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

• Two trinuclear Co(II) and Ni(II) complexes with a unsymmetrically salamo type ligand were synthesized and characterized structurally. • Two terminal Co(II) atoms of complex 1 possess penta-coordinated trigonal bipyramid geometries, the central Co(II) atom exhibits a hexa-coordinated octahedral geometry, while all three Ni(II) atoms of complex 2 have hexa-coordinated octahedral geometries. • Molecular electrostatic potential analysis, hirshfeld surface analysis, and interaction region indicator analysis of complexes 1 and 2 were investigated. Two trinuclear Co(II) and Ni(II) complexes, [{Co 3 (L) 2 (μ -OAc) 2 } 2 ]·3CH 2 Cl 2 (1) and [Ni 3 (L) 2 (μ -OAc) 2 (EtOH) 2 ]·2EtOH (2) have been successfully obtained by a new nonsymmetrical salamo type ligand H 2 L with Co(OAc) 2 ·4H 2 O and Ni(OAc) 2 ·6H 2 O, respectively. Single crystal X-ray diffraction analysis revealed that complex 1 is an unsymmetric trinuclear structure, two tetradentate N 2 O 2 -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 H 2 L 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. Two trinuclear Co(II) and Ni(II) nonsymmetrically salamo type complexes, [{Co 3 (L) 2 (μ -OAc) 2 } 2 ]·3CH 2 Cl 2 (1) and [Ni 3 (L) 2 (μ -OAc) 2 (EtOH) 2 ]·2EtOH (2) have been successfully synthesized and characterized structurally. Molecular electrostatic potential analysis, interaction region indicator analysis, Hirshfeld surfaces analyses, DFT calculations and fluorescent properties of the Co(Ⅱ) and Ni(Ⅱ) complexes were also studied. [Display omitted] [ABSTRACT FROM AUTHOR]