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1.
Notwithstanding its simple structure, the chemistry of nitric oxide (NO) is complex. As a radical, NO is highly reactive. NO also has profound effects on the cardiovascular system. In order to regulate NO levels, direct therapeutic interventions include the development of numerous NO donors. Most of these donors release NO in a single high‐concentration burst, which is deleterious. N‐Nitrosated secondary amines release NO in a slow, sustained, and rate‐tunable manner. Two new precursors to sustained NO‐releasing materials have been characterized. N‐[2‐(3,4‐Dimethoxyphenyl)ethyl]‐2,4‐dinitroaniline, C16H17N3O6, (I), crystallizes with one independent molecule in the asymmetric unit. The adjacent amine and nitro groups form an intramolecular N—H…O hydrogen bond. The anti conformation about the phenylethyl‐to‐aniline C—N bond leads to the planes of the arene and aniline rings being approximately perpendicular. Molecules are linked into dimers by weak intermolecular N—H…O hydrogen bonds such that each amine H atom participates in a three‐center interaction with two nitro O atoms. The dimers pack so that the arene rings of adjacent molecules are not parallel and π–π interactions do not appear to be favored. N‐(4‐Methylsulfonyl‐2‐nitrophenyl)‐l ‐phenylalanine, C16H16N2O6S, (II), with an optically active center, also crystallizes with one unique molecule in the asymmetric unit. The l enantiomer was established via the configuration of the starting material and was confirmed by refinement of the Flack parameter. As in (I), there is an intramolecular N—H…O hydrogen bond between adjacent amine and nitro groups. The conformation of the molecule is such that the arene rings display a dihedral angle of ca 60°. Unlike (I), molecules are not linked via intermolecular N—H…O hydrogen bonds. Rather, the carboxylic acid H atom forms a classic, approximately linear, O—H…O hydrogen bond with a sulfone O atom. Pairs of molecules related by twofold rotation axes are linked into dimers by two such interactions. The packing pattern features a zigzag arrangement of the arene rings without apparent π–π interactions. These structures are compared with reported analogues, revealing significant differences in molecular conformation, intermolecular interactions, and packing that result from modest changes in functional groups. The structures are discussed in terms of potential NO‐release capability.  相似文献   

2.
By the reaction of benzoyl chloride, potassium isothiocyanate and the appropriate halogenoaniline, i.e. 2/3/4‐(bromo/iodo)aniline, we have obtained five new 1‐benzoyl‐3‐(halogenophenyl)thioureas, namely, 1‐benzoyl‐3‐(2‐bromophenyl)thiourea and 1‐benzoyl‐3‐(3‐bromophenyl)thiourea, C14H11BrN2OS, and 1‐benzoyl‐3‐(2‐iodophenyl)thiourea, 1‐benzoyl‐3‐(3‐iodophenyl)thiourea and 1‐benzoyl‐3‐(4‐iodophenyl)thiourea, C14H11IN2OS. Structural and conformational features of the compounds have been analyzed using X‐ray diffraction and theoretical calculations. The novel compounds were characterized by solid‐state IR and 1H/13C NMR spectroscopy. The conformations and intermolecular interactions, such as hydrogen bonds, π–π and S(6)…π stacking, and X…O (X = I or Br), I…S and I…π, have been examined and rationalized, together with four analogous compounds described previously in the literature. The set of nine compounds was chosen to examine how a change of the halogen atom and its position on the phenyl ring affects the molecular and crystal structures.  相似文献   

3.
Recrystallization of the title compound, [Fe(C5H5)(C14H13N2O3)], from a mixture of n‐hexane and dichloromethane gave the new polymorph, denoted (I), which crystallizes in the same space group (P) as the previously reported structure, denoted (II). The Fe—C distances in (I) range from 2.015 (3) to 2.048 (2) Å and the average value of the C—C bond lengths in the two cyclopentadienyl (Cp) rings is 1.403 (13) Å. As indicated by the smallest C—Cg1—Cg2—C torsion angle of 1.4° (Cg1 and Cg2 are the centroids of the two Cp rings), the orientation of the Cp rings in (I) is more eclipsed than in the case of (II), for which the value was 15.3°. Despite the pronounced conformational similarity between (I) and (II), the formation of self‐complementary N—H...O hydrogen‐bonded dimers represents the only structural motif common to the two polymorphs. In the extended structure, molecules of (I) utilize C—H...O hydrogen bonds and, unlike (II), an extensive set of intermolecular C—H...π interactions. Fingerprint plots based on Hirshfeld surfaces are used to compare the packing of the two polymorphs.  相似文献   

