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1.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(6):481-485
In solid‐state engineering, cocrystallization is a strategy actively pursued for pharmaceuticals. Two 1:1 cocrystals of 5‐fluorouracil (5FU; systematic name: 5‐fluoro‐1,3‐dihydropyrimidine‐2,4‐dione), namely 5‐fluorouracil–5‐bromothiophene‐2‐carboxylic acid (1/1), C5H3BrO2S·C4H3FN2O2, (I), and 5‐fluorouracil–thiophene‐2‐carboxylic acid (1/1), C4H3FN2O2·C5H4O2S, (II), have been synthesized and characterized by single‐crystal X‐ray diffraction studies. In both cocrystals, carboxylic acid molecules are linked through an acid–acid R 22(8) homosynthon (O—H…O) to form a carboxylic acid dimer and 5FU molecules are connected through two types of base pairs [homosynthon, R 22(8) motif] via a pair of N—H…O hydrogen bonds. The crystal structures are further stabilized by C—H…O interactions in (II) and C—Br…O interactions in (I). In both crystal structures, π–π stacking and C—F…π interactions are also observed. 相似文献
2.
Carlos M. Sanabría Alirio Palma Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(3):332-337
In the structure of (6R*,11R*)‐5‐acetyl‐11‐ethyl‐6,11‐dihydro‐5H‐dibenzo[b,e]azepine‐6‐carboxylic acid, C19H19NO3, (I), the molecules are linked into sheets by a combination of O—H...O and C—H...O hydrogen bonds; in the structure of the monomethyl analogue (6RS,11SR)‐5‐acetyl‐11‐ethyl‐2‐methyl‐6,11‐dihydro‐5H‐dibenzo[b,e]azepine‐6‐carboxylic acid, C20H21NO3, (II), the molecules are linked into simple C(7) chains by O—H...O hydrogen bonds; and in the structure of the dimethyl analogue (6RS,11SR)‐5‐acetyl‐11‐ethyl‐1,3‐dimethyl‐6,11‐dihydro‐5H‐dibenzo[b,e]azepine‐6‐carboxylic acid, C21H23NO3, (III), a combination of O—H...O, C—H...O and C—H...π(arene) hydrogen bonds links the molecules into a three‐dimensional framework structure. None of these structures exhibits the R22(8) dimer motif characteristic of simple carboxylic acids. 相似文献
3.
Katarzyna
lepokura Tadeusz Lis 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):m76-m78
In the crystal structure of the title compond, alternatively called poly[calcium(II)‐di‐μ‐carboxymethylphosphonato], [Ca(C2H4O5P)2]n or [Ca(H2AP)2]n, one of the phosphonate O atoms of the phosphonocarboxylate monoanion lies nearly antiperiplanar (ap) to the carboxylic acid C atom. The phosphonate P atom is located −sc and +ac relative to the carboxylic acid O atoms. The overall structure has a layered architecture. The Ca2+ cations lie on a twofold axis and are bridged by the phosphonate O atoms to form chains along the c axis, giving layers parallel to (100). There are medium‐strength O—H⃛O and C—H⃛O hydrogen‐bonding interactions stabilizing the layers, and O—H⃛O hydrogen bonds connect adjacent layers. 相似文献
4.
Mwaffak Rukiah Mahmoud Al‐Ktaifani 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(5):o166-o170
The structures of the title compounds, C9H8O3S, (I), and C13H11NO5S, (II), were determined by X‐ray powder diffraction. Both were solved using the direct‐space parallel tempering algorithm and refined using the Rietveld method. In (I), the C—S—C bond angle is slightly smaller than normal, indicating more p character in the bonding orbitals of the S atom. The carboxylic acid group joins across an inversion centre to form a dimer. The crystal packing includes a weak C—H...O hydrogen bond between an aromatic C—H group and a carboxylic acid O atom to form a two‐dimensional network parallel to (10). The C—S—C bond angle in (II) is larger than its counterpart in (I), indicating that the S atom of (II) has less p character in its bonding orbitals than that of (I), according to Bent's rule. The crystal structure of (II) includes weak C—H...O hydrogen bonds between the H atoms of the methylene groups and carbonyl O atoms, forming a three‐dimensional network. 相似文献
5.
