The coupling of oxetane (trimethylene oxide) and carbon dioxide catalyzed by VO(acac)<smal... more The coupling of oxetane (trimethylene oxide) and carbon dioxide catalyzed by VO(acac)<small>< sub>2</sub></small> in the presence of an onium salt was studied. The process was found to be highly selective and quantitative for the production of the six-membered cyclic carbonate ...
... Carlos AL Filgueiras, a Adolfo Horn Jr, a R. Alan Howie, b * Janet MS Skakle b and James L. W... more ... Carlos AL Filgueiras, a Adolfo Horn Jr, a R. Alan Howie, b * Janet MS Skakle b and James L. Wardell a. ... Its structure, confirming its identity, is the same as that reported by Morosin &Montgomery [Acta Cryst. (1969 [Morosin, B. & Montgomery, H. (1969). Acta Cryst. ...
The preparations of cis-2,4,5-triaryl-4,5-dihydro-1 H-imidazoles, (aryl = thien-2-yl or pyridin-2... more The preparations of cis-2,4,5-triaryl-4,5-dihydro-1 H-imidazoles, (aryl = thien-2-yl or pyridin-2-yl) from aryl aldehydes, ammonium chloride and triethylamine in methanol, and their conversions to the trans-isomers are reported. Crystal structures of cis-( 1: aryl = pyridin-2-yl), cis-[ 1: aryl = thien-2-yl·0.5H 2O], trans-( 1: aryl = thien-2-yl), and trans-{[( 1: aryl = pyridin-2-yl)H] +[OAc] -·3H 2O}, have been determined and compared with related structures.
The synthesis, X-ray crystal structure and spectroscopic and electrochemical properties of the ne... more The synthesis, X-ray crystal structure and spectroscopic and electrochemical properties of the new dinuclear copper(II) complex [Cu2(Hbtppnol)CH3COO](ClO4)2 (1), employing the novel unsymmetric dinucleating ligand N-(2-hydroxybenzyl)-N,N′,N′-tris(2-pyridylmethyl)-1,3-diaminopropan-2-ol (H2btppnol), are presented. This complex could be a relevant model for the axial interaction of a phenolic substrate to tyrosinase during cresolase activity.
We report herein the characterization by electrospray ionization (ESI) mass spectrometry (MS), ma... more We report herein the characterization by electrospray ionization (ESI) mass spectrometry (MS), matrix assisted laser desorption ionization (MALDI-MS) and potentiometric titration of three iron(III) compounds: [Fe(III)(HPClNOL)Cl2]·NO3 (1), [Cl(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)Cl]·Cl2·H2O (2) and [(SO4)(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)(SO4)]·6H2O (3), where HPClNOL= 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol). Despite the fact that the compounds have distinct structures in solid state and non-buffered solution, all compounds present similar ESI and MALDI mass spectra in a buffered medium (pH 7.0). At this pH, the species [(PClNOL)Fe(III)-(μ-O)-Fe(III)(PClNOL)](2+) (m/z 354) was observed for all the compounds under investigation. Potentiometric titration confirms a similar behavior for all compounds, indicating that the dihydroxo form [(OH)(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)(OH)](2+) is the major species at pH 7.0, for all the compounds. The products of the interaction between compounds (1), (2) and (3) and dAMP (2'-deoxyadenosine-5'-monophosphate) in a buffered medium (pH 7.0) were identified by MALDI-MS/MS. The fragmentation data obtained by MS/MS allow one to identify the nature of the interaction between the iron(III) compounds and dAMP, revealing the direct interaction between the iron center and phosphate groups.
The reaction of V IV O(salen) with [Et 4 N][SnBr 3 ] in air proceeds via an initial reduction to ... more The reaction of V IV O(salen) with [Et 4 N][SnBr 3 ] in air proceeds via an initial reduction to give a [V III (salen)] + intermediate, which is then oxidised to dark green [V V O(salen)(H 2 O)]Br, 1. As determined by X-ray crystallography, 1 in the solid state contains hexacoordinate ...
... Complex 2 exhibited the best results, reaching as high as 68.9% of total yield in 24 h with H... more ... Complex 2 exhibited the best results, reaching as high as 68.9% of total yield in 24 h with H 2O 2 . In general, H 2 O 2 showed better results than tert-butyl hydroperoxide as terminal oxidant. ... 2.3. Synthesis of {[Cu(BMPA)Cl 2 ][Cu(BMPA)(H 2 O)Cl][Cu(BMPA)Cl][CuCl 4 ]} (2). ...
The X-ray molecular structure and, magnetic, and spectroscopic properties, as well as the analysi... more The X-ray molecular structure and, magnetic, and spectroscopic properties, as well as the analysis of the structural behavior in solution of a novel nickel (II) complex [Ni2 (HBPClNOL) 2 (OAc)](ClO4) 1 are reported. Complex 1 was prepared by the reaction between the ...
The structure of the [Mn (HPClNOL)(η1-NO3)(η2-NO3)] 1 complex [HPClNOL= 1-(bis-pyridin-2-ylmethyl... more The structure of the [Mn (HPClNOL)(η1-NO3)(η2-NO3)] 1 complex [HPClNOL= 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol] in the solid-state and in H2O/MeOH solution was investigated by monocrystal X-ray diffraction and ESI (+)–MS/MS. X-ray reveals that 1 is a ...