4.
The crystal structures of three quinuclidine‐based compounds, namely (1‐azabicyclo[2.2.2]octan‐3‐ylidene)hydrazine monohydrate, C7H13N3·H2O ( 1 ), 1,2‐bis(1‐azabicyclo[2.2.2]octan‐3‐ylidene)hydrazine, C14H22N4 ( 2 ), and 1,2‐bis(1‐azoniabicyclo[2.2.2]octan‐3‐ylidene)hydrazine dichloride, C14H24N42+·2Cl? ( 3 ), are reported. In the crystal structure of 1 , the quinuclidine‐substituted hydrazine and water molecules are linked through N—H…O and O—H…N hydrogen bonds, forming a two‐dimensional array. The compound crystallizes in the centrosymmetric space group P21/c. Compound 2 was refined in the space group Pccn and exhibits no hydrogen bonding. However, its hydrochloride form 3 crystallizes in the noncentrosymmetric space group Pc. It shows a three‐dimensional network structure via intermolecular hydrogen bonding (N—H…C and N/C—H…Cl). Compound 3 , with its acentric structure, shows strong second harmonic activity.  相似文献   

5.
The title compound, C10H11N3O3S, (I), crystallizes as the NH tautomer. The two rings subtend an interplanar angle of 72.54 (4)°. An intramolecular hydrogen bond is formed from the NH2 group to a sulfonyl O atom. The molecular packing involves layers of molecules parallel to the bc plane at x≃ 0, 1 etc., with two classical linear hydrogen bonds (amino–sulfonyl and pyrazoline–carbonyl N—H...O) and a further interaction (amino–sulfonyl N—H...O) completing a three‐centre system with the intramolecular contact. The analogous phenyl derivative, (II) [Elgemeie, Hanfy, Hopf & Jones (1998). Acta Cryst. C 54 , 136–138], crystallizes with essentially the same unit cell and packing pattern, but with two independent molecules that differ significantly in the orientation of the phenyl groups. The space group is P21/c for (I) but P21 for (II), which is thus a pseudosymmetric counterpart of (I).  相似文献   

6.
4‐Antipyrine [4‐amino‐1,5‐dimethyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐one] and its derivatives exhibit a range of biological activities, including analgesic, antibacterial and anti‐inflammatory, and new examples are always of potential interest and value. 2‐(4‐Chlorophenyl)‐N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)acetamide, C19H18ClN3O2, (I), crystallizes with Z′ = 2 in the space group P, whereas its positional isomer 2‐(2‐chlorophenyl)‐N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)acetamide, (II), crystallizes with Z′ = 1 in the space group C2/c; the molecules of (II) are disordered over two sets of atomic sites having occupancies of 0.6020 (18) and 0.3980 (18). The two independent molecules of (I) adopt different molecular conformations, as do the two disorder components in (II), where the 2‐chlorophenyl substituents adopt different orientations. The molecules of (I) are linked by a combination of N—H…O and C—H…O hydrogen bonds to form centrosymmetric four‐molecule aggregates, while those of (II) are linked by the same types of hydrogen bonds forming sheets. The related compound N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)‐2‐(3‐methoxyphenyl)acetamide, C20H21N3O3, (III), is isomorphous with (I) but not strictly isostructural; again the two independent molecules adopt different molecular conformations, and the molecules are linked by N—H…O and C—H…O hydrogen bonds to form ribbons. Comparisons are made with some related structures, indicating that a hydrogen‐bonded R22(10) ring is the common structural motif.  相似文献   

7.
The asymmetric unit of the racemic form of the title compound, C12H15NOS, contains four crystallographically independent molecules. The olefinic bond connecting the 2‐thienyl and 1‐azabicyclo[2.2.2]octan‐3‐ol moieties has Z geometry. Strong hydrogen bonding occurs in a directed co‐operative O—H...O—H...O—H...O—H R44(8) pattern that influences the conformation of the molecules. Co‐operative C—H...π interactions between thienyl rings are also present. The average dihedral angle between adjacent thienyl rings is 87.09 (4)°.  相似文献   

