Organometallic compounds : LXIX. Synthesis and properties of the first chiral triorganostannyl-manganese complex

Methyl-1-naphthylphenylstannyltetracarbonyl(diphenyl-N-methyl-N-(S)-1-phenylethylaminophosphine)manganese (I) has been prepared by two different routes from racemic methyl-1-naphthylphenyltin chloride. Fractional recrystallizations yielded two diastereomeric fractions with fx205-1 = +40.3° and —71.4°, respectively, which have identical NMR and IR spectra.     

Diorganotin 2-fluorocinnamates and 4-fluorophenylacetates: Synthesis,characterization and in vitro antitumour activity

The synthesis and characterization by spectroscopy of several new di-n-butyltin and diethyltin 2-fluorocinnamates and 4-fluorophenylacetates are described. In vitro tests on two human tumour cell lines, MCF-7, a mammary tumour, and WiDr, a colon carcinoma, showed that two of these compounds are more active than cisplatin. Other in vitro tests performed by the NCI, USA on a panel of human tumour cell line show that one of them, bis[di-n-butyl(2-fluorophenylacetato)tin] oxide, is characterized by statistically significant D, D_TGI and D sensitivities, but non-significant D_H and MGD_H selectivities, whereas the analogous 2-fluorocinnamate shows no such significant values.     

Polarized emission of individual self-assembled oligo(p-phenylenevinylene)-based nanofibers on a solid support

We have prepared 5 nm diameter, micrometer long tetra(p-phenylenevinylene) (OPV)-based nanofibers on a graphite surface. The fluorescence emission of an individual fiber shows a profound polarization over its entire length that directly corresponds to its orientation on the substrate. Quantitative analysis of the fluorescence polarization, including the depolarizing effect of the underlying graphite, evidences the high degree of organization within chiral fibers with the OPV molecules perpendicular to the fiber axis. The control of the internal order within self-assembled fibers, and the ability to measure it, is a crucial step to obtain uniform organic fibers that can be applied in nanosized electronics at room temperature.     

Does the valence state index reflect the stability of neutral boron subhalide clusters?

The numbers of valence structures (NVS) and the valence state indexes (VSI) have been determined for a series of 2n framework electron clustersviz. polyhedral boron subhalides B _n X _n (n=6–12) and compared with those obtained for the parent B _n H _n ^2– dianions. The VSI does not reflect the experimental stabilities.