Efficient Suzuki⁻Miyaura C-C Cross-Couplings Induced by Novel Heterodinuclear Pd-bpydc-Ln Scaffolds.
An easy access to a series of previously unreported heterodinuclear Pd-Ln compounds, Pd-bpydc-La, Pd-bpydc-Ce and Pd-bpydc-Nd (bpydc = 2,2'-bipyridine-5,5'-dicarboxylate) has been developed. The Pd-Ln hybrid networks were effectively applied as catalysts in Suzuki⁻Miyaura C-C cross-coupling reactions of 4-bromoanisole and 4-bromobenzonitrile with phenylboronic acid, under mild conditions. A systematic investigation revealed Pd-bpydc-Nd as the most active catalyst. In all cases, reaction yields varied with the base, catalyst loading and substantially augmented with temperature (from 30 to 60 °C). Substituent effects were operative when changing from 4-bromoanisole to 4-bromobenzonitrile. The key role played by the lanthanides, aromatic substrate and base, in modulating the Pd-catalytic cycle has been highlighted. Importantly, the new catalysts proved to be stable in air and vs. functionalities and are quite efficient in Suzuki⁻Miyaura carbon-carbon bond formation conducted in protic solvents.
['Ding|Fu|F|', 'Li|Yanli|Y|', 'Yan|Pingxuan|P|', 'Deng|Yan|Y|', 'Wang|Dongping|D|', 'Zhang|Yajing|Y|', 'Dragutan|Ileana|I|', 'Dragutan|Valerian|V|', 'Wang|Kangjun|K|']
D002384:Catalysis D018360:Crystallography, X-Ray D028581:Lanthanoid Series Elements D015394:Molecular Structure D010165:Palladium D013696:Temperature
Suzuki–Miyaura cross-coupling dinuclear complexes heterobimetallic catalysts rare-earth metals