名称:
Synthesis, characterization and molecular structures of homo- and heterometallic nickel(II) aminoalkoxides Ni(η2-ORN)2 and Ni(Ni0.25Cu0.75)2(μ3-OH)(μ-OAc)(η1-OAc)2(μ,η2-ORN)2(η2-RNOH) (RN=CHMeCH2NMe2)
摘要:
Soluble Ni(II) alkoxides, namely the dimethylaminoisopropoxide clathrate with toluene, Ni(eta (2)-ORN)(2).C7H8 (I) and the solvent free crystalline Ni(ORN)(2) (R-N = CHMeCH2NMe2) species (II), obtained by sublimation of I in vacuo, were characterized by X-ray diffraction. The reaction between Ni(ORN)(2) and copper carboxylates such as propionate and copper acetate hydrate in hydrocarbons afforded [CuNi2(O2CEt)(3)(ORN)(3)((ROH)-O-N)] (III) and [Ni(Ni0.25CU0.75)(2)(mu (3)-OH)(mu -OAc)(eta (1)-OAc)(2)(mu, eta (2) -ORN)(2)(eta (2)-(ROH)-O-N)] (IV), respectively. The structures of I and II are based on square planar molecules of the trans isomer. The structure of IV corresponds to triangular aggregates with a M-3(mu (3)-OH) central core. The remarkable feature is the presence of three types of coordination sphere, one metal is coordinated octahedrally and corresponds to nickel and the other two have square pyramidal and square planar coordinations, respectively, and an electronic density corresponding to Cu (75%) and Ni (25%). The monodentate behavior of the two acetato ligands is stabilized by intramolecular hydrogen bonding involving the hydroxyl functionalities of the mu (3)-hydroxo (2.776(9) Angstrom) and the solvated aminoalcohol ligand (2,573(6) Angstrom). Magnetic data in the 20-300 K temperature range for III and IV account for three uncoupled metal centers at high temperature whereas ferromagnetic exchange interactions are likely below 20 K. (C) 2001 Elsevier Science Ltd. All rights reserved.