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Jason B Love - One of the best experts on this subject based on the ideXlab platform.
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controlling uranyl Oxo Group interactions to Group 14 elements using polypyrrolic schiff base macrocyclic ligands
Dalton Transactions, 2016Co-Authors: Nicola L Bell, Polly L Arnold, Jason B LoveAbstract:Heterodinuclear uranyl/Group 14 complexes of the aryl- and anthracenyl-linked Schiff-base macrocyclic ligands LMe and LA were synthesised by reaction of UO2(H2L) with M{N(SiMe3)2}2 (M = Ge, Sn, Pb). For complexes of the anthracenyl-linked ligand (LA) the Group 14 metal sits out of the N4-donor plane by up to 0.7 A resulting in relatively short M⋯OUO distances which decrease down the Group; however, the solid state structures and IR spectroscopic analyses suggest little interaction occurs between the Oxo and Group 14 metal. In contrast, the smaller aryl-linked ligand (LMe) enforces greater interaction between the metals; only the PbII complex was cleanly accessible although this complex was relatively unstable in the presence of HN(SiMe3)2 and some organic oxidants. In this case, the equatorial coordination of pyridine-N-oxide causes a 0.08 A elongation of the endo UO bond and a clear interaction of the uranyl ion with the Pb(II) cation in the second donor compartment.
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control of Oxo Group functionalization and reduction of the uranyl ion
Inorganic Chemistry, 2015Co-Authors: Polly L Arnold, Annefrederique Pecharman, Rianne M Lord, Guy M Jones, Emmalina Hollis, Gary S Nichol, Laurent Maron, Jian Fang, Thomas Davin, Jason B LoveAbstract:Uranyl complexes of a large, compartmental N8-macrocycle adopt a rigid, “Pacman” geometry that stabilizes the UV oxidation state and promotes chemistry at a single uranyl Oxo-Group. We present here new and straightforward routes to singly reduced and Oxo-silylated uranyl Pacman complexes and propose mechanisms that account for the product formation, and the byproduct distributions that are formed using alternative reagents. Uranyl(VI) Pacman complexes in which one Oxo-Group is functionalized by a single metal cation are activated toward single-electron reduction. As such, the addition of a second equivalent of a Lewis acidic metal complex such as MgN″2 (N″ = N(SiMe3)2) forms a uranyl(V) complex in which both Oxo-Groups are Mg functionalized as a result of Mg–N bond homolysis. In contrast, reactions with the less Lewis acidic complex [Zn(N″)Cl] favor the formation of weaker U–O–Zn dative interactions, leading to reductive silylation of the uranyl Oxo-Group in preference to metalation. Spectroscopic, crysta...
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Oxo Group 14 element bond formation in binuclear uranium v pacman complexes
Chemistry: A European Journal, 2013Co-Authors: Guy M Jones, Polly L Arnold, Jason B LoveAbstract:Simple and versatile routes to the functionalization of uranyl-derived U(V)-Oxo Groups are presented. The Oxo-lithiated, binuclear uranium(V)-Oxo complexes [{(py)3LiOUO}2(L)] and [{(py)3LiOUO}(OUOSiMe3)(L)] were prepared by the direct combination of the uranyl(VI) silylamide "ate" complex [Li(py)2][(OUO)(N")3] (N" = N(SiMe3)2) with the polypyrrolic macrocycle H4L or the mononuclear uranyl (VI) Pacman complex [UO2(py)(H2L)], respectively. These Oxo-metalated complexes display distinct U-O single and multiple bonding patterns and an axial/equatorial arrangement of Oxo ligands. Their ready availability allows the direct functionalization of the uranyl Oxo Group leading to the binuclear uranium(V) Oxo-stannylated complexes [{(R3Sn)OUO}2(L)] (R = nBu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium-Oxo-Group exchange occurred in reactions with [TiCl(OiPr)3] to form U-O-C bonds [{(py)3LiOUO}(OUOiPr)(L)] and [(iPrOUO)2(L)]. Overall, these represent the first family of uranium(V) complexes that are Oxo-functionalised by Group 14 elements.
