Iridium complexes with ligands of 1,8-Naphthyridine-2-carboxylic acid derivatives-preparation and catalysis

Complexation of 1,8-naphthyridine(Np)-2-carboxylic derivatives L-1-L-3 [L-1 = Np-2-COOH, L-2 = Np-2-CONH2, L-3 = Np-2-CONHCH2Py] with [Ir(COD)(mu-OMe)](2) yielded the corresponding complexes [Ir(COD)(L-n)] (1 similar to 3, n = 1 similar to 3, respectively). The potential tridentate L-3 behaves as a bidentate donor in the complex 3. Treatment of L-1 with [Ir(COD)Cl](2) under nitrogen atmosphere gave a Ir(III) hydride complex [Ir(COD)(L-1)HCl] (4). However, carrying out the reaction in the presence of oxygen rendered a Ir(III) dichloride species [Ir(COD)(L-1)Cl-2] (5). All these complexes were characterized by spectroscopic analyses and X-ray single crystal determination. Catalytic activity of iridium complexes in amination of amines with alcohols was screened. It appears that iridium amido complexes 2 and 3 show excellent catalytic activity on amination of anilines with alcohols in the presence of Cs2CO3 at 120 degrees C. (c) 2020 Published by Elsevier B.V.