Publications

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A series of cerium alkoxides were synthesized from the reaction of Ce{N[Si(CH3)3]2}3 and the appropriate alcohol: neopentyl alcohol [H-OCH2C(CH3) 3 = H-ONep], tert-butyl alcohol [H-OC(CH3)3 = H-OtBu], o-(tert-butyl)phenol {H-OC6H4[C(CH 3)3]-2 = H-oBP), 2,6-dimethylphenol [H-OC 6H3(CH3)2-2,6 = H-DMP], 2,6-diisopropylphenol {H-OC6H3[CH(CH3) 2]2-2,6 = H-DIP}, 2,6-di-tert-butylphenol {H-OC 6H3[C(CH3)3]2-2,6 = H-DBP}, or 2,6-diphenylphenol [H-OC6H3(C6H 5)2-2,6 = H-DPP] using toluene (tol), tetrahydrofuran (THF) or pyridine (py). The precursors were characterized as [Ce(μ-ONep) 2(ONep)]4 (1), Ce4(μ3-OtBu) 3(μ-OtBu)4(OtBu)5 (2), Ce 3(μ3-OtBu)3(H-OtBu)2(OtBu) 3(H-OtBu)2 (2a), Ce(OBP)3(THF)3 (3), [Ce(μ-DMP)(DMP)2(solv)2]2 [solv = THF (4) and py (4a)], Ce(DIP)3(THF)3 (5), Ce(DPP) 3(THF)2 (6). Once isolated, several of these species were further reacted with a series of sterically varied carboxylic acid modifiers including isobutyric acid [H-O2CCH(CH3)2 = H-OPc] and trimethylacetic acid [H-O2CC(CH3)3 = H-OBc]. The products were isolated as [Ce(OR)(μ-ORc)(μc-ORc) (py)]2 [OR = oBP, OBc: 7; DMP, OPc: 8; DMP, OBc: 9; DIP, OPc: 10]. These compounds were identified by single-crystal X-ray diffraction and powder XRD analyses. Several novel structure types are added to the cerium alkoxide family of compounds. © Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

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In the crystal structure of the title compound, C{sub 4}H{sub 4}N{sub 2}O{sub 3}, the packing is dominated by intermolecular carbonyl-carbonyl interactions and N-H...O hydrogen bonds.

We report a simple, rapid approach to synthesize water-soluble and biocompatible fluorescent quantum dot (QD) micelles by encapsulation of monodisperse, hydrophobic QDs within surfactant/lipid micelles. Analyses of UV-vis and photo luminescence spectra, along with transmission electron microscopy, indicate that the water-soluble semiconductor QD micelles are monodisperse and retain the optical properties of the original hydrophobic QDs. The QD micelles were shown to be biocompatible and exhibited little or no aggregation when taken up by cultured rat hippocampal neurons.

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The fundamental chemical behavior of the AlCl{sub 3}/SO{sub 2}Cl{sub 2} catholyte system was investigated using {sup 27}Al NMR spectroscopy, Raman spectroscopy, and single-crystal X-ray diffraction. Three major Al-containing species were found to be present in this catholyte system, where the ratio of each was dependent upon aging time, concentration, and/or storage temperature. The first species was identified as [Cl{sub 2}Al({mu}-Cl)]{sub 2} in equilibrium with AlCl{sub 3}. The second species results from the decomposition of SO{sub 2}Cl{sub 2} which forms Cl{sub 2}(g) and SO{sub 2}(g). The SO{sub 2}(g) is readily consumed in the presence of AlCl{sub 3} to form the crystallographically characterized species [Cl{sub 2}Al({mu}-O{sub 2}SCl)]{sub 2} (1). For 1, each Al is tetrahedrally (T{sub d}) bound by two terminal Cl and two {mu}-O ligands whereas, the S is three-coordinated by two {mu}-O ligands and one terminal Cl. The third molecular species also has T{sub d}-coordinated Al metal centers but with increased oxygen coordination. Over time it was noted that a precipitate formed from the catholyte solutions. Raman spectroscopic studies show that this gel or precipitate has a component that was consistent with thionyl chloride. We have proposed a polymerization scheme that accounts for the precipitate formation. Further NMR studies indicate that the precipitate is in equilibrium with the solution.

Tetrahydrofurfuryl alcohol (H-OTHF) was successfully reacted with a series of aluminum alkyls (AlR{sub 3}) to yield compounds of the general formula [R{sub 2}Al({mu}-OTHF)]{sub 2} where R = CH{sub 3} (1), CH{sub 2}CH{sub 3} (2), and CH{sub 2}CH(CH{sub 3}){sub 2} (3). Further, reactivity studies showed that the alkyls for 1 were easily exchanged, forming compounds of the general formula [Me(OR)Al({mu}-OTHF)]{sub 2} where OR = OC{sub 6}H{sub 3}(Me){sub 2}-2,6 (4), OC{sub 6}H{sub 3}(CMe{sub 3}){sub 2}-2,6 (5a), and OSi(C{sub 6}H5){sub 3} (6). For 5a, reflux temperatures were required to get the full exchange; otherwise the asymmetric derivative [Me(OR)Al({mu}-OTHF){sub 2}AlMe{sub 2}] (5b) was isolated. The bulk powders of 1-6 were found to be in agreement with the crystal structures on the basis of elemental analyses and multinuclear solid state NMR studies. Multinuclear solution state NMR studies indicate that the alkyl OTHF derivatives have cis/trans isomers due to the chiral proton on the OTHF ligand.