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Cortlandt G Pierpont - One of the best experts on this subject based on the ideXlab platform.
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coordination complexes of molybdenum with 3 6 di tert butylcatechol addition products of dmso Pyridine n oxide and triphenylarsine oxide to the putative movio 3 6 dbcat 2 monomer and self assembly of the chiral movio 3 6 dbcat 2 4 square
2004Co-Authors: Caiming Liu, Ebbe Nordlander, Derek Schmeh, Richard K Shoemaker, Cortlandt G PierpontAbstract:Molybdenum complexes of 3,6-di-tert-butylcatechol have been prepared from the reaction between [Mo(CO)6] and 3,6-di-tert-butyl-1,2-benzoquinone. A putative "[MoO(3,6-DBCat)2]" monomer is assumed to form initially by reaction with trace quantities of oxygen. Condensation of the reaction mixture leads to the formation of oligomeric products, including the [{MoO(3,6-DBCat)2}4] chiral square isolated by chromatographic separation. Molybdenum centers at the corner of the square are bridged by oxo ligands centered along edges. Four-fold and inversion crystallographic symmetry gives tetramers as either or isomers, and the crystal structure consists of parallel columns of squares with the same chirality. Addition of O-Subst (O-Subst = dmso, Pyridine N-Oxide, triphenylarsine oxide) ligands to [MoO(3,6-DBCat)2] occurs selectively to give cis-[MoO(O-Subst)(3,6-DBCat)2] products. All three addition complexes are fluxional in solution. The temperature-dependent stereodymanic behavior of [MoO(dmso)(3,6-DBCat)2] has been shown to occur via a trigonal prismatic intermediate (Bailar twist) that conserves the cis disposition of oxo and dmso ligands. Electrochemical and chemical reduction reactions have been investigated for [MoO(dmso)(3,6-DBCat)2] with interest in displacement of SMe2 with formation of cis-[MoO2(3,6-DBCat)2]2-. Cyclic voltammetry shows an irreversible two-electron reduction for the complex at -0.852 V (vs Fc/Fc+). Chemical reduction using CoCp2 was observed to give a product with an electronic spectrum that is generally associated with cis-[MoO2(Cat)2]2- complexes. Structural characterization revealed that the product was [CoCp2][MoO(3,6-DBCat)2], possibly formed as the product of dmso displacement upon one-electron reduction of [MoO(dmso)(3,6-DBCat)2]. (Less)
Silas C Blackstock - One of the best experts on this subject based on the ideXlab platform.
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heterocyclic n oxide ch o hydrogen bonding part 3 crystal packing of 2 2 biPyridine 1 1 dioxide and Pyridine n oxide
1998Co-Authors: Satish G Bodige, M A Zottola, S E Mckay, Silas C BlackstockAbstract:Abstract Short intermolecular CH⋯O contacts of 2.212(2) and 2.325(2) A are found in the crystal structure of 2,2′-biPyridine-1,1′-dioxide (BPDO) and are assigned as CH⋯O hydrogen bonds based on geometric criteria and quantum mechanical calculations. The pattern of BPDO association yields a two-dimensional CH⋯O hydrogen-bonded array in the BPDO crystal. Each BPDO molecule participates in eight CH⋯O hydrogen bonds, which occur in two distinct pairs as centric R 2 2 (8) and acentric R 2 2 (12) dimeric linkages whose binding enthalpies are estimated to be −6.7 and −2.3 kcal mol −1 , respectively, by AM1 calculations. Self-association via CH⋯O hydrogen bonding of the parent molecule, Pyridine N-Oxide (PO), is also considered. In solution, PO molecules are postulated to form CH⋯O bonded R 2 2 (8) dimers with an estimated binding energy of −5 to −8 kcal mol −1 . In the crystal, PO molecules associate to give a three-dimensional network via CH⋯O hydrogen bonding.
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supramolecular networks via Pyridine n oxide ch o hydrogen bonding in the crystal structures of 2 2 dithiobis Pyridine n oxide and its complexes with 1 2 4 5 tetracyanobenzene and pyromellitic dianhydride
1997Co-Authors: Satish G Bodige, Robin D Rogers, Silas C BlackstockAbstract:CH···O hydrogen bonding in crystals of 2,2′-dithiobis(Pyridine N-Oxide) (DTPO) supports network formation.
Caiming Liu - One of the best experts on this subject based on the ideXlab platform.
