共查询到20条相似文献,搜索用时 0 毫秒
1.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(1):21-30
Doubly and triply hydrogen‐bonded supramolecular synthons are of particular interest for the rational design of crystal and cocrystal structures in crystal engineering since they show a high robustness due to their high stability and good reliability. The compound 5‐methyl‐2‐thiouracil (2‐thiothymine) contains an ADA hydrogen‐bonding site (A = acceptor and D = donor) if the S atom is considered as an acceptor. We report herein the results of cocrystallization experiments with the coformers 2,4‐diaminopyrimidine, 2,4‐diamino‐6‐phenyl‐1,3,5‐triazine, 6‐amino‐3H‐isocytosine and melamine, which contain complementary DAD hydrogen‐bonding sites and, therefore, should be capable of forming a mixed ADA–DAD N—H…S/N—H…N/N—H…O synthon (denoted synthon 3sN·S;N·N;N·O), consisting of three different hydrogen bonds with 5‐methyl‐2‐thiouracil. The experiments yielded one cocrystal and five solvated cocrystals, namely 5‐methyl‐2‐thiouracil–2,4‐diaminopyrimidine (1/2), C5H6N2OS·2C4H6N4, (I), 5‐methyl‐2‐thiouracil–2,4‐diaminopyrimidine–N,N‐dimethylformamide (2/2/1), 2C5H6N2OS·2C4H6N4·C3H7NO, (II), 5‐methyl‐2‐thiouracil–2,4‐diamino‐6‐phenyl‐1,3,5‐triazine–N,N‐dimethylformamide (2/2/1), 2C5H6N2OS·2C9H9N5·C3H7NO, (III), 5‐methyl‐2‐thiouracil–6‐amino‐3H‐isocytosine–N,N‐dimethylformamide (2/2/1), (IV), 2C5H6N2OS·2C4H6N4O·C3H7NO, (IV), 5‐methyl‐2‐thiouracil–6‐amino‐3H‐isocytosine–N,N‐dimethylacetamide (2/2/1), 2C5H6N2OS·2C4H6N4O·C4H9NO, (V), and 5‐methyl‐2‐thiouracil–melamine (3/2), 3C5H6N2OS·2C3H6N6, (VI). Synthon 3sN·S;N·N;N·O was formed in three structures in which two‐dimensional hydrogen‐bonded networks are observed, while doubly hydrogen‐bonded interactions were formed instead in the remaining three cocrystals whereby three‐dimensional networks are preferred. As desired, the S atoms are involved in hydrogen‐bonding interactions in all six structures, thus illustrating the ability of sulfur to act as a hydrogen‐bond acceptor and, therefore, its value for application in crystal engineering. 相似文献
2.
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
3.
4.
5.
Balasubramanian Sridhar 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(12):1042-1047
Multicomponent crystals or cocrystals play a significant role in crystal engineering, the main objective of which is to understand the role of intermolecular interactions and to utilize such understanding in the design of novel crystal structures. Molecules possessing carboxylic acid and amide functional groups are good candidates for forming cocrystals. β‐Resorcylic acid monohydrate, C7H6O4·H2O, (I), crystallizes in the triclinic space group P with one β‐resorcylic acid molecule and one water molecule in the asymmetric unit. The cocrystal thymine–β‐resorcylic acid–water (1/1/1), C5H6N2O2·C7H6O4·H2O, (II), crystallizes in the orthorhombic space group Pca21, with one molecule each of thymine, β‐resorcylic acid and water in the asymmetric unit. All available donor and acceptor atoms in (I) and (II) are utilized for hydrogen bonding. The acid and amide functional groups are well known for the formation of self‐complementary acid–acid and amide–amide homosynthons. In (I), an acid–acid homosynthon is observed, while in (II), an amide–acid heterosynthon is present. In (I), the β‐resorcylic acid molecule exhibits the expected intramolecular S(6) motif between the hydroxy and carbonyl O atoms, and an intermolecular R22(8) dimer motif between the carboxylic acid groups; only the former motif is observed in (II). The water solvent molecule in (I) propagates the discrete dimers into two‐dimensional hydrogen‐bonded sheets. In (II), thymine and β‐resorcylic acid molecules do not form self‐complementary amide–amide and acid–acid homosynthons; instead, a thymine–β‐resorcylic acid heterosynthon is observed. With the help of the water molecule, this heterosynthon is aggregated into a three‐dimensional hydrogen‐bonded network. The absence of thymine base pairing in (II) might be linked to the availability of additional functional groups and the preference of the donor and acceptor hydrogen‐bond combinations. 相似文献
6.
