Molecular structures of three coordinate zinc and cadmium complexes that feature beta-diketiminato and anilido-imine ligands

作者：Pang Keliang; Rong Yi; Parkin Gerard^*

来源：Polyhedron, 2010, 29(8): 1881-1890.

DOI：10.1016/j.poly.2010.02.020

• Zinc, Cadmium
• beta-Diketiminato
• Anilido-imine
• Alkyl
• Perfluorophenyl

A series of zinc and cadmium complexes of the beta-diketiminato and anilido-imine classes of ligands, namely [BDI(Ar)], [Al(Ar)] and [AI(Ar,Pr2i)], have been synthesized and structurally characterized by X-ray diffraction. For example, the zinc and cadmium alkyl compounds [Al(Ar)]ZnEt and [Al(Ar)]CdMe have been synthesized via the reactions of [Al(Ar)]H with Et(2)Zn and Me(2)Cd, respectively, while [Al(Ar)]ZnN(SiMe(3))(2) has been obtained by treatment of [Al(Ar)]H with Zn[N(SiMe(3))(2)](2). Single crystal X-ray diffraction studies establish that the metal centers in each of these complexes are trigonal planar. Comparison of the molecular structures of [Al(Ar)]CdMe and [BDI(Ar)]CdMe demonstrates that the cadmium methyl moiety lies in the plane of the annulated lAlArl ligand, whereas there is considerable displacement for [BDI(Ar)]CdMe. [AI(Ar,NPr2i)], an anilido-imine ligand that incorporates a CH(2)CH(2)NPr(2)(i) tether, has been synthesized via a sequence involving condensation of 2-fluorobenzaldehyde with H(2)NCH(2)CH(2)NPr(2)(i), followed by treatment with ArNHLi. X-ray diffraction demonstrates that the lithium has a T-shaped coordination environment which is supplemented by an agostic interaction with a C-H bond of one of the isopropyl groups of the NPr(2)(i) moiety. However, while the NPr(2)(i) group of the tether coordinates to lithium in [Al(Ar,NPr2i)]ZnMe, it does not coordinate to the zinc center of [AI(Ar,NME2)]ZnMe. The structure of [AI(Ar,NPr2i)]ZnMe is also in marked contrast to that reported for [AI(Ar,NPr2i)]ZnMe, in which the NMe(2) group does coordinate to the zinc center. The M-C bonds of [Al(Ar,NPr2i)]ZnMe, [BDI(Ar)]ZnEt and [BDI(Ar)]CdMe are cleaved by B(C(6)E(5))(3) to give the perfluorophenyl derivatives [BDI(Ar)]ZnC(6)F(5) and [BDI(Ar)]CdC(6)F(5). Interestingly, the C(6)F(5) groups are almost orthogonal to the planes of the chelating ligands in the zinc complexes, [Al(Ar,NPr2i)]ZnC(6)F(5) and [BDI(Ar)]ZnC(6)E(5), whereas the C(6)F(5) and [BDI(Ar)] ligands of [BDI(Ar)]CdC(6)F(5) reside in the same plane. In addition to 1:1 [Al(Ar,NPr2)]ZnX complexes, it is also possible to synthesize the 2:1 complex [AI(ArNPr2i)](2) which is consistent with the [Al(Ar,NPr2i)] ligand being less sterically demanding than the [BDI(Ar)] ligand.

• 出版日期2010-5-27