189,542 research outputs found
Synthesis and coordination chemistry of hybrid polydentate and halide-substituted stibines and bismuthines
No full textHalostibines and halobismuthines EMenX3-n (E = Sb, Bi; X = Cl, Br; n = 1, 2) display both Lewis acidic and Lewis basic characteristics. A series of adducts with neutral N- and O-donor ligands, [EMeX2(L)] (L = 2,2’-bipyridine, 1,10-phenanthroline, tetramethylethylenediamine) and [SbMeX2(L)2] (L = Ph3PO, Me3PO) were isolated and characterised by X-ray crystallography, 1H (and where appropriate 31P{1H}) NMR spectroscopy and microanalysis. Each complex is monomeric, displaying a distorted square pyramidal geometry around E, with two basal cis halides and the Me group apical. Combination of EMe2X with neutral ligands results in rearrangement at E to yield [EMeX2(L)] or [SbMeX2(L)2] once again as the isolable products. Reaction of SbMenBr3-n (n = 1, 2) with transition metal acceptors gives complexes in which the halostibines behave as Lewis bases. Examination of trends in the crystallographic and spectroscopic data of [M(CO)5(SbMenBr3-n)] (M = Cr, W; n = 1-3) from this work and the literature concluded that the halostibines have a significant ?-acceptor ability, which increases with increased halide substitution. Other transition metal complexes with L = SbMe2Br, [CpFe(CO)2(L)][BF4], [CpFe(CO)(L)2]Br (Cp = cyclopentadienyl) and [Mn(CO)6-n(L)n][CF3SO3] (n = 1, 3) were isolated and contain hypervalent, Sb···O, Sb···F or Sb···Br contacts between ions. Reaction of BiMe2Br with transition metal acceptors results in rearrangement at Bi; the only bismuthine complexes isolated contained the BiMe3 ligand.The hybrid distibine S(CH2-2-C6H4SbMe2)2 and its methiodide [S(CH2-2-C6H4SbMe3)2][I]2 were synthesised and the X-ray structure of the latter determined. Systematic investigations into transition metal complexes of this and other hybrid distibine ligands were undertaken. These ligands coordinate in a bidentate bridging mode in the 1:2 complexes [{CpFe(CO)2}2(L)][BF4] (L = O{(CH2)2SbR2}2 (R = Me, Ph), MeN(CH2-2-C6H4SbMe2)2, S(CH2-2-C6H4SbMe2)2) and [{M(CO)5}2(L)] (M = Cr, W; L = O{(CH2)2SbR2}2 (R = Me, Ph)), a bidentate chelating mode in [M(CO)4(L)] (M = Cr, W; L = O{(CH2)2SbMe2}2, MeN(CH2-2-C6H4SbMe2)2) or a tridentate mode in [M(CO)3(S(CH2-2-C6H4SbMe2)2)] (M = Cr, Mo) and [Mn(CO)3(L)] [CF3SO3] (L = MeN(CH2-2-C6H4SbMe2)2, S(CH2-2-C6H4SbMe2)2). In the latter examples the central hetero-atom of the ligand is coordinated to the transition metal centre. In those cases where it is not, hypervalent interactions between this hetero-atom and one or both coordinated Sb atoms are sometimes, but not always, observed. Comparisons have been drawn with the chemistry of the corresponding hybrid dibismuthine ligands. The hybrid tristibine ligand N(CH2-2-C6H4SbMe2)3 was synthesised and preliminary investigations of its coordination chemistry carried out. It acts as a tridentate ligand via the three Sb donors in [Mn(CO)3(L)][CF3SO3] and [Cu4Br4(L)2], with the ligand fixed in a propeller-like conformation. In the latter, a Cu2Br4 core with a short Cu···Cu distance is observed. [Cu(L)] [BF4] was isolated, in which tetradentate coordination of the ligand has been proposed.Transition metal complexes were characterised by 1H and 13C{1H} NMR spectroscopy and microanalysis, and where appropriate infrared and 55Mn or 63Cu NMR spectroscopies and mass spectrometry. The majority of these complexes have also been structurally characterised by single crystal X-ray diffraction
[Letter from Benjamin N. Woodson to Lloyd Bentsen - January 16, 1978]
No full textRecommendation letter from Benjamin N. Woodson to Lloyd M. Bentsen, United States Senate, for a Federal Judge's position for Frank M. Pinedo
La enfermedad histórica de la hermenéutica y su transformación dialéctica. El pensamiento débil entre Gadamer y Benjamin
No full textEl presente trabajo tiene por fin mostrar cómo la hermenéutica nihilista de Gianni Vattimo mediante su crítica a la hermenéutica ontológica de Gadamer recupera la figura de Walter Benjamin y la asocia al proyecto de Heidegger. Esto lleva a que el presente trabajo, en primer lugar, describa cuáles son las críticas que Vattimo le realiza a Gadamer; y, en segundo lugar, muestre cómo es posible aunar la filosofía de Heidegger con el pensamiento crítico de Benjamin. Por último, se indica mediante la congruencia de estos autores cómo es posible la construcción de un sujeto post-metafísico</p
