NiII-Mediated Coupling between Iminoisoindolinones and Nitriles Leading to Unsymmetrical 1,3,5-Triazapentadienato Complexes

Abstract

Treatment of nickel acetate Ni(OAc)2.4H2O with 2 equiv of various 3-iminoisoindolin-1-ones in a suspension of RCN in the presence of triethanolamine leads to the formation of the nickel 1,3,5-triazapentadienato complexes [Ni{NHC(R)NC(C6R1R2R3R4CON)}2] (1-17) isolated in good 50-83% yields. The reaction proceeds under relatively mild conditions (from 5 to 7 h at 25-115 degrees C, depending on the boiling point of the nitrile) and has a general character insofar as it was successfully conducted with various nitriles RCN bearing donor (R = Me, Et, Prn, Pri, Bun), weak donor (R = CH2Ph, CH2C6H4OMe-p), acceptor (R = CH2Cl), and strong acceptor (R = CCl3) groups R of different steric hindrance and also with the nonsubstituted iminoisoindolinone (3-iminoisoindolin-1-one) or the iminoisoindolinones bearing donor methyl (3-imino-5-methylisoindolin-1-one) or acceptor fluoro (4,5,6,7-tetrafluoro-3-iminoisoindolin-1-one) groups in the benzene ring.