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Oxo functionalization and reduction of the uranyl ion through lanthanide element bond homolysis synthetic structural and bonding analysis of a series of singly reduced uranyl rare earth 5f1 4fn complexes
Journal of the American Chemical Society, 2013Co-Authors: Polly L Arnold, Jason B Love, Emmalina Hollis, Gary S Nichol, Laurent Maron, N Magnani, Jean Christophe Griveau, R Caciuffo, Ludovic CastroAbstract:The heterobimetallic complexes [{UO2Ln(py)2(L)}2], combining a singly reduced uranyl cation and a rare-earth trication in a binucleating polypyrrole Schiff-base macrocycle (Pacman) and bridged through a uranyl Oxo-Group, have been prepared for Ln = Sc, Y, Ce, Sm, Eu, Gd, Dy, Er, Yb, and Lu. These compounds are formed by the single-electron reduction of the Pacman uranyl complex [UO2(py)(H2L)] by the rare-earth complexes LnIII(A)3 (A = N(SiMe3)2, OC6H3But2-2,6) via homolysis of a Ln–A bond. The complexes are dimeric through mutual uranyl exo-Oxo coordination but can be cleaved to form the trimetallic, monouranyl “ate” complexes [(py)3LiOUO(μ-X)Ln(py)(L)] by the addition of lithium halides. X-ray crystallographic structural characterization of many examples reveals very similar features for monomeric and dimeric series, the dimers containing an asymmetric U2O2 diamond core with shorter uranyl U═O distances than in the monomeric complexes. The synthesis by LnIII–A homolysis allows [5f1-4fn]2 and Li[5f1-4fn] ...
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the effect of the equatorial environment on Oxo Group silylation of the uranyl dication a computational study
Chemistry: A European Journal, 2010Co-Authors: Jason B Love, Polly L Arnold, Ahmed Yahia, Laurent MaronAbstract:: A theoretical investigation of the reductive Oxo-Group silylation reaction of the uranyl dication held in a Pacman macrocylic environment has been carried out. The effect of the modeling of the Pacman ligand on the reaction profiles is found to be important, with the dipotassiation of a single Oxo Group identified as a key component in promoting the reaction between the Si-X and uranium-Oxo bonds. This reductive silylation reaction is also proposed to occur in an aqueous environment but was found not to operate on bare ions; in this latter case, substitution of a ligand in the equatorial plane was the most likely reaction. These results demonstrate the importance of the presence but not the identity of the equatorial ligands upon the silylation of the uranyl U-O bond.
Polly L Arnold - One of the best experts on this subject based on the ideXlab platform.
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controlling uranyl Oxo Group interactions to Group 14 elements using polypyrrolic schiff base macrocyclic ligands
Dalton Transactions, 2016Co-Authors: Nicola L Bell, Polly L Arnold, Jason B LoveAbstract:Heterodinuclear uranyl/Group 14 complexes of the aryl- and anthracenyl-linked Schiff-base macrocyclic ligands LMe and LA were synthesised by reaction of UO2(H2L) with M{N(SiMe3)2}2 (M = Ge, Sn, Pb). For complexes of the anthracenyl-linked ligand (LA) the Group 14 metal sits out of the N4-donor plane by up to 0.7 A resulting in relatively short M⋯OUO distances which decrease down the Group; however, the solid state structures and IR spectroscopic analyses suggest little interaction occurs between the Oxo and Group 14 metal. In contrast, the smaller aryl-linked ligand (LMe) enforces greater interaction between the metals; only the PbII complex was cleanly accessible although this complex was relatively unstable in the presence of HN(SiMe3)2 and some organic oxidants. In this case, the equatorial coordination of pyridine-N-oxide causes a 0.08 A elongation of the endo UO bond and a clear interaction of the uranyl ion with the Pb(II) cation in the second donor compartment.
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subtle interactions and electron transfer between u iii np iii or pu iii and uranyl mediated by the Oxo Group
Angewandte Chemie, 2016Co-Authors: Polly L Arnold, Annefrederique Pecharman, Emmalina Hollis, Michal S Dutkiewicz, Markus Zegke, Olaf Walter, Christos Apostolidis, N Magnani, J C Griveau, E ColineauAbstract:A dramatic difference in the ability of the reducing An(III) center in AnCp3 (An=U, Np, Pu; Cp=C5 H5 ) to Oxo-bind and reduce the uranyl(VI) dication in the complex [(UO2 )(THF)(H2 L)] (L="Pacman" Schiff-base polypyrrolic macrocycle), is found and explained. These are the first selective functionalizations of the uranyl Oxo by another actinide cation. At-first contradictory electronic structural data are explained by combining theory and experiment. Complete one-electron transfer from Cp3 U forms the U(IV) -uranyl(V) compound that behaves as a U(V) -localized single molecule magnet below 4 K. The extent of reduction by the Cp3 Np Group upon Oxo-coordination is much less, with a Np(III) -uranyl(VI) dative bond assigned. Solution NMR and NIR spectroscopy suggest Np(IV) U(V) but single-crystal X-ray diffraction and SQUID magnetometry suggest a Np(III) -U(VI) assignment. DFT-calculated Hirshfeld charge and spin density analyses suggest half an electron has transferred, and these explain the strongly shifted NMR spectra by spin density contributions at the hydrogen nuclei. The Pu(III) -U(VI) interaction is too weak to be observed in THF solvent, in agreement with calculated predictions.
