Trinuclear and polymeric cobalt(II or II/III) complexes with an arylhydrazone of acetoacetanilide and their application in cyanosilylation of aldehydes

The new trinuclear [Co II (H 2 O) 2 (Me 2 NCHO) 2 {Co III (1κ NOO′ :2κ O″ -μ-HL)} 2 (1κ NOO′ )]·2H 2 O ( 1 ) and polymeric [Co II (1κ NOO′ :2κ O″ -μ-HL)(MeOH) 2 ] n ( 2 ) complexes were isolated by the reaction of ( Z )-2-(2-(1,3-dioxo-1-(phenylamino)butan-2-ylidene)hydrazinyl)benzoic acid (H 3 L) with CoCl 2 ·6H 2 O and Co(ClO 4 ) 2 ·6H 2 O, respectively, in a mixture of DMF/MeOH (1/10, v/v), in the presence of Et 3 N at room temperature, and characterized by IR and ESI-MS spectroscopies, elemental and X-ray crystal structural analyses. In both structures the cobalt centres display distorted octahedral geometries. The structural units in 1 and 2 are connected via intermolecular hydrogen bonds involving the coordinated HL 2− and the bound and non-bound water molecules (in 1 ) or the methanol ligands (in 2 ) which provides supramolecular networks. 1 and 2 are catalyst precursors for the cyanosilylation reaction of a variety of both aromatic and aliphatic aldehydes with trimethylsilyl cyanide leading to the corresponding cyanohydrin trimethylsilyl ethers in high yields (up to 89%) in methanol and at room temperature.