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Ultrawideline 35Cl solid-state nuclear magnetic resonance (SSNMR) spectra of a series of 12 tin chlorides were recorded. The magnitude of the 35Cl quadrupolar coupling constant (CQ) was shown to consistently indicate the chemical state (oxidation number) of the bound Sn center. The chemical state of the Sn center was independently verified by tin Mössbauer spectroscopy. CQ(35Cl) values of >30 MHz correspond to Sn(IV), while CQ(35Cl) readings of <30 MHz indicate that Sn(II) is present. Tin-119 SSNMR experiments would seem to be the most direct and effective route to interrogating tin in these systems, yet we show that ambiguous results can emerge from this method, which may lead to an incorrect interpretation of the Sn oxidation number. The accumulated 35Cl NMR data are used as a guide to assign the Sn oxidation number in the mixed-valent metal complex Ph3PPdImSnCl2. The synthesis and crystal structure of the related Ph3PPtImSnCl2are reported, and 195Pt and 35Cl SSNMR experiments were also used to investigate its Pt–Sn bonding. Plane-wave DFT calculations of 35Cl, 119Sn, and 195Pt NMR parameters are used to model and interpret experimental data, supported by computed 119Sn and 195Pt chemical shift tensor orientations. Given the ubiquity of directly bound Cl centers in organometallic and inorganic systems, there is tremendous potential for widespread usage of 35Cl SSNMR parameters to provide a reliable indication of the chemical state in metal chlorides.

The addition of (2-ethynyl-3-methoxy-2-methylcyclopropyl)benzene to Tip2Si═SiTipPh, a disilene with an asymmetric substitution pattern, was investigated. The regiochemistry of the ring-opened products indicates a stepwise mechanism with a biradical intermediate. The results are consistent with those obtained in similar experiments with symmetrically substituted disilenes.

Background: In recent years, there has been a growing interest in the environmental relevance of the presence of several pharmaceutical compounds and their metabolites in water. To avoid further accumulation of these compounds and their metabolites in the aquatic environment, several research groups are investigating chemical and photochemical methods that could be applied in their destruction and subsequent removal from natural and wastewater. Objective & Method: Different chemical advanced oxidation processes are being developed to destroy organic pollutants in water. Most of these methods are based on the production of HO• radicals that are known to be highly reactive and strong oxidizing agents. In aqueous chemical processes, these radicals can be generated using a variety of reagents and under different reaction conditions such as O3, H2O2/UV, TiO2/UV, O3/UV, H2O2/Fe2+, H2O2/Fe2+/UV and O3/Fe2+/Cu2+/UV. This review is a survey on recent advances in the application of different chemical advanced oxidation processes to mineralize pharmaceuticals. Paracetamol was selected as a model compound since its structure is the main component or metabolite of several anesthetic and analgesic compounds. The degradation of paracetamol by different advanced oxidation methods has been investigated by a combination of techniques (TOC, UV-Vis, IR, HPLC and GC-MS) in order to determine the optimal reaction conditions, kinetics, intermediate and product compounds generated. Conclusion: Understanding the basic concepts about reaction conditions, intermediates and mechanistic details on mineralization of paracetamol will be quite useful for future applications of several techniques in the removal of this and other structurally related pharmaceutical and aromatic compounds from water.

The electronic structures of a series of gallium complexes are examined using X-ray absorption spectroscopy (XAS) in combination with ab initio calculations. The chemical states of Ga are strongly affected by the ligands and the bonding environment. For complexes containing multiple gallium sites, we demonstrate that XAS can identify the chemical state of each unique gallium center. A reliable understanding of the chemical nature of the core element in a coordination complex with strong core–ligand interaction can be obtained only when both experimental and theoretical approaches are combined.

Bis(trimethylsilyl)methanesulfonyl and tris(trimethylsilyl)methanesulfonyl chlorides (2cand 2d, respectively), have been prepared for the first time. Reactions of 2dwith nucleophiles give products evidently derived from bis(trimethylsilyl)sulfene (1c). Reaction of 2cwith piperidine gives the same piperidide as that from 2d, presumably via 1cformed by dehydrochlorination of 2c, whereas water and fluoride ion yield products consistent with their formation via trimethylsilylsulfene (1b) formed from 2cby attack at silicon with loss of the trimethylsilyl and chloro groups. No evidence for any enhanced stability in 1cwas found.Key words: sulfonyl chlorides, sulfenes, silylsulfonyl chlorides, silylsulfenes, desilylation.