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control of Oxo Group functionalization and reduction of the uranyl ion
Inorganic Chemistry, 2015Co-Authors: Polly L Arnold, Annefrederique Pecharman, Rianne M Lord, Guy M Jones, Emmalina Hollis, Gary S Nichol, Laurent Maron, Jian Fang, Thomas Davin, Jason B LoveAbstract:Uranyl complexes of a large, compartmental N8-macrocycle adopt a rigid, “Pacman” geometry that stabilizes the UV oxidation state and promotes chemistry at a single uranyl Oxo-Group. We present here new and straightforward routes to singly reduced and Oxo-silylated uranyl Pacman complexes and propose mechanisms that account for the product formation, and the byproduct distributions that are formed using alternative reagents. Uranyl(VI) Pacman complexes in which one Oxo-Group is functionalized by a single metal cation are activated toward single-electron reduction. As such, the addition of a second equivalent of a Lewis acidic metal complex such as MgN″2 (N″ = N(SiMe3)2) forms a uranyl(V) complex in which both Oxo-Groups are Mg functionalized as a result of Mg–N bond homolysis. In contrast, reactions with the less Lewis acidic complex [Zn(N″)Cl] favor the formation of weaker U–O–Zn dative interactions, leading to reductive silylation of the uranyl Oxo-Group in preference to metalation. Spectroscopic, crysta...
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Oxo Group 14 element bond formation in binuclear uranium v pacman complexes
Chemistry: A European Journal, 2013Co-Authors: Guy M Jones, Polly L Arnold, Jason B LoveAbstract:Simple and versatile routes to the functionalization of uranyl-derived U(V)-Oxo Groups are presented. The Oxo-lithiated, binuclear uranium(V)-Oxo complexes [{(py)3LiOUO}2(L)] and [{(py)3LiOUO}(OUOSiMe3)(L)] were prepared by the direct combination of the uranyl(VI) silylamide "ate" complex [Li(py)2][(OUO)(N")3] (N" = N(SiMe3)2) with the polypyrrolic macrocycle H4L or the mononuclear uranyl (VI) Pacman complex [UO2(py)(H2L)], respectively. These Oxo-metalated complexes display distinct U-O single and multiple bonding patterns and an axial/equatorial arrangement of Oxo ligands. Their ready availability allows the direct functionalization of the uranyl Oxo Group leading to the binuclear uranium(V) Oxo-stannylated complexes [{(R3Sn)OUO}2(L)] (R = nBu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium-Oxo-Group exchange occurred in reactions with [TiCl(OiPr)3] to form U-O-C bonds [{(py)3LiOUO}(OUOiPr)(L)] and [(iPrOUO)2(L)]. Overall, these represent the first family of uranium(V) complexes that are Oxo-functionalised by Group 14 elements.
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Oxo functionalization and reduction of the uranyl ion through lanthanide element bond homolysis synthetic structural and bonding analysis of a series of singly reduced uranyl rare earth 5f1 4fn complexes
Journal of the American Chemical Society, 2013Co-Authors: Polly L Arnold, Jason B Love, Emmalina Hollis, Gary S Nichol, Laurent Maron, N Magnani, Jean Christophe Griveau, R Caciuffo, Ludovic CastroAbstract:The heterobimetallic complexes [{UO2Ln(py)2(L)}2], combining a singly reduced uranyl cation and a rare-earth trication in a binucleating polypyrrole Schiff-base macrocycle (Pacman) and bridged through a uranyl Oxo-Group, have been prepared for Ln = Sc, Y, Ce, Sm, Eu, Gd, Dy, Er, Yb, and Lu. These compounds are formed by the single-electron reduction of the Pacman uranyl complex [UO2(py)(H2L)] by the rare-earth complexes LnIII(A)3 (A = N(SiMe3)2, OC6H3But2-2,6) via homolysis of a Ln–A bond. The complexes are dimeric through mutual uranyl exo-Oxo coordination but can be cleaved to form the trimetallic, monouranyl “ate” complexes [(py)3LiOUO(μ-X)Ln(py)(L)] by the addition of lithium halides. X-ray crystallographic structural characterization of many examples reveals very similar features for monomeric and dimeric series, the dimers containing an asymmetric U2O2 diamond core with shorter uranyl U═O distances than in the monomeric complexes. The synthesis by LnIII–A homolysis allows [5f1-4fn]2 and Li[5f1-4fn] ...
