Photo-fragmentation of the closo-carboranes Part 1: Energetics of Decomposition

The ionic fragmentation following B 1s and C 1s excitation of three isomeric carborane cage compounds [closo-dicarbadodecaboranes: orthocarborane (1,2-C2B10H12), metacarborane (1,7-C2B10H12), and paracarborane (1,12-C2B10H12)], is compared with the energetics of decomposition. The fragmentation yields for all three molecules are quite similar. Thermodynamic cycles are constructed for neutral and ionic species in an attempt to systemically characterize single ion closo-carborane creation and fragmentation processes. Lower energy decomposition processes are favored. Among the ionic species, the photon induced decomposition isdominated by BH+ and BH2+ fragment loss. Changes in ion yield associated with core to bound excitations are observed

A new bend magnet beam line for scanning transmission x-ray microscopy at the Advanced Light Source

The high brightness of the bend magnets at the Advanced Light Source has been exploited to illuminate a Scanning Transmission X-ray Microscope (STXM). This is the first diffraction-limited scanning x-ray microscope to operate with useful count rate on a synchrotron bend magnet source. A simple, dedicated beam line has been built covering the range of photon energy from 250 eV to 600 eV. Ease of use and operational availability are radically improved compared to previous installations using undulator beams. This facility provides radiation for C 1s, N 1s and O 1s near edge x-ray absorption spectro-microscopy with a spectral resolution up to about 1:5000 and with STXM count rates in excess of 1 MHz

Adduct formation between diphenyltin dichloride and 2-phenyl-1,3-dithiane trans-1-trans-3-dioxide: preparation, spectroscopy, crystal and molecular structure of Ph2SnCl2.CH2(CH2)2SOCH(Ph)SO

A new pentacoordinate Sn (IV) adduct was prepared from diphenyltin (IV) dichloride and the disulphoxide 2-phenyl-1,3-dithiane trans-1, trans-3-dioxide. Spectroscopic and X-ray diffraction studies showed the new compound to be a rare example of a pentacoordinate 1:1 adduct between an organometallic Sn (IV) species and a neutral ligand. In spite of being difunctional, the ligand is monodentate as a result of its peculiar geometry. Moreover, the adduct does not show any evidence of strong intermolecular interactions, forming discrete molecules