7.
Vanessa Kristina Seiler Wilhelm Maximilian Hützler Michael Bolte 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(5):379-388
In order to examine the preferred hydrogen‐bonding pattern of various uracil derivatives, namely 5‐(hydroxymethyl)uracil, 5‐carboxyuracil and 5‐carboxy‐2‐thiouracil, and for a conformational study, crystallization experiments yielded eight different structures: 5‐(hydroxymethyl)uracil, C5H6N2O3, (I), 5‐carboxyuracil–N,N‐dimethylformamide (1/1), C5H4N2O4·C3H7NO, (II), 5‐carboxyuracil–dimethyl sulfoxide (1/1), C5H4N2O4·C2H6OS, (III), 5‐carboxyuracil–N,N‐dimethylacetamide (1/1), C5H4N2O4·C4H9NO, (IV), 5‐carboxy‐2‐thiouracil–N,N‐dimethylformamide (1/1), C5H4N2O3S·C3H7NO, (V), 5‐carboxy‐2‐thiouracil–dimethyl sulfoxide (1/1), C5H4N2O3S·C2H6OS, (VI), 5‐carboxy‐2‐thiouracil–1,4‐dioxane (2/3), 2C5H4N2O3S·3C6H12O3, (VII), and 5‐carboxy‐2‐thiouracil, C10H8N4O6S2, (VIII). While the six solvated structures, i.e. (II)–(VII), contain intramolecular S(6) O—H…O hydrogen‐bond motifs between the carboxy and carbonyl groups, the usually favoured R22(8) pattern between two carboxy groups is formed in the solvent‐free structure, i.e. (VIII). Further R22(8) hydrogen‐bond motifs involving either two N—H…O or two N—H…S hydrogen bonds were observed in three crystal structures, namely (I), (IV) and (VIII). In all eight structures, the residue at the ring 5‐position shows a coplanar arrangement with respect to the pyrimidine ring which is in agreement with a search of the Cambridge Structural Database for six‐membered cyclic compounds containing a carboxy group. The search confirmed that coplanarity between the carboxy group and the cyclic residue is strongly favoured. 相似文献
8.
Yunxia Yang Lihua Li Li Zhang Wenjing Dong Keying Ding 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(12):981-989
Polymorphism is the ability of a solid material to exist in more than one form or crystal structure and this is of interest in the fields of crystal engineering and solid‐state chemistry. 2,2′‐(Disulfanediyl)dibenzoic acid (also called 2,2′‐dithiosalicylic acid, DTSA) is able to form different hydrogen bonds using its carboxyl groups. The central bridging S atoms allow the two terminal arene rings to rotate freely to generate various hydrogen‐bonded linking modes. DTSA can act as a potential host molecule with suitable guest molecules to develop new inclusion compounds. We report here the crystal structures of three new polymorphs of the inclusion compound of DTSA and trimethylamine, namely trimethylazanium 2‐[(2‐carboxyphenyl)disulfanyl]benzoate 2,2′‐(disulfanediyl)dibenzoic acid monosolvate, C3H10N+·C14H9O4S2−·C14H10O4S2, (1), tetrakis(trimethylazanium) bis{2‐[(2‐carboxyphenyl)disulfanyl]benzoate} 2,2′‐(disulfanediyl)dibenzoate 2,2′‐(disulfanediyl)dibenzoic acid monosolvate, 4C3H10N+·2C14H9O4S2−·C14H8O4S22−·C14H10O4S2, (2), and trimethylazanium 2‐[(2‐carboxyphenyl)disulfanyl]benzoate, C3H10N+·C14H9O4S2−, (3). In the three polymorphs, DTSA utilizes its carboxyl groups to form conventional O—H…O hydrogen bonds to generate different host lattices. The central N atoms of the guest amine molecules accept H atoms from DTSA molecules to give the corresponding cations, which act as counter‐ions to produce the stable crystal structures via N—H…O hydrogen bonding between the host acid and the guest molecule. It is noticeable that although these three compounds are composed of the same components, the final crystal structures are totally different due to the various configurations of the host acid, the number of guest molecules and the inducer (i.e. ancillary experimental acid). 相似文献
9.