Irena Matulkov Ivana Císaov Ivan Nmec Jan Fbry 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(10):927-933
The X‐ray single‐crystal structure determinations of the chemically related compounds 2‐amino‐1,3,4‐thiadiazolium hydrogen oxalate, C2H4N3S+·C2HO4−, (I), 2‐amino‐1,3,4‐thiadiazole–succinic acid (1/2), C2H3N3S·2C4H6O4, (II), 2‐amino‐1,3,4‐thiadiazole–glutaric acid (1/1), C2H3N3S·C5H8O4, (III), and 2‐amino‐1,3,4‐thiadiazole–adipic acid (1/1), C2H3N3S·C6H10O4, (IV), are reported and their hydrogen‐bonding patterns are compared. The hydrogen bonds are of the types N—H...O or O—H...N and are of moderate strength. In some cases, weak C—H...O interactions are also present. Compound (II) differs from the others not only in the molar ratio of base and acid (1:2), but also in its hydrogen‐bonding pattern, which is based on chain motifs. In (I), (III) and (IV), the most prominent feature is the presence of an R22(8) graph‐set motif formed by N—H...O and O—H...N hydrogen bonds, which are present in all structures except for (I), where only a pair of N—H...O hydrogen bonds is present, in agreement with the greater acidity of oxalic acid. There are nonbonding S...O interactions present in all four structures. The difference electron‐density maps show a lack of electron density about the S atom along the S...O vector. In all four structures, the carboxylic acid H atoms are present in a rare configuration with a C—C—O—H torsion angle of ∼0°. In the structures of (II)–(IV), the C—C—O—H torsion angle of the second carboxylic acid group has the more common value of ∼|180|°. The dicarboxylic acid molecules are situated on crystallographic inversion centres in (II). The Raman and IR spectra of the title compounds are presented and analysed. 相似文献
6.
Synthesis, Crystal Structure, and Thermal Decomposition of Mg(H2O)6[B12H12] · 6 H2O By reaction of an aqueous solution of the free acid (H3O)2[B12H12] with MgCO3 and subsequent isothermic evaporation of the resulting solution to dryness, colourless, bead‐shaped single crystals of the dodecahydrate of magnesium dodecahydro closo‐dodecaborate Mg(H2O)6[B12H12] · 6 H2O (cubic, F4132; a = 1643.21(9) pm, Z = 8) emerge. The crystal structure is best described as a NaTl‐type arrangement in which the centers of gravity of the quasi‐icosahedral [B12H12]2— anions (d(B—B) = 178—180 pm, d(B—H) = 109 pm) occupy the positions of Tl— while the Mg2+ cations occupy the Na+ positions. A direct coordinative influence of the [B12H12]2— units at the Mg2+ cations is however not noticeable. The latter are octahedrally coordinated by six water molecules forming isolated hexaaqua complex cations [Mg(H2O)6]2+ (d(Mg—O) = 206 pm, 6×). In addition, six “zeolitic” water molecules are located in the crystal structure for the formation of a strong O—Hδ+···δ—O‐hydrogen bridge‐bonding system. The evidence of weak B—Hδ—···δ+H—O‐hydrogen bonds between water molecules and anionic [B12H12]2— clusters is also considered. Investigations on the dodecahydrate Mg[B12H12] · 12 H2O (≡ Mg(H2O)6[B12H12] · 6 H2O) by DTA/TG measurements showed that its dehydration takes place in two steps within a temperature range of 71 and 76 °C as well as at 202 °C, respectively. Thermal treatment eventually leads to the anhydrous magnesium dodecahydro closo‐dodecaborate Mg[B12H12]. 相似文献
7.
Karna Wijaya Oliver Moers Peter G. Jones Armand Blaschette 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(2):167-169
The crystal structure of the title compound, C5H7N2+·C12H10NO4S2−, consists of two independent cation–anion pairs, A and B. Within each pair, the H—N—C—N*—H grouping (N*—H is the pyridinium function) and one N—S—O moiety of the anion are linked by N*—H⃛N and N—H⃛O hydrogen bonds to form an antidromic ring motif of type R22(8). The remaining amino donors give rise to N—H⃛O hydrogen bonds, connecting the ion pairs into A–B–A–B– chains. The structure testifies to the persistence of the R22(8) motif in question, which was previously detected as a highly robust supramolecular synthon in a series of onium di(methanesulfonyl)amidates. The structure is pseudosymmetric; the anion positions correspond to space group P21/n, but those of the cations do not. 相似文献
8.
