No abstract

The title compound, [Cu8(C8H24O2Si)2(C3H7NO)8].C4H4N2.C3H7NO, features a sandwich-like cage enclosing a pyrazine molecule, both situated on a centre of inversion. In addition, the crystal structure contains one dimethylformamide molecule which is disordered over a centre of inversion. The copper layer, containing eight atoms, is located between two siloxanolate fragments. The whole structure of Cu atoms and siloxanolate rings is distorted by the pyrazine molecule, leading to an oval form. As a result, the angles between the Cu atoms differ at the copper layer. The difference in the angles could lead to some deviations in the Cu-Cu exchange interactions within the copper ring, which is of interest for molecular magnetism.

A new hexanuclear copper(II) sandwich complex based on two 12-membered macrocyclic methylsiloxanolate ligands, [Cu 6 {(MeSiO 2 ) 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 P2 1 /n (No. 14), with a = 13.3728(5) Å, b = 15.4281(7) Å, c = 17.4335(7) Å, β = 98.932(3)°and Z = 2. The unit cell contains two identical molecular clusters, each consisting of six interacting Cu 2+ (S = ½) ions. Within the cluster the six oxygen-bridged Cu 2+ ions are arranged in an almost regular hexagon. An analysis of the high-temperature part of the magnetic susceptibility re-

No abstract

Key indicatorsSingle-crystal X-ray study T = 173 K Mean (C-C) = 0.009 Å R factor = 0.046 wR factor = 0.133 Data-to-parameter ratio = 15.9For details of how these key indicators were automatically derived from the article, seeMolecules of the title compound, [Cu 4 Na 4 (C 6 H 5 O 2 Si) 12 -(C 4 H 10 O) 8 ], are located on special positions of site symmetry 4. The Cu atoms are coordinated in a square planar fashion. The Na atoms, on the other hand, show an irregular sixfold coordination mode. The molecular conformation is stabilized by O-HÁ Á ÁO hydrogen bonds.