The crystal structure of triphenylphosphonium cyclopentadienylide has been determined from an X-ray crystallographic investigation. Mo Ka radiation was used and the X-ray intensities were measured with a computer-controlled diffractometer. The space group is monoclinic, Plfn; the lattice constants are a = 10.564, b = 8.986, c = 18.708 Á, ß = 93.410; there are four molecules per cell. The amount of ylene-ylide character (ca. 20-80%) is estimated from the P-C bond length, the -electron delocalization in the five ring evaluated from the C-C distances, and from the plus charge on P obtained from the P photoelectron spectrum. These data are compared with the results from a previously reported MO analysis. The conformations about the P-C (five ring) bond in the compound and about the P-Cbonds in a number of other ylides can be explained in terms of the orientations necessary for C p-orbital overlap with the two P d orbitals of symmetry.
The aluminum (2p) electron spectra of several anhydrous and “hydrous ” aluminum oxides have been recorded, and the binding energies have been measured. A simple electrostatic model is employed to explain the observed shift in binding energy and relate it to differences in structure and hydrogen bonding. Two conclusions can be drawn: structural differences must be considered when interpreting photoelectron spectra for inorganic crystalline substances; and hydrogen bonding with anions may have a measurable effect on the binding energy of core electrons of the cations.
X-Ray photoelectron spectroscopy (ESCA) has been used to measure the tin (3ds/2) electron binding energies for octahedral tin complexes of formula [(CHsCHdíNhtSnXs-nY,,]. The binding energies are found to correlate linearly with average ligand electronegativities, Mossbauer isomer shifts, and estimated atomic charges on the tin atom.The results are discussed in terms of these molecular parameters.
The single crystal x-ray structure of racemic glycerol 1,2-(di-11bromoundecanoate)-3-(p-toluenesulfonate), a sulfolipid analogous to the membrane phospholipids, reveals a folded conformation.
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