Gordana Pavlovi Lidija Barii Vladimir Rapi Veronika Kova
《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):m55-m57
Heteroannularly substituted ferrocene derivatives can act as model systems for various hydrogen‐bonded assemblies of biomolecules formed, for instance, by means of O—H⋯O and N—H⋯O hydrogen bonding. The crystal structure analysis of 1′‐(tert‐butoxycarbonylamino)ferrocene‐1‐carboxylic acid, [Fe(C10H14NO2)(C6H5O2)] or (C5H4COOH)Fe(C5H4NHCOOC(CH3)3, reveals two independent molecules within the asymmetric unit, and these are joined into discrete dimers by two types of intermolecular hydrogen bonds, viz. O—H⋯O and N—H⋯O. The –COOH and –NHCOOR groups are archetypes for dimer formation via two eight‐membered rings. The O—H⋯O hydrogen bonds [2.656 (3) and 2.663 (3) Å] form a cyclic carboxylic acid dimer motif. Another eight‐membered ring is formed by N—H⋯O hydrogen bonds [2.827 (3) and 2.854 (3) Å] between the N—H group and an O atom of another carbamoyl moiety. The dimers are assembled in a herring‐bone fashion in the bc plane. 相似文献
9.
Fiona Brady John F. Gallagher Carol Murphy 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(3):365-368
The title compounds, C12H13NO4, are derived from l ‐threonine and dl ‐threonine, respectively. Hydrogen bonding in the chiral derivative, (2S/3R)‐3‐hydroxy‐2‐(1‐oxoisoindolin‐2‐yl)butanoic acid, consists of O—Hacid?Oalkyl—H?O=Cindole chains [O?O 2.659 (3) and 2.718 (3) Å], Csp3—H?O and three C—H?πarene interactions. In the (2R,3S/2S,3R) racemate, conventional carboxylic acid hydrogen bonding as cyclical (O—H?O=C)2 [graph set R22(8)] is present, with Oalkyl—H?O=Cindole, Csp3—H?O and C—H?πarene interactions. The COOH group geometry differs between the two forms, with C—O, C=O, C—C—O and C—C=O bond lengths and angles of 1.322 (3) and 1.193 (3) Å, and 109.7 (2) and 125.4 (3)°, respectively, in the chiral structure, and 1.2961 (17) and 1.2210 (18) Å, and 113.29 (12) and 122.63 (13)°, respectively, in the racemate structure. The O—C=O angles of 124.9 (3) and 124.05 (14)° are similar. The differences arise from the contrasting COOH hydrogen‐bonding environments in the two structures. 相似文献
10.
Viktor Vrbel Július Sivý Peter af tefan Marchalín 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(8):817-822
Molecules of (S)‐6‐oxo‐1‐(thiophen‐2‐ylmethyl)piperidine‐2‐carboxylic acid, C11H13NO3S, crystallize as single enantiomers in the space group P21 and the thiophene ring is disordered over two positions, while (S)‐6‐oxo‐1‐(thiophen‐3‐ylmethyl)piperidine‐2‐carboxylic acid, C11H13NO3S, crystallizes as a single enantiomer in the space group P212121. Their absolute configurations were confirmed by anomalous dispersion effects in diffraction measurements on the crystals. The molecules of each compound are linked by a combination of strong O—H...O hydrogen bonds and weak C—H...O interactions, resulting in two‐ and three‐dimensional networks, respectively, in the crystal structures. 相似文献
11.
Dubravka Matkovi‐alogovi Jasminka Popovi Zora Popovi Igor Picek
eljka Soldin 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):m39-m40
The title compound, [HgBr(C7H4NO4)(H2O)], was obtained by the reaction of an aqueous solution of mercury(II) bromide and pyridine‐2,6‐dicarboxylic acid (picolinic acid, dipicH2). The shortest bond distances to Hg are Hg—Br 2.412 (1) Å and Hg—N 2.208 (5) Å; the corresponding N—Hg—Br angle of 169.6 (1)° corresponds to a slightly distorted linear coordination. There are also four longer Hg—O interactions, three from dipicH? [2.425 (4) and 2.599 (4) Å within the asymmetric unit, and 2.837 (4) Å from a symmetry‐related molecule] and one from the bonded water molecule [2.634 (4) Å]. The effective coordination of Hg can thus be described as 2+4. The molecules are connected to form double‐layer chains parallel to the y axis by strong O—H?O hydrogen bonds between carboxylic acid groups of neighbouring molecules, and by weaker hydrogen bonds involving both H atoms of the water molecule and the O atoms of the carboxylic acid groups. 相似文献
12.
