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1.
Barbara Hachua Maria Nowak Joachim Kusz 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(7):o357-o360
The crystal structure of the title compound, C10H12O4·H2O, consists of (3,4‐dimethoxyphenyl)acetic acid and water molecules linked by O—H...O hydrogen bonds to form cyclic structures with graph‐set motifs R12(5) and R44(12). These hydrogen‐bond patterns result in a three‐dimensional network with graph‐set motifs R44(20) and R44(22), and the formation of larger macrocycles, respectively. The C—C bond lengths and the endocyclic angles of the benzene ring show a noticeable asymmetry, which is connected with the charge‐transfer interaction of the carboxyl or methoxy groups and the benzene ring. The title compound is one of the simple carboxylic acid systems that form hydrates. Thus, the significance of this study lies in the analysis of the interactions in this structure and the aggregations occurring via hydrogen bonds in two crystalline forms of (3,4‐dimethoxyphenyl)acetic acid, namely the present hydrate and the anhydrous form [Chopra, Choudhury & Guru Row (2003). Acta Cryst. E 59 , o433–o434]. The correlation between the IR spectrum of this compound and its structural data are also discussed. 相似文献
2.
S. Athimoolam S. Natarajan 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(5):o283-o286
The title adduct, 4‐aminobenzoic acid–l ‐proline–water (1/2/1), C7H7NO2·2C5H9NO2·H2O, contains two independent proline chains with a C(5) motif, each of the head‐to‐tail type and each held together by N—H...O hydrogen bonds, propagated parallel to the b and c axes of the unit cell. Thus, the proline residues aggregate parallel to the ac plane. 4‐Aminobenzoic acid (PABA) residues are arranged on both sides of the proline aggregate and are connected through water O atoms, which act as acceptors for PABA and as hydrogen‐bond donors to the amino acids. The characteristic features of PABA, viz. twisting of the carboxyl plane from the aromatic ring and the formation of a head‐to‐tail chain motif [C(8)] along the b axis, are observed. A distinct feature of the structure is that no proton transfer occurs between proline and PABA. 相似文献
3.
Dominik Cin
i Branko Kaitner 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(4):o226-o229
In the title compounds, 4‐carboxyanilinium bromide, C7H8NO2+·Br−, (I), and 4‐acetylanilinium bromide, C8H10NO+·Br−, (II), each asymmetric unit contains a discrete cation with a protonated amino group and a halide anion. Both crystal structures are characterized by two‐dimensional hydrogen‐bonded networks. The ions in (I) are connected via N—H...Br, N—H...O and O—H...Br hydrogen bonds, with three characteristic graph‐set motifs, viz. C(8), C21(4) and R32(8). The centrosymmetric hydrogen‐bonded R22(8) dimer motif characteristic of carboxylic acids is absent. The ions in (II) are connected via N—H...Br and N—H...O hydrogen bonds, with two characteristic graph‐set motifs, viz. C(8) and R42(8). The significance of this study lies in its illustration of the differences between the supramolecular aggregations in two similar compounds. The presence of the methyl group in (II) at the site corresponding to the hydroxyl group in (I) results in a significantly different hydrogen‐bonding arrangement. 相似文献
4.
Alan Barcon Andrew P. J. Brunskill Hugh W. Thompson Roger A. Lalancette 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(2):o140-o142
The title monohydrate, C7H10O3·H2O, aggregates as a complex hydrogen‐bonding network, in which the water molecule accepts a hydrogen bond from the carboxyl group of one molecule and donates hydrogen bonds to ketone and carboxyl Czdbnd;O functions in two additional molecules, yielding a sheet‐like structure of parallel ribbons. The keto acid adopts a chiral conformation through rotation of the carboxyl group by 62.50 (15)° relative to the plane defined by its point of attachment and the ketone C and O atoms. Two C—H⋯O close contacts exist in the structure. 相似文献
5.
