1,720,957 research outputs found
Conformational And Electronic Interaction Studies Of Some P-substituted α-methylsulfonyl-α-diethoxyphosphorylacetophenones
No full textThe analysis of the IR carbonyl band of the α-methylsulfonyl-α-diethoxyphosphoryl p-substituted acetophenones p-Y-Ph-C(O)CH(SO2Me)[P(O)(OEt)2] (Y = OMe 1, H 2, F 3, Cl 4, Br 5 and NO2 6) supported by HF/6-31G(d,p) ab initio calculations of the α-methylsulfonyl-α-diethoxyphosphoryl acetophenone 2, indicated the existence of a single stable c1 conformer in gas phase and in solvents of increasing polarity, along with the presence of second less stable conformation in gas phase. The c1 conformer present the (SO2Me) group and the [P(O)(OEt2)] groups in a syn-clinal (gauche) geometry and is stabilised through of the Oδ-(CO)...Pδ+(PO), Oδ-[PO(OEt)]...Cδ+(CO), Oδ-(PO)...Cδ+(CO), Oδ-(CO)...Sδ+(SO2Me) and Oδ-(SO2)...Cδ+(CO) electronic interactions along with Hδ+(SO2Me).... Oδ-(CO), Hδ+(CH2)[POEt].... Oδ-(SO2Me), Hδ+(o-Ph).... Oδ-(CO) and Hδ+(o′-Ph).... Oδ-(PO) intramolecular hydrogen bonds. The almost constant negative carbonyl frequency shifts (Δν) for the title compounds 1-6 with respect to the parent acetophenones 7-14 corroborates the prevalence of the electronic interactions over the -Iσ inductive effect of the α-substituents for the title compounds and gives strong support for the existence of the crossed Oδ-(CO)...Sδ+(SO2Me) and Oδ-(SO2)...Cδ+(CO) (charge transfer and electrostatic); Oδ-(CO)...Pδ+(PO) and Oδ-[PO(OEt)]...Cδ+(CO), (electrostatic) interactions. © 2008 Elsevier B.V. All rights reserved.8921-3300304Distefano, G., Dal Colle, M., Bertolasi, V., Olivato, P.R., Bonfada, E., Mondino, M.G., (1991) J. Chem Soc., Perkin Trans., 2, p. 1195Olivato, P.R., Bonfada, E., Rittner, R., (1992) Magn. Reson. Chem., 30, p. 81Dal Colle, M., Bertolasi, V., de Palo, M., Distefano, G., Jones, D., Modelli, A., Olivato, P.R., (1995) J. Chem. Phys., 99, p. 15011Olivato, P.R., Guerrero, S.A., Rittner, R., (1997) Phosphorus Sulfur Silicon, 130, p. 155Olivato, P.R., Hui, M.LT., Rodrigues, A., Ruiz Filho, R., Rittner, R., Zukerman-Schpector, J., Distefano, G., Dal Colle, M., (2003) J. Mol. Struct., 645, p. 259Olivato, P.R., Reis, A.K.C.A., Ruiz Filho, R., Zukerman-Schpector, J., Rittner, R., (2004) J. Mol. Struct. (Theochem.), 677, p. 199Olivato, P.R., Ruiz Filho, R., Zuckerman-Schpector, J., Dal Colle, M., Distefano, G., (2001) J. Chem. Soc., Perkin Trans., 2, p. 97Jones, D., Dal Colle, M., Distefano, G., Ruiz Filho, R., Olivato, P.R., (2001) J. Organomet. Chem., 625, p. 121Olivato, P.R., Reis, A.K.C.A., Zukerman-Schpector, J., Tormena, C., Rittner, R., Domingues, N.L.C., Dal Colle, M., (2006) J. Mol. Struct., 798, p. 57Sega, E.M., Reis, A.K.C.A., Olivato, P.R., Rodrigues, A., Carvalho, J.E., Castilho, R.F., Rittner, R., Höehr, N.F., (2008) Clin. Chim. Acta, 389, p. 177Reis, A.K.C.A., Olivato, P.R., Rittner, R., (2005) Magn. Reson. Chem., 43, p. 85Galactic Industries Corporation, 1991-1998M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman, V.G. Zakrzewski, J.A. Montgomery Jr., R.E. Stratmann, J.C. Burant, S. Dapprich, J.M. Millam, A.D. Daniels, K.N. Kudin, M.C. Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C. Adamo, S. Clifford, J. Ochterski, G.A. Petersson, P.Y. Ayala, Q. Cui, K. Morokuma, D.K. Malick, A.D. Rabuck, K. Raghavachari, J.B. Foresman, J. Cioslowski, J.V. Ortiz, B.B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. Gomperts, R.L. Martin, D.J. Fox, T. Keith, M.A. Al-Laham, C.Y. Peng, A. Nanayakkara, C. Gonzalez, M. Challacombe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, J.L. Andres, M. Head-Gordon, E.S. Repogle, J.A. Pople, Gaussian 98, Revision A.6, Gaussian, Pittsburg, PA, 1998Riddick, J.A., Bunger, W.B., (1970) Techniques of Organic Chemistry, vol. II: Organic Solvents. third ed., , Wiley, New YorkMarch, J., (1985) Advanced Organic Chemistry. third ed., , Wiley, New YorkHansh, C., Leo, A., Hoekman, D., (1995) Exploring QSAR Hydrophobic, Electronic and Steric Constants, , American Chemical Society, Washington, D