《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
10.
Nickel‐catalyzed Buchwald–Hartwig amination of pyrimidin‐2‐yl tosylates with indole,benzimidazole and 1,2,4‐triazole
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Nickel‐catalyzed Buchwald–Hartwig amination of pyrimidin‐2‐yl tosylates with indole and benzimidazole was achieved using Ni(dppp)Cl2 as catalyst, yielding a variety of novel C2‐substituted pyrimidine derivatives in good yields. This reaction proved to be tolerant of various pyrimidin‐2‐yl tosylates bearing either electron‐donating or electron‐withdrawing groups as well as nucleophiles including indole, benzimidazole and 1,2,4‐triazole. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
11.
12.
Eric Bosch 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(10):748-752
Weak interactions between organic molecules are important in solid‐state structures where the sum of the weaker interactions support the overall three‐dimensional crystal structure. The sp‐C—H…N hydrogen‐bonding interaction is strong enough to promote the deliberate cocrystallization of a series of diynes with a series of dipyridines. It is also possible that a similar series of cocrystals could be formed between molecules containing a terminal alkyne and molecules which contain carbonyl O atoms as the potential hydrogen‐bond acceptor. I now report the crystal structure of two cocrystals that support this hypothesis. The 1:1 cocrystal of 1,4‐diethynylbenzene with 1,3‐diacetylbenzene, C10H6·C10H10O2, (1), and the 1:1 cocrystal of 1,4‐diethynylbenzene with benzene‐1,4‐dicarbaldehyde, C10H6·C8H6O2, (2), are presented. In both cocrystals, a strong nonconventional ethynyl–carbonyl sp‐C—H…O hydrogen bond is observed between the components. In cocrystal (1), the C—H…O hydrogen‐bond angle is 171.8 (16)° and the H…O and C…O hydrogen‐bond distances are 2.200 (19) and 3.139 (2) Å, respectively. In cocrystal (2), the C—H…O hydrogen‐bond angle is 172.5 (16)° and the H…O and C…O hydrogen‐bond distances are 2.25 (2) and 3.203 (2) Å, respectively. 相似文献
13.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(2):177-185
We report a novel 1:1 cocrystal of β‐alanine with dl ‐tartaric acid, C3H7NO2·C4H6O6, (II), and three new molecular salts of dl ‐tartaric acid with β‐alanine {3‐azaniumylpropanoic acid–3‐azaniumylpropanoate dl ‐tartaric acid–dl ‐tartrate, [H(C3H7NO2)2]+·[H(C4H5O6)2]−, (III)}, γ‐aminobutyric acid [3‐carboxypropanaminium dl ‐tartrate, C4H10NO2+·C4H5O6−, (IV)] and dl ‐α‐aminobutyric acid {dl ‐2‐azaniumylbutanoic acid–dl ‐2‐azaniumylbutanoate dl ‐tartaric acid–dl ‐tartrate, [H(C4H9NO2)2]+·[H(C4H5O6)2]−, (V)}. The crystal structures of binary crystals of dl ‐tartaric acid with glycine, (I), β‐alanine, (II) and (III), GABA, (IV), and dl ‐AABA, (V), have similar molecular packing and crystallographic motifs. The shortest amino acid (i.e. glycine) forms a cocrystal, (I), with dl ‐tartaric acid, whereas the larger amino acids form molecular salts, viz. (IV) and (V). β‐Alanine is the only amino acid capable of forming both a cocrystal [i.e. (II)] and a molecular salt [i.e. (III)] with dl ‐tartaric acid. The cocrystals of glycine and β‐alanine with dl ‐tartaric acid, i.e. (I) and (II), respectively, contain chains of amino acid zwitterions, similar to the structure of pure glycine. In the structures of the molecular salts of amino acids, the amino acid cations form isolated dimers [of β‐alanine in (III), GABA in (IV) and dl ‐AABA in (V)], which are linked by strong O—H…O hydrogen bonds. Moreover, the three crystal structures comprise different types of dimeric cations, i.e. (A…A)+ in (III) and (V), and A+…A+ in (IV). Molecular salts (IV) and (V) are the first examples of molecular salts of GABA and dl ‐AABA that contain dimers of amino acid cations. The geometry of each investigated amino acid (except dl ‐AABA) correlates with the melting point of its mixed crystal. 相似文献
14.