S. Athimoolam S. Natarajan 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(10):o612-o617
In the title compounds, C7H8NO2+·NO3−, (I), C7H8NO2+·ClO4−·H2O, (II), and 2C7H8NO2+·SO42−, (III), the carboxyl planes of the 4‐carboxyphenylammonium cations are twisted from the aromatic plane. A homonuclear C(8) hydrogen‐bonding motif of 4‐carboxyphenylammonium cations is observed in both (I) and (II), leading to `head‐to‐tail' layers. The cations in (III) form carboxyl group dimers, making a graph‐set motif of R22(8). In all the structures, anions connect the cationic layers and an infinite chain running along the c axis is observed, having the C22(6) graph‐set motif. Interestingly, in (II), the anions are connected through weak hydrogen bonds involving the water molecules, leading to a graph‐set motif of R44(12). Alternate hydrophobic and hydrophilic layers are observed in all three compounds as a result of the column‐like arrangement of the aromatic rings of the cations and the anions. Furthermore, in (I), head‐to‐tail N—H⋯O interactions and interactions linking the cations and anions form an R64(16) hydrogen‐bonding motif, resulting in a pseudo‐inversion centre at (, , 0). 相似文献
6.
Graham Smith Raymond C. Bott Daniel E. Lynch 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):1155-1156
The 1:1 adduct of 4‐aminobenzoic acid (PABA) with 4‐am‐inobenzonitrile (PABN), C7H7NO2·C7H6N2, consists of a primary centrosymmetric cyclic hydrogen‐bonded PABA dimer interaction [O?O 2.640 (3) Å] peripherally linked into chains by weaker hydrogen bonds via a head‐to‐tail PABN interaction [N?N 3.179 (4) and N?O 3.062 (4) Å], and is linked between the chains by amine‐N (PABN) to amine‐N (PABA) interactions [N?N 3.233 (5) Å]. No proton transfer occurs. 相似文献
7.
Manuela Ramos Silva Ana Matos Beja Susana H. Lopes Jos Antnio Paixo Abílio J. F. N. Sobral A. M. d'A. Rocha Gonsalves 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):o685-o687
In the title compound, C16H17NO3·H2O, the pyrrole ring is distorted slightly from ideal C2v symmetry. Three strong hydrogen bonds link the substituted pyrrole and water molecules to form infinite chains, in which the hydrogen bonds form rings and chain patterns. Two intermolecular C—H?π interactions maintain the internal cohesion between these chains. The molecular structure differs slightly from that of the isolated molecule calculated by ab initio quantum‐mechanical calculations. In the latter model, the non‐H substituent atoms share the plane of the pyrrole ring, except for the phenyl group, which lies almost perpendicular to this plane. 相似文献
8.
Gerzon Delgado Asilo J. Mora Ali Bahsas 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(8):965-967
The title compound, 4‐piperidiniocarboxylate (isonipecotic acid), crystallizes as a zwitterion and incorporates one water molecule, i.e. C6H11NO2·H2O. The piperidine ring adopts a chair conformation and the α‐carboxylate group is oriented in the equatorial position. The combination of the interactions between the α‐amino and α‐carboxylate groups and the water molecules builds a three‐dimensional assembly of hydrogen bonds. 相似文献
9.
Rim Benali‐Cherif Radhwane Takouachet El‐Eulmi Bendeif Nourredine Benali‐Cherif 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(3):323-325
The crystal structure of a polymorph of 4‐aminobenzoic acid (PABA), C7H7NO2, at 100 K is noncentrosymmetric, as opposed to centrosymmetric in the structures of the other known polymorphs. The two crystallographically independent PABA molecules form pseudocentrosymmetric O—H...O hydrogen‐bonded dimers that are further linked by N—H...O hydrogen bonds into a three‐dimensional network. The benzene rings stack in the b direction. The CO2 moieties are bent out slightly from the benzene ring plane. 相似文献
10.