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Spectroscopic And Theoretical Studies Of Some P-substituted α-ethylsulfonylacetophenones
No full textThe preferred conformations of p-substituted α- ethylsulfonylacetophenones, Y-PhC(O)CH2SO2Et (Y=OMe 1, Me 2, H 3, F 4, Cl 5, Br 6, CN 7 and NO2 8) are determined by νCO IR analysis, HF/6-31G** computations (1, 3, 5, 7 and 8) and X-ray diffraction for 5 and 7. The match between IR frequencies and intensities of the carbonyl doublet components in carbon tetrachloride (first overtone) and the results of the calculations indicates that the lower frequency component corresponds to the more stable gauche (g) conformer, while the higher frequency component is related to the quasi-cis (q-c) one. The gauche conformer (g) (ca. 85%) prevails over the quasi-cis conformer (q-c) population, and the q-c/g population ratio increases on going from electron-attracting to electron-donating substituents, both in the gas phase and in solution. These trends are discussed in terms of O(SO2)δ-⋯C(CO)δ+ charge transfer (CT), O(CO)δ-⋯S(SO2)δ+ (Coulombic interaction), H[CH2(Et)]δ+⋯O(CO)δ-, H δ+(2′)(o-Ph)⋯O(CO)δ- and Hδ+(6′) (o-Ph)⋯O(SO2)δ- hydrogen bonds and electrostatic interactions, along with the πCO/σ C-S* and πCO*/σC-S orbital interactions, which stabilise the g rotamer. The stabilisation of the q-c rotamer through O(CO)δ-⋯S (SO2)δ+ (CT), Hδ+(2′) (o-Ph)⋯O(CO)δ- and H [CH2(Et)]δ+⋯O(CO)δ- hydrogen bond interactions is counterbalanced by O (CO)δ-⋯O(SO2)δ- electrostatic repulsion, which destabilises significantly this rotamer. The X-ray diffraction analyses show that 5 and 7, in the solid, adopt the cis (c′) conformation, which is stabilised through intermolecular hydrogen bonds involving the acidic α-methylene Hδ+(3A), H(3B) and m-phenyl Hδ+(5′)[m-Ph] hydrogen atoms and the Oδ-(6), Oδ-(7) sulfonyl and O δ-(1) carbonyl oxygen atoms. © 2004 Elsevier B.V. All rights reserved.6771-3199209Lumbroso, H., Bertin, D.M., Olivato, P.R., Bonfada, E., Mondino, M.G., Hase, Y., (1989) J. Mol. Struct., 213, p. 115Olivato, P.R., Mondino, M.G., (1991) Phosphorus Sulfur Silicon Relat. Elem., 59, p. 219Olivato, P.R., Bonfada, E., Rittner, R., (1992) Magn. Reson. Chem., 30, p. 81Distefano, G., Dal Colle, M., Bertolasi, V., Olivato, P.R., Bonfada, E., Mondino, M.G., (1991) J. Chem. Soc. Perkin Trans., 2, p. 1195Dal Colle, M., Bertolasi, V., De Palo, M., Distefano, G., Jones, D., Modelli, A., Olivato, P.R., (1995) J. Chem. Phys., 99, p. 15011Olivato, P.R., Guerrero, S.A., R.Rittner (1997) Phosphorus Sulfur Silicon Relat. Elem., 130, p. 155Olivato, P.R., Bueno, E., Guerrero, S.A., Zukerman-Schpector, J., (1998) Proceedings of the 18th International Symposium on the Organic Chemistry of Sulfur, , Italy: Florence. Abstract BookOlivato, P.R., Reis, A.K.C.A., Zukerman-Schpector, J., Rittner, R., (2004) J. Mol. Struct. (Theochem), 671, p. 97Galactic Industries Corporation, 1991-1998Guerrero, S.A., (1985), PhD. Thesis. Instituto de Química, Universidade de São PauloAltomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., (1993) J. Appl. Cryst., 26, p. 343Sheldrick, G.M., (1997) SHELXL97 Programs for Crystal Structure Analysis (Release 97-2), , Germany: University of GöttingenNardelli, M., (1995) J. Appl. Cryst., 28, p. 659Farrugia, L.J., (1999) J. Appl. Cryst., 32, p. 837Farrugia, L.J., (1997) J. Appl. Cryst., 30, p. 565Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., (1998) GAUSSIAN 98, Revision A.6, , Gaussian, Pittsburg, PA(1970) Techniques of Organic Chemistry Third Ed. Organic Solvents, 2. , J.A. Riddick, & W.B. Bunger. New York: WileyBellamy, L.J., (1975) Advances in Infrared Group Frequencies, , London: Chapman and HallGaset, A., Lafaille, A., Verdier, A., Lattes, A., (1968) Bull. Soc. Chim. Fr., p. 4108March, J., (1985) Advanced Organic Chemistry 3rd Ed., , New York: Wile
Conformational And Electronic Interaction Studies Of Some P-substituted α-bromo-α-ethylsulfonylacetophenones