8.
The novel tetraphenylethylene derivative 4‐methyl‐N‐[3‐(1,2,2‐triphenylethenyl)phenyl]benzenesulfonamide (abbreviated as MTBF), C33H27NO2S, was synthesized successfully and characterized by single‐crystal X‐ray diffraction, high‐resolution mass spectroscopy and 1H NMR spectroscopy. MTBF crystallizes in the centrosymmetric monoclinic space group P21/c. In the crystal structure, the MTBF molecules are connected into a one‐dimensional band and then a two‐dimensional sheet by hydrogen bonds of the N—H…O and C—H…O types. The sheets are further linked to produce a three‐dimensional network via C—H…π interactions. The molecules aggregate via these intermolecular forces, which restrain the intramolecular motions (RIM) and decrease the energy loss in the aggregation state, so as to open the radiative channels, and thus MTBF exhibits excellent fluorescence by aggregation‐induced emission (AIE) enhancement.  相似文献   

9.
Six closely related N‐[3‐(2‐chlorobenzoyl)‐5‐ethylthiophen‐2‐yl]arylamides have been synthesized and structurally characterized, together with a representative reaction intermediate. In each of N‐[3‐(2‐chlorobenzoyl)‐5‐ethylthiophen‐2‐yl]benzamide, C20H16ClNO2S, (I), N‐[3‐(2‐chlorobenzoyl)‐5‐ethylthiophen‐2‐yl]‐4‐phenylbenzamide, C26H20ClNO2S, (II), and 2‐bromo‐N‐[3‐(2‐chlorobenzoyl)‐5‐ethylthiophen‐2‐yl]benzamide, C20H15BrClNO2S, (III), the molecules are disordered over two sets of atomic sites, with occupancies of 0.894 (8) and 0.106 (8) in (I), 0.832 (5) and 0.168 (5) in (II), and 0.7006 (12) and 0.2994 (12) in (III). In each of N‐[3‐(2‐chlorobenzoyl)‐5‐ethylthiophen‐2‐yl]‐2‐iodobenzamide, C20H15ClINO2S, (IV), and N‐[3‐(2‐chlorobenzoyl)‐5‐ethylthiophen‐2‐yl]‐2‐methoxybenzamide, C21H18ClNO3S, (V), the molecules are fully ordered, but in N‐[3‐(2‐chlorobenzoyl)‐5‐ethylthiophen‐2‐yl]‐2,6‐difluorobenzamide, C20H14ClF2NO2S, (VI), which crystallizes with Z′ = 2 in the space group C2/c, one of the two independent molecules is fully ordered, while the other is disordered over two sets of atomic sites having occupancies of 0.916 (3) and 0.084 (3). All of the molecules in compounds (I)–(VI) exhibit an intramolecular N—H…O hydrogen bond. The molecules of (I) and (VI) are linked by C—H…O hydrogen bonds to form finite zero‐dimensional dimers, which are cyclic in (I) and acyclic in (VI), those of (III) are linked by C—H…π(arene) hydrogen bonds to form simple chains, and those of (IV) and (V) are linked into different types of chains of rings, built in each case from a combination of C—H…O and C—H…π(arene) hydrogen bonds. Two C—H…O hydrogen bonds link the molecules of (II) into sheets containing three types of ring. In benzotriazol‐1‐yl 3,4‐dimethoxybenzoate, C15H13N3O4, (VII), the benzoate component is planar and makes a dihedral angle of 84.51 (6)° with the benzotriazole unit. Comparisons are made with related compounds.  相似文献   

10.
The molecules of 5‐amino‐1‐(4‐methoxybenzoyl)‐3‐methylpyrazole, C12H13N3O2, (I), and 5‐amino‐3‐methyl‐1‐(2‐nitrobenzoyl)pyrazole, C11H10N4O3, (II), both contain intramolecular N—H...O hydrogen bonds. The molecules of (I) are linked into a chain of rings by a combination of N—H...N and N—H...π(arene) hydrogen bonds, while those of (II) are linked into a three‐dimensional framework structure by N—H...N and C—H...O hydrogen bonds.  相似文献   

