Structural and spectroscopic characteristics of [Ni{(Ph₂P)₂N-S-CHMePh-P,P鈥瞹X₂], X = Cl, Br: Catalytic activity and selectivity in Kumada and Suzuki-Miyaura coupling reactions

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• 作者：Ioannis Stamatopoulos^a ; Martin Pla膷ek^b ; Vassilis Psycharis^c ; Aris Terzis^c ; Jan Svoboda^b ; ^{jan.svoboda@natur.cuni.cz} ; Panayotis Kyritsis^a ; ^{kyritsis@chem.uoa.gr} ; Ji艡í ; Vohlí ; dal^b ; ^{vohlidal@natur.cuni.cz}
• 关键词：Nickel complex ; P&ndash ; N&ndash ; P ligand ; X-ray crystallography ; Homogeneous catalysis ; Kumada coupling ; Suzuki&ndash ; Miyaura coupling
• 刊名：Inorganica Chimica Acta
• 出版年：2012
• 期刊代码：40_00201693
• 类别：ch
• 出版时间：30 May, 2012
• 卷：387
• 期：Complete
• 页码：390-395
• 文件大小：404 K

摘要

The [Ni{(Ph₂P)₂N-S-CHMePh-P,P鈥瞹Br₂] complex was prepared by a ligand-exchange reaction between [Ni(dme)Br₂] (dme is 1,2-dimethoxyethane) and the P-N-P ligand (Ph₂P)₂N(S-CHMePh). X-ray crystallography revealed a square planar NiP₂Br₂ coordination sphere, i.e., the presence of a four-membered Ni-P-N-P ring. The same structural features with nearly equal values of the X-Ni-X, P-Ni-P and P-N-P angles have been earlier revealed for the isomorphous [M{(Ph₂P)₂N-S-CHMePh-P,P鈥瞹Cl₂], M = Ni, Pd, complexes. The structure of the above complexes significantly differs from that of [Ni(dppp)Cl₂] (dppp is 1,3-bis{diphenylphosphine}propane). This NiP₂Cl₂-type complex comprises a six-membered Ni-P-C-C-C-P ring, with significantly larger P-Ni-P and much smaller Cl-Ni-Cl angles. The ¹H and ³¹P NMR properties of [Ni{(Ph₂P)₂N-S-CHMePh-P,P鈥瞹Br₂] are consistent with its crystal structure. The [Ni{(Ph₂P)₂N-S-CHMePh-P,P鈥瞹X₂] complexes were tested as catalysts in Kumada and Suzuki-Miyaura coupling reactions, and their reactivity was compared with that of [Ni(dppp)Cl₂]. The differences observed in their catalytic efficiency are discussed with regards to their structural characteristics.