Dominik Cin
i Branko Kaitner 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(2):o101-o104
In the title compounds, C7H8NO2+·Br−, (I), and C7H8NO2+·I−, (II), the asymmetric unit contains a discrete 3‐carboxyanilinium cation, with a protonated amine group, and a halide anion. The compounds are not isostructural, and the crystal structures of (I) and (II) are characterized by different two‐dimensional hydrogen‐bonded networks. The ions in (I) are connected into ladder‐like ribbons via N—H...Br hydrogen bonds, while classic cyclic O—H...O hydrogen bonds between adjacent carboxylic acid functions link adjacent ribbons to give three characteristic graph‐set motifs, viz. C21(4), R42(8) and R22(8). The ions in (II) are connected via N—H...I, N—H...O and O—H...I hydrogen bonds, also with three characteristic graph‐set motifs, viz. C(7), C21(4) and R42(18), but an O—H...O interaction is not present. 相似文献
11.
Graham Smith Urs D. Wermuth 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(5):534-537
The structures of two ammonium salts of 3‐carboxy‐4‐hydroxybenzenesulfonic acid (5‐sulfosalicylic acid, 5‐SSA) have been determined at 200 K. In the 1:1 hydrated salt, ammonium 3‐carboxy‐4‐hydroxybenzenesulfonate monohydrate, NH4+·C7H5O6S−·H2O, (I), the 5‐SSA− monoanions give two types of head‐to‐tail laterally linked cyclic hydrogen‐bonding associations, both with graph‐set R44(20). The first involves both carboxylic acid O—H...Owater and water O—H...Osulfonate hydrogen bonds at one end, and ammonium N—H...Osulfonate and N—H...Ocarboxy hydrogen bonds at the other. The second association is centrosymmetric, with end linkages through water O—H...Osulfonate hydrogen bonds. These conjoined units form stacks down c and are extended into a three‐dimensional framework structure through N—H...O and water O—H...O hydrogen bonds to sulfonate O‐atom acceptors. Anhydrous triammonium 3‐carboxy‐4‐hydroxybenzenesulfonate 3‐carboxylato‐4‐hydroxybenzenesulfonate, 3NH4+·C7H4O6S2−·C7H5O6S−, (II), is unusual, having both dianionic 5‐SSA2− and monoanionic 5‐SSA− species. These are linked by a carboxylic acid O—H...O hydrogen bond and, together with the three ammonium cations (two on general sites and the third comprising two independent half‐cations lying on crystallographic twofold rotation axes), give a pseudo‐centrosymmetric asymmetric unit. Cation–anion hydrogen bonding within this layered unit involves a cyclic R33(8) association which, together with extensive peripheral N—H...O hydrogen bonding involving both sulfonate and carboxy/carboxylate acceptors, gives a three‐dimensional framework structure. This work further demonstrates the utility of the 5‐SSA− monoanion for the generation of stable hydrogen‐bonded crystalline materials, and provides the structure of a dianionic 5‐SSA2− species of which there are only a few examples in the crystallographic literature. 相似文献
12.
Maria E. Sulbaran Gerzon E. Delgado Asilo J. Mora Ali Bahsas Hector Novoa de Armas Norbert Blaton 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(9):o543-o545
In the title compound, C6H8N2O2S, also known as N‐acetyl‐2‐thiohydantoin–alanine, the molecules are joined by N—H...O hydrogen bonds, forming centrosymmetric R22(8) dimers; these dimers are linked by C—H...O interactions to form R22(10) rings, thus forming C22(10) chains that run along the [101] direction. 相似文献
13.