11.
Zinc thiocyanate complexes have been found to be biologically active compounds. Zinc is also an essential element for the normal function of most organisms and is the main constituent in a number of metalloenzyme proteins. Pyrimidine and aminopyrimidine derivatives are biologically very important as they are components of nucleic acids. Thiocyanate ions can bridge metal ions by employing both their N and S atoms for coordination. They can play an important role in assembling different coordination structures and yield an interesting variety of one‐, two‐ and three‐dimensional polymeric metal–thiocyanate supramolecular frameworks. The structure of a new zinc thiocyanate–aminopyrimidine organic–inorganic compound, (C6H9ClN3)2[Zn(NCS)4]·2C6H8ClN3·2H2O, is reported. The asymmetric unit consist of half a tetrathiocyanatozinc(II) dianion, an uncoordinated 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidinium cation, a 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine molecule and a water molecule. The ZnII atom adopts a distorted tetrahedral coordination geometry and is coordinated by four N atoms from the thiocyanate anions. The ZnII atom is located on a special position (twofold axis of symmetry). The pyrimidinium cation and the pyrimidine molecule are not coordinated to the ZnII atom, but are hydrogen bonded to the uncoordinated water molecules and the metal‐coordinated thiocyanate ligands. The pyrimidine molecules and pyrimidinium cations also form base‐pair‐like structures with an R22(8) ring motif via N—H…N hydrogen bonds. The crystal structure is further stabilized by intermolecular N—H…O, O—H…S, N—H…S and O—H…N hydrogen bonds, by intramolecular N—H…Cl and C—H…Cl hydrogen bonds, and also by π–π stacking interactions.  相似文献   

12.
The title compound 3,3′‐[o‐phenyl­enebis­(methyl­eneoxy)]­bis(6‐chloro­flavone), C38H24Cl2O6, (I), crystallizes in the monoclinic space group C2/c, with the molecules lying across twofold rotation axes so that there is half a mol­ecule in the asymmetric unit, while the other title compound, 3,3′‐propyl­ene­dioxy­bis­[6‐chloro‐2‐(2‐furyl)‐4H‐1‐benzopyran‐4‐one], C29H18Cl2O8, (II), crystallizes in monoclinic space group P21/n with one mol­ecule in the asymmetric unit. In both compounds, the benzopyran moiety is nearly planar, with dihedral angles between the two fused rings of 1.43 (8)° in (I), and 2.54 (7) and 3.00 (6)° with respect to the benzopyran moieties in the two halves of (II). The furan rings are twisted by 8.3 (1) and 8.4 (1)° in the two halves of (II). In both compounds, the molecular structure is stabilized by intramolecular C—H⃛O hydrogen bonds, while the crystal packing is stabilized by C—H⃛Cl and C—H⃛O intermolecular hydrogen bonds in (I) and (II), respectively.  相似文献   

13.
Crystals of the title compound, C2H6N4S, are built up from nonplanar 1‐(diaminomethylene)thiourea molecules. Pairs of molecules related by inversion are linked by N—H...N hydrogen bonds to form dimeric units, and weak N—H...S interactions link these dimeric units into a three‐dimensional framework.  相似文献   

14.
The title compound, C19H21N3O4S, crystallizes in the space group P2/c with two molecules in the asymmetric unit. The conformation of both molecules is very similar and is mainly determined by an intramolecular N—H...O hydrogen bond between a urea N atom and a sulfonyl O atom. The O and second N atom of the urea groups are involved in dimer formation via N—H...O hydrogen bonds. The intramolecular hydrogen‐bonding motif and conformation of the C—SO2—NH(C=O)—NH—C fragment are explored and compared using the Cambridge Structural Database and theoretical calculations. The crystal packing is characterized by π–π stacking between the 5‐cyanobenzene rings.  相似文献   

