Structure Of Monohydrate Research Articles

Structure of (−)589-tris(3,3'-dimethyl-2,2'-bipyridine)rhodium(III) triperchlorate monohydrate

Structure of (−)₅₈₉-tris(3,3'-dimethyl-2,2'-bipyridine)rhodium(III) triperchlorate monohydrate

Structural studies of analgesics and their interactions. V. The crystal and molecular structure of metamizol monohydrate

Metamizol, Na[Ct3H16N3045], C13H16N304S-Na +, a sulphonyl derivative of amidopyrine, is perhaps the most widely used non-narcotic analgetic and antiinflammatory pyrazolone derivative. The monohydrate of the compound crystallizes in the monoclinic space group P2Jc with eight molecules in a unit cell of dimensions a = 9.143 (3), b = 49.50 (2), c = 7.314 (2)/k and fl = 90.9 (1) °. The structure was solved by direct methods and refined to an R value of 0.080 for 4466 observed reflections. The two crystallographically independent molecules in the structure have similar dimensions. The elongated molecules are hydrophobic at one end and hydrophilic at the other with the middle portion partly hydrophobic and partly hydrophilic. The pyrazolone group in the structure has dimensions similar to those found in uncomplexed antipyrine and amidopyrine. The crystal structure can be described as consisting of double layers of metamizol molecules stacked perpendicular to the b axis. The adjacent double layers are separated by a layer of Naions and water molecules.

A Refinement of the Crystal Structure of Creatine Monohydrate

Abstract The crystal structure of creatine monohydrate has been refined from three-dimensional X-ray data. This refinement introduces minor modifications to the positional and thermal parameters and confirmed the zwitter ion structure.

Conformation of the choline phosphate zwitterion. Crystal and molecular structure of cyclopentylphosphorylcholine monohydrate, [(CH3)3N+CH2CH2O](c-C5H9O)P(O).lovin.O.H2O

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConformation of the choline phosphate zwitterion. Crystal and molecular structure of cyclopentylphosphorylcholine monohydrate, [(CH3)3N+CH2CH2O](c-C5H9O)P(O).lovin.O.H2ORaghupathy Sarma, Fausto Ramirez, Poojappan Narayanan, Brian McKeever, Hiroshi Okazaki, and James F. MarecekCite this: J. Am. Chem. Soc. 1978, 100, 14, 4453–4458Publication Date (Print):July 1, 1978Publication History Published online1 May 2002Published inissue 1 July 1978https://doi.org/10.1021/ja00482a023RIGHTS & PERMISSIONSArticle Views78Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (680 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Conformational analysis of 8-azanucleosides. Crystal and molecular structure of 8-azatubercidin monohydrate, a nucleoside analog exhibiting the "high anti" conformation

Conformational analysis of 8-azanucleosides. Crystal and molecular structure of 8-azatubercidin monohydrate, a nucleoside analog exhibiting the "high anti" conformation

The crystal structure and conformation of the cyclic dipeptide cyclo(-L-seryl-L-histidyl-) monohydrate

The crystal structure and conformation of the cyclic dipeptide <i>cyclo</i>(-<scp>L</scp>-seryl-<scp>L</scp>-histidyl-) monohydrate

The crystal and molecular structure of tetrakis(diacetamide)calcium(II) chlorate monohydrate

Abstract The crystal structure of tetrakis(diacetamide)calcium(II) chlorate monohydrates [Ca(DA)4]ClO3)2·H2O, has been determined from three-dimensional X-ray data. The complex has the cell parameters a = 12.399(3) A, b = 7.900(2) A, c = 14.725(3) A, β = 98.35(2)°, Z = 2. The unit cell is monoclinic, space group P2/c. The structure was determined by direct methods and refined anisotropically by block-diagonal least squares to a conventional unweighted R of 0.11. The calcium ion is 8-coordinated and its coordination sphere can be described as a square antiprism formed by eight carbonyl oxygens from 4 diacetamide ligands; two ligands are related to the other two by a two-fold rotation axis. One of the amide nitrogens is hydrogen bonded to a chlorate oxygen. In addition, hydrogen bondingbetween an amide nitrogen and an uncoordinated water molecule results in the formation of infinite chains parallel to [100]. Calcium-oxygen distances fall within the range 2.41–2.44 A.

Crystal structure of anhydrous cholesterol.

