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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Complexos de zinco(II) contendo ligantes hidrotris(pirazolil)borato altamente impedidos : síntese, reatividade e estrutura no estado sólido

Klitzke, Joice Sandra January 2009 (has links)
A química de coordenação e reatividade dos complexos de zinco(II) contendo ligantes mono aniônicos hidrotris(pirazolil)borato substituídos por grupos 3,3,3 - mesitil (TpMs) e 3,3,5 - mesitil (TpMs*) foram investigadas. A metátese dos sais Tl[TpMs] ou Tl[TpMs*] com ZnCl2, ZnEt2, e Zn(OAc)2 permitiu a formação dos compostos correspondentes puros TpMsZnCl, TpMsZnEt, TpMs*ZnEt e TpMsZnOAc. O composto TpMs*ZnEt, lentamente, desproporcionou-se em solução de benzeno para produzir o complexo bis(ligante) (k²-TpMs*)2Zn. Alternativamente, o complexo TpMsZnOAc, como também TpMsZnOCOPh e [TpMs*ZnOAc]2 foram preparados por acidólise dos complexos análogos TpMsZnEt e TpMs*ZnEt com o correspondente ácido carboxílico. Não foi observada reação entre TpMsZnEt e TpMs*ZnEt com os álcoois (ROH; R = Me, Et, iPr, Bn), enquanto que as reações de metátese de Tl[TpMs] com ZnEt(OR) levaram à formação do complexo TpMsZnEt, ao invés do complexo desejado zinco-alcóxido. Compostos TpMsZnCl, TpMsZnEt, TpMs*ZnEt, TpMsZnOAc, TpMsZnOCOPh, [TpMs*ZnOAc]2 foram caracterizados por análise elementar, espectroscopia de RMN de ¹H e ¹³C, e TpMsZnCl, TpMsZnEt, TpMsZnOAc, (k²-TpMs*)2Zn e [TpMs*ZnOAc]2 por estudos de difração de raio-X. Os compostos TpMsZnCl, TpMsZnEt, TpMsZnOAc e (k²-TpMs*)2Zn adotaram uma estrutura monomérica no estado sólido enquanto que o composto [TpMs*ZnOAc]2 existe como um dímero em ponte anti-sin por grupos acetato. O complexo (k2-TpMs*)2Zn é tetracoordenado, representando um raro modo de coordenação bidentado dos ligantes TpMs*. Os resultados foram racionalizados em termos da restrição estérea, que envolve o átomo de zinco, causada pelos ligantes TpMs e TpMs*. / The coordination chemistry and reactivity of zinc(II) complexes supported by monoanionic hydrotris(pyrazolyl)borate ligands substituted by 3,3,3-mesityl groups (TpMs) and 3,3,5-mesityl groups (TpMs*) have been investigated. Salt metathesis of ZnCl2, ZnEt2, and Zn(OAc)2 with Tl[TpMs] or Tl[TpMs*] cleanly afforded the corresponding compounds TpMsZnCl, TpMsZnEt, TpMs*ZnEt and TpMsZnOAc. Compound TpMs*ZnEt slowly disproportionates in benzene solution to afford the bis(ligand) complex (k²-TpMs*)2Zn. Acetate complex TpMsZnOAc as well as TpMsZnOCOPh and [TpMs*ZnOAc]2 were alternatively prepared by acidolysis of the parent ethyl complexes with the corresponding carboxylic acid. No reaction was observed between TpMsZnEt and TpMs*ZnEt and alcohols (ROH; R = Me, Et, iPr, Bn), while salt metathesis reactions of ZnEt(OR) with Tl[TpMs] led to TpMsZnEt instead of the desired zincalkoxide complex. Compounds TpMsZnCl, TpMsZnEt, TpMs*ZnEt, TpMsZnOAc, TpMsZnOCOPh, [TpMs*ZnOAc]2 were characterized by elemental analysis, ¹H and ¹³C NMR spectroscopy, as well as by X-ray diffraction studies for TpMsZnCl, TpMsZnEt, TpMsZnOAc, (k²-TpMs*)2Zn and [TpMs*ZnOAc]2. The former compounds adopt a monomeric structure in the solid state while [TpMs*ZnOAc]2 exists as an anti-syn bridged acetate dimer. Complex (k2-TpMs*)2Zn is fourcoordinated, featuring a rare bidentate coordination mode of the TpMs* ligands. The results are rationalized in terms of the variable steric constraint around the zinc atom provided by the TpMs and TpMs* ligands.
2