15.
In the title compounds, C11H18N2, (II), and C13H20N2O, (III), the pyrrolidine rings have twist conformations. Compound (II) crystallizes with two independent molecules (A and B) in the asymmetric unit. The mean planes of the pyrrole and pyrrolidine rings are inclined to one another by 89.99 (11) and 89.35 (10)° in molecules A and B, respectively. In (III), the amide derivative of (II), the same dihedral angle is much smaller, at only 13.42 (10)°. In the crystal structure of (II), the individual molecules are linked via N—H...N hydrogen bonds to form inversion dimers, each with an R22(12) graph‐set motif. In the crystal structure of (III), the molecules are linked via N—H...O hydrogen bonds to form inversion dimers with an R22(16) graph‐set motif.  相似文献   

16.
The title compound, C18H18N4OS2, was prepared by reaction of S,S‐diethyl 2‐thenoylimidodithiocarbonate with 5‐amino‐3‐(4‐methylphenyl)‐1H‐pyrazole using microwave irradiation under solvent‐free conditions. In the molecule, the thiophene unit is disordered over two sets of atomic sites, with occupancies of 0.814 (4) and 0.186 (4), and the bonded distances provide evidence for polarization in the acylthiourea fragment and for aromatic type delocalization in the pyrazole ring. An intramolecular N—H...O hydrogen bond is present, forming an S(6) motif, and molecules are linked by N—H...O and N—H...N hydrogen bonds to form a ribbon in which centrosymmetric R22(4) rings, built from N—H...O hydrogen bonds and flanked by inversion‐related pairs of S(6) rings, alternate with centrosymmetric R22(6) rings built from N—H...N hydrogen bonds.  相似文献   

17.
The title compound, C24H24N2O3S, exhibits antifungal and antibacterial properties. The compound crystallizes with two molecules in the asymmetric unit, with one molecule exhibiting `orientational disorder' in the crystal structure with respect to the cyclohexene ring. The o‐toluidine groups in both molecules are noncoplanar with the respective cyclohexene‐fused thiophene ring. In both molecules, there is an intramolecular N—H...N hydrogen bond forming a pseudo‐six‐membered ring which locks the molecular conformation and eliminates conformational flexibility. The crystal structure is stabilized by O—H...O hydrogen bonds; both molecules in the asymmetric unit form independent chains, each such chain consisting of alternating `ordered' and `disordered' molecules in the crystal lattice.  相似文献   

18.
In the title compound, C21H18N2OS2, a strong intramolecular N—H...O hydrogen bond [N...O = 2.642 (3) Å] between the amide N atom and the benzoyl O atom forms an almost planar six‐membered ring in the central part of the molecule. In the crystal, molecules are packed through weak N—H...S interactions. Intra‐ and intermolecular hydrogen bonds and van der Waals interactions are the stabilizing forces for the crystal structure.  相似文献   

19.
Racemic 2,4(6)‐di‐O‐benzoyl‐myo‐inositol 1,3,5‐orthoformate, C21H18O8, (1) , shows a very efficient intermolecular benzoyl‐group migration reaction in its crystals. However, the presence of 4,4′‐bipyridine molecules in its cocrystal, C21H18O8·C10H8N2, (1)·BP , inhibits the intermolecular benzoyl‐group transfer reaction. In (1) , molecules are assembled around the crystallographic twofold screw axis (b axis) to form a helical self‐assembly through conventional O—H...O hydrogen‐bonding interactions. This helical association places the reactive C6‐O‐benzoyl group (electrophile, El) and the C4‐hydroxy group (nucleophile, Nu) in proximity, with a preorganized El...Nu geometry favourable for the acyl transfer reaction. In the cocrystal (1)·BP , the dibenzoate and bipyridine molecules are arranged alternately through O—H...N interactions. The presence of the bipyridine molecules perturbs the regular helical assembly of the dibenzoate molecules and thus restricts the solid‐state reactivity. Hence, unlike the parent dibenzoate crystals, the cocrystals do not exhibit benzoyl‐transfer reactions. This approach is useful for increasing the stability of small molecules in the crystalline state and could find application in the design of functional solids.  相似文献   

20.
The title compound, C19H20O6, crystallizes in the centrosymmetric space group P21/c with one mol­ecule in the asymmetric unit. The mol­ecule is approximately planar and the dihedral angle between the phenyl rings is 11.0 (1)°. The H atoms of the central propenone group are trans. There is an intramolecular O—H⃛O hydrogen bond and the mol­ecules are crosslinked by four intermolecular C—H⃛O hydrogen bonds, producing a three‐dimensional network.  相似文献   

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