Papers by Bernardo Herold
Apresentam-se as várias traduções alemãs da Bíblia e a sua génese ao longo da história. Mencionam... more Apresentam-se as várias traduções alemãs da Bíblia e a sua génese ao longo da história. Mencionam-se primeiramente os textos manuscritos e as versões gregas, latinas, góticas, vetero-inglesas e alemãs existentes antes do século XV. Seguidamente mostra-se o papel da Reforma Protestante da Igreja no século XVI e a importância da invenção da imprensa de tipos móveis, como razões para a criação de novas traduções. Descrevem-se os textos que serviram de base a essas traduções, nomeadamente os textos masoréticos da Bíblia Hebraica e em parte os da Septuaginta para o Antigo Testamento e a edição crítica do Textus Receptus por Erasmo de Roterdão para o Novo Testamento. Relatam-se os trabalhos de tradução de Lutero e da escola de Zurique nos respectivos contextos da História da Reforma, bem como o papel da tradução de Lutero como modelo para outras línguas de países da Reforma Luterana. Comparam-se as versões alemãs entre si e com as noutras línguas de países da Reforma Calvinista. Analisam-...
Imprensa da Universidade de Coimbra eBooks, Jan 22, 2016
A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitali... more A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitalis, UC Pombalina e UC Impactum, pressupõem a aceitação plena e sem reservas dos Termos e Condições de Uso destas Bibliotecas Digitais, disponíveis em https://digitalis.uc.pt/pt-pt/termos. Conforme exposto nos referidos Termos e Condições de Uso, o descarregamento de títulos de acesso restrito requer uma licença válida de autorização devendo o utilizador aceder ao(s) documento(s) a partir de um endereço de IP da instituição detentora da supramencionada licença. Ao utilizador é apenas permitido o descarregamento para uso pessoal, pelo que o emprego do(s) título(s) descarregado(s) para outro fim, designadamente comercial, carece de autorização do respetivo autor ou editor da obra. Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso. Joaquim dos Santos e Silva: um pioneiro português da Química moderna
Boletim da Sociedade Portuguesa de Química, Jun 1, 2012
Bulletin des Sociétés Chimiques Belges, Sep 1, 2010
Magnetic Resonance in Chemistry, Dec 1, 1989
The 13C NMR spectrum of 10,10‐diphenyl‐9‐phenanthrone was assigned unambiguously using 2D 13C,1H ... more The 13C NMR spectrum of 10,10‐diphenyl‐9‐phenanthrone was assigned unambiguously using 2D 13C,1H shift correlated NMR spectra, optimized either for one‐bond or long‐range 13C1H couplings, and 2D RELAY NMR spectra. This information allowed the structures of a number of substituted 10,10‐diphenyl‐9‐phenanthrones to be deduced from their 13C NMR spectra. The results provide an insight into the mechanism of the reaction of 9‐fluorenone with chlorodiphenylmethyllithium.
Journal of the Chemical Society, 1991
ABSTRACT Six tetraaryloxiranes 1a–f(Scheme 4) were reduced (Schemes 1–3) with alkali metals (M = ... more ABSTRACT Six tetraaryloxiranes 1a–f(Scheme 4) were reduced (Schemes 1–3) with alkali metals (M = Li, Na, K, Cs) in eight polar aprotic solvents under an inert atmosphere. The organometallic solutions thus obtained were hydrolysed and the reaction products analysed. Similar experiments were carried out where the same solutions were quenched with D2O or Mel. In some cases the same solutions were studied by NMR and ESR spectroscopy before quenching. A stepwise reduction mechanism was established where the transfer of a first electron produces CO-bond scission in the oxirane ring, yielding a short-lived radical anion 4 or 5(Scheme 1), i.e. a tetraaryl-β-oxidoethyl radical. This intermediate can either eliminate oxygen as metal oxide (MO) to produce a tetraarylethylene 24(Scheme 2) or be further reduced to a dianion 8 or 9(Scheme 1). This anion yields, upon hydrolysis, low yields, if any, of the corresponding tetraphenylethanol 15 or 16(Z = H). The larger proportion of the dianion, after the first protonation step, yielding anion 11 or 12, undergoes CC-bond scission which leads eventually to the corresponding ketone and diarylmethane 19+ 20 or 21+23(Z = H)(Scheme 2). Other possible pathways were excluded through experiments where other possible intermediates were generated. These led to different end products. A triparametric linear correlation as a function of solvent parameters ETN and DN, as well as the cationic radius, was established for the influence of the nature of the solvent and counter-ion on the ratio between the rates of formation of products stemming from metal oxide (MO) elimination by the ring-opened radical anion 4 or 5(Schemes 1 and 2) and rates of formation of products stemming from further reduction of the same radical anion to the dianion 8 or 9, thus confirming the mechanism established.
