Thesis (Ph. D.)--University of Wisconsin--Madison, 1926. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Reaction of hydrogen selenide with l-methyl (ene)-1,3-diones in ethanolic hydrogen chloride containing iron(III) chloride affords either bis(3-methyl(ene)-1,2-diselenolium)tetrachloroferrates (II) or tris(1-niethyl(ene)-1,3-diselenato)iron(II) complexes, and 2,4,6,8-tetraselenaadamantanes, Bis(3-methyl (ene)-1,2-diselenelium) tetrachloroferrates (II) are readily converted into the corresponding perchlorates. Dimethylthipformamide condenses with both 3 methyl(ene)-1,2-diselenolium perchlorates and tris(l-methyl (ene)-l,-3-diselenato) iron (III) complexes to give 3-(2-dimethylaminovinyl)-1,2-diseleolium (Vilsmeier) salts, These salts react with sodium hydroxide to form 3-acylmethylne-3H-l,2-dise1enoles, with sodium hydrogen sulphide to give 1-thia-6,6a-dise1napentalene, and with sodium hydrogen selenide, to form 1,6, 6a-diselenapentalenes, and with sodium hydrogen selenide to fom 1, 6, 6a-triselenapentalenes. In addition, treatment of 3-(2-dimethylamino-1-methylvinyl)-4-methy1-1, 2-dislenolium percholorate with sodium hydroxide, sodium hydrogen sulphide, and sodium hydrogen selenide affords 3, 5-dimethyl-4H-pyran-4-selenoketpne, 3, 5-dimethyl- 4H-thopyran-4-seleoacetone, and 3, 5-Dimthyl-4H-slenopyran-4-selenoketone respectively. 3, 5Dimethyl-4H-selenopyran-4-selotone is hydrolysed to 3,5-dimethyl-4H-selenopyrap-4-on in wet chloroform solutton. As a dry crystalline solid, 3,5-dimethyl-4Hr-selemopyrao-4-selenoketone is a tmospherically oxidised to 3, 5-dimethyl-4H-selenopyran-4-one, 3-(l- formylethylidene)-4-methyl-3H-l,2-diselenole, and 3,4-dmethyl-1,6-dioxa-6a-selenapnta1ene, 3,4-Dimthyl-l,6,6a-triselenapentalene and 4,5-dihydro-3H-bnzo[cd)]. 1,6,6a-trisolonapenalene are formed by treatment of 3-(l-formylethy1idene)-4-methyl-3H,1-2-diselenole and 3-formyl-5,6-dihydro-411-bonzo[c]1,2-diselenole respectively with phosphoryl chloride in dpiethylformamide and subsequent addition f aqueous potassium selenosulphate or potassium selenotrithionate. Compounds containing oxygen and selenium atoms in the 1- and 6, positons of the 6a-selenapentalene ring, when treated with phosphorus pentasulpc.1e, form 1,6-dithta-6a-selenapentalnes provided the 2- and 5-positions are unsubstituted. The structures of 3-acylmethylene-3H-l,2-diselenoles and 1-thia-6,6a-diselenapontalenes are discussed in relation to spectroscopic data and compared with those of 3-acymetbylene-3H-l,2dithioes and 6a-thiathiophthepo respectively, The crystal structures of 6a-thiathiophthene, 1,6.dftia-6a-selenapentalene, and 1 ,6,6a-triselnapentalene are compared and the structures of l,6-dithia-6a-selepapeptalenes and 1,6,6a-triselenapentlenes are discussed in relation to spectroscopic data, A bicyclic structure containing an oygen-selenium-oxygen bonding sequence is proposed for 3,4-dimethyl-1,6dipxa6a-selenapentaleqe on the basis of its N.M.R and I.R, spectra. The mechanism of the rearrangement of 6a-thiathiopbthenes by aqueous sodium sulphide to 4H-thiopyran-4-thiones has been studied with sodium sulphide-S-35. The initial step in the rearrangement is a reductive cleavage of sulphur-sulphur bond forming an anion which is then susceptible to nucleophilic attack by sulphide ion at the 2- (and/or 5-) position(s).

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Thesis (Ph. D.)--University of Wisconsin--Madison, 1923. / Typescript. With this is bound: The action of selenium oxychloride upon ethylene, propylene, butylene and amylene / By Carl E. Frick. Reprinted from Journal of the American Chemical Society, Vol. XLV, no. 7 (July 1923), p. [1795]-1800. Includes bibliographical references.

