Dinuclear NHC-palladium complexes containing phosphine spacers: synthesis, X-ray structures and their catalytic activities towards the Hiyama coupling reactionElectronic supplementary information (ESI) available: Selected bond lengths and angles for compounds 1-6 and 1H, 13C and 31P NMR spectra of compounds 1-6. CCDC 950139-950142, 971319, 971320. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4dt00180j

• Main Authors: Yang, Jin, Li, Pinhua, Zhang, Yicheng, Wang, Lei
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c4dt00180j

Six dinuclear N- heterocyclic carbene (NHC) palladium complexes, [PdCl 2 (IMes)] 2 ( μ -dppe) ( 1 ), [PdCl 2 (IPr)] 2 ( μ -dppe) ( 2 ), [PdCl 2 (IMes)] 2 ( μ -dppb) ( 3 ), [PdCl 2 (IPr)] 2 ( μ -dppb) ( 4 ), [PdCl 2 (IMes)] 2 ( μ -dpph) ( 5 ), and [PdCl 2 (IPr)] 2 ( μ -dpph) ( 6 ) [IMes = N , N ′-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene; IPr = N , N ′-bis-(2,6-di( iso -propyl)phenyl)imidazol-2-ylidene; dppe = 1,2-bis(diphenylphosphino)ethane, dppb = 1,4-bis(diphenylphosphino)butane; and dpph = 1,6-bis(diphenylphosphino)hexane], have been synthesized through bridge-cleavage reactions of chloro-bridged dimeric compounds, [Pd( μ -Cl)(Cl)(NHC)] 2 , with the corresponding diphosphine ligands. The obtained compounds were fully characterized by 1 H NMR, 13 C NMR and 31 P NMR spectroscopy, FT-IR, elemental analysis and single-crystal X-ray crystallography. Moreover, further explorations of the catalytic potential of the dinuclear carbene palladium complexes as catalysts for the Pd-catalyzed transformations have been performed under microwave irradiation conditions, and the complexes exhibited moderate to good catalytic activity in the Hiyama coupling reaction of trimethoxyphenylsilane with aryl chlorides. Six dinuclear N- heterocyclic carbene-palladium complexes were synthesized from [Pd( μ -Cl)(Cl)(NHC)] 2 and Ph 2 P(CH 2 ) n PPh 2 , and their catalytic activities towards the Hiyama reaction were investigated.