Andreas Lemmerer 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(8):746-752
A series of five binary complexes, i.e. three cocrystals and two molecular salts, using 2‐chloro‐4‐nitrobenzoic acid as a coformer have been produced with five commonly available compounds, some of pharmaceutical relevance, namely, 2‐chloro‐4‐nitrobenzoic acid–isonicotinamide (1/1), C7H4ClNO4·C6H6N2O, 2‐chloro‐4‐nitrobenzoic acid–3,3‐diethylpyridine‐2,4(1H,3H)‐dione (2/1), 2C7H4ClNO4·C9H13NO2, 2‐chloro‐4‐nitrobenzoic acid–pyrrolidin‐2‐one (1/1), C7H4ClNO4·C4H7NO, 2‐carboxypiperidinium 2‐chloro‐4‐nitrobenzoate, C6H12NO2?·C7H3ClNO4?, and (2‐hydroxyethyl)ammonium 2‐chloro‐4‐nitrobenzoate, C2H8NO+·C7H3ClNO4?. The coformer falls under the classification of a `generally regarded as safe' compound. All five complexes make use of a number of different heteromeric hydrogen‐bonded interactions. Intermolecular potentials were evaluated using the CSD‐Materials module. 相似文献
15.
Kyle A. Powers David K. Geiger 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(3):329-335
The isostructural salts benzene‐1,2‐diaminium bis(pyridine‐2‐carboxylate), 0.5C6H10N22+·C6H4NO2?, (1), and 4,5‐dimethylbenzene‐1,2‐diaminium bis(pyridine‐2‐carboxylate), 0.5C8H14N22+·C6H4NO2?, (2), and the 1:2 benzene‐1,2‐diamine–benzoic acid cocrystal, 0.5C6H8N2·C7H6O2, (3), are reported. All of the compounds exhibit extensive N—H…O hydrogen bonding that results in interconnected rings. O—H…N hydrogen bonding is observed in (3). Additional π–π and C—H…π interactions are found in each compound. Hirshfeld and fingerprint plot analyses reveal the primary intermolecular interactions and density functional theory was used to calculate their strengths. Salt formation by (1) and (2), and cocrystallization by (3) are rationalized by examining pKa differences. The R22(9) hydrogen‐bonding motif is common to each of these structures. 相似文献
16.
In the presence of N, N′‐dicyclohexylcarbodiimide, 2‐aminopyridine and its derivatives (2) condensed with 2, 2‐di‐hydropolyfluoroalkanoic adds (1) to give the corresponding amides. Subsequent intramolecular Micheal addition‐elimination reactions of the fluorine‐containing amides under basic conditions gave 4‐fluoroalkyl‐2H‐pyrido[1,2‐a]pyrimidin‐2‐ones (3) in good yields. 相似文献
17.