Call number: LD2668 .T4 1952 M3 / Master of Science

The current work investigates the photocatalytic reduction of selenium (Se) ions, selenate Se(VI) and selenite Se(IV), from two perspectives: Se ion removal from water and wastewater and the formation of nano-Se compounds. Se ion pollution has become an environmental issue in recent years, and hence there is an urgent need for an efficient removal technique. In addition, there is increasing interest in the formation of nano-size semiconductors for niche applications. Since Se is a semiconductor, its formation onto the semiconductor TiO2 could lead to the discovery of new composite materials. The current study has successfully elucidated the mechanism of Se ions reduction by photocatalysis. Factors such as the simultaneous adsorption of the Se ions (the electron scavenger in this case) and a suitable organic compound (the hole scavenger), and the chemical properties of the hole scavenger were crucial for effective and efficient Se ions photoreduction. Optimum conditions in relation to pH, concentrations and types of hole scavenger were reported and discussed. It was also found that stoichiometric adsorption ratio of formate and selenate resulted to optimum photoreduction rate. A modified Langmuir-Hinshelwood kinetic model that considered the simultaneous adsorption of both solutes was derived. The current investigation has also seen the successful formation Se deposits of different morphologies onto the TiO2 particles. Discrete Se particles of various sizes in the nano-size range as well as a Se film were deposited onto the TiO2 particles under different initial experimental conditions. The Se-TiO2 composite semiconductor was explored for the removal of cadmium Cd2+ ions, which resulted in the formation of CdSe-TiO2 systems. The photoreduction of Se ions using silver-modified TiO2 showed the enhanced reduction of Se ions to Se2- in the form of H2Se gas. It is suggested that the H2Se gas generated from the current photoreduction process could be used as a safer and cheaper technique in the formation of Se-compounds such copper selenide, cadmium selenide and zinc selenide. All these compounds were widely used in optical and semiconducting devices.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 116-127).

A general route to 1-chloro-1,2,4,6-selenatriazines with substuents on 3,5 positions has been developed by the reactions of N-imidoylamidines with selenium tetrachloride. The mechanism for these reactions is discussed according to the observed intermediates. At least two intermediates exist. One of the intermediates, 1,1-dichloro-3-trichloromethyl-4H-5-diisopropylphenyl-1,2,4,6-selenatriazine, was identified by 1HNMR, Mass spectroscopy and X-ray crystallography. 1-Chloro-1,2,4,6-selenatriazines were synthesized in high yield and fully characterized. Five 1-chloro-1,2,4,6-selenatriazine crystal structures were obtained. Reduction of 1-chloro-1,2,4,6-selenatriazines with triphenylamtimony immediately produced the corresponding selenatriazinyl radicals in hot acetonitrile. Pure radicals were obtained by in-situ crystallization as their dimers from reaction. Two crystal structures were obtained for 3-trifluoromethyl-5-p-tolyl-1,2,4,6-selenatriazinyl dimer and 3-trifluoromethyl-5-p-methyloxyphenyl-1,2,4,6-selenatriazinyl dimer. EPR spectroscopy measured all radicals coupling to three unique nitrogen atoms with 7 broad lines. There is no resolvable hyperfine coupling to 77Se, 37Cl/19F and phenyl protons. / xv, 172 leaves : ill. ; 29 cm.

The complexes Cp(,2)M(SH)(,2), where M = Ti and Zr, have been prepared and treated with S(,8) and >N-S(,x)-NN = benzimidazolyl, phthalimidyl and x = 1, 2, to give the metallacyclohexasulfanes Cp(,2)MS(,5). Reaction of Cp(,2)TI(SH)(,2) with >N-SR, where >N = phthalimidyl, succinimidyl, gave the complexes Cp(,2)Ti(S(,2)R)(,2) (R = CHMe(,2)) and Cp(,2)Ti(SR)(S(,3)R) (R = Ph, 4-C(,6)H(,4)Me). The thiolates Cp(,2)Ti(Cl)SR and Cp(,2)Ti(SR)(,2) (R = CHMe(,2), CMe(,3), Ph, 4-C(,6)H(,4)Me) were prepared for comparison. Treatment of the complexes Cp(,2)MCl(,2) with anhydrous solutions of Li(,2)E(,x) gave the complexes Cp(,2)ME(,5), where M = Ti, Zr, Hf and E = S, Se. The compounds (RCp)(,2)TiS(,5) (R = Me, SiMe(,3)),CH(,2)Cp(,2)TiS(,5), and (Me(,5)Cp)CpTiS(,5) were prepared similarly. Reaction of Li(,2)S(,x) with (Me(,5)Cp)(,2)MCl(,2) gave the metallacyclotetrasulfanes (Me(,5)Cp)(,2)MS(,3). The complex Cp(,2)Ti{S(CH(,2))(,3)S} was synthesized. Variable temperature ('1)H NMR studies established the barriers ((DELTA)G('(NOT=))) for ME(,x) and TiS(,2)C(,3) ring reversal in the above complexes. The crystal structures of Cp(,2)Ti(SPh)(S(,3)Ph), Cp(,2)MS(,5), and (Me(,5)Cp)(,2)TiS(,3) are discussed.