Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

The use of conductivity measurements in organic solvents for the characterisation of coordination compounds

Organic chemists have always been fascinated by the cyclopropane subunit.1 The smallest cycloalkane is found as a basic structural element in a wide range of naturally occurring compounds.2 Moreover, many cyclopropane-containing unnatural products have been prepared to test the bonding features of this class of highly strained cycloalkanes3 and to study enzyme mechanism or inhibition.4 Cyclopropanes have also been used as versatile synthetic intermediates in the synthesis of more functionalized cycloalkanes5,6 and acyclic compounds.7 In recent years, most of the synthetic efforts have focused on the enantioselective synthesis of cyclopropanes.8 This has remained a challenge ever since it was found that the members of the pyrethroid class of compounds were effective insecticides.9 New and more efficient methods for the preparation of these entities in enantiomerically pure form are still evolving, and this review will focus mainly on the new methods that have appeared in the literature since 1989. It will elaborate on only three types of stereoselective cyclopropanation reactions from olefins: the halomethylmetal-mediated cyclopropanation reactions (eq 1), the transition metal-catalyzed decomposition of diazo compounds (eq 2), and the nucleophilic addition-ring closure sequence (eqs 3 and 4). These three processes will be examined in the context of diastereoand enantiocontrol. In the last section of the review, other methods commonly used to make chiral, nonracemic cyclopropanes will be briefly outlined.

Stereoselective Cyclopropanation Reactions

Publisher Summary This is one of two articles in this volume that is concerned with the borane-carborane structural pattern. In the other, Williams has shown how the pattern reflects the coordination number preferences of the various atoms involved. The purpose of the present article is to note some bonding implications of the pattern, and to show its relevance to a wide range of other compounds, including metal clusters, metal-hydrocarbon 7∼ complexes, and various neutral or charged hydrocarbons. Boranes and carboranes may be regarded as cluster compounds in the sense defined by Cotton; they contain a finite group or skeleton of atoms held together entirely, mainly, or at least to a significant extent by bonding directly between those atoms, even though some other atoms may be associated intimately with the cluster. Examples of their structural pattern, however, can be found far beyond the confines of what is normally regarded as cluster chemistry, so this survey includes many systems not commonly referred to as clusters.

Structural and Bonding Patterns in Cluster Chemistry

Porphyrin-based photosensitizers for use in photodynamic therapy

A bisamide-bisthiol ligand containing fatty acid substituted thiol useful for producing Tc-labelled radiodiagnostic imaging agents is described. The ligand forms a complex with the radionuclide 99mTc suitable for administration as a radiopharmaceutical to obtain images of the heart for diagnosis of myocardial disfunction.

Technetium radiodiagnostic fatty acids derived from bisamide bisthiol ligands

Radiopharmaceutical compounds are disclosed. A tropane compound is linked through the N atom at the 8-position to a chelating ligand capable of complexing technetium or rhenium to produce a neutral labeled complex that selectively binds to the dopamine transporter. These compounds can be prepared as separate diastereoisomers as well as a mixture of diastereoisomers. Also disclosed are radiopharmaceutical kits for preparing the labeled radiopharmaceutical compounds.

Dopamine transporter imaging agents

We have studied the effectiveness of various reducing agents in the production of the well-characterized complex [99TcO(SCH2CH2S)2]- from pertechnetate in aqueous solution. The reductants tested included sodium dithionite, hypophosphorous acid, formamidine sulfinic acid, dithiothreitol, hydrazine, and hydroxylamine. Of these, only sodium dithionite in the pH range 11--13 was found to give quantitative yields of the required technetium complex.

http://jnm.snmjournals.org/content/21/3/279.full.pdf

A survey of reducing agents for the synthesis of tetraphenylarsonium oxotechnetiumbis(ethanedithiolate) from [99Tc] pertechnetate in aqueous solution.

Trigonal bipyramidal compounds of technetium with a tetradentate umbrella ligand

Two general routes for the preparation of technetium complexes with aromatic amine, chloride, and alkoxide ligands are presented. The reactions of the tetrachlorooxotechnetate(V) anion of (n-Bu{sub 4}N)(TcOCl{sub 4}) with pyridine in tetrahydrofuran/alcohol solvent or of the dioxotetrakis(pyridine)technetium(V) cation of (TcO{sub 2}(py){sub 4})Cl with LiCl in sulfuric acid/alcohol both yield a neutral alkoxydichlorooxobis(pyridine)technetium(V) complex. The same isomer appears to result from either route. The analogous thiazole derivatives may be prepared in a like manner. The complex chloro(1,2-ethanediolato)oxo(1,10-phenanthroline)technetium(V), TcOCl(C{sub 2}H{sub 4}O{sub 2})(C{sub 12}H{sub 8}N{sub 2}), is prepared from (n-Bu{sub 4}N)(TcOCl{sub 4}) with 1,2-ethanediol and 1,10-phenanthroline in methanol. This complex was characterized by ir, uv/vis, and {sup 1}H and {sup 99}Tc NMR spectroscopies and by fast atom bombardment mass spectrometry. Further insight into the bonding in this complex comes from the single-crystal x-ray structure determination. The space group is monoclinic, P2{sub 1}/c, with a = 7.440 (2) {angstrom}, b = 8.928 (3) {angstrom}, c = 21.355 (4) {angstrom}, {beta} = 92.48 (2){degree}, V = 1417.2 (7) {angstrom}{sup 3}, and Z = 4. The structure was solved by standard methods and refined to R = 0.051 and R{sub w} = 0.036 based on 1859 reflections. The oxo and chloride ligands are mutually cis inmore » the highly distorted octahedral coordination sphere. The unusually long Tc-Cl bond length (2.418 (2) {angstrom}) is attributed to a trans influence exerted by the coordinated diolate. This effect combined with short lengths for the C-C bond (1.491 (1) {angstrom}) and for the O-Tc-O linkage (1.924 (4), 1.902 (3) {angstrom}) suggests partial multiple bonding between the technetium and the diolate. 38 references, 2 figures, 3 tables.« less

Alan Davison

Papers

Technetium radiodiagnostic fatty acids derived from bisamide bisthiol ligands

Dopamine transporter imaging agents

A survey of reducing agents for the synthesis of tetraphenylarsonium oxotechnetiumbis(ethanedithiolate) from [99Tc] pertechnetate in aqueous solution.

Trigonal bipyramidal compounds of technetium with a tetradentate umbrella ligand

Synthesis and characterization of technetium(V) complexes with amine, alcoholate, and chloride ligands