Download or read book Conformationaly Analysis of Some Nitrogen Containing Molecules by Spectroscopic and Theoretical Methods written by Jennifer Leigh Ives and published by . This book was released on 1992 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Masters Theses in the Pure and Applied Sciences written by Wade H. Shafer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS)* at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dis semination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the though that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volumes were handled by an international publishing house to assure improved service and broader dissemi nation. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 37 (thesis year 1992) a total of 12,549 thesis titles from 25 Canadian and 153 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this impor tant annual reference work. While Volume 37 reports theses submitted in 1992, on occasion, certain uni versities do report theses submitted in previous years but not reported at the time.
Download or read book Conformational Analysis and Absolute Configuration Determination of Some Organic and Coordination Chemistry Compounds Using Chiroptical Spectroscopy and DFT Calculations written by Zahra Dezhahang and published by . This book was released on 2015 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: My PhD thesis projects revolve around three main parts, namely synthesis, conformational analysis, and absolute configuration determination of a number of chiral Schiff base ligands and axial chiral binaphthyl type ligands or molecules and some of their transition metal complexes in solution. To obtain the structural information of these chiral systems in solution, chiroptical spectroscopic techniques, such as electronic and vibrational circular dichroism (ECD and VCD) spectroscopy, as well as the related linear spectroscopy, i.e., IR and UV-Vis spectroscopy, have been used as the main experimental tools. In addition, density functional theory (DFT) has been employed to perform all calculations for the conformational searches, geometry optimizations, and simulations of VA, VCD, UV-Vis, and ECD spectra. Comparison of the theoretical and experimental spectra has been utilized to provide detailed and rigorous spectral interpretations and therefore to extract essential structural properties of the targeted species in solution. To account for the bulk solvent environment, the implicit solvation approach, i.e. the polarizable continuum model (PCM), has been applied where no strong solvent-solute hydrogen-bonding interactions are expected. Initial conformational analyses of the systems studied have been performed using small basis sets, such as 6-31G(d). For the final calculations, several larger basis sets, namely 6-31++G(d,p), 6-311++G(d,p), and cc-pVTZ have been used for the C, H, N, O atoms and the LanL2DZ basis sets for the metal atoms. We found that flexible ligands, such as the multidentate nitrogen donor ligands, BINAP and related ligands, show a number of minima on their potential energy surfaces. Further coordination to one or more metal centers often introduces dramatically the structural rigidity and consequently results in a smaller number of minima. For example, in the case of Pd(BINAP)Cl2 and Pd(TOLBINAP)Cl2, a single conformation has been identified in solution. Especially for the VCD spectra observed, it has been demonstrated that the gas phase models failed to capture the experimental optical responses properly, and the inclusion of solvent whether implicitly or explicitly has been shown to be of high importance. In addition, in the study of a triply axial chiral binaphthyl based molecule, it has been demonstrated that the solute concentration may play a crucial role on its conformational landscape as well as its axial chirality in solution. To probe structural properties including induced chirality at the metal centers, the bis(pyrrol-2-ylmethyleneamine)-cyclohexane (H2L) ligand and its five metal complexes (e.g. Ni (II), Cu (II), Pd (II), Pt (II), and Zn (II)) have been synthesized and their VA, VCD, UV-Vis and ECD spectra have been recorded and analyzed. We found that while M-Ni-(R,R)-L, M-Cu-(R,R)-L, M-Pd-(R,R)-L, and M-Pt-(R,R)-L complexes take on the mono-nuclear geometries, the [M-Zn-(R,R)-L]2 complex in solution exists in the dinuclear geometry. Furthermore, these metal complexes take on M-helicity as dictated by the chirality of the (R,R)-ligand.
Download or read book Conformational Analysis written by G Chiurdoglu and published by Elsevier. This book was released on 2012-12-02 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conformational Analysis: Scope and Present Limitations contains the proceedings of the Brussels International Symposium on Conformational Analysis held in Brussels, Belgium, in September 1969. The papers focus on the theoretical aspects and applications of conformational analysis, such as those concerning the aliphatic and especially the cyclic series. Topics covered include the geometry of five-membered rings; conformational transmission in steroids; conformational aspects of N-quaternization; and applications of nuclear magnetic resonance spectrometry in conformational studies of cyclohexane derivatives. This book is comprised of 20 chapters and begins with a discussion on the conformational aspects of some five-membered ring compounds based mainly on observed (diffraction methods) and calculated torsional angles. The reader is then introduced to nuclear magnetic resonance studies of the conformations and conformational barriers in cyclic molecules; conformational studies of six-membered heterocycles; conformational transmission in steroids; and solvolytic cyclizations involving double bonds. The remaining chapters explore the conformational analysis of methylcyclohexane, cyclohexane systems, and carbonium ions; conformations of membrane-active cyclodepsipeptides; energetics of isomeric transition states and competitive reaction pathways in conformational analysis; and conformational aspects of the reaction of the 1-methylcyclodecane-l,6-diols with acid. This monograph will be of interest to organic chemists.
Download or read book Modern Conformational Analysis written by Helena Dodziuk and published by Analysis and Control Methods f. This book was released on 1995 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text describes the importance of molecular organization in organic chemical and biological systems, the quantum foundations of molecular spatial structure, molecular symmetry, chirality and physical methods for studying molecular geometry.
