Rare earth metal complexes based on β-diketiminato and novel linked bis(β-diketiminato) ligands: Synthesis, structural characterization and catalytic application in epoxide/CO2-copolymerization
摘要:
Mesityl substituted beta-diketiminato lanthanum and yttrium complexes [(BDI)Ln{N(SiRMe2)}(2)] (BDI = ArNC(Me)CHC(Me)-NAr, Ar = 2,4,6-Me3C6H2, Ln = La, R = Me (1), H (2a); Ln = Y, R = H (2b)) can be prepared via facile amine elimination starting from [La(N(SiMe3)(2)}(3)] and [Ln{N(SiHMe2)(2)}(3)(THF)(2)] (Ln = Y, La), respectively. The X-ray crystal structure analysis of 1 revealed a distorted tetrahedral geometry around lanthanum with a eta(2)-bound beta-diketiminato ligand. A series of novel ethylene- and cyclohexyl-linked bis(beta-diketiminato) ligands [C2H4(BDAr)(2)]H-2 and [Cy(BDIAr)(2)]H-2 [Ar = Mes (=2,4,6-Me3C6H2), DEP (=2,6-Et2C6H3), DIPP (=2,6-i-Pr2C6H3)] were synthesized in a two step condensation procedure. The corresponding bis(beta-diketiminato) yttrium and lanthanum complexes were obtained via amine elimination. The X-ray crystal structure analysis of the ethylene-bridged bis(beta-diketiminato) complex [{CyH4(BDIMes)(2)}YN(SiMe3)(2)] (3b) and cyclohexyl-bridged complexes [{Cy(BDIMes)(2)}LaN(SiMe2)(2)] (7) and [{Cy(BDIDEP)(2)} LaN(SiMe3)(2)] (8) revealed a distorted square pyramidal coordination geometry around the rare earth metal, in which the amido ligand occupies the apical position and the two linked beta-diketiminato moieties form the basis. The geometry of the bis(beta-diketiminato) ligands depends significantly on the linker unit. While complexes with an ethylene-linked ligand adopt a cisoid arrangement of the two aromatic substituents, complexes with cyclohexyl linker adopt a transoid arrangement. Either one (3b) or both (7, 8) of the beta-diketiminato moieties are tilted out of the eta(2) coordination mode, resulting in close Ln(...)C contacts. The beta-diketiminato and linked bis(beta-diketiminato) complexes were moderately active in the copolymerization of cyclohexene oxide with CO2. A maximum of 92% carbonate linkages were obtained using the ethylene-bridged bis(beta-diketiminato) complex [{C2H4(BDIMes)(2)}LaN(SiHMe2)(2)] (4). (c) 2005 Elsevier B.V. All rights reserved.
Synthesis and structural characterisation of novel linked bis(β-diketiminato) rare earth metal complexes
作者:Daniela V. Vitanova、Frank Hampel、Kai C. Hultzsch
DOI:10.1039/b501930c
日期:——
Rare earth metal complexes based on novel linked bis(β-diketiminato) ligands have been prepared via amine elimination and their structural characterisation revealed that the linker unit has significant influence on the geometry and coordination mode of the ancillary ligand.
Two β‐Diketiminate Zinc Complexes with 1‐D Chain and Dinuclear Topologies: Synthesis, Structures, and Catalytic Behavior
作者:Liang Zhang、Yafei Li、Li Wang、Zhu Cao、Qian Zhang、Yahong Li
DOI:10.1002/ejic.202200079
日期:2022.7.19
Two β-diketiminate zinccomplexes with structurally interesting 1-D chain and dinuclearstructures were synthesized and characterized. The chaincomplex exhibits high catalytic activity toward borylation of aryl iodides with B2Pin2.