The electronic structure and chemical bonding in a recently synthesized inorganic fullerene-like molecule, {[CuCl]20[Cp*FeP5]12 [Cu(CH3CN)2+ Cl-]5}, has been studied by a density functional approach. Geometrical optimization of the three basic structural units of the molecule is performed with Amsterdam Density Functional Program. The results are in agreement with the experiment. Localized MO抯 obtained by Boys-Foster method give a clear picture of the chemical bonding in this molecule. The reason why CuCl can react with Cp*FeP5 in solvent CH3CN to form the fullerene-like molecule is explained in terms of the soft-hard Lewis acid base theory and a new concept of covalence.
Many polynuclear Cu(I) compounds have been synthesized, but the problem whether there is direct or no direct Cu-Cu bonding in these compounds is not clear. The electronic structure of [CuNRR′]4 type clusters was investigated by using density functional methods. The results of geometrical optimization are in good agreement with experiment, and the localization of MO’s shows that there are four Cu-Cu s bonds to form the square Cu4 ring in addition to the four bridging Cu-N-Cu bonds. A concept of the covalence of molecular fragments is proposed to describe the bonding in these clusters.
A self-designed test machine of continuously semisolid extending extrusion was made to produce the flat bar of A2017 alloy. The slurry of A2017 alloy with spherical or elliptical structures was obtained. During manufacturing semisolid A2017 alloy by the proposed process, the spherical grain was formed with the application of the large force provided by the rough roll. By controlling the casting temperature, the products of A2017 alloy with fine surfaces and rectangular transections of 14 mm×25 mm were produced. The microstructure of the product is fine with the stripped appearance. The fracture strength and elongation of the product are increased by 100 MPa and 29%, respectively.
