Structural, theoretical and optical investigations of two lateral twisting trinuclear Co(II) and Ni(II) salamo type complexes

Abstract

Two trinuclear Co(II) and Ni(II) complexes, [{Co3(L)2(μ-OAc)2}2]·3CH2Cl2 (1) and [Ni3(L)2(μ-OAc)2(EtOH)2]·2EtOH (2) have been successfully obtained by a new nonsymmetrical salamo type ligand H2L with Co(OAc)2·4H2O and Ni(OAc)2·6H2O, respectively. Single crystal X-ray diffraction analysis revealed that complex 1 is an unsymmetric trinuclear structure, two tetradentate N2O2-donor ligand (L)2- units are coordinated to three Co(II) atoms where two terminal Co(II) atoms are penta-coordinated lateral twisting trigonal bipyramidal geometries but central Co(II) atom is hexa-coordinated lateral twisting octahedral configuration. Complex 2 is a centrosymmetrical trinuclear structure, all of the three Ni(II) atoms are hexa-coordinated lateral twisting octahedral configurations. In addition, complexes 1 and 2 have been characterized by physicochemical and spectroscopic methods. Molecular electrostatic potential analysis revealed that the phenolic oxygen atoms in the ligand H2L have nucleophilic reactions with Co(II) and Ni(II) atoms to form chemical bonds. Hirshfeld surfaces analyses showed that H···H/H···H interactions are the predominant, indicating the presence of great amount hydrogen bonds in complexes 1 and 2. IRI analyses indicated the presence of weak hydrogen bonding interactions that made complexes 1 and 2 more stable.