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A new hexanuclear copper(II) sandwich complex based on two 12-membered macrocyclic methylsiloxanolate ligands, [Cu6{(MeSiO2)6}2]·6DMF, was synthesized and characterized by single-crystal X-ray diffraction analysis and magnetic measurements. The cluster compound crystallizes in the monoclinic system, space group P21/n (No. 14), with a = 13.3728(5) A, b = 15.4281(7) A, c = 17.4335(7) A, β = 98.932(3)° and Z = 2. The unit cell contains two identical molecular clusters, each consisting of six interacting Cu2+ (S = ) ions. Within the cluster the six oxygen-bridged Cu2+ ions are arranged in an almost regular hexagon. An analysis of the high-temperature part of the magnetic susceptibility reveals that the complex has a strong average ferromagnetic Cu–Cu exchange interaction of |Jav/kB| = (50.4 ± 1) K with a high-spin S = 3 ground state. A satisfactory fit for the magnetic susceptibility and the magnetization in the whole accessible temperature range is obtained from a Heisenberg model with nonuniform exchange couplings within a ring, corresponding to a system of two weakly coupled trimers with a ferromagnetic intratrimer exchange coupling of |J/kB| = 72.5 K and a ferromagnetic intertrimer exchange coupling of |J′/kB| = 7 K. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

A new hexanuclear copper(II) sandwich complex based on two 10-membered macrocyclic phenylsiloxanolate ligands, {Cu6[(C6H5SiO2)5]2(OH)2(C10H8N2)2}·4(DMF)·3(H2O) (1), was synthesized and characterized by single-crystal X-ray diffraction and measurements of the magnetic susceptibility and isothermal magnetization. The cluster compound crystallizes in the triclinic system, space group P (No. 2), with a = 14.925(3) A, b = 16.745(2) A, c = 23.053(3) A, α = 83.079(9)°, β = 84.836(13)°, γ = 65.019(17)°, and Z = 2. The unit cell contains two identical molecules, each consisting of six interacting Cu2+ (S = 1/2) ions. Within the molecule, the six Cu2+ ions are arranged in two almost linear, parallel trimers. While pairs of oxygen atoms link the Cu2+ ions within the trimers, single oxygen atoms residing at the ends of the trimers provide the strongest intertrimer bonds. Magnetic measurements reveal an antiferromagnetic intratrimer exchange interaction, J/kB = 85 K, as the dominant magnetic coupling of the complex. By introducing a weak antiferromagnetic intertrimer coupling, J′/kB = 3.5 K, a satisfactory description of the magnetic behavior over a wide range of temperature and magnetic field is obtained. The departure of the model curves from the data at the lowest available temperature indicates the presence of additional, weak intra- and/or intermolecular interactions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

The alkali-metal-directed hydrolysis of phenyltrialkoxysilanes, PhSi(OR)3 (R = Me, Et, nBu), was performed under various reaction conditions. The alkali metal ions were used both as templating entities and as structural elements. The crystalline sodium and potassium phenylsiloxanolates (Na-PhS and K-PhS) were obtained in two different molecular compositions based on a cis-tetraphenylcyclotetrasiloxanolate, cis-[PhSi(O)O−]4, or on a cis-triphenylcyclotrisiloxanolate, cis-[PhSi(O)O−]3, anions assembled into a chain or double-layer supramolecular structure through coordination with alkali cations and hydrogen-bonding contacts. Conditions for selective preparation of crystalline Na-PhS or K-PhS of both structural types were identified. The molecular and crystal structures of [(Na+)3{PhSi(O)O−}3]·8H2O (2), [(Na+)3{PhSi(O)O−}3]·4H2O·1EtOH (3) and [(K+)3{PhSi(O)O−}3]2·7H2O·3MeOH (4) were determined by single-crystal X-ray analysis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Five silsesquioxanes (RSiO3/2)2n with R = siloxy and n = 4, 5 have been investigated by X-ray crystallography, MALDI-TOF mass spectrometry, and differential scanning calorimetry (DSC).

Catalytic hydrogenation of olefins containing functionalized silicon groups affords the saturated products in good yields. Chloro and alkoxy substituents at the silicon atom remain unaffected and, in the case of heterocyclic compounds, the cyclic or bicyclic moieties remain intact. The 2-silanorbornanes 4, 5, and 6 were synthesized from the corresponding 2-silanorbornenes 1, 2, and 3, and organosilanes 13 and 14 possessing the cyclopentyl group, were prepared from the cyclopentenyl-substituted precursors 10 and 12. The 3-vinyl-substituted silacyclobutanes 15, 17, and 18 were also hydrogenated in a simple apparatus with diethyl ether or THF as solvent, and Pd/C as a recoverable catalyst system. A basic organosilicon compound, trichloro(vinyl)silane, is hydrogenated in a nearly quantitative yield to form the saturated trichloro(ethyl)silane; this emphasizes the general applicability of this method.