Synthesis, characterization and molecular structures of homo- and heterometallic nickel(II) aminoalkoxides Ni(eta(2)-ORN)(2) 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) (R-N =CHMeCH2NMe2)

Soluble Ni(II) alkoxides, namely the dimethylaminoisopropoxide clathrate wi th 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 base d on square planar molecules of the trans isomer. The structure of IV corre sponds to triangular aggregates with a M-3(mu (3)-OH) central core. The rem arkable feature is the presence of three types of coordination sphere, one metal is coordinated octahedrally and corresponds to nickel and the other t wo have square pyramidal and square planar coordinations, respectively, and an electronic density corresponding to Cu (75%) and Ni (25%). The monodent ate behavior of the two acetato ligands is stabilized by intramolecular hyd rogen 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 f or three uncoupled metal centers at high temperature whereas ferromagnetic exchange interactions are likely below 20 K. (C) 2001 Elsevier Science Ltd. All rights reserved.