1323155-90-3Relevant academic research and scientific papers
Coordination and catalytic properties of a semihomologous Dppf congener, 1-(diphenylphosphino)-1′-[(diphenylphosphino)methyl]ferrocene
Stepnicka, Petr,Cisarova, Ivana,Schulz, Jiri
, p. 4393 - 4403 (2011/10/18)
Alcohol Ph2PfcCH2OH (2, fc = ferrocene-1,1′- diyl) reacts smoothly with Ph2PH and Me3SiCl/NaI in acetonitrile to give 1-(diphenylphosphino)-1′-[(diphenylphosphino)methyl] ferrocene (1), a new ferrocene diphosphine that fills the obvious gap left between the well-studied 1,1′-bis(diphenylphosphino)ferrocene (dppf) and its bis-spaced analogue, 1,1′-bis[(diphenylphosphino)methyl]ferrocene. The P-oxidized alcohols Ph2P(E)fcCH2OH (E = O, 3; S, 4) behave similarly, yielding the corresponding semichalcogenides Ph 2P(E)fcCH2PPh2 (E = O, 5; S, 6). Exhaustive oxidations of 1 with hydrogen peroxide or elemental sulfur produce Ph 2P(E)fcCH2P(E)Ph2 (E = O, 7; S, 8), while similar oxidations of 5 and 6 afford the unsymmetric bis-chalcogenides Ph 2P(O)fcCH2P(S)Ph2 (9) and Ph 2P(S)fcCH2P(O)Ph2 (10), respectively. Compounds 1 and 3-10 were characterized by spectral methods, and the crystal structures of 3 and 8-10 were determined by single-crystal X-ray diffraction analysis. Compound 1 reacts with group 10 metal dichloride precursors to give the respective chelate complexes [MCl2(1-κ2P,P′)] (11, M = Ni; 12, M = Pd; and 13, M = Pt). The Ni complex is paramagnetic and tetrahedral; the Pd and Pt complexes are expectedly square-planar and diamagnetic. Crystal structures of 11-13 reveal less acute ligand bite angles (P-M-P′) than those observed in the analogous dppf complexes, the difference being considerably larger for the Ni complex than in the less flexible square-planar complexes. Similarly to dppf and fc(CH 2PPh2)2, ligand 1 reacts with [(L NC)PdCl]2 (LNC = [2-(dimethylamino)methyl] phenyl) to give a diphosphine-bridged complex, [(μ-1){(LNC)PdCl} 2] (14), whereas the reaction with the mononuclear precursor [(L NC)Pd(MeCN)2]ClO4 yields a mixture of isomeric bis-chelates [(LNC)Pd(1-κ2P,P′)]ClO 4 (15a,b). Catalytic tests in Pd-catalyzed Suzuki-Miyaura cross-coupling and in Pd-catalyzed cyanation of aryl halides with K 4[Fe(CN)6]?3H2O suggest that introduction of one methylene spacer group into the structure of dppf influences catalytic performance only marginally.
