The amidinato compounds [GaMe,L] [L = RNCR'NR (R, R' = H, alkyl or aryl)], [GaMe(PhNCPhNPh),], [GaEt(PhNCMeNPh),] and [Ga(PhNCRNPh),] (R = Me or Ph) have been isolated from the reaction of the appropriate gallium trialkyl with 1, 2 and 3 mol of amidine RNCR'N(H)R, respectively. The chloro derivatives [GaCl,{ RNCR'N(H)R)] (R = Ph or p-ClC,H,; R' = Me) and [GaC12(p-C1C,H,NCMeNC,H,C1-p)l have also been prepared. The compounds have been fully characterised, and mass spectrometric data indicate that the volatile dimethylgallium derivatives exist as either monomers or dimers in the gas phase. X-Ray crystallographic studies on [GaMe,(PhNCPhNPh)] and [GaMe(PhNCPhNPh),] revealed monomeric structures and the presence of chelating amidinate ligands, with distorted tetrahedral and trigonal-bipyramidal co-ordination respectively at the metal centres. Cleavage of the Ga-Me bond occurs on photolysis in the presence of a spin-trapping agent, and thermal decomposition of the solids leads to the formation of gallium nitride.* Non-SZ units employed: G = T, eV z 1.60 x 10 l 9 J.
A range of polymer-supported bidentate amine Cu II complexes have been synthesized based on linear polymers, crosslinked resins and hydrogels as precursor species. Linear styrene, acrylate and methacrylate structures have been examined along with reactive crosslinked resins derived from vinylbenzyl chloride, glycidyl methacrylate and methacrylic acid (Amberlite IRC-50). Hydrogels based on hydroxyethyl methacrylate, hydroxyethyl acrylate and hydroxypropyl acrylate, each copolymerized with a diamine containing monomer, have also been prepared.Each Cu II -complexed polymer has been assessed as a catalyst in the hydrolytic decomposition of the nerve agent, Sarin, as a possible strategy for developing selfdecontaminating materials and coatings for both personnel and equipment in the event of a nerve agent challenge in the field.Based on the measured half-lives for hydrolysis of Sarin all of the polymer Cu II complexes show remarkable catalytic activity relative to the rate of the uncatalyzed hydrolysis reaction. The linear polymethacrylate-based catalysts are the most active followed by the linear polystyrene-based species, the macroporous polymethacrylates and the polystyrene resins. The polymethacrylate hydrogels are the least effective. It seems therefore that the hydrophilic/hydrophobic balance is important in controlling Sarin access to the catalytic sites, and this seems to be optimal in the linear polymethacrylate-based catalysts. The results are discussed further in the context of the existing literature.
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