Mathias O. Senge Kevin M. Smith 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(9):o537-o541
The crystal and molecular structures of 4‐ethyl‐3,5‐dimethylpyrrole‐2‐carbaldehyde, C10H15NO, (I), benzyl 3,5‐dimethylpyrrole‐2‐carboxylate, C14H15NO2, (II), benzyl 4‐acetyl‐3,5‐dimethylpyrrole‐2‐carboxylate, C16H17NO3, (III), dimethyl 3,5‐dimethylpyrrole‐2,4‐dicarboxylate, C10H13NO4, (IV), 4‐ethyl‐3,5‐dimethyl‐2‐(p‐tosylacetyl)pyrrole, C17H21NO3S, (V), and ethyl 4‐(2‐ethoxycarbonyl‐2‐hydroxyacryloyl)‐3,5‐dimethylpyrrole‐2‐carboxylate, C15H19NO6, (VI), were determined at 130 K. Compounds (I), (II), (IV), (V) and (VI) form hydrogen‐bonded dimers [N—H⋯O=C = 1.97 (2)–2.03 (3) Å]. Four dimers, viz. (I) and (IV)–(VI), have inversion symmetry, while the dimer of (II) has twofold symmetry. Only (III) forms polymeric chains involving hydrogen bonds between the pyrrole H atom and the acetyl carbonyl group [H⋯O = 1.97 (2) Å] and is further stabilized by CH3⋯O interactions (C—H⋯O = 2.28–2.49 Å). Compound (VI) was found to occur as the enol ether in the crystal. 相似文献
14.
Diana Becerra Braulio Insuasty Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(2):o79-o86
The molecules of racemic 3‐benzoylmethyl‐3‐hydroxyindolin‐2‐one, C16H13NO3, (I), are linked by a combination of N—H...O and O—H...O hydrogen bonds into a chain of centrosymmetric edge‐fused R22(10) and R44(12) rings. Five monosubstituted analogues of (I), namely racemic 3‐hydroxy‐3‐[(4‐methylbenzoyl)methyl]indolin‐2‐one, C17H15NO3, (II), racemic 3‐[(4‐fluorobenzoyl)methyl]‐3‐hydroxyindolin‐2‐one, C16H12FNO3, (III), racemic 3‐[(4‐chlorobenzoyl)methyl]‐3‐hydroxyindolin‐2‐one, C16H12ClNO3, (IV), racemic 3‐[(4‐bromobenzoyl)methyl]‐3‐hydroxyindolin‐2‐one, C16H12BrNO3, (V), and racemic 3‐hydroxy‐3‐[(4‐nitrobenzoyl)methyl]indolin‐2‐one, C16H12N2O5, (VI), are isomorphous in space group P. In each of compounds (II)–(VI), a combination of N—H...O and O—H...O hydrogen bonds generates a chain of centrosymmetric edge‐fused R22(8) and R22(10) rings, and these chains are linked into sheets by an aromatic π–π stacking interaction. No two of the structures of (II)–(VI) exhibit the same combination of weak hydrogen bonds of C—H...O and C—H...π(arene) types. The molecules of racemic 3‐hydroxy‐3‐(2‐thienylcarbonylmethyl)indolin‐2‐one, C14H11NO3S, (VII), form hydrogen‐bonded chains very similar to those in (II)–(VI), but here the sheet formation depends upon a weak π–π stacking interaction between thienyl rings. Comparisons are drawn between the crystal structures of compounds (I)–(VII) and those of some recently reported analogues having no aromatic group in the side chain. 相似文献
15.
Jing Zhang Xueliang Hou Weifeng Bu Lixin Wu Ling Ye Guangdi Yang Yuguo Fan 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):o663-o664
The title compound (systematic name: 4,4′‐ethylenedipyridinium dimaleate), C12H12N22+·2C4H3O4?, is a 1:2 adduct of 1,2‐bis(4‐pyridyl)ethylene (BPE) and maleic acid (MA). The interaction between the two components in the molecular complex is due to intermolecular hydrogen bonding via an N+—H?O? hydrogen bond. 相似文献
16.
Hugh W. Thompson Roger A. Lalancette 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(7):841-843
In the the title compound, 1,7‐dimethyl‐8‐oxo‐4bα,7α‐gibba‐1,3,4a(10a)‐triene‐10β‐carboxylic acid monohydrate, C18H20O3·H2O, the water of hydration accepts a hydrogen bond from the carboxyl and donates hydrogen bonds to the carboxyl carbonyl and the ketone in two different screw‐related neighbors, which are mutually translational, yielding a complex three‐dimensional hydrogen‐bonding array. 相似文献
17.
