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Instruments / Technical Area	Publication Details	Published
	Synthesis, AACVD and X-ray crystallographic structures of group 13 monoalkoxometallanes Caroline Knapp , Leah Pemberton , Claire Carmault , David Pugh , Paul Mcmillan , Sarah Barnett , Derek A. Tocher Main Group Chemistry 9, 31-40 DOI: 10.3233/MGC-2010-0002 Show Abstract ▼ Abstract: The group 13 monoalkoxometallanes [Me_{2}Ga(OC(CH_{3})_{2}CH_{2}OMe)]_{2} (1) and [Me_{2}In(OCH(CH_{3})CH_{2}OMe)]_{2} (2), incorporating donor functionalised alkoxides, were synthesised from the reaction of GaMe_{3} or InMe_{3} with ROH (R=C(CH_{3})_{2}CH_{2}OMe (1); R=CH(CH_{3})CH_{2}OMe (2)) in toluene. X-ray crystallography showed that both compounds adopt dimeric structures with a planar M_{2}O_{2} ring, and each group 13 atom is coordinated in a distorted trigonal bipyramidal geometry. The AACVD reaction of GaMe_{3} and ROH (R =C(CH_{3})_{2}CH_{2}OMe, CH_{2}CH_{2}OMe, CH_{2}CH_{2}NMe_{2}) resulted in the formation of thin films of Ga_{2}O_{3} on glass substrates at 450°C. The gallium oxide films were analyzed by scanning electron microscopy, X-ray powder diffraction, energy dispersive analysis of X-rays, wavelength dispersive analysis of X-rays and X-ray photoelectron spectroscopy. This CVD technique offers a rapid, convenient route to Ga_{2}O_{3}, which involves the in situ formation of dimethylgallium alkoxides, of the type [Me_{2}Ga(?-OR)]_{2} similar to compound 1.	Mar 2010
NONE-No attached Diamond beamline	The observed and energetically feasible crystal structures of 5-substituted uracils Sarah Barnett , A. T. Hulme , N. Issa , T. C. Lewis , L. S. Price , D. A. Tocher , S. L. Price New Journal Of Chemistry 32 (10), 1761-1775 DOI: 10.1039/b806763e Show Abstract ▼ Abstract: A search of the Cambridge Structural Database for crystal structures of 5-substituted uracils shows that, although there is a recurrent motif with symmetric hydrogen bonding and interdigitation of the 5-substituent R, a range of other hydrogen bonded ribbons, sheets and three-dimensional motifs are possible. In order to try and rationalize this, we have performed a combination of experimental studies and computational searches for low energy structures for the 12 simple 5-substituted uracils with R = H, CH3, CH2CH3, CHCH2, CN, OH, NH2, NO2, F, Cl, Br and I. Crystallization experiments on these compounds yielded the first single crystal X-ray determinations of 5-ethyluracil and 5-cyanouracil, as well as low temperature redeterminations of the disordered structures of 5-chlorouracil and 5-bromouracil. The lattice energies were calculated for the known crystal structures and compared with the computed lattice energy landscape for each molecule (except R = Br and I). Although the symmetric ribbon motif often dominates the computed crystal energy landscape, all of the molecules show a variety of different hydrogen bonding structures within a small energy range (5 kJ mol−1) of the global minimum and exhibit quite a diverse range of energetically competitive motifs. Thus, the range of crystallization outcomes, from polymorphism and other multiple forms, to the difficulty in growing single crystals (R = CHCH2 and NH2) probably reflects the sensitivity of the various hydrogen bonding motifs to the substituent and limited range of crystallization conditions that can be applied.	Oct 2008
NONE-No attached Diamond beamline	Synthesis and structures of gallium alkoxides S. Basharat , C. E. Knapp , C. J. Carmalt , S. Barnett , D. A. Tocher New Journal Of Chemistry 32 (9), 1513-1518 DOI: 10.1039/b801579a Show Abstract ▼ Abstract: Homoleptic gallium tris(alkoxides) [Ga(OR)3]2 were prepared by the reaction of [Ga(NMe2)3]2 (1) and excess ROH (R = CH2CH2NMe2 (2), CH(CH3)CH2NMe2 (3), C(CH3)2CH2OMe (4), CH2CH2OMe (5)) in toluene at room temperature. Compounds 2–5 were isolated as colourless oils. The side-products, [Ga(OCH2CH2NMe2)2Cl] (6), [Ga(OCH(CH3)CH2NMe2)2Cl] (7) and [Ga(OC(CH3)2CH2OMe)Cl2]2 (8) were also isolated in low yield during the synthesis of 2, 3 and 4, respectively. However, compounds 6 and 7 were also prepared directly from the reaction of [Ga(NMe2)2Cl] and 2 equivalents of ROH (6, R = CH2CH2NMe2; 7, R = CH(CH3)CH2NMe2). Similarly, compound 8 was isolated from the reaction of [Ga(NMe2)Cl2] and 1 equivalent of HOC(CH3)2CH2OMe. Single crystal X-ray crystallography showed that the gallium bis(alkoxides) (6 and 7) are monomeric in the solid state with the gallium centre adopting a distorted trigonal bipyramidal geometry. In contrast, the gallium mono(alkoxide) 8 is dimeric	Sep 2008
NONE-No attached Diamond beamline	Syntheses, X-ray structures and CVD studies of diorganoalkoxogallanes S. Basharat , C. J. Carmalt , R. Palgrave , S. Barnett , D. A. Tocher , H. O. Davies Journal Of Organmetallic Chemistry 693 (10), 1787-1796 DOI: 10.1016/j.jorganchem.2008.01.042 Show Abstract ▼ Abstract: Structural studies by X-ray crystallography have been carried out for a range of diorganoalkoxogallanes incorporating donor-functionalized ligands. The compounds [Et2Ga(?-OR)]2 (1, R = CH2CH2NMe2; 2, R = CH(CH3)CH2NMe2; 3, C(CH3)2CH2OMe; 4, R = CH(CH2NMe2)2) adopt dimeric structures with a planar Ga2O2 ring, and each gallium atom is coordinated in a distorted trigonal bipyramidal geometry. Low pressure chemical vapor deposition (CVD) of 2 and 4 resulted in the formation of oxygen deficient gallium oxide thin films on glass. However, the reaction of Et3Ga and ROH (R = CH2CH2NMe2, CH(CH3)CH2NMe2, C(CH3)2CH2OMe, CH(CH2NMe2)2) in toluene under aerosol assisted (AA)CVD conditions afforded stoichiometric Ga2O3 thin films on glass. This CVD technique offers a rapid, convenient route to Ga2O3, which involves the in situ formation of diethylalkoxogallanes, of the type [Et2Ga(?-OR)]2, the structures of which are described in this paper. The gallium oxide films were deposited at 450 °C and analyzed by scanning electron microscopy (SEM), X-ray powder diffraction, wavelength dispersive analysis of X-rays (WDX), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.	Feb 2008

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