303745-38-2Relevant articles and documents
Versatile Coordination and C-C Coupling of Diphosphine-Tethered Imine Ligands with Ni(II) and Ni(0)
Verhoeven, Dide G. A.,Negenman, Hidde A.,Orsino, Alessio F.,Lutz, Martin,Moret, Marc-Etienne
, p. 10846 - 10856 (2018/09/14)
Ligands that can adapt their coordination mode to the electronic properties of a metal center are of interest to support catalysis or small molecule activation processes. In this context, the ability of imine moieties to bind in either an n1(N)-fashion via σ-donation of the lone pair or, less commonly, in an n 2(C,N)-fashion via π-coordination is potentially attractive for the design of new metal-ligand cooperative systems. Herein, the coordination chemistry of chelating ligands with a diphosphine imine framework (PCNP) to nickel is investigated. The imine moiety binds in an n 1(N)-fashion in a Ni(II)Cl2 complex. The uncommon n 2(C,N)-interaction is obtained in Ni(0) complexes in the presence of a PPh3 coligand. Increasing the bulk on the phosphine side-arms in the Ni(0) complexes, by substituting phenyl for o-tolyl groups, leads to a distinct binding mode in which only one of the phosphorus atoms is coordinated. In the absence of a coligand, a mixture of two different dimeric Ni(0) complexes is formed. In one of them, the imine adopts an uncommon n 1(N) n 2(C,N) bridging mode of the ligand to nickel, while the second one may involve reactivity on the ligand by the formation of a new C-C bond by oxidative coupling. The latter is supported by the isolation and structural characterization of a crystalline bis-CO derivative featuring a C-C bond formed by oxidative coupling of two imine moieties.
Stereospecific polymerization of 1,3-butadiene catalyzed by cobalt complexes bearing N-containing diphosphine PNP ligands
Chen, Lin,Ai, Pengfei,Gu, Jianming,Jie, Suyun,Li, Bo-Geng
, p. 55 - 61 (2012/11/07)
A series of cobalt complexes bearing N-containing diphosphine PNP ligands has been synthesized and characterized. The nature of the ligand structure affects the binding of the ligand to the cobalt center and determines the coordination geometry of the cobalt complexes. All the complexes have been employed to catalyze the polymerization of 1,3-butadiene, in combination with methylaluminoxane (MAO) or ethylaluminum sesquichloride (EASC) as the cocatalyst. Both the nature of the ligand and the type of cocatalyst had a remarkable influence on the polymerization activity, microstructure and molecular weight of the resulting polymers. The [Co]/MAO catalytic systems resulted in relatively lower conversions of butadiene and cis-1,4 contents in the polymers than the corresponding [Co]/EASC catalytic systems. Upon activation with EASC, the polymerization behaviors of the catalytic systems were also affected by the reaction parameters.
Synthesis, structure and kinetics of Group 6 metal carbonyl complexes containing a new ′P2N′ mixed donor multidentate ligandt
Ainscough, Eric W.,Brodie, Andrew M.,Buckley, Paul D.,Burrell, Anthony K.,Kennedy, Steven M. F.,Waters, Joyce M.
, p. 2663 - 2671 (2007/10/03)
The ′P2N′ mixed donor ligand 2-(diphenyIphosphino)-N-[2-(diphenylphosphino)benzylidene]aniline (PNCHP) reacted with [Cr(CO)4(NBD)] and [M(CO)4(C5H,N)2] (M = Mo or W; NBD = norbornadiene; CjH,N = piperidine) to yield cw-[Cr(CO)4(PNCHP-K2N,/J)] and m-[M(CO)4(PNCHP-κ2/′,/ )] respectively. PNCHP behaves as a ′P,N′ bidentate ligand when M is Cr and a ′P,P′ bidentate ligand when M is Mo or W. Heating m-[Cr(CO)4(PNCHPκ2N,P)] or cw-[M(CO)4(PNCHP-κ2P,.P′)] (M = Mo or W) in toluene affords the complexes ;jjer-[M(CO)3(PNCHPκ3P,N,P′)] (M = Cr, Mo or W). Reaction of PNCHP with [Mo(CO)3(CHT)] (CHT = 1,3,5-cycloheptatriene) in cold toluene yieIds/ac-[Mo(CO)3(PNCHP-κ3V,P′)] which readily isomerises to ;;;er-[Mo(CO)3(PNCHP-κ3P,7V,P′)] in solution. PNCHP reacts with UV-irradiated tetrahydrofuran solutions of [M(CO)6] (M = Cr or W) to yield phosphorus bound co-ordination isomers of [M(CO)5(PNCHP-K′P)J. The same reaction when carried out with one half equivalent of PNCHP yields the PNCHP bridged dinuclear species [{M(CO)5}2(PNCHP-κ2P,/ )J. The compounds have been characterised by spectroscopic means and the single crystal structures of c-[Cr(CO)4(PNCHP-K-4.P)], cw-[W(CO)4(PNCHP-κ2P,.P′)], icr-[Mo(CO)3(PNCHP-κ3/′,N,/ )] and [{W(CO)5}2(PNCHPκ2P,/)] determined. In addition, the isomerisation kinetics offac- to mer-[Mo(CO)3(PNCHP-KJ.P,yV,/ )] has been studied to determine rate constants and thermodynamic activation parameters. The Royal Society of Chemistry 2000.