Edward E. vila Asilo J. Mora Gerzon E. Delgado Belkis M. Ramírez Alí Bahsas Sonia Koteich 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(10):o759-o761
In the title compound, C7H13NO2·0.5H2O, cis‐4‐aminocyclohexanecarboxylic acid exists as a zwitterion and co‐crystallizes with water molecules in a 2:1 amino acid–water ratio. The cyclohexane ring adopts a chair conformation, with the carboxylate and ammonium groups in axial and equatorial positions, respectively. The basic motif in the crystal structure is a sandwich structure, formed by two amino acid units linked by head‐to‐tail hydrogen bonds. Hydrogen bonds of the type N+—H⋯O—C—O− link these motifs, forming helicoidally extended chains running along the c axis. The water molecule lies on a twofold axis and interacts with the chains by means of O—H⋯O hydrogen bonds. 相似文献
13.
Teshome B. Yisgedu Xuenian Chen Hima K. Lingam Zhenguo Huang Edward A. Meyers Sheldon G. Shore Ji‐Cheng Zhao 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(1):m1-m3
The asymmetric unit of the title salt, 2NH4+·B10H102−·1.5H2O or (NH4)2B10H10·1.5H2O, (I), contains two B10H102− anions, four NH4+ cations and three water molecules. (I) was converted to the anhydrous compound (NH4)2B10H10, (II), by heating to 343 K and its X‐ray powder pattern was obtained. The extended structure of (I) shows two types of hydrogen‐bonding interactions (N—H...O and O—H...O) and two types of dihydrogen‐bonding interactions (N—H...H—B and O—H...H—B). The N—H...H—B dihydrogen bonding forms a two‐dimensional sheet structure, and hydrogen bonding (N—H...O and O—H...O) and O—H...H—B dihydrogen bonding link the respective sheets to form a three‐dimensional polymeric network structure. Compound (II) has been shown to form a polymer with the accompanying loss of H2 at a faster rate than (NH4)2B12H12 and we believe that this is due to the stronger dihydrogen‐bonding interactions shown in the hydrate (I). 相似文献
14.
Graham Smith Urs D. Wermuth 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(9):o327-o331
The structures of the open‐chain amide carboxylic acid rac‐cis‐2‐[(2‐methoxyphenyl)carbamoyl]cyclohexane‐1‐carboxylic acid, C15H19NO4, (I), and the cyclic imides rac‐cis‐2‐(4‐methoxyphenyl)‐3a,4,5,6,7,7a‐hexahydroisoindole‐1,3‐dione, C15H17NO3, (II), chiral cis‐3‐(1,3‐dioxo‐3a,4,5,6,7,7a‐hexahydroisoindol‐2‐yl)benzoic acid, C15H15NO4, (III), and rac‐cis‐4‐(1,3‐dioxo‐3a,4,5,6,7,7a‐hexahydroisoindol‐2‐yl)benzoic acid monohydrate, C15H15NO4·H2O, (IV), are reported. In the amide acid (I), the phenylcarbamoyl group is essentially planar [maximum deviation from the least‐squares plane = 0.060 (1) Å for the amide O atom] and the molecules form discrete centrosymmetric dimers through intermolecular cyclic carboxy–carboxy O—H...O hydrogen‐bonding interactions [graph‐set notation R22(8)]. The cyclic imides (II)–(IV) are conformationally similar, with comparable benzene ring rotations about the imide N—Car bond [dihedral angles between the benzene and isoindole rings = 51.55 (7)° in (II), 59.22 (12)° in (III) and 51.99 (14)° in (IV)]. Unlike (II), in which only weak intermolecular C—H...Oimide hydrogen bonding is present, the crystal packing of imides (III) and (IV) shows strong intermolecular carboxylic acid O—H...O hydrogen‐bonding associations. With (III), these involve imide O‐atom acceptors, giving one‐dimensional zigzag chains [graph‐set C(9)], while with the monohydrate (IV), the hydrogen bond involves the partially disordered water molecule which also bridges molecules through both imide and carboxy O‐atom acceptors in a cyclic R44(12) association, giving a two‐dimensional sheet structure. The structures reported here expand the structural database for compounds of this series formed from the facile reaction of cis‐cyclohexane‐1,2‐dicarboxylic anhydride with substituted anilines, in which there is a much larger incidence of cyclic imides compared to amide carboxylic acids. 相似文献
15.