CHOLESTEROL, the most abundant steroid in the animal kingdom, is found mainly as a component in cell membranes and lipoproteins. The presence of the hydrophilic C(3) hydroxyl group in this otherwise hydrophobic molecule allows cholesterol to occupy a position at polar–nonpolar interfaces. Crystals of 3-hydroxy steroids and their hydrates show a tendency towards double layer structures with an end-for-end arrangement of approximately parallel molecules1. As this molecular organisation is generally similar to that in membranes, it can be expected that some of the principles of intermolecular association in membranes might be revealed in the molecular packing in the crystal structures. Another common feature in these structures is the presence of more than one molecule in the crystallographic asymmetric unit. While this is a complicating factor in structure analysis, it clearly increases the amount of information regarding preferred conformation and intermolecular association to be gained from a structure determination. Craven2 has recently reported the remarkable crystal structure of one form of cholesterol monohydrate. The arrangement of the eight crystallographically independent molecules in the triclinic cell shows unusual local pseudo-symmetry. One pair of molecules is related to another by a non-crystallographic b/2 translation, while a third pair, oriented end-for-end relative to the first, is related to the fourth by a similar a/2 translation. Non-crystallographic twofold rotation symmetry relates members of the first and the third pairs. The overall structure is a stacking of bilayers of 33.9 A total thickness. We report here that anhydrous cholesterol crystals are also triclinic, with eight independent molecules per cell. This structure offers additional insight into the packing of cholesterol molecules, and a comparison with the monohydrate structure.

ChemInform Abstract: THE CONFORMATIONS OF OLIGOSACCHARIDES. III. THE CRYSTAL AND MOLECULAR STRUCTURE OF MELIBIOSE MONOHYDRATE

The crystal structure of α-melibiose monohydrate (C12H22O11·H2O) was determined by direct methods using two-dimensional cosine invariants. The space group is P212121, with Z=4 and unit cell dimensions of a=15.814(5), b=10.924(5), c=8.903(4) A. The structure was refined to R=0.044 for 1439 reflections measured with MoKα radiation. Difference synthesis indicated the partial (15%) random substitution of α-melibiose molecules by the β-anomer. The molecular conformation of α-melibiose is almost the same as that previously found in the melibiose moiety of raffinose, although some of the bond lengths and angles are significantly different. The molecules are linked by complex hydrogen-bond systems which consist of six-link finite chains and five-membered closed loops.

The molecular structure of an aldosterone 18-glucopyranosiduronate

The crystal and molecular structure of aldosterone 18R-α- d-glucopyranosiduronic acid tetraacetate methyl ester was determined by X-ray analysis in order to ascertain the stereochemistry of the glycosidic bond and the configuration at C(18). The C(18) stereochemistry was found to be the same as that observed in the crystal structure of aldosterone monohydrate, and the C-ring has similar strain as shown by the C(11)-C(12)-C(13) valency angle of 98°. The sugar ring, which has a 4C 1 conformation, is approximately parallel to the steroid nucleus and is located above the aldosterone 17β-side chain.

A comparative analysis of structural parameters obtained by diffractometer and scanning-densitometer measurements

The structure of cytosine monohydrate has been redetermined with reflexion data obtained from automatic digital scanning of Weissenberg films. The previous determination with diffractometer data [McClure & Craven, Acta Cryst. (1973), B29, 1234--1238] converged to an R of 0.037, with average estimated standard deviations of 0002 A and 015 ° in derived bond lengths and angles. The photographic data set converged to an R of 0-0672 with e.s.d.'s of 0-004--0-005 A and 0.3-0.4 °. Normal probability plots showed that the positional (and the derived geometric) parameters were very comparable; the vibrational parameters were rather less so, some systematic error being apparent. The overall conclusion from the study is that the two data sets have given essentially the same positional description of the structure.

The Conformations of Oligosaccharides. III. The Crystal and Molecular Structure of Melibiose Monohydrate

Abstract The crystal structure of α-melibiose monohydrate (C12H22O11·H2O) was determined by direct methods using two-dimensional cosine invariants. The space group is P212121, with Z=4 and unit cell dimensions of a=15.814(5), b=10.924(5), c=8.903(4) Å. The structure was refined to R=0.044 for 1439 reflections measured with MoKα radiation. Difference synthesis indicated the partial (15%) random substitution of α-melibiose molecules by the β-anomer. The molecular conformation of α-melibiose is almost the same as that previously found in the melibiose moiety of raffinose, although some of the bond lengths and angles are significantly different. The molecules are linked by complex hydrogen-bond systems which consist of six-link finite chains and five-membered closed loops.

Relationship between the mutagenic and base-stacking properties of halogenated uracil derivatives: The crystal structures of 5-chloro- and 5-bromouracil

