the nature of the anion and the substituent in the arylidene fragment. Non-covalent interactions and main supramolecular motifs present in the crystals of the obtained compounds have been characterized. It has been shown that trifluoroacetate and nitrate complexes of copper(II) with arylidene-pyrroline ligands have fundamentally different structures. A dependence of the structure of copper complexes containing trifluoroacetate anions on the type of substituent in the para-position of the arylidene fragment has been discovered. It has been shown that the crystalline packing of complexes, in addition to typical stacking interactions for systems with extended planar fragments, is determined by the type of functional groups present in its structure. For example, crystals of compounds with halogen-containing 3-aryliden-1-pyrrolines are formed due to Hal…Hal interactions, nitrate complexes due to anion-anion, Lp…π, O…O, and Hal…O interactions involving nitrate anions, and silver complexes due to Ag…Hal, Ag…O, and Ag…π interactions. The geometric parameters of the detected interactions indicate their sufficiently high energy. Quantum-topological analysis of non-covalent interactions has also been conducted for silver complexes, demonstrating their binding nature and estimating their energy.