Investigations on the Crystal Structure of Lithium Dodecahydro‐closo‐dodecaborate from Aqueous Solution: Li2(H2O)7[B12H12] By neutralization of an aqueous solution of the acid (H3O)2[B12H12] with lithium hydroxide (LiOH) and subsequent isothermic evaporation of the resulting solution to dryness, it was possible to obtain the heptahydrate of lithium dodecahydro‐closo‐dodecaborate Li2[B12H12] · 7 H2O (≡ Li2(H2O)7[B12H12]). Its structure has been determined from X‐ray single crystal data at room temperature. The compound crystallizes as colourless, lath‐shaped, deliquescent crystals in the orthorhombic space group Cmcm with the lattice constants a = 1215.18(7), b = 934.31(5), c = 1444.03(9) pm and four formula units in the unit cell. The crystal structure of Li2(H2O)7[B12H12] can not be described as a simple AB2‐structure type. Instead it forms a layer‐like structure analogous to the well‐known barium compound Ba(H2O)6[B12H12]. Characteristic feature is the formation of isolated cation pairs [Li2(H2O)7]2+ in which the water molecules form two [Li(H2O)4]+ tetrahedra with eclipsed conformation, linked to a dimer via a common corner. The bridging oxygen atom (∢(Li‐ O ‐Li) = 112°) thereby formally substitutes Ba2+ in Ba(H2O)6[B12H12] according to (H2 O )Li2(H2O)6[B12H12]. A direct coordinative influence of the [B12H12]2— cluster anions to the Li+ cations is not noticeable, however. The positions of the hydrogen atoms of both the water molecules and the [B12H12]2— units have all been localized. In addition, the formation of B‐Hδ—···δ+H‐O‐hydrogen bonds between the water molecules and the hydrogen atoms from the anionic [B12H12]2— clusters is considered and their range and strength is discussed. The dehydratation of the heptahydrate has been investigated by DTA‐TG measurements and shown to take place in two steps at 56 and 151 °C, respectively. Thermal treatment leads to the anhydrous lithium dodecahydro‐closo‐dodecaborate Li2[B12H12], eventually. 相似文献
16.
Ben‐Yong Lou Xiao‐Dong Huang Xiang‐Chao Lin 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(6):o310-o311
4,4′‐Bipyridine cocrystallizes with 3‐hydroxy‐2‐naphthoic acid in a 1:2 ratio to give a centrosymmetric three‐component supramolecular adduct, namely 3‐hydroxy‐2‐naphthoic acid–4,4′‐bipyridine (2/1), C11H8O3·0.5C10H8N2, in which 4,4′‐bipyridine is located on an inversion center. The pyridine–carboxylic acid heterosynthon generates an infinite one‐dimensional hydrogen‐bonded chain viaπ–π interactions between naphthyl and 4,4′‐bipyridine groups. The one‐dimensional chains are further assembled into a three‐dimensional network by weak C—H⋯π interactions between pyridyl and naphthyl rings, and C—H⋯O interactions between 3‐hydroxy‐2‐naphthoic acid molecules. 相似文献
17.
Kang Zheng Changjian Xie Xiaowei Li Weiwei Wu Ao Li Shaosong Qian Qiuxiang Pang 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(5):389-397
The crystal structures of the antimicrobial drug tinidazole [ TNZ ; systematic name: 1‐(2‐ethylsulfonylethyl)‐2‐methyl‐5‐nitroimidazole, C8H13N3O4S] and the 1:1 cocrystal of TNZ with the naturally occurring compound vanillic acid ( VA ; systematic name: 4‐hydroxy‐3‐methoxybenzoic acid, C8H8O4), namely, the TNZ – VA cocrystal, were determined by single‐crystal X‐ray analysis at 100 K. The supramolecular structure of the TNZ – VA cocrystal is composed of a carboxylic acid dimer and an O—H…N(heterocycle) synthon in the form of layers made up of O—H…N and O—H…O hydrogen bonds. The layers are joined via C—H…O hydrogen bonds, π–π stacking and C—H…π interactions. The energy framework analysis, together with interaction energy calculations using the DLPNO‐CCSD(T) method, indicates that the TNZ – VA cocrystal inherits strong interactions from the TNZ and VA crystals, which accounts for the enhanced thermal stability and reduced dissolution rate. To the best of our knowledge, this is the first example of a cocrystal containing TNZ . 相似文献
18.
