Browsing by Subject "structural-characterization"

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CO2 Adsorption Properties of a Ca(II)-Based Organophosphonium Coordination Material
(2012-01) Ibarra, Ilich A.; Tan, Kristina E.; Lynch, Vincent M.; Humphrey, Simon M.; Ibarra, Ilich A.; Tan, Kristina E.; Lynch, Vincent M.; Humphrey, Simon M.
PCM-14 is a dense coordination polymer formed from Ca(II) and an unusual organophosphonium ligand. The dehydrated framework contains 3-coordinate Ca(II) sites within catenated, chiral 3,3-connected nets. PCM-14 exhibits a stark CO2 sorption selectivity over H-2, N-2 and O-2. The maximum CO2 uptake was shown to be highly sensitive to the material pretreatment evacuation temperature.
Group 13 Decamethylmetallocenium Cations
(2007-12) Macdonald, Charles L. B.; Gorden, John D.; Voigt, Andreas; Filipponi, Silvia; Cowley, Alan H.; Macdonald, Charles L. B.; Gorden, John D.; Voigt, Andreas; Filipponi, Silvia; Cowley, Alan H.
Salts containing the decamethylmetallocenium cations, [( C5Me5) M-2](+) ( or Cp*M-2(+)) of the group 13 "metals" B, Al and Ga have been prepared using a variety of synthetic routes. Precursor molecules of the type Cp*2MX ( X = Cl, Br, Me) exhibit structural features that vary significantly depending on the size and electronegativity of the central atom. While salt metathesis, halide abstraction and methanide abstraction methods represent viable routes for the preparation of salts of Cp*B-2(+) and Cp*Al-2(+), acidolysis of a Cp* group from Cp*Ga-3 is the most reliable method for the synthesis of the analogous gallium cation. Gallocenium cations are less stable than either of the lighter congeneric cations since they prove to be susceptible to decomposition reactions involving the "back-transfer" of ligands from the counter anion. Density functional theory (DFT) calculations revealed that, whereas Cp*Ga-2(+) is predicted to adopt a molecular structure more similar to that of Cp*B-2(+), the electronic structure of the gallium cation bears a greater resemblance to that of Cp*Al-2(+).