Synthesis, structure and catalytic activity of novel five-membered Pd(II) and Pt(II) metallaheterocycles based on 1,2-bis(3,5-dimethylisoxazol-4-yl-methylsulfanyl)lethane

摘要

Novel palladium(II) and platinum(II) heterocycles were synthesized based 1,2-bis(3,5-dimethylisoxazol-4-ylmethylsulfanyl)ethane. According to X-ray Crystallographic data in molecule there are two bonds between divalent sulfur atoms and metal atom S-Pd-S to form a five-membered palladacycle in the twistconformation with trans orientation of isoxazole rings. The syn-anti-isomerization for the palladaheterocycle in the solution is observed. The activation energy Delta H not equal, Delta S not equal and rate of reversible syn-antiisomerization were established by the dynamic H-1 NMR method and quantum-chemical calculations. Proposed mechanism of syn-anti-isomerization of palladacycle via an open-chain forms was offered. It was shown that metallaheterocycle - cis-S,S-dichloro 1,2-[di-(3,5-dimethylisoxazol-4-yl)methylsulfanyl]ethane palladium(II) is efficient catalyst in the amination reaction of allyl phenyl ether and Sonogashira reaction. (C) 2018 Elsevier B.V. All rights reserved.