Pavla Perlikova - One of the best experts on this subject based on the ideXlab platform.
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synthesis cytostatic antimicrobial and anti hcv activity of 6 substituted 7 het aryl 7 deazapurine ribonucleosides
Journal of Medicinal Chemistry, 2014Co-Authors: Petr Naus, Olga Caletkova, Petr Konecný, Petr Džubak, Kateřina Bogdanova, Milan Kolař, Jana Vrbkova, Lenka Postova Slavětinska, Eva Tloustova, Pavla PerlikovaAbstract:A series of 80 7-(het)aryl- and 7-ethynyl-7-deazapurine ribonucleosides bearing a methoxy, methylsulfanyl, methylamino, dimethylamino, methyl, or Oxo Group at position 6, or 2,6-disubstituted derivatives bearing a methyl or amino Group at position 2, were prepared, and the biological activity of the compounds was studied and compared with that of the parent 7-(het)aryl-7-deazaadenosine series. Several of the compounds, in particular 6-substituted 7-deazapurine derivatives bearing a furyl or ethynyl Group at position 7, were significantly cytotoxic at low nanomolar concentrations whereas most were much less potent or inactive. Promising activity was observed with some compounds against Mycobacterium bovis and also against hepatitis C virus in a replicon assay.
Laurent Maron - One of the best experts on this subject based on the ideXlab platform.
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control of Oxo Group functionalization and reduction of the uranyl ion
Inorganic Chemistry, 2015Co-Authors: Polly L Arnold, Annefrederique Pecharman, Rianne M Lord, Guy M Jones, Emmalina Hollis, Gary S Nichol, Laurent Maron, Jian Fang, Thomas Davin, Jason B LoveAbstract:Uranyl complexes of a large, compartmental N8-macrocycle adopt a rigid, “Pacman” geometry that stabilizes the UV oxidation state and promotes chemistry at a single uranyl Oxo-Group. We present here new and straightforward routes to singly reduced and Oxo-silylated uranyl Pacman complexes and propose mechanisms that account for the product formation, and the byproduct distributions that are formed using alternative reagents. Uranyl(VI) Pacman complexes in which one Oxo-Group is functionalized by a single metal cation are activated toward single-electron reduction. As such, the addition of a second equivalent of a Lewis acidic metal complex such as MgN″2 (N″ = N(SiMe3)2) forms a uranyl(V) complex in which both Oxo-Groups are Mg functionalized as a result of Mg–N bond homolysis. In contrast, reactions with the less Lewis acidic complex [Zn(N″)Cl] favor the formation of weaker U–O–Zn dative interactions, leading to reductive silylation of the uranyl Oxo-Group in preference to metalation. Spectroscopic, crysta...
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Oxo functionalization and reduction of the uranyl ion through lanthanide element bond homolysis synthetic structural and bonding analysis of a series of singly reduced uranyl rare earth 5f1 4fn complexes
Journal of the American Chemical Society, 2013Co-Authors: Polly L Arnold, Jason B Love, Emmalina Hollis, Gary S Nichol, Laurent Maron, N Magnani, Jean Christophe Griveau, R Caciuffo, Ludovic CastroAbstract:The heterobimetallic complexes [{UO2Ln(py)2(L)}2], combining a singly reduced uranyl cation and a rare-earth trication in a binucleating polypyrrole Schiff-base macrocycle (Pacman) and bridged through a uranyl Oxo-Group, have been prepared for Ln = Sc, Y, Ce, Sm, Eu, Gd, Dy, Er, Yb, and Lu. These compounds are formed by the single-electron reduction of the Pacman uranyl complex [UO2(py)(H2L)] by the rare-earth complexes LnIII(A)3 (A = N(SiMe3)2, OC6H3But2-2,6) via homolysis of a Ln–A bond. The complexes are dimeric through mutual uranyl exo-Oxo coordination but can be cleaved to form the trimetallic, monouranyl “ate” complexes [(py)3LiOUO(μ-X)Ln(py)(L)] by the addition of lithium halides. X-ray crystallographic structural characterization of many examples reveals very similar features for monomeric and dimeric series, the dimers containing an asymmetric U2O2 diamond core with shorter uranyl U═O distances than in the monomeric complexes. The synthesis by LnIII–A homolysis allows [5f1-4fn]2 and Li[5f1-4fn] ...
