94394-59-9Relevant academic research and scientific papers
N-Heterocyclic Carbene-Ytterbium Amide as a Recyclable Homogeneous Precatalyst for Hydrophosphination of Alkenes and Alkynes
Yuan, Jia,Hu, Hongfan,Cui, Chunming
, p. 5778 - 5785 (2016/04/20)
The N-heterocyclic carbene-ytterbium(II) amides (NHC)2Yb[N(SiMe3)2]2 (1: NHC: 1,3,4,5-tetramethylimidazo-2-ylidene (IMe4); 2: NHC: 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (IiPr)) and the NHC-stabilized rare-earth phosphide (IMe4)3Yb(PPh2)2 (3) have been synthesized and fully characterized. Complexes 1-3 are active precatalysts for the hydrophosphination of alkenes, alkynes, and dienes and exhibited much superior catalytic activity to that of the NHC-free amide (THF)2Yb[N(SiMe)2]2. Complex 1 is the most active precursor among the three complexes. In particular, complex 1 can be recycled and recovered from the reaction media after the catalytic reactions. Furthermore, it was found that complex 3 could catalyze the polymerization of styrene to yield atactic polystyrenes with low molecular weights. To the best of our knowledge, complex 1 represents the first rare-earth complex that can be recovered after catalytic reactions.
Synthesis and molecular structures of divalent bridged bis(guanidinate) europium complexes and their application in intermolecular hydrophosphination of alkenes and alkynes
Liu, Qianqian,Wang, Chuanyong,Zhang, Xingmin,Xue, Mingqiang,Yao, Yingming,Zhang, Yong,Shen, Qi
supporting information, p. 10447 - 10454 (2016/12/06)
The reaction of anhydrous EuCl3 with one equiv. of lithium salt of a three-carbon bridged bis(guanidinate) Li2L1 (L1 = [iPr(Me3Si)NC(NiPr)N(CH2)3NC(NiPr)N(SiMe3)iPr]) in THF afforded chloride EuIIIL1Cl(THF)2 (1). The reduction reaction of complex 1 with Na/K alloy in a molar ratio of 1?:?1.2 in THF gave a novel EuII complex supported by an unexpected new bridged bis(guanidinate) ligand L3, [EuIIL3]2 (L3 = [iPr(Me3Si)NC(NiPr)N(CH2)3N(SiMe3)C(NiPr)2]) (2), through the redistribution of one guanidinate in L1 during the reduction. Complex 2 was structurally characterized to be a binuclear complex in which two Eu metals are connected together by two L3 ligands that adopted a μ-η1:η2:η2 coordination mode for one L3 ligand and a μ-η2:η2:η2 mode for the other. Treatment of the in situ formed EuIIIL2Cl(THF)2 (L2 = 1,8-C10H6{NC(NiPr)(NHiPr)}2) by the reaction of EuCl3 with 0.5 equiv. of [Li2L22Li2] in THF with Na/K alloy yielded a novel EuII complex [EuIIL2(THF)]2 (3) in good yield. Complex 3 was characterized by an X-ray crystal structure analysis. Complex 3 features an unusual μ-η1:η2:η2 coordination mode of the bridged bis(guanidinate) ligand onto EuII. Complexes 2 and 3 are efficient pre-catalysts for the intermolecular hydrophosphination of alkenes and alkynes to give exclusively anti-Markovnikov products and mainly anti-addition products for the alkyne reactions. For these transformations, the best performances were observed with complex 2.
Preparation of β-Substituted trans-Ethylene Diphenylphosphines and Sulphides by P(O) and P(S)-activated Olefination
Gloyna, Dieter
, p. 360 - 366 (2007/10/02)
Methylene bis-diphenylphosphine monoxide (3c) in toluene reacts regiospecifically and stereoselectively with aldehydes in the presence of potassium tert-butoxide to β-substituted trans-ethylene diphenylphosphines 6, which can be oxidized to the sulphides 2 by sulphur in acetone.These sulphides 2 are to be obtained also directly from methylene bis-diphenylphosphine oxide sulphide 3b and methylene bis-diphenylphosphine disulphide 3d, respectively, under the same olefination conditions.But the yields are smaller and the purification of the raw products is much more difficult, if 3d is used.