Download or read book Research Grants Index written by National Institutes of Health (U.S.). Division of Research Grants and published by . This book was released on 1975 with total page 1224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Conformational Analysis of Molecules by NMR Spectroscopy Using Vicinal 13C 13C Coupling Constants written by and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of one hundred and nine rigid and flexible molecules (dibenzofurans, biphenyls, fluorenes, fluorenones and diphenyl ethers) with a range of substituents have been studied with a view to obtaining conformational data from vicinal 13C-,13C coupling constants. The molecules were characterized primarily by nuclear magnetic resonance spectroscopy (proton, carbon-13, fluorine-19, nitrogen-15, heteronuclear (13C-1H)correlation spectroscopy, DEPT-90/DEPT-135, NOE spectroscopy). Finally, the INADEQUATE experiment was used to obtain 13C-13C coupling constants. Twelve novel crystal structures were obtained from the study, and conformations obtained for biphenyls and diphenyl ethers compared with conformational studies by other methods, indicating that the lowest energy conformations can be retained in both solid and solution states, provided that other factors, (e.g. crystal packing forces) are not dominant.Comparison of our data, using state-of-the-art techniques for assignments, with previous theoretical predictions of conformations from carbon chemical shifts proved unsatisfactory. Attempts to use vicinal carbon coupling constants to obtain a dihedral angle dependence were unsuccessful. For rigid molecules, vicinal coupling constants could not be assigned with confidence and the dihedral angle dependent contribution could not be quantified because of the multifactorial nature of these couplings. Previous literature strongly suggests that these coupling constants do not exhibit a dihedral angle dependence. Previous literature has also shown that the vicinal coupling constants required in the present study for the conformational analysis of biphenyls do not exhibit a dihedral angle dependence. The dihedral angle dependent contributions from vicinal coupling constants in certain diphenyl ethers were completely eclipsed by additional "through-space" coupling. The results of a molecular mechanics study showed that it was not possible to obtain conformer distributions for biphenyls or diphenyl ethers. Therefore, Karplus-type equations for these molecules could not be formulated. This work represents one of the most comprehensive and diverse NMR analyses of dibenzofurans, diphenyl ethers and biphenyls, and makes a significant contribution to the carbon coupling constant data currently available.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 956 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Masters Theses in the Pure and Applied Sciences written by W. H. Shafer and published by Springer Science & Business Media. This book was released on 1994 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 37 (thesis year 1992) reports a total of 12,549 thesis titles from 25 Canadian and 153 US universities (theses submitted in previous years but only now reported are indicated by the thesis year shown in parenthesis). The organization, like that of past years, consists of thesis titles arrange
Download or read book Grants and Awards for Fiscal Year written by National Science Foundation (U.S.) and published by . This book was released on 1978 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 908 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography of Mass Spectroscopy Literature for 1970 written by and published by . This book was released on 1972 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 17 0 NMR Spectroscopy in Organic Chemistry written by David W. Boykin and published by CRC Press. This book was released on 2020-08-27 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive review of the application of 17O NMR spectroscopy to organic chemistry. Topics include the theoretical aspects of chemical shift, quadrupolar and J coupling; 17O enrichment; the effect of steric interactions on 17O chemical shifts of functional groups in flexible and rigid systems; the application of 17O NMR spectroscopy to hydrogen bonding investigations; mechanistic problems in organic and bioorganic chemistry; and 17O NMR spectroscopy of oxygen monocoordinated to carbon in alcohols, ethers, and derivatives. Recent results that show correlations between molecular geometry, determined by X-ray studies and estimated by molecular mechanics calculations, and 17O chemical shifts are also covered. 17O Spectroscopy in Organic Chemistry provides important reference information for organic chemists and other scientists interested in 17O NMR spectroscopy as a tool for obtaining new structural and chemical data about organic molecules.
Download or read book Subject Index of Current Research Grants and Contracts Administered by the National Institute of General Medical Sciences written by National Institute of General Medical Sciences (U.S.). Division of Research Grants and published by . This book was released on 1976 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Subject Index of Current Research Grants and Contracts Administered by the National Institute of General Medical Sciences written by National Institute of General Medical Sciences (U.S.) and published by . This book was released on 1976 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OAR Cumulative Index of Research Results written by and published by . This book was released on 1967 with total page 1264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Chiroptical Spectroscopy Volume 2 written by Nina Berova and published by John Wiley & Sons. This book was released on 2012-03-27 with total page 884 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an introduction to the important methods of chiroptical spectroscopy in general, and circular dichroism (CD) in particular, which are increasingly important in all areas of chemistry, biochemistry, and structural biology. The book can be used as a text for undergraduate and graduate students and as a reference for researchers in academia and industry. Experimental methods and instrumentation are described with topics ranging from the most widely used methods (electronic and vibrational CD) to frontier areas such as nonlinear spectroscopy and photoelectron CD, as well as the theory of chiroptical methods and techniques for simulating chiroptical properties. Applications of chiroptical spectroscopy to problems in organic stereochemistry, inorganic stereochemistry, and biochemistry and structural biology are also discussed, and each chapter is written by one or more leading authorities with extensive experience in the field.
