研究了双(甲基亚氨基膦酰基)吡啶配体(L)与铜中心的配位。如通过X射线晶体学和MAS 31 P NMR所观察到的,使用溴化铜(I)前体可以得到[ L CuBr](2),其中只有一个亚氨基膦烷臂与金属配位。通过VT- 31 P NMR证明了其在溶液中的通量行为,并通过DFT计算对其进行了研究。另一方面,L与[Cu(CH 3 CN)4 ] PF 6的配位得到二聚体[ L 2 Cu 2 ](PF 6)2(3)其中两个铜中心不具有如X射线晶体学所示的相同的配位球。添加强配体(例如PEt 3)可以制备阳离子单体铜络合物(4),其中L的行为与2中观察到的相似。的铜(合成II)配合物也通过化学氧化来实现2,其示出在-0.36不可逆的氧化VS。的Fc + / Fc的,或直接通过的协调大号到的CuBr 2。在[ L CuBr 2 ](5),L采用钳式配合。最后,研究了铜(I)配合物2和3在环丙烷化反应和[3
研究了双(甲基亚氨基膦酰基)吡啶配体(L)与铜中心的配位。如通过X射线晶体学和MAS 31 P NMR所观察到的,使用溴化铜(I)前体可以得到[ L CuBr](2),其中只有一个亚氨基膦烷臂与金属配位。通过VT- 31 P NMR证明了其在溶液中的通量行为,并通过DFT计算对其进行了研究。另一方面,L与[Cu(CH 3 CN)4 ] PF 6的配位得到二聚体[ L 2 Cu 2 ](PF 6)2(3)其中两个铜中心不具有如X射线晶体学所示的相同的配位球。添加强配体(例如PEt 3)可以制备阳离子单体铜络合物(4),其中L的行为与2中观察到的相似。的铜(合成II)配合物也通过化学氧化来实现2,其示出在-0.36不可逆的氧化VS。的Fc + / Fc的,或直接通过的协调大号到的CuBr 2。在[ L CuBr 2 ](5),L采用钳式配合。最后,研究了铜(I)配合物2和3在环丙烷化反应和[3
Transition metal P-N complexes as polymerization catalysts
申请人:LANXESS Deutschland GmbH
公开号:EP2641909A1
公开(公告)日:2013-09-25
The present invention provides new metal complexes which can be advantageously used for homo- or copolymerization of at least one diene monomer optionally in the presence of one or more copolymerisable comonomers and which in particular provide cis-polydienes starting from conjugated dienes.
Synthesis and Reactivity of Low-Valent f-Element Iodide Complexes with Neutral Iminophosphorane Ligands
作者:Thibault Cheisson、Louis Ricard、Frank W. Heinemann、Karsten Meyer、Audrey Auffrant、Grégory Nocton
DOI:10.1021/acs.inorgchem.8b01259
日期:2018.8.6
ytterbium and samarium centers, as well as the trivalent uranium cation. The reactivity of the ytterbium adducts with benzophenone was found to be dependent on the steric demand of the supporting iminophosphorane ligand. In particular, a rare example of a stable charge-separated ketyl radical species is reported with ytterbium. Additionally, divalent thulium was observed to induce a reductive coupling
This paper reports the synthesis of a series of complexes based on the bis(pentamethylcyclopentadienyl)ytterbium(II) (1; Cp*Yb-2) and bis(tetramethylphospholyl)ytterbium(II) (2; Tmp(2)Yb) fragments bearing an additional neutral bis(methyliminophosphoranyl)pyridine ligand (L) on which the steric demand is modulated at the phosphorus position (triethyl, L-Et; triphenyl, LPh; tricyclohexyl, L-Cy) to yield the original complexes Cp*2YbLEt (1-L-Et), Cp*2YbLPh (1-LPh), Tmp2YbL(Et) (2-L-Et), Tmp2YbLPh (2-LPh), and Tmp2YbL(Cy) (2-L-Cy), while no reaction occurs between 1 and L-Cy. The crystal structures of these sterically crowded complexes are reported as well as room-temperature NMR data for all the complexes. The solid-state coordination mode of LR differs depending on the nature of the fragments 1 and 2 and on the steric bulk of LR. The crystal structure of the divalent Tmp2Yb(py)2 (3) is also reported for structural and spectroscopic comparisons. Interestingly, in both 2-L-Et and 2-L-Cy, one of the two Tmp ligands coordinates in an eta(1) rather than in an eta(5) fashion, a relevant coordination mode for the study of sterically induced reductions. The behavior of those complexes in solution varies with the sterics and electronics of the ligands, as demonstrated by variable-temperature NMR experiments. In solution, the 1JYbP coupling is used to track the coordination mode of the Tmp ligand and a large difference in the 1JYbP coupling constant allows the distinction between an eta(5) coordination mode and a dynamic eta(5)-eta(1) switch.