Markos M. Papadakis Jorge A. Pavon Roger A. Lalancette Hugh W. Thompson 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o167-o170
The two δ‐keto carboxylic acids of the title, both C10H14O3, are epimeric at the site of carboxyl attachment. The endo (3α) epimer, (I), has its keto‐acid ring in a boat conformation, with the tilt of the carboxyl group creating conformational chirality. The molecules form hydrogen bonds by centrosymmetric pairing of carboxyl groups across the corners of the chosen cell [O⃛O = 2.671 (2) Å and O—H⃛O = 179 (2)°]. Two close intermolecular C—H⃛O contacts exist for the ketone. The exo (3β) epimer exists in the closed ring–chain tautomeric form as the lactol, 8‐hydroxy‐9‐oxatricyclo[5.3.1.03,8]undecan‐10‐one, (II). The molecules have conformational chirality, and the hydrogen‐bonding scheme involves intermolecular hydroxyl‐to‐carbonyl chains of molecules screw‐related in b [O⃛O = 2.741 (2) Å and O—H⃛O = 177 (2)°]. 相似文献
19.
Xiang‐Gao Meng Cui‐Xia Cheng Gang Yan 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(5):o217-o221
All three title compounds, C4H7N2+·C4H5O4−, (I), C4H7N2+·C5H7O4−, (II), and C4H7N2+·C6H9O4−·H2O, (III), can be regarded as 1:1 organic salts. The dicarboxylic acids join through short acid bridges into infinite chains. Compound (I) crystallizes in the noncentrosymmetric Cmc21 space group and the asymmetric unit consists of a hydrogen succinate anion located on a mirror plane and a 2‐methylimidazolium cation disordered across the same mirror. The other two compounds crystallize in the triclinic P space group. The carboxylic acid H atom in (II) is disordered over both ends of the anion and sits on inversion centres between adjacent anions, forming symmetric short O...H...O bridges. Two independent anions in (III) sit across inversion centres, again with the carboxylic acid H atom disordered in short O...H...O bridges. The molecules in all three compounds are linked into two‐dimensional networks by combinations of imidazolium–carboxylate N+—H...O and carboxylate–carboxylate O—H...O hydrogen bonds. The two‐dimensional networks are further linked into three‐dimensional networks by C—H...O hydrogen bonds in (I) and by Owater—H...O hydrogen bonds in (III). According to the ΔpKa rule, such 1:1 types of organic salts can be expected unambiguously. However, a 2:1 type of organic salt may be more easily obtained in (II) and (III) than in (I). 相似文献
20.
Magorzata Szczesio Andrzej Olczak Katarzyna Gobis Henryk Foks Marek L. Gwka 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(10):o373-o376
Methyl 2‐(3,4‐dichlorobenzoyl)‐1‐methylhydrazinecarbodithioate, C10H10Cl2N2OS2, (F1), butyl 2‐(3,4‐dichlorobenzoyl)‐1‐methylhydrazinecarbodithioate, C13H16Cl2N2OS2, (F2), and 3,4‐dichloro‐N‐(2‐sulfanylidene‐1,3‐thiazinan‐3‐yl)benzamide, C11H10Cl2N2OS2, (F3), were studied by X‐ray diffraction to test our hypothesis that planarity of aryloylhydrazinedithiocarbazic acid esters is a prerequisite for tuberculostatic activity. All compounds examined in this study are inactive and nonplanar due to twists along two specific bonds in the central frame of the molecules. The significant twist at the N—N bond, with an C—N—N—C(S) torsion angle of about 85°, results from repulsion caused by a methyl substituent at the N′ atom of the hydrazide group. The other twist is that within the benzoyl group at the C(O)—Ph bond, i.e. the N—C(=O)—C(phenyl)—C torsion angle: the values found in the studied structures (25–30°) are in agreement with those observed in other compounds containing a similar fragment. As some nonplanar benzoyl derivatives are active, it seems that planarity of the hydrazinedithioate fragment is more important for tuberculostatic activity than planarity of the aryloyl group. 相似文献