RESUMO
A new family of bi-, tetra-, penta-, and hexanickel cagelike phenylsilsesquioxanes 1-6 was obtained by self-assembly and transmetalation procedures. Their crystal structures were established by single-crystal X-ray analysis, and features of crystal packing relevant to the network formation were studied by a topological analysis. Compounds 1, 2, and 4 are isolated architectures, while 3, 5, and 6 present extended 1D and 3D networks. The investigation of magnetic properties revealed the presence of ferro- (1 and 3-5) or antiferromagnetic (2 and 6) interactions between Ni(II) ions, giving rise in the most cases (1, 2, and 4-6) to the presence of a slow relaxation of the magnetization, which can originate from the spin frustration.
RESUMO
New hexanuclear nickel(II) silsesquioxane [(PhSiO1.5)12(NiO)6(NaCl)] (1) was synthesized as its dioxane-benzonitrile-water complex (PhSiO1,5)12(NiO)6(NaCl)(C4H8O2)13(PhCN)2(H2O)2 and studied by X-ray and topological analysis. The compound exhibits cylinder-like type of molecular architecture and represents very rare case of polyhedral complexation of metallasilsesquioxane with benzonitrile. Complex 1 exhibited catalytic activity in activation of such small molecules as light alkanes and alcohols. Namely, oxidation of alcohols with tert-butylhydroperoxide and alkanes with meta-chloroperoxybenzoic acid. The oxidation of methylcyclohexane gave rise to the isomeric ketones and unusual distribution of alcohol isomers.
Assuntos
Níquel/química , Compostos de Organossilício/química , Peróxidos/química , Catálise , OxirreduçãoRESUMO
Fine-tuning of the reaction between alkali metal siloxanolate [PhSi(O)ONa]n and [Ni(NH3)6]Cl2 allowed us to design new hexa- [(PhSiO1,5)12(NiO)6(H2O)(DMSO)9] () and pentanuclear [(PhSiO1,5)10(NiO)5(NaOH)(DMF)7] () cage-like silsesquioxanes. Their specific structures were studied by single crystal X-ray diffraction and topological analyses. Compound is the first example of a pentanuclear "cylinder"-like metallasilsesquioxane. Magnetic property investigations demonstrate the presence of a slow relaxation of the magnetization, induced by spin glass-like behavior in both cases.