Journal ArticleDOI
Supramolecular structure of 1H-pyrazoles in the solid state: a crystallographic and ab initio study
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TLDR
The proposed semi-quantitative model, which explains most hydrogen-bonded motifs as a combination of the effects of substituents at C3 and C5, has been examined as a function of the steric and polarizability effects of these substituent effects represented by molar refractivity.Abstract:
The secondary structure of 1H-unsubstituted pyrazole derivatives bearing only one hydrogen donor group and one or more acceptor groups has been analyzed in terms of some descriptors representing the substituents at C3 and C5. The substituent at C4 appears to affect mainly the tertiary or quaternary structure of these compounds. The proposed semi-quantitative model, which explains most hydrogen-bonded motifs as a combination of the effects of substituents at C3 and C5, has also been examined as a function of the steric and polarizability effects of these substituents represented by molar refractivity. The model also applies to other five-membered rings (1,2,4-triazoles, 1,2,4-diazaphospholes and 1,2,4-diazaarsoles). Furthermore, ab initio calculations at RHF/6-31G* have been performed to discover the relative stability of three of the four hydrogen-bond patterns displayed by several symmetrical pyrazoles (dimers, trimers, tetramers). The fourth motif, catemers, has only been discussed geometrically.read more
Citations
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Tautomeric equilibria in relation to pi-electron delocalization.
Journal ArticleDOI
Infrared and ab initio studies of hydrogen bonding and proton transfer in the complexes formed by pyrazoles
TL;DR: In this paper, the results of experimental studies and quantum mechanical calculations of vibrational spectra and structure of hydrogen bonded complexes formed by pyrazole and 3,5-dimethylpyrazole (DMP) are presented.
Journal ArticleDOI
Fluorinated tris(pyrazolyl)borates. Syntheses and characterization of sodium and copper complexes of [HB(3-(CF3),5-(Ph)Pz) 3]-
TL;DR: In this article, a trispyrazolyl)boratosodium adduct was synthesized from the corresponding pyrazole and NaBH4 in high yield, which forms stable adducts with oxygen-based donors like THF and water.
Journal ArticleDOI
The Structure of Pyrazoles in the Solid State: A Combined CPMAS, NMR, and Crystallographic Study
Rosa M. Claramunt,Pilar Cornago,Verónica Torres,Elena Pinilla,M. Rosario Torres,André Samat,Vladimir Lokshin,Magali Vales,José Elguero +8 more
TL;DR: The structures of six N-unsubstituted pyrazoles, three already known and three newly synthesized, have been studied by a combination of X-ray crystallography, multinuclear NMR (solution and solid state), and density functional theory (DFT) calculations.
Journal ArticleDOI
Synthesis, structure and properties of tetrameric gold(I) 3,5-di-tert-butyl–pyrazolate
Guang Yang,Raphael G. Raptis +1 more
TL;DR: In this paper, the reaction of Au(tht)Cl and 3,5-tBu2-pzH (pZH=pyrazole) in the presence of a base gives a tetranuclear complex as its only crystalline product.
References
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Journal ArticleDOI
Self—Consistent Molecular Orbital Methods. XII. Further Extensions of Gaussian—Type Basis Sets for Use in Molecular Orbital Studies of Organic Molecules
TL;DR: In this article, two extended basis sets (termed 5-31G and 6 -31G) consisting of atomic orbitals expressed as fixed linear combinations of Gaussian functions are presented for the first row atoms carbon to fluorine.
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Self‐consistent molecular orbital methods 25. Supplementary functions for Gaussian basis sets
TL;DR: In this paper, a modified basis set of supplementary diffuse s and p functions, multiple polarization functions (double and triple sets of d functions), and higher angular momentum polarization functions were defined for use with the 6.31G and 6.311G basis sets.
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Supramolecular Synthons in Crystal Engineering—A New Organic Synthesis
TL;DR: In this article, the authors show that crystal engineering is a new organic synthesis, and that rather than being only nominally relevant to organic chemistry, this subject is well within the mainstream, being surprisingly similar to traditional organic synthesis in concept.
Journal Article
Crystal engineering : the design of organic solids
TL;DR: The Atom-Atom Potential Method and the Close-Packing Model for Molecular Crystals as mentioned in this paper have been used to predict the crystal structures of organic molecules using the Kitaigorodskii model.
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The development of versions 3 and 4 of the Cambridge Structural Database System
F.H. Allen,John E. Davies,Jean J. Galloy,Owen Johnson,Olga Kennard,Clare F. Macrae,Eleanor M. Mitchell,Gary F. Mitchell,J. Michael Smith,David G. Watson +9 more
TL;DR: The CSD itself acts as a computerized depository for large-volume numerical results for some 30 journals and may conveniently be categorized according to its "dimensionality", as described below and illustrated in Figure 1.