The carbon–carbon bonding in cubane is shown not to be along the C–C vectors between carbon atoms at the corners of a cube. Instead, the bonding is “bent” as seen in a new single-crystal X-ray structure of cubane at 93 K. The bent bond angles and lengths are compared with the geometric angles and with predictions. The distortions from the tetrahedral angle of the sp3-hybridized carbon atoms are shown to be relatively small in cubane, unlike those in cyclopropane, which are large. Despite this and other differences, cubane and cyclopropane have similar reactivity, a fact that has not been widely recognized. It is suggested that cubane might mimic the chemistry of the cyclopropane ring in the pharmacology of some cyclopropane-containing drugs.

Inorganic−organic hybrid materials [Ni(py)4]2V10O29 (1) and [Ni2(py)5(H2O)3]V4O12 (2) have been synthesized and characterized by infrared spectroscopy, thermogravimetry, magnetometry, and complete single crystal structure analysis. The crystal structures of 1 and 2 exhibit novel three-dimensional covalent networks. The framework structure in 1 contains polyoxometallate groupings of stoichiometry {V10O29} which are constructed from two cyclic {V4O12} units bound to centrosymmetric {V2O7} species. V−O−Ni bridges in the a- and b-directions join these units to two crystallographically independent trans-[Ni(py)4O2] octahedra. The nickel- and vanadium-based moieties occupy alternating channels along the c-direction. The structure of 2 consists of octahedral species [Ni(py)3(H2O)O2] and [Ni(py)2(H2O)2O2] which are linked into a three-dimensional covalent network by the sharing of oxygen atom vertices with tetrahedral {VO4} groups. Compounds 1 and 2 are thermally stable up to 200 and 175 °C, respectively. Both compounds show Curie−Weiss type magnetic behavior over the temperature range 1.9−300 K. The effective magnetic moment in both cases is 3.0 μB, revealing the presence of significant orbital contribution. Single ion magnetization as a function of magnetic field showed linear behavior for 1 and 2 over the range of 0−1 T. At a magnetic field of 9 T, 1 approaches saturation at 2 μB per Ni2+ ion, whereas 2 does not approach saturation well.

A new type of mixed-valence polyoxoanionic cluster, [VV13VIV3O42(Cl)]8−, composed of 14 {VO5} square pyramids and 2 {VO4} tetrahedral units, hosting a chloride ion has been synthesized and characterized.

Six- and eight-membered hydrogen-bonded water clusters of novel structure types have been found in crystalline hydrates.