The coupling of oxetane (trimethylene oxide) and carbon dioxide catalyzed by VO(acac)<smal... more The coupling of oxetane (trimethylene oxide) and carbon dioxide catalyzed by VO(acac)<small>< sub>2</sub></small> in the presence of an onium salt was studied. The process was found to be highly selective and quantitative for the production of the six-membered cyclic carbonate ...
... Carlos AL Filgueiras, a Adolfo Horn Jr, a R. Alan Howie, b * Janet MS Skakle b and James L. W... more ... Carlos AL Filgueiras, a Adolfo Horn Jr, a R. Alan Howie, b * Janet MS Skakle b and James L. Wardell a. ... Its structure, confirming its identity, is the same as that reported by Morosin &Montgomery [Acta Cryst. (1969 [Morosin, B. & Montgomery, H. (1969). Acta Cryst. ...
The preparations of cis-2,4,5-triaryl-4,5-dihydro-1 H-imidazoles, (aryl = thien-2-yl or pyridin-2... more The preparations of cis-2,4,5-triaryl-4,5-dihydro-1 H-imidazoles, (aryl = thien-2-yl or pyridin-2-yl) from aryl aldehydes, ammonium chloride and triethylamine in methanol, and their conversions to the trans-isomers are reported. Crystal structures of cis-( 1: aryl = pyridin-2-yl), cis-[ 1: aryl = thien-2-yl·0.5H 2O], trans-( 1: aryl = thien-2-yl), and trans-{[( 1: aryl = pyridin-2-yl)H] +[OAc] -·3H 2O}, have been determined and compared with related structures.
The synthesis, X-ray crystal structure and spectroscopic and electrochemical properties of the ne... more The synthesis, X-ray crystal structure and spectroscopic and electrochemical properties of the new dinuclear copper(II) complex [Cu2(Hbtppnol)CH3COO](ClO4)2 (1), employing the novel unsymmetric dinucleating ligand N-(2-hydroxybenzyl)-N,N′,N′-tris(2-pyridylmethyl)-1,3-diaminopropan-2-ol (H2btppnol), are presented. This complex could be a relevant model for the axial interaction of a phenolic substrate to tyrosinase during cresolase activity.
We report herein the characterization by electrospray ionization (ESI) mass spectrometry (MS), ma... more We report herein the characterization by electrospray ionization (ESI) mass spectrometry (MS), matrix assisted laser desorption ionization (MALDI-MS) and potentiometric titration of three iron(III) compounds: [Fe(III)(HPClNOL)Cl2]·NO3 (1), [Cl(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)Cl]·Cl2·H2O (2) and [(SO4)(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)(SO4)]·6H2O (3), where HPClNOL= 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol). Despite the fact that the compounds have distinct structures in solid state and non-buffered solution, all compounds present similar ESI and MALDI mass spectra in a buffered medium (pH 7.0). At this pH, the species [(PClNOL)Fe(III)-(μ-O)-Fe(III)(PClNOL)](2+) (m/z 354) was observed for all the compounds under investigation. Potentiometric titration confirms a similar behavior for all compounds, indicating that the dihydroxo form [(OH)(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)(OH)](2+) is the major species at pH 7.0, for all the compounds. The products of the interaction between compounds (1), (2) and (3) and dAMP (2'-deoxyadenosine-5'-monophosphate) in a buffered medium (pH 7.0) were identified by MALDI-MS/MS. The fragmentation data obtained by MS/MS allow one to identify the nature of the interaction between the iron(III) compounds and dAMP, revealing the direct interaction between the iron center and phosphate groups.
The reaction of V IV O(salen) with [Et 4 N][SnBr 3 ] in air proceeds via an initial reduction to ... more The reaction of V IV O(salen) with [Et 4 N][SnBr 3 ] in air proceeds via an initial reduction to give a [V III (salen)] + intermediate, which is then oxidised to dark green [V V O(salen)(H 2 O)]Br, 1. As determined by X-ray crystallography, 1 in the solid state contains hexacoordinate ...
... Complex 2 exhibited the best results, reaching as high as 68.9% of total yield in 24 h with H... more ... Complex 2 exhibited the best results, reaching as high as 68.9% of total yield in 24 h with H 2O 2 . In general, H 2 O 2 showed better results than tert-butyl hydroperoxide as terminal oxidant. ... 2.3. Synthesis of {[Cu(BMPA)Cl 2 ][Cu(BMPA)(H 2 O)Cl][Cu(BMPA)Cl][CuCl 4 ]} (2). ...
The X-ray molecular structure and, magnetic, and spectroscopic properties, as well as the analysi... more The X-ray molecular structure and, magnetic, and spectroscopic properties, as well as the analysis of the structural behavior in solution of a novel nickel (II) complex [Ni2 (HBPClNOL) 2 (OAc)](ClO4) 1 are reported. Complex 1 was prepared by the reaction between the ...
The structure of the [Mn (HPClNOL)(η1-NO3)(η2-NO3)] 1 complex [HPClNOL= 1-(bis-pyridin-2-ylmethyl... more The structure of the [Mn (HPClNOL)(η1-NO3)(η2-NO3)] 1 complex [HPClNOL= 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol] in the solid-state and in H2O/MeOH solution was investigated by monocrystal X-ray diffraction and ESI (+)–MS/MS. X-ray reveals that 1 is a ...
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