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coordination complexes of molybdenum with 3 6 di tert butylcatechol addition products of dmso Pyridine n oxide and triphenylarsine oxide to the putative movio 3 6 dbcat 2 monomer and self assembly of the chiral movio 3 6 dbcat 2 4 square
2004Co-Authors: Caiming Liu, Ebbe Nordlander, Derek Schmeh, Richard K Shoemaker, Cortlandt G PierpontAbstract:Molybdenum complexes of 3,6-di-tert-butylcatechol have been prepared from the reaction between [Mo(CO)6] and 3,6-di-tert-butyl-1,2-benzoquinone. A putative "[MoO(3,6-DBCat)2]" monomer is assumed to form initially by reaction with trace quantities of oxygen. Condensation of the reaction mixture leads to the formation of oligomeric products, including the [{MoO(3,6-DBCat)2}4] chiral square isolated by chromatographic separation. Molybdenum centers at the corner of the square are bridged by oxo ligands centered along edges. Four-fold and inversion crystallographic symmetry gives tetramers as either or isomers, and the crystal structure consists of parallel columns of squares with the same chirality. Addition of O-Subst (O-Subst = dmso, Pyridine N-Oxide, triphenylarsine oxide) ligands to [MoO(3,6-DBCat)2] occurs selectively to give cis-[MoO(O-Subst)(3,6-DBCat)2] products. All three addition complexes are fluxional in solution. The temperature-dependent stereodymanic behavior of [MoO(dmso)(3,6-DBCat)2] has been shown to occur via a trigonal prismatic intermediate (Bailar twist) that conserves the cis disposition of oxo and dmso ligands. Electrochemical and chemical reduction reactions have been investigated for [MoO(dmso)(3,6-DBCat)2] with interest in displacement of SMe2 with formation of cis-[MoO2(3,6-DBCat)2]2-. Cyclic voltammetry shows an irreversible two-electron reduction for the complex at -0.852 V (vs Fc/Fc+). Chemical reduction using CoCp2 was observed to give a product with an electronic spectrum that is generally associated with cis-[MoO2(Cat)2]2- complexes. Structural characterization revealed that the product was [CoCp2][MoO(3,6-DBCat)2], possibly formed as the product of dmso displacement upon one-electron reduction of [MoO(dmso)(3,6-DBCat)2]. (Less)
Eric P A Talbot - One of the best experts on this subject based on the ideXlab platform.
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gold catalyzed redox synthesis of imidazo 1 2 a Pyridines using Pyridine n oxide and alkynes
2014Co-Authors: Eric P A Talbot, Jeffrey Mckenna, Melodie S W Richardson, Dean F TosteAbstract:The reaction is sensitive to the steric effects and does not tolerate tBu- or mesityl-substituents.
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gold catalysed redox synthesis of imidazo 1 2 a Pyridine using Pyridine n oxide and alkynes
2014Co-Authors: Eric P A Talbot, Melodie Richardson, Jeffrey Mckenna, Dean F TosteAbstract:A mild, catalytic, atom economical synthesis of imidazo[1,2-a]Pyridines has been developed: catalytic PicAuCl2 in the presence of an acid produces a range imidazo[1,2-a]Pyridines in good yield. This strategy is mild and forseen to be of particular use for the installation of stereogenic centers adjacent to the imidazo[1,2-a]Pyridine ring without loss of enantiomeric excess.
Richard K Shoemaker - One of the best experts on this subject based on the ideXlab platform.
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coordination complexes of molybdenum with 3 6 di tert butylcatechol addition products of dmso Pyridine n oxide and triphenylarsine oxide to the putative movio 3 6 dbcat 2 monomer and self assembly of the chiral movio 3 6 dbcat 2 4 square
2004Co-Authors: Caiming Liu, Ebbe Nordlander, Derek Schmeh, Richard K Shoemaker, Cortlandt G PierpontAbstract:Molybdenum complexes of 3,6-di-tert-butylcatechol have been prepared from the reaction between [Mo(CO)6] and 3,6-di-tert-butyl-1,2-benzoquinone. A putative "[MoO(3,6-DBCat)2]" monomer is assumed to form initially by reaction with trace quantities of oxygen. Condensation of the reaction mixture leads to the formation of oligomeric products, including the [{MoO(3,6-DBCat)2}4] chiral square isolated by chromatographic separation. Molybdenum centers at the corner of the square are bridged by oxo ligands centered along edges. Four-fold and inversion crystallographic symmetry gives tetramers as either or isomers, and the crystal structure consists of parallel columns of squares with the same chirality. Addition of O-Subst (O-Subst = dmso, Pyridine N-Oxide, triphenylarsine oxide) ligands to [MoO(3,6-DBCat)2] occurs selectively to give cis-[MoO(O-Subst)(3,6-DBCat)2] products. All three addition complexes are fluxional in solution. The temperature-dependent stereodymanic behavior of [MoO(dmso)(3,6-DBCat)2] has been shown to occur via a trigonal prismatic intermediate (Bailar twist) that conserves the cis disposition of oxo and dmso ligands. Electrochemical and chemical reduction reactions have been investigated for [MoO(dmso)(3,6-DBCat)2] with interest in displacement of SMe2 with formation of cis-[MoO2(3,6-DBCat)2]2-. Cyclic voltammetry shows an irreversible two-electron reduction for the complex at -0.852 V (vs Fc/Fc+). Chemical reduction using CoCp2 was observed to give a product with an electronic spectrum that is generally associated with cis-[MoO2(Cat)2]2- complexes. Structural characterization revealed that the product was [CoCp2][MoO(3,6-DBCat)2], possibly formed as the product of dmso displacement upon one-electron reduction of [MoO(dmso)(3,6-DBCat)2]. (Less)
