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Rosa M. Claramunt

Bio: Rosa M. Claramunt is an academic researcher from National University of Distance Education. The author has contributed to research in topics: Tautomer & Nuclear magnetic resonance spectroscopy. The author has an hindex of 41, co-authored 449 publications receiving 7556 citations. Previous affiliations of Rosa M. Claramunt include Saint Petersburg State University & Complutense University of Madrid.


Papers
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Journal ArticleDOI
TL;DR: In this article, a new class of ultraviolet stabilizers, C-(2'-hydroxyphenyl)pyrazoles, is described, in which there is an intramolecular hydrogen bond (IMHB).
Abstract: A new class of ultraviolet stabilizers, the C-(2'-hydroxyphenyl)pyrazoles, is described. The combined use of X-ray crystallography [3(5)-(2'-hydroxyphenyl)pyrazole (5), 1-methyl-3-(2'hydroxyphenyl)pyrazole (7), and 1-methyl-5-(2'-hydroxyphenyl)pyrazole (8)], NMR ( 1 H and 13 C), and UV spectroscopies allows the determination of the major tautomers, the coplanarity of both rings if present, and the existence of hydrogen bonds. Compounds 5 and 7, in which there is an intramolecular hydrogen bond (IMHB), do not fluoresce in cyclohexane. Solvent and temperature experiments prove that for these compounds in cyclohexane proton transfer took place in the excited singlet state but not in the tripler state (phosphorescence) and that the latter one is of higher than the former

141 citations

Journal ArticleDOI
TL;DR: (1)H-(13)C two-dimensional magic-angle spinning (MAS) solid-state NMR correlation spectra, recorded with the MAS-J-HMQC experiment, are presented and chemical shifts calculated by using the GIPAW (Gauge Including Projector Augmented Waves) plane-wave pseudopotential approach are presented.
Abstract: H-1-C-13 two-dimensional magic-angle spinning (MAS) solid-state NMR correlation spectra, recorded with the MAS-J-HMQC experiment, are presented for campho[2,3-c]pyrazole. For each C-13 moiety, there are six resonances associated with the six distinct molecules in the asymmetric unit cell (Z' = 6). The one-bond C-H correlations observed in the 2D H-1-C-13 MAS-J-HMQC spectra allow the experimental determination of the H-1 and C-13 chemical shifts associated with the separate CH, CH2, and CH3 groups. H-1 and C-13 chemical shifts calculated by using the GIPAW (Gauge Including Projector Augmented Waves) plane-wave pseudopotential approach are presented. Calculations for the whole unit cell (12 x 29 = 348 atoms, with geometry optimization of all atoms) allow the assignment of the experimental H-1 and C-13 chemical shifts to the six distinct molecules, The calculated chemical shifts for the full crystal structure are compared with those for isolated molecules as extracted from the geometry-optimized crystal structure. In this way, the effect of intermolecular interactions on the observed chemical shifts is quantified. In particular, the calculations are sufficiently precise to differentiate the small (<1 ppm) differences between the H-1 chemical shifts of the six resonances associated with each distinct CH or CH2 moiety.

120 citations


Cited by
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Journal ArticleDOI
01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations

Journal ArticleDOI
TL;DR: SUPERFLIP is a computer program that can solve crystal structures from diffraction data using the recently developed charge-flipping algorithm and has been successfully compiled and tested on a variety of operating systems.
Abstract: SUPERFLIP is a computer program that can solve crystal structures from diffraction data using the recently developed charge-flipping algorithm. It can solve periodic structures, incommensurately modulated structures and quasicrystals from X-ray and neutron diffraction data. Structure solution from powder diffraction data is supported by combining the charge-flipping algorithm with a histogram-matching procedure. SUPERFLIP is written in Fortran90 and is distributed as a source code and as precompiled binaries. It has been successfully compiled and tested on a variety of operating systems.

3,600 citations

01 Jan 2007
TL;DR: The Third edition of the Kirk-Othmer encyclopedia of chemical technology as mentioned in this paper was published in 1989, with the title "Kirk's Encyclopedia of Chemical Technology: Chemical Technology".
Abstract: 介绍了Kirk—Othmer Encyclopedia of Chemical Technology(化工技术百科全书)(第五版)电子图书网络版数据库,并对该数据库使用方法和检索途径作出了说明,且结合实例简单地介绍了该数据库的检索方法。

2,666 citations

Journal ArticleDOI
TL;DR: The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.
Abstract: The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

2,582 citations