Book review : Benjamin Burombo by N. Bhebe
No full textReview of: N. Bhebe. Benjamin Burombo. Harare: College Press, 198
Benjamin: suas concepções e propostas em seu ensaio "a tarefa do tradutor"
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Estudos da Tradução, Florianópolis, 2015.Neste trabalho pretende-se analisar o ensaio de Walter Benjamin ?A tarefa do tradutor? levando em conta suas influências, concepções e alguns de seus precursores filosóficos e assim chegar a uma interpretação a partir de suas propostas do que é traduzir para Benjamin.Abstract : This paper aims to examine Walter Benjamin's essay "The Task of the Translator" taking into account their influences, ideas and some of its philosophical precursors and thus arrive at an interpretation from their proposals than it is to translate Benjamin
Public worship and practical theology in the work of Benjamin Keach (1640-1704)
No full textThe late seventeenth century was a critical and fruitful period
for the Particular Baptists of England. Severely persecuted following
the Restoration, toleration in 1689 brought its own perils.
Particular Baptists were fortunate in having several strong leaders,
especially the London trio of Hanserd Knollys, William Kiffin, and
Benjamin Keach. Such a small and severely persecuted group as the
Baptists could afford little time for academic pursuits, thus of
necessity most of their theology was practical in nature.
Benjamin Keach (1640-1704) was the most outstanding practical
theologian among the English Particular Baptists of the late
seventeenth century. This dissertation is a study of Keach, in
particular his writings on public worship and practical theology.
Although Keach was a prolific author, he has been almost completely
neglected by scholars.
After a biographical sketch of Keach, this study considers his
writings on public worship and practical theology. In the area of
worship, Keach made two outstanding contributions: First, he was the
most vocal apologist for Baptist views on Baptism of his period.
Secondly, and more importantly, his hymn writing and defense of hymn
singing broke new ground, not just for Baptists, but for English
Protestantism, in general. In addition to his contributions in these
areas, he also dealt with the laying on of hands and the sabbath day
worship controversy.
Keach's contributions to practical theology fall into two main
groups: his writings that concern religious education and those that
deal with polity. In addition to these, Keach's vigorous advocacy of
a high Calvinist soteriology are also considered under the rubric of
practical theology. Keach's most important (although not his most
positive) contribution in this area were his soteriological writings.
Although well within the bounds of orthodoxy, some of the tendencies
in Keach's soteriology were taken up by the following generation of
Baptist leaders and developed into a stultifying hyper-Calvinism that
handicapped Baptist evangelism and missions.
In the conclusion, Keach's contributions to a theory of practical
theology are considered
[Letter from John Benjamin Magee to T. N. Carswell - December 10, 1941]
No full textA letter written to Mr. T. N. Carswell, Parramore Post No. 57, American Legion, Abilene, Texas, from John Benjamin Magee, President, Cornell College, Mount Vernon, Iowa, dated December 10, 1941. John Benjamin Magee defines Americanism
Stability of oscillatory gravity wave trains with energy dissipation and Benjamin-Feir instability
No full textThe Benjamin-Feir instability describes the instability of a uniform oscillatory wave train in an irrotational flow subject to small perturbation of wave number, amplitude and frequency. Their instability analysis is based on the perturbation around the second order Stokes wave which satisfies the dynamic and kinematic free-surface boundary conditions up to the second order. In the same irrotational flow and perturbation framework of the Benjamin-Feir analysis, the perturbation in the present paper is around a nonlinear oscillatorywave train which solves exactly the dynamic free-surface boundary conditionand satisfies the kinematic free-surface boundary condition up to the third or-der. It is shown that the nonlinear oscillatory wave train is stable with respectto the perturbation when the irrotational flow involves small Rayleigh energydissipation
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