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The synthesis and structural analysis of two novel families of three-component reversible redox cycles [(C(2)B(9)H(11))M(mu-SPh)(2)](2)(n)PPN(n) (M = Mo, n = 2-, 2; 1-, 3; 0, 4; and M = W, n = 2-, 6; 1-, 7; 0, 8), where the cleavage and re-formation of the carborane cage C-C bond is observed during the redox reaction, are reported. Electronic saturation of the metal center (18e center) and the lack of bulky substituents on the carborane cage suggest that the deformed carborane cages in 2.PPN(2), 6.PPN(2), and 7.PPN invoke a new kind of deformed cage ("semicloso" framework). The XPS results show that the unprecedented competition for electron density between the metal center and the carborane cage is involved in the cleavage and formation of the carborane C-C bond.

The adsorption of thiophene on Ge(100) has been studied using scanning tunneling microscopy (STM), high-resolution core-level photoemission spectroscopy (HRPES), and density functional theory (DFT) calculations. Until now, thiophene is known to react with the Ge(100) dimer through a [4 + 2] cycloaddition reaction at room temperature, similar to the case of thiophene on Si(100). However, we found that thiophene has two adsorption geometries on Ge(100) at room temperature, such as a kinetically favorable Ge−S dative bonding configuration and a thermodynamically stable [4 + 2] cycloaddition adduct. Moreover, our STM results show that under 0.25 ML thiophene molecules preferentially produce one-dimensional molecular chain structures on Ge(100) via the Ge−S dative bonding configuration.

The adsorption and decomposition of AlCl3 on Ge(100) was studied using scanning tunneling microscopy (STM) and high-resolution core-level photoemission spectroscopy (HRCLPES). Through the analysis of the STM image and Ge 3d and Cl 2p core-level spectra of AlCl3 on Ge(100), we found that an AlCl3 molecule reacts with two Ge atoms via a cycloaddition reaction, which forms Cl−Ge and AlCl2−Ge without breaking AlCl3. Additionally, by considering valence shell electron pair repulsion (VSEPR) arguments, the effect of molecular structure on the surface chemistry was explained. To our knowledge, the adsorption of Lewis acid molecules on a semiconductor surface has not been studied in detail. These are the first results for the adsorption structures of Lewis acid molecule on Ge(100).