The photolysis of Si,Si-di-tert-butyltetramesitylsiladigermirane in the presence of methylmagnesium iodide at 15°C has been investigated. Five products were isolated and identified from the complex product mixture: mesityldimethylgermane, dimesitylmethylgermane, (di-tert-butylmethylsilyl)mesitylmethylgermane, meta-(di-tert-butylmethylsilyl)toluene, and para-(di-tert-butylmethylsilyl)toluene. The characterization of these compounds and proposed mechanisms for their formation will be discussed.Key words: germasilene, Grignard reagents, germylmagnesium compounds.

Evidence for the formation of a biradical intermediate in the addition reactions of aldehydes to tetramesitylgermasilene and tetramesityl-disilene is presented.

A series of triazenes of type ArN=N—NH—CH2CO2Et, N-arylazoglycinc ethyl esters, have been prepared by coupling the arene diazonium salt, ArN2+•X−, with ethyl glycinate, NH2CH2CO2Et; an electron-withdrawing substituent, e.g. NO2, CN, CO2R, and Cl, in the orthoor paraposition of the aryl group is essential for efficient coupling. The p-substituted arylazoglycine ethyl esters cyclize when treated with alcoholic potassium hydroxide to afford the potassium salts of the 1-aryl-5-hydroxy-1,2,3-triazoles, which can be obtained free by acidification of the potassium salt solution with acetic acid. Reaction of the potassium salts with acetic anhydride yields the 1-aryl-5-acetoxy-1,2,3-triazoles. The5-hydroxytriazoles, when heated in ethanol, rearrange to α-diazoacetanilides, ArNH•COCHN2. The diazoamides can be obtained in low yield directly from the triazenes by prolonged refluxing in ethanol. o-Substituted aryltriazenes do not cyclize under the same conditions but fragment to the arylamine.

Evidence for a radical pathway in the cycloaddition reactions of alkenes to tetramesitylgermasilene and tetramesityldisilene is presented.

Si K-edge X-ray Absorption Fine Structures (XAFS) spectroscopy has been used to study the structure and bonding of a series of highly symmetric organosilicon compounds, Si(CH3)4, Ge[Si(CH3)3]4, Si[Ge(CH3)3]4, and Si[Si(CH3)3]4, in the gas phase. It was found that there is a significant difference in the absorption coefficient in the near-edge region between local Si–Si interactions in these compounds and long-range Si–Si interactions in crystalline solids and that the Si—Si bond length in the molecule Si[Si(CH3)3]4is 2.364(10) Å and the Si—Ge bond lengths in Si[Ge(CH3)3]4and Ge[Si(CH3)3]4are 2.38(3) Å and 2.396(15) Å, respectively. These results and their comparison to Si—Si and Si—Ge interatomic distances in crystalline solids are discussed. Keywords: XAFS, EXAFS, organosilicon, Si—Ge bond length.

The synthesis and reactivity of a gallium(I) cationic complex using [12]crown-4 as a stabilizing ligand were explored. The synthesis of [Ga([12]crown-4)][GaCl4] was achieved in one step from commercially available starting materials. Anion exchange was utilized to replace the reactive tetrachlorogallate anion for the perfluorophenylborate anion. [Ga([12]crown-4)][B(C6F5)4] was analyzed using XPS, which allowed for the classification of the gallium(I)-crown ether complex as electron-deficient. Reactions of the gallium(I)-crown ether complex with Cp*K and cryptand[2.2.2] demonstrated the facile synthesis of a known gallium(I) compound as well as the generation of new gallium(I) complexes, highlighting the use of the gallium(I)-crown ether complex as an effective starting material for new gallium(I) complexes.

Tetrakis(trimethylgermyl)silane can be synthesized by the addition of four equivalents of trimethylgermyllithium to tetrachlorosilane. Treatment of tetrakis(trimethylgermyl)silane with methyllithium gives tris(trimethylgermyl)silyllithium, which was trapped with aqueous hydrochloric acid, chlorotrimethylsilane or methyl iodide to yield tris(trimethylgermyl)silane, tris(trimethylgermyl)(trimethylsilyl)silane, or methyltris(trimethylgermyl)silane, respectively. Chlorination of tris(trimethylgermyl)silane affords dichlorobis(trimethylgermyl)silane.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.