Three-dimensional X-ray diffraction data were used to determine the crystal structures of 5-chlorouracil and 5-bromouracil, two mutagenic pyrimidine analogs that can substitute for thymine in DNA. Crystals of the two compounds are nearly isostructural. The space group is P2 1 c , with a = 8.450(6), b = 6.842(3), c = 11.072(16) a ̊ , β = 123.53(19)° for 5-chlorouracil, and a = 8.598(3), b = 6.886(1), c = 11.417(5) a ̊ , β = 123.93(3)° for 5-bromouracil. Intensity data were collected with an automated diffractometer. The structures were refined by full-matrix least-squares to R = 0.058 for 5-chlorouracil and R = 0.027 for 5-bromouracil. The analogs form planar, hydrogen-bonded ribbons that are nearly identical to those found in the crystal structure of thymine monohydrate. As in many other structures of 5-halogenated uracil derivatives, the bases assume a stacking pattern that permits intimate contacts between the halogen substituents and the pyrimidine rings of adjacent bases. This stacking pattern involves halogen contacts that are significantly shorter than normal van der Waals interactions. The crystallographic results provide additional evidence that halogen substituents influence the stacking patterns of uracil derivatives, while exerting little direct effect on the hydrogen-bonding properties. The observed stacking patterns are consistent with the hypothesis that altered stacking interactions may account for the mis-pairing between 5-halogenated uracil bases and guanine residues within double-helical nucleic acids.

STRUCTURAL STUDY OF MUCOPOLYSACCHARIDE, CRYSTAL STRUCTURE OF CHONDROSINE MONOHYDRATE

Abstract The structure of chondrosine monohydrate was determined by an X-ray study. The zwitter-ionic character of the molecule and the intermolecular hydrogen bondings stabilize the crystal structure. An intramolecular hydrogen bond is found between the axial oxygen O(4′) and the ring oxygen O(5). The galactosamine moiety has α-configuration in the crystalline state.

The crystal and molecular structure of dichloro(S-methyl-L-cysteine)palladium(II) monohydrate

The crystal and molecular structure of dichloro(<i>S</i>-methyl-<scp>L</scp>-cysteine)palladium(II) monohydrate

CRYSTAL AND MOLECULAR STRUCTURE OF MELEZITOSE MONOHYDRATE

Abstract The crystal structure of melezitose monohydrate has been solved by a non-centrosymmetric direct method and refined to an R index of 0.068. The relative orientation of the glucose and fructose units in sucrose moiety is very similar to that found in sucrose itself. There are no intramolecular hydrogen bonds. Two bifurcated hydrogen bonds were found.

Effects of sulfur substituents on base stacking and hydrogen bonding. Crystal structure of 6-thioguanosine monohydrate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffects of sulfur substituents on base stacking and hydrogen bonding. Crystal structure of 6-thioguanosine monohydrateUlf Thewalt and Charles E. BuggCite this: J. Am. Chem. Soc. 1972, 94, 25, 8892–8898Publication Date (Print):December 1, 1972Publication History Published online1 May 2002Published inissue 1 December 1972https://doi.org/10.1021/ja00780a041RIGHTS & PERMISSIONSArticle Views162Altmetric-Citations55LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (803 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Structure of L-asparagine monohydrate by neutron diffraction

Structure of L-asparagine monohydrate by neutron diffraction

An X-ray study of the hydrogen bonding in the crystalline L-arginine phosphate monohydrate complex

The crystal structure of the L-arginine phosphate monohydrate complex has been determined from 1453 three-dimensional X-ray diffractometer data and refined by least-squares methods to a residual of R = 3.9 %. The X-ray results suggest that the L-arginine molecule is deprotonated at the carboxyl group and protonated at the guanidyl and amino groups and that the phosphate ion carries one negative charge. The L-arginine molecule is in a less extended conformation than found previously and both the guanidinium group and the carboxyl-C system are essentially planar. The crystal structure is interlaced by an intricate hydrogen-bonding scheme with apparently one bifurcated hydrogen bond involving atom N ~. The symmetrical guanidinium-phosphate ion geometry proposed for the interaction of basic proteins with DNA is not found in the L-arginine-phosphate monohydrate structure. It may therefore be inferred that the symmetrical complex is not necessarily preferred over a more complicated hydrogen bonding arrangement. The same structure has been published recently by Aoki, Nagamo & Iitaka (Acta Cryst. (1971). B27, 11).

Direct methods in neutron crystallography: structure of L-proline monohydrate by symbolic addition and tangent refinement.

“DIRECT METHODS” for the solution of crystal structures lead directly to the phases of the structure factors from the distribution of the intensities of Bragg reflexions. Most of these methods depend on the assumption that the scattering density is everywhere positive, an unassailable assumption for the electron density associated with X-ray scattering. In neutron diffraction the scattering density for hydrogen atoms is negative, so that it becomes questionable whether the same techniques are applicable. One possible answer to the question has been suggested by Karle in the squared structure approach1, and the structure of glycolic acid has been solved by Ellison and Levy2 following Karle's suggestion. Sikka3 has suggested that the conventional symbolic addition method4 may be used in neutron crystallography when the scattering by hydrogen is less than 1/3 of the total scattering: where bi is the neutron scattering length. The structure of trichloroacetic acid, Cl3CCO2H, was solved by direct methods from neutron diffraction data by Jonsson et al. (unpublished work). This is a centrosymmetric structure, and the amount of hydrogen scattering is small, so that a successful structure solution by application of the Σ2 relationship4 was not surprising.