In mononuclear [Zn(C10H9N3)2(N3)2]·H2O, the zinc atom has an approximate octahedral geometry, coordinated with four pyridyl nitrogen atoms derived from two bis(2‐pyridyl)amine molecules and two terminal nitrogen donors of the azide anions. Hydrogen‐bonding interactions extend this structure to form a double‐layer architecture. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
18.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(3):289-294
Reactions between potassium tetraiodidoaurate(III) and pyridine (py, C5H5N) or 3,4‐lutidine (3,4‐dimethylpyridine, 3,4‐lut, C7H9N) were tested as possible sources of azaaromatic complexes of gold(III) iodide, but all identifiable products contained gold(I). The previously known structure dipyridinegold(I) diiodidoaurate(I), [Au(py)2]+·[AuI2]−, ( 3 ) [Adams et al. (1982). Z. Anorg. Allg. Chem. 485 , 81–91], was redetermined at 100 K. The reactions with 3,4‐lutidine gave three different types of crystal in small quantities. 3,4‐Dimethylpyridine–3,4‐dimethylpyridinium diiodidoaurate(I), [(3,4‐lut)2H]+·[AuI2]−, ( 1 ), consists of an [AuI2]− anion on a general position and two [(3,4‐lut)2H]+ cations across twofold axes. Bis(3,4‐dimethylpyridine–3,4‐dimethylpyridinium) diiodidoaurate(I) iodide, [(3,4‐lut)2H+]2·[AuI2]−·I−, ( 2 ), crystallizes as two polymorphs, each forming pseudosymmetric inversion twins, in the space groups P21 and Pc (but resembling P21/m and P2/c), respectively. These are essentially identical layer structures differing only in their stacking patterns and thus might be regarded as polytypes. 相似文献
19.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(9):743-748
In the salt trimethoprimium ferrocenecarboxylate [systematic name: 2,4‐diamino‐5‐(3,4,5‐trimethoxybenzyl)pyrimidin‐1‐ium ferrocene‐1‐carboxylate], (C14H19N4O3)[Fe(C5H5)(C6H4O2)], (I), of the antibacterial compound trimethoprim, the carboxylate group interacts with the protonated aminopyrimidine group of trimethoprim via two N—H…O hydrogen bonds, generating a robust R 22(8) ring motif (heterosynthon). However, in the cocrystal 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–ferrocene‐1‐carboxylic acid (1/1), [Fe(C5H5)(C6H5O2)]·C6H8ClN3, (II), the carboxyl–aminopyrimidine interaction [R 22(8) motif] is absent. The carboxyl group interacts with the pyrimidine ring via a single O—H…N hydrogen bond. The pyrimidine rings, however, form base pairs via a pair of N—H…N hydrogen bonds, generating an R 22(8) supramolecular homosynthon. In salt (I), the unsubstituted cyclopentadienyl ring is disordered over two positions, with a refined site‐occupation ratio of 0.573 (10):0.427 (10). In this study, the two five‐membered cyclopentadienyl (Cp) rings of ferrocene are in a staggered conformation, as is evident from the C…Cg …Cg …C pseudo‐torsion angles, which are in the range 36.13–37.53° for (I) and 22.58–23.46° for (II). Regarding the Cp ring of the minor component in salt (I), the geometry of the ferrocene ring is in an eclipsed conformation, as is evident from the C…Cg …Cg …C pseudo‐torsion angles, which are in the range 79.26–80.94°. Both crystal structures are further stabilized by weak π–π interactions. 相似文献
20.
Structures of N—(2,3,4,6—Tetra—O—acetyl—β—D—glycosyl) thiocarbamic Benzoyl Hydrazine 总被引:1,自引:0,他引:1
The crystal structure of N-(2,3,4,6-tetra-O-acetyl-β-D-gly-cosyl)-thiocarbamic benzoyl hydrazine(C22H27N3O9S) was determined by X-ray diffracton method.The hexopyranosyl ring adopts a chair conformation.All the ring substituents are in the equatorial positions.The acetoxyl-methyl group is in synclinal conformation.The S atom is in synperiplanar conformation while the benzoyl hydrazine moiety is anti-periplanar.The thiocarbamic moiety is almost companar with the benzoyl hydrazine group.There are two intramolecular hydrogen bonds and one intermolecular hydrogen bond for each molecule in the crystal structure.The molecules form a network structure through intermolecular hydrogen bonds. 相似文献