Christopher Glidewell John N. Low Janet M. S. Skakle James L. Wardell 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(4):o201-o203
Molecules of the title compound, [(4‐nitrophenyl)sulfanyl]acetic acid, C8H7NO4S, are linked by paired O—H?O hydrogen bonds [H?O 1.81 Å, O?O 2.6456 (15) Å and O—H?O 178°] into centrosymmetric dimers containing an R(8) motif. A single C—H?O hydrogen bond having a nitro O atom as acceptor [H?O 2.47 Å, 3.3018 (19) Å and C—H?O 147°] links the dimers into a molecular ladder, and neighbouring ladders are weakly linked into sheets by aromatic π–π‐stacking interactions. 相似文献
18.
Molecular dynamics simulation of the Michaelis complex, phospho‐enzyme intermediate, and the wild‐type and C12S mutant have been carried out to examine hydrogen‐bonding interactions in the active site of the bovine low molecular weight protein‐tyrosine phosphatase (BPTP). It was found that the Sγ atom of the nucleophilic residue Cys‐12 is ideally located at a position opposite from the phenylphosphate dianion for an inline nucleophilic substitution reaction. In addition, electrostatic and hydrogen‐bonding interactions from the backbone amide groups of the phosphate‐binding loop strongly stabilize the thiolate anion, making Cys‐12 ionized in the active site. In the phospho‐enzyme intermediate, three water molecules are found to form strong hydrogen bonds with the phosphate group. In addition, another water molecule can be identified to form bridging hydrogen bonds between the phosphate group and Asp‐129, which may act as the nucleophile in the subsequent phosphate hydrolysis reaction, with Asp‐129 serving as a general base. The structural difference at the active site between the wild‐type and C12S mutant has been examined. It was found that the alkoxide anion is significantly shifted toward one side of the phosphate binding loop, away from the optimal position enjoyed by the thiolate anion of the wild‐type enzyme in an SN2 process. This, coupled with the high pKa value of an alcoholic residue, makes the C12S mutant catalytically inactive. These molecular dynamics simulations provided details of hydrogen bonding interactions in the active site of BPTP, and a structural basis for further studies using combined quantum mechanical and molecular mechanical potential to model the entire dephosphorylation reaction by BPTP. © 2000 John Wiley & Sons, Inc. J Comput Chem 21: 1192–1203, 2000 相似文献
19.
Kasthuri Balasubramani Packianathan Thomas Muthiah Urszula Rychlewska Agnieszka Plutecka 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(10):o586-o588
The title compound, 2,4‐diamino‐5‐(4‐chlorophenyl)‐6‐ethylpyrimidine‐1,3‐diium dinitrate, C12H15ClN42+·2NO3−, contains two crystallographically independent pyrimethamine (PMN) molecules, which differ in the relative orientations of the pyrimidine and benzene rings and of the ethyl substitutents. In both pyrimethamine molecules, all the pyrimidine N atoms are protonated, unlike most related compounds, in which only one pyrimidine N atom is protonated. The two pyrimethamine moieties are bridged by a variety of N—H⋯O(nitrate) interactions, including some three‐centre hydrogen bonds. 相似文献
20.
G. Prchniak J. Zo M. Daszkiewicz A. Pietraszko V. Videnova‐Adrabiska 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(7):o434-o436
The crystal structure of the title compound, C12H12O6P2, displays two different regions alternating along the a axis: a hydrogen‐bonded region encompassing the end‐positioned phosphonic acid groups and a hydrophobic region formed by the aromatic spacers. The asymmetric unit contains only half of the biphenyl‐4,4′‐diphosphonic acid (4,4′‐bpdp) molecule, which is symmetric with an inversion centre imposed at the mid‐point between the two aromatic rings. The periodic organization of the molecules is controlled by two strong O—H...O interactions between the phosphonic acid sites. Weak C—H...π interactions are established in the aromatic regions. 相似文献