Complexos de zinco(II) contendo ligantes hidrotris(pirazolil)borato altamente impedidos : síntese, reatividade e estrutura no estado sólido

Klitzke, Joice Sandra January 2009 (has links)
A química de coordenação e reatividade dos complexos de zinco(II) contendo ligantes mono aniônicos hidrotris(pirazolil)borato substituídos por grupos 3,3,3 - mesitil (TpMs) e 3,3,5 - mesitil (TpMs*) foram investigadas. A metátese dos sais Tl[TpMs] ou Tl[TpMs*] com ZnCl2, ZnEt2, e Zn(OAc)2 permitiu a formação dos compostos correspondentes puros TpMsZnCl, TpMsZnEt, TpMs*ZnEt e TpMsZnOAc. O composto TpMs*ZnEt, lentamente, desproporcionou-se em solução de benzeno para produzir o complexo bis(ligante) (k²-TpMs*)2Zn. Alternativamente, o complexo TpMsZnOAc, como também TpMsZnOCOPh e [TpMs*ZnOAc]2 foram preparados por acidólise dos complexos análogos TpMsZnEt e TpMs*ZnEt com o correspondente ácido carboxílico. Não foi observada reação entre TpMsZnEt e TpMs*ZnEt com os álcoois (ROH; R = Me, Et, iPr, Bn), enquanto que as reações de metátese de Tl[TpMs] com ZnEt(OR) levaram à formação do complexo TpMsZnEt, ao invés do complexo desejado zinco-alcóxido. Compostos TpMsZnCl, TpMsZnEt, TpMs*ZnEt, TpMsZnOAc, TpMsZnOCOPh, [TpMs*ZnOAc]2 foram caracterizados por análise elementar, espectroscopia de RMN de ¹H e ¹³C, e TpMsZnCl, TpMsZnEt, TpMsZnOAc, (k²-TpMs*)2Zn e [TpMs*ZnOAc]2 por estudos de difração de raio-X. Os compostos TpMsZnCl, TpMsZnEt, TpMsZnOAc e (k²-TpMs*)2Zn adotaram uma estrutura monomérica no estado sólido enquanto que o composto [TpMs*ZnOAc]2 existe como um dímero em ponte anti-sin por grupos acetato. O complexo (k2-TpMs*)2Zn é tetracoordenado, representando um raro modo de coordenação bidentado dos ligantes TpMs*. Os resultados foram racionalizados em termos da restrição estérea, que envolve o átomo de zinco, causada pelos ligantes TpMs e TpMs*. / The coordination chemistry and reactivity of zinc(II) complexes supported by monoanionic hydrotris(pyrazolyl)borate ligands substituted by 3,3,3-mesityl groups (TpMs) and 3,3,5-mesityl groups (TpMs*) have been investigated. Salt metathesis of ZnCl2, ZnEt2, and Zn(OAc)2 with Tl[TpMs] or Tl[TpMs*] cleanly afforded the corresponding compounds TpMsZnCl, TpMsZnEt, TpMs*ZnEt and TpMsZnOAc. Compound TpMs*ZnEt slowly disproportionates in benzene solution to afford the bis(ligand) complex (k²-TpMs*)2Zn. Acetate complex TpMsZnOAc as well as TpMsZnOCOPh and [TpMs*ZnOAc]2 were alternatively prepared by acidolysis of the parent ethyl complexes with the corresponding carboxylic acid. No reaction was observed between TpMsZnEt and TpMs*ZnEt and alcohols (ROH; R = Me, Et, iPr, Bn), while salt metathesis reactions of ZnEt(OR) with Tl[TpMs] led to TpMsZnEt instead of the desired zincalkoxide complex. Compounds TpMsZnCl, TpMsZnEt, TpMs*ZnEt, TpMsZnOAc, TpMsZnOCOPh, [TpMs*ZnOAc]2 were characterized by elemental analysis, ¹H and ¹³C NMR spectroscopy, as well as by X-ray diffraction studies for TpMsZnCl, TpMsZnEt, TpMsZnOAc, (k²-TpMs*)2Zn and [TpMs*ZnOAc]2. The former compounds adopt a monomeric structure in the solid state while [TpMs*ZnOAc]2 exists as an anti-syn bridged acetate dimer. Complex (k2-TpMs*)2Zn is fourcoordinated, featuring a rare bidentate coordination mode of the TpMs* ligands. The results are rationalized in terms of the variable steric constraint around the zinc atom provided by the TpMs and TpMs* ligands.
3

