Well‐Defined Binuclear Co(II) Complexes: Synthesis, Structure, Characterizations and Catalytic Applications in Cyanosilylation of Various Aldehydes under Solvent‐Free Conditions

Abstract Two well‐defined novel binuclear cobalt (II) [Co( H 2 L 1 )] 2 and [Co( H 2 L 2 )] 2 compounds are presented. Binuclear cobalt (II) complexes ( 1 – 2 ) containing 1,1′‐binaphthyl derived tetradentate (N 2 O 2 ) donor ligands H 2 L 1 and H 2 L 2 , namely 3,3‐bis[((2,6‐diisopropylphenyl)imino)methyl]‐[1,1′‐binaphthalene‐2,2′‐dioxodicobalt(II) and 3,3′‐bis‐[((2,6‐diethyl‐phenyl)imino)‐ethyl]‐[1,1′]‐binaphtyl‐2,2′‐dioxocobalt(II) complexes were synthesized and isolated for the first time. Various spectroscopic techniques, including UV‐visible spectra, magnetic susceptibility, cyclic voltammetry, elemental analysis, mass spectrometry, and single‐crystal X‐ray diffraction were used to structurally characterize these binuclear cobalt(II) complexes. The binuclear cobalt (II) [Co( H 2 L 1 )] 2 and [Co( H 2 L 2 )] 2 complexes ( 1 – 2 ) demonstrated excellent catalytic activity in the cyanosilylation reaction of various aryl aldehydes to value‐added cyanohydrins at room temperature under solvent‐free conditions.