Boletim da Sociedade Portuguesa de Química, Sep 1, 2011
Boletim da Sociedade Portuguesa de Química, Mar 1, 2014
ChemInform, Aug 23, 2010
ChemInform Abstract The ESR spectra of the radical anions of the diarylfurans (I) are studied in ... more ChemInform Abstract The ESR spectra of the radical anions of the diarylfurans (I) are studied in several polar aprotic solvents with the cations of Li, Na, K, Rb, and Cs as counter-ions.
Journal of the American Chemical Society, Jun 1, 1965
positions much more resistant to solvent exchange than in those compounds previously labeled by g... more positions much more resistant to solvent exchange than in those compounds previously labeled by gas chromatographic means. It also provides access to labeling possibilities for those compounds which cannot be volatilized or which would be damaged by the temperatures of the gas chromatographic column. Perhaps the greatest immediate advantage over gas chromatographic labeling techniques is the sample capacity of liquid-solid adsorption columns which extends to gram quantities without special equipment.
Pure and Applied Chemistry, Jun 23, 2018
Flavonoid structures, found in nature or obtained by synthesis, may be very complex. These Recomm... more Flavonoid structures, found in nature or obtained by synthesis, may be very complex. These Recommendations provide a guide for flavonoid aglycone names. This will also allow the construction of the names for their polyglycosylated species with clarity and conciseness. A joint working party of IUPAC/IUBMB members has prepared these recommendations, which establish rules for the general nomenclature of flavonoids, providing examples of acceptable trivial names, and names derived from trivial names, together with semi-systematic and fully systematic names that follow the published IUPAC recommendations.
Boletim da Sociedade Portuguesa de Química, Mar 1, 2008
Journal of the Chemical Society, 1987
ABSTRACT E.s.r. spectra of radicals derived by addition of several alkali-metals to 1,2-bispentam... more ABSTRACT E.s.r. spectra of radicals derived by addition of several alkali-metals to 1,2-bispentamethylbenzoyl-, 1,2-dimesitoyl-, 1-benzoyl-2-mesitoyl-, and 1,2,4,5-tetramesitoyl-benzene were studied in nine aprotic solvents. The electron spin densities at the alkali-metal obtained from the experimental alkalimetal couplings together with previously published values (12 solvents combined with Li, Na, K, Rb, and Cs) correlate linearly with the empirical solvent parameters ETN(30) and DN, and with the radius of the alkali cation. This is interpreted as a consequence of the interionic distance being controlled by dipolarity and Lewis basicity of the solvent, along with the cation radius.