No full textThe preferred conformations of p-substituted α-bromo-α- ethylsulfonylacetophenones Y-PhC(O)CH(Br)SO2Et (Y=OMe 1, Me 2, H 3, Cl 4, Br 5, CN 6 and NO2 7) are determined by νCO IR analysis; HF/6-31G** ab initio computations and X-ray diffraction (for 3). In the gas phase, compound 3 shows the existence of two stable conformers. The more stable and more polar c1 conformer presents the α-ethylsulfonyl and the α-bromo substituents in syn-periplanar (quasi-cis) and syn-clinal (gauche) geometries, respectively, with respect to the carbonyl group. For the second, less stable and less polar, c2 conformer, both the α substituents assume a syn-clinal (gauche) geometry. The larger stabilisation of the c1 conformer relative to c 2, in the gas phase, is attributed to the summing up of the n Br/π*CO and σC-Br/ π*CO hyperconjugative interactions and OCOδ-⋯SSO2δ+, H CH2[SO2Et]⋯OCOδ- and OSO2δ-⋯CCOδ+ orbital and electrostatic interactions, which are stronger for the c 1 conformer relative to c2. In solution, only the more polar c1 conformer has been detected, due to its stronger solvation energy relative to that of the c2 conformer. The mean carbonyl frequency shifts (Δν) close to zero, in CCl4, for the single νCO band of the title compounds 1-7 gives further support for its assignment to the c1 conformer as both the quasi-cis conformer of the α-ethylsulfonylacetophenones and the gauche conformer of the α-bromocetophenones present (Δν) values close to zero. X-ray diffraction analysis for 3 indicates that it exists in the solid state in the c′1 conformation, which is reasonably close to the c 1 one, and it is stabilised intramolecularly by the same interactions responsible for the stabilisation of conformer c1 in the gas phase. Furthermore, these molecules form centro-symmetric dimers in the crystal, which are stabilised through two pairs of intermolecular hydrogen bonds, i.e. H[o-Ph]δ+⋯OSO2δ- and H[α-CH]δ+⋯OSO2δ-. © 2004 Elsevier B.V. All rights reserved.6711-397104Olivato, P.R., Rittner, R., (1996) Rev. Heteroat. Chem., 15, p. 115Distefano, G., Dal Colle, M., Bertolasi, V., Olivato, P.R., Bonfada, E., Mondino, M.G., (1991) J. Chem. Soc. Perkin Trans., 2, p. 1195Olivato, P.R., Bonfada, E., Rittner, R., (1992) Magn. Reson. Chem., 30, p. 81Dal Colle, M., Bertolasi, V., De Palo, M., Distefano, G., Jones, D., Modelli, A., Olivato, P.R., (1995) J. Chem. Phys., 99, p. 15011Olivato, P.R., Guerrero, S.A., Rittner, R., (1997) Phosphorus, Sulfur Silicon, 130, p. 155Guerrero, S.A., Barros, J.R.T., Wladislaw, B., Rittner, R., Olivato, P.R., (1983) J. Chem. Soc. Perkin Trans., 2, p. 1053Distefano, G., Granozzi, G., Bertoncello, R., Olivato, P.R., Guerrero, S.A., (1987) J. Chem. Soc. Perkin Trans., 2, p. 1459Olivato, P.R., Guerrero, S.A., Santos, P.S., (1989) Spectrosc. Lett., 22, p. 675Sega, E., Reis, A.K.C.A., Olivato, P.R., Rittner, R., Hoehr, N.F., unpublished resultsBorowitz, G., Borowitz, I.J., The Perkow and related reactions (1992) Handbook of Organophosphorus Chemistry, pp. 115-172. , R. Engel. New York: Marcel DekkerGaydou, E.M., Bianchini, J.-P., (1976) Can. J. Chem., 54, p. 3626Reis, A.K.C.A., (2003) PhD Thesis, Instituto de Química, , Universidade de São Paulo(1991) Galactic Industries CorporationSheldrick, G., (1986) SHELXS86, Program for Solution of Crystal Structures, , Germany: University of GottingenSheldrick, G.M., (1997) SHELXS97, Program for the Refinement of Crystal Structures, , Germany: University of GottingenZsolnai, L., (1995) ZORTEP, An iterative molecular graphics program, , Germany: University of HeidelbergFrisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., (1998) GAUSSIAN98, Revision A.6, , Pittsburgh, PA: Gaussian IncOrganic Solvents 3rd Ed. (1970) Techniques of Organic Chemistry, 2. , J.A. Riddick, & W.B. Bunger. New York: WileyMarch, J., Advanced Organic Chemistry (1985) 3rd Ed., , New York: WileyBellamy, L.J., (1975) Advances in Infrared Group Frequencies, , London: Chapman and Hal
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