Synthesis of NN palladium complexes and six-membered CN palladacycles from 1-N- and 2-N-benzylindazoles

Publication date: Available online 21 March 2018 Source:Journal of Organometallic Chemistry Author(s): Ludmila A. Bulygina, Natalya S. Khrushcheva, Zinaida S. Klemenkova, Konstantin A. Lyssenko, Aleksander S. Peregudov, Viacheslav I. Sokolov The reaction of 1-N-benzylindazole (1) and 2-N-benzylindazole (1a) with Na2PdCl4 in MeOH afforded the NN coordinated complexes Pd(1)2Cl2 (2) as the only trans-isomer and Pd(1a)2Cl2 (2a) as the 1:1 mixture of cis and trans isomers. Direct palladation of 1 and 1a using Pd(OAc)2 in AcOH led to the corresponding μ-acetato-dimeric complexes (3 and 3a) with six-membered palladacycles as the mixtures of syn and anti isomers. The reaction of 3 and 3a with LiCl in aqueous acetone gave the μ-Cl-dimeric complexes 5 and 5a where the acetate groups were replaced by Cl. The following addition of PPh3 to the solution of 5 and 5a in CH2Cl2 generated the mononuclear adducts 7 and 7a. NMR spectroscopy data supported the proposed structures of all complexes. The solid-state structure of 7 and 7a was determined by the single-crystal X-ray diffraction methods and indicated a boat conformation of both 6-membered palladacycles. Graphical abstract

Source: Journal of Organometallic Chemistry - March 22, 2018 Category: Chemistry Source Type: research