Copper(II) complexes with carboxylic- or sulfonic-functionalized arylhydrazones of acetoacetanilide and their application in cyanosilylation of aldehydes

The new copper(II) complexes [Cu(HL1)(H2O)(CH3OH)] (1, H3L1 = (Z)-2-(2-(1,3-dioxo-1-(phenylamino)butan-2-ylidene)hydrazinyl)benzoic acid) and [Cu(HL2)(H2O)(CH3OH)] (2, NaH2L2 = sodium (Z)-2-(2-(1,3-dioxo-1-(phenylamino)butan-2-ylidene)hydrazinyl)benzenesulfonate) were synthesized and characterized by IR and ESI-MS spectroscopies, elemental and X-ray crystal structural analyses. The coordination environment of the central copper(II) has a square pyramidal geometry, three sites being occupied by (HL1,2)2−, which chelates in the O,N,O fashion, while the two other sites are filled with the water and methanol ligands. Multiple intra- and intermolecular non-covalent interactions between the (HL1,2)2−, water and methanol ligands lead to supramolecular network. Both compounds 1 and 2 act as homogenous catalysts for the cyanosilylation reaction of a variety of both aromatic and aliphatic aldehydes with trimethylsilyl cyanide affording the corresponding cyanohydrin trimethylsilyl ethers in high yields (up to 90%) and at room temperature. © 2017 Elsevier B.V.