Complexos de zinco(II) contendo ligantes hidrotris(pirazolil)borato altamente impedidos : síntese, reatividade e estrutura no estado sólido

Klitzke, Joice Sandra January 2009 (has links)
A química de coordenação e reatividade dos complexos de zinco(II) contendo ligantes mono aniônicos hidrotris(pirazolil)borato substituídos por grupos 3,3,3 - mesitil (TpMs) e 3,3,5 - mesitil (TpMs*) foram investigadas. A metátese dos sais Tl[TpMs] ou Tl[TpMs*] com ZnCl2, ZnEt2, e Zn(OAc)2 permitiu a formação dos compostos correspondentes puros TpMsZnCl, TpMsZnEt, TpMs*ZnEt e TpMsZnOAc. O composto TpMs*ZnEt, lentamente, desproporcionou-se em solução de benzeno para produzir o complexo bis(ligante) (k²-TpMs*)2Zn. Alternativamente, o complexo TpMsZnOAc, como também TpMsZnOCOPh e [TpMs*ZnOAc]2 foram preparados por acidólise dos complexos análogos TpMsZnEt e TpMs*ZnEt com o correspondente ácido carboxílico. Não foi observada reação entre TpMsZnEt e TpMs*ZnEt com os álcoois (ROH; R = Me, Et, iPr, Bn), enquanto que as reações de metátese de Tl[TpMs] com ZnEt(OR) levaram à formação do complexo TpMsZnEt, ao invés do complexo desejado zinco-alcóxido. Compostos TpMsZnCl, TpMsZnEt, TpMs*ZnEt, TpMsZnOAc, TpMsZnOCOPh, [TpMs*ZnOAc]2 foram caracterizados por análise elementar, espectroscopia de RMN de ¹H e ¹³C, e TpMsZnCl, TpMsZnEt, TpMsZnOAc, (k²-TpMs*)2Zn e [TpMs*ZnOAc]2 por estudos de difração de raio-X. Os compostos TpMsZnCl, TpMsZnEt, TpMsZnOAc e (k²-TpMs*)2Zn adotaram uma estrutura monomérica no estado sólido enquanto que o composto [TpMs*ZnOAc]2 existe como um dímero em ponte anti-sin por grupos acetato. O complexo (k2-TpMs*)2Zn é tetracoordenado, representando um raro modo de coordenação bidentado dos ligantes TpMs*. Os resultados foram racionalizados em termos da restrição estérea, que envolve o átomo de zinco, causada pelos ligantes TpMs e TpMs*. / The coordination chemistry and reactivity of zinc(II) complexes supported by monoanionic hydrotris(pyrazolyl)borate ligands substituted by 3,3,3-mesityl groups (TpMs) and 3,3,5-mesityl groups (TpMs*) have been investigated. Salt metathesis of ZnCl2, ZnEt2, and Zn(OAc)2 with Tl[TpMs] or Tl[TpMs*] cleanly afforded the corresponding compounds TpMsZnCl, TpMsZnEt, TpMs*ZnEt and TpMsZnOAc. Compound TpMs*ZnEt slowly disproportionates in benzene solution to afford the bis(ligand) complex (k²-TpMs*)2Zn. Acetate complex TpMsZnOAc as well as TpMsZnOCOPh and [TpMs*ZnOAc]2 were alternatively prepared by acidolysis of the parent ethyl complexes with the corresponding carboxylic acid. No reaction was observed between TpMsZnEt and TpMs*ZnEt and alcohols (ROH; R = Me, Et, iPr, Bn), while salt metathesis reactions of ZnEt(OR) with Tl[TpMs] led to TpMsZnEt instead of the desired zincalkoxide complex. Compounds TpMsZnCl, TpMsZnEt, TpMs*ZnEt, TpMsZnOAc, TpMsZnOCOPh, [TpMs*ZnOAc]2 were characterized by elemental analysis, ¹H and ¹³C NMR spectroscopy, as well as by X-ray diffraction studies for TpMsZnCl, TpMsZnEt, TpMsZnOAc, (k²-TpMs*)2Zn and [TpMs*ZnOAc]2. The former compounds adopt a monomeric structure in the solid state while [TpMs*ZnOAc]2 exists as an anti-syn bridged acetate dimer. Complex (k2-TpMs*)2Zn is fourcoordinated, featuring a rare bidentate coordination mode of the TpMs* ligands. The results are rationalized in terms of the variable steric constraint around the zinc atom provided by the TpMs and TpMs* ligands.

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