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the effect of the equatorial environment on Oxo Group silylation of the uranyl dication a computational study
Chemistry: A European Journal, 2010Co-Authors: Jason B Love, Polly L Arnold, Ahmed Yahia, Laurent MaronAbstract:: A theoretical investigation of the reductive Oxo-Group silylation reaction of the uranyl dication held in a Pacman macrocylic environment has been carried out. The effect of the modeling of the Pacman ligand on the reaction profiles is found to be important, with the dipotassiation of a single Oxo Group identified as a key component in promoting the reaction between the Si-X and uranium-Oxo bonds. This reductive silylation reaction is also proposed to occur in an aqueous environment but was found not to operate on bare ions; in this latter case, substitution of a ligand in the equatorial plane was the most likely reaction. These results demonstrate the importance of the presence but not the identity of the equatorial ligands upon the silylation of the uranyl U-O bond.
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a dft study of the single electron reduction and silylation of the u o bond of the uranyl dication in a macrocyclic environment
Chemical Communications, 2009Co-Authors: Ahmed Yahia, Jason B Love, Polly L Arnold, Laurent MaronAbstract:A DFT study of the reduction and silylation of the uranyl U–O bond in a macrocyclic complex shows the importance of the initial dipotassiation in THF solution, and a slightly downhill reaction pathway for the Oxo Group functionalisation.
Michael A J Rodgers - One of the best experts on this subject based on the ideXlab platform.
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synthesis and excited state dynamics of μ Oxo Group iv metal phthalocyanine oligomers trimers and tetramers
Journal of Physical Chemistry A, 2004Co-Authors: Tissa C Gunaratne, Vance O Kennedy, Malcolm E Kenney, Michael A J RodgersAbstract:Two μ-Oxo silicon phthalocyanines have been synthesized and subjected to photophysical examination. The results have been compared to the monomeric and dimeric systems published previously. The Q-bands in the ground state absorption spectra undergo a blue shift with respect to the monomer due to an excitonic interaction of the transition dipoles of the coplanar silicon phthalocyanine units having central symmetry along the Si−O−Si axis, with no significant molecular orbital overlap. This excitonic interaction generates a new set of excited states. The Q-band shift (with respect to the monomer) is greater as the number of phthalocyanine rings is increased consistent with the molecular exciton model of a linear polymer. On suprananosecond time scales, photoexcitation generated optical absorptions of triplet states that decayed with intrinsic lifetimes in the tens of microseconds region. These were quenched in the presence of O2 with bimolecular rate constants for the trimer and tetramer of near 2 × 106 M-1 ...
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synthesis and excited state dynamics of μ Oxo Group iv metal phthalocyanine dimers a laser photoexcitation study
Journal of Physical Chemistry A, 2001Co-Authors: Anna Paola Pelliccioli, Malcolm E Kenney, Kevin B Henbest, Gwanghoon Kwag, Terri R Carvagno, Michael A J RodgersAbstract:The synthesis of two metal phthalocyanine monomers, GePc[OSi(n-C6H13)3]2 and SnPc[OSi(n-C6H13)3]2, and two μ-Oxo-bridged dimers, (n-C6H13)3SiOSiPcOGePcOSi(n-C6H13)3 and (n-C6H13)3SiOSiPcOSnPcOH, are described. The ground-state absorption spectra and excited-state dynamics of these compounds together with those of (n-C6H13)3SiOSiPcOSiPcOSi(n-C6H13)3 have been measured. The absorption spectra of the dimers are blue shifted with respect to the monomers and whereas the latter exhibit a strong fluorescence in the visible, the dimers show only a weak emission in the near-IR. These observations are characteristic for the presence of exciton interactions in all three dimers, as had been reported earlier for the Si−O−Si dimer. Subnanosecond laser flash photolysis experiments on all five compounds yielded triplet−triplet absorption spectra, triplet lifetimes, triplet quantum yields, and bimolecular rate constants for quenching of the triplet states by O2. The triplet quantum yields and lifetime for the monomers and...