Journal of the Chemical Society, 1988
ABSTRACT Six tetraaryloxiranes 1a–f(Scheme 4) were reduced (Schemes 1–3) with alkali metals (M = ... more ABSTRACT Six tetraaryloxiranes 1a–f(Scheme 4) were reduced (Schemes 1–3) with alkali metals (M = Li, Na, K, Cs) in eight polar aprotic solvents under an inert atmosphere. The organometallic solutions thus obtained were hydrolysed and the reaction products analysed. Similar experiments were carried out where the same solutions were quenched with D2O or Mel. In some cases the same solutions were studied by NMR and ESR spectroscopy before quenching. A stepwise reduction mechanism was established where the transfer of a first electron produces CO-bond scission in the oxirane ring, yielding a short-lived radical anion 4 or 5(Scheme 1), i.e. a tetraaryl-β-oxidoethyl radical. This intermediate can either eliminate oxygen as metal oxide (MO) to produce a tetraarylethylene 24(Scheme 2) or be further reduced to a dianion 8 or 9(Scheme 1). This anion yields, upon hydrolysis, low yields, if any, of the corresponding tetraphenylethanol 15 or 16(Z = H). The larger proportion of the dianion, after the first protonation step, yielding anion 11 or 12, undergoes CC-bond scission which leads eventually to the corresponding ketone and diarylmethane 19+ 20 or 21+23(Z = H)(Scheme 2). Other possible pathways were excluded through experiments where other possible intermediates were generated. These led to different end products. A triparametric linear correlation as a function of solvent parameters ETN and DN, as well as the cationic radius, was established for the influence of the nature of the solvent and counter-ion on the ratio between the rates of formation of products stemming from metal oxide (MO) elimination by the ring-opened radical anion 4 or 5(Schemes 1 and 2) and rates of formation of products stemming from further reduction of the same radical anion to the dianion 8 or 9, thus confirming the mechanism established.
Journal of the Chemical Society, Faraday Transactions, 1991
ABSTRACT The radical anions of 1,3-diarylbenzo[c]furans (1–4) obtained by reduction with alkali m... more ABSTRACT The radical anions of 1,3-diarylbenzo[c]furans (1–4) obtained by reduction with alkali metals have been studied by EPR, ENDOR and TRIPLE resonance. For 1˙– and 2˙–, the inequivalence of both ortho hydrogens of each aryl substituent was established, and a small dihedral angle between the benzo[c]furan system and each aryl ring. For 3˙– and 4˙–, the four ortho methyl groups of the aryl substituents in positions 1 and 3 were found to be magnetically equivalent, and the dihedral angle was estimated to be ca. 70°. From the distribution of spin density and excess negative charge for each of the anions and the nature of the alkali-metal counter-ion, conclusions can be drawn about the position of the cation in each case. The lifetimes of the radical anions increase in the order of decreasing electron spin density and excess negative charge density on the furan ring.
Journal of the Chemical Society, Faraday Transactions, 1993
ABSTRACT The chemical reduction of (Z)-1,2-bis(2,4,6-trimethylbenzoyl)ethene, 1, and (E)-1,2-bis(... more ABSTRACT The chemical reduction of (Z)-1,2-bis(2,4,6-trimethylbenzoyl)ethene, 1, and (E)-1,2-bis(2,4,6-trimethylbenzoyl)-ethene, 2, with alkali metals and magnesium amalgam in ethereal solvents has been studied by electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR) and TRIPLE resonance spectroscopies. The structure of the radical ion pairs obtained from 1 exhibits strong dependence upon cation size, solvent polarity and temperature. It was found that (Z)-isomeric ion pairs 1˙– M+ are favoured under conditions involving more ion association, for example, in systems with small counterions, low solvating power of the solvent and at high temperatures. Z–E isomerization occurred at temperatures as low as 193 K even for lithium ion pairs in 1,2-dimethoxyethane. The resulting (E)-isomers decayed significantly with increasing temperature, yielding secondary reduction products. The final paramagnetic species, referred to as D in the text, has strikingly distinct hyperfine data which could be ascribed to a structurally different ion pair resulting from intramolecular cyclization that may occur in the (E)-exo-endo isomeric ion pair. The arguments in favour of such a structure are corroborated by INDO calculations.
Journal of the Chemical Society, 1990
ESR and ENDOR/TRIPLE resonance studies are reported for the ion pairs derived from the non-planar... more ESR and ENDOR/TRIPLE resonance studies are reported for the ion pairs derived from the non-planar ketyls of tribenzotropone (1), dibenzotropone (2) and dibenzosuberone (3) with different alkali metal cations. The observation of three different alkali hyperfine splitting constants (hfs) in some ENDOR spectra may indicate the presence of three different stereoisomers of these ion pairs. All hfs data and their temperature dependence can be interpreted in terms of three different ion pair structures. The proton hfs are well interpreted in terms of McLachlan's spin-density calculations. Support for the geometries proposed for the three stereoisomers is provided by INDO calculations of the spin densities at the lithium cation.
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Papers by Bernardo Herold