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1.  6-{5-Amino-3-tert-butyl-4-[(E)-(3-methyl-1,2,4-thiadiazol-5-yl)diazen­yl]-1H-pyrazol-1-yl}-1,3,5-triazine-2,4(1H,3H)-dione–1-methyl­pyrrolidin-2-one–water (1/1/1) 
In the title compound, C13H16N10O2S·C5H9NO·H2O, the entire 1-methylpyrrolidin-2-one (NMP) mol­ecule is disordered over two sites with occupancies of 0.488 (5) and 0.512 (5). The six-membered triazine ring and the two five-membered pyrazole and thiadia­zole rings, together with the diazene (–N=N–) linkage are almost coplanar (r.m.s. deviation for the non-H atoms = 0.0256 Å) with methyl groups from the tert-butyl substituent on the pyrazole ring located above and below the plane. Three intra­molecular N—H⋯N hydrogen bonds contribute to the planarity of the system. The O atom of the NMP mol­ecule is hydrogen bonded to an O—H group of water. In turn, the water mol­ecule is hydrogen bonded to the mono-azo skeleton through inter­molecular N—H⋯O and O—H⋯N hydrogen bonds. At both ends of the long mol­ecular axis of the main mol­ecule there are inter­molecular N—H⋯N hydrogen bonds, arranged in a head-to-tail fashion, between the N—H group of the triazine ring of one mol­ecule and the N atom of the thia­diazole ring of a neighboring mol­ecule. These form a polymeric chain along [110] or [10]. The main mol­ecules are stacked alternately along the b axis, which effectively cancels their dipole moments. In addition, pairs of alternate molecules are dimerized via inter­molecular hydrogen bonds involving the solvent mol­ecules.
PMCID: PMC2983887  PMID: 21580749
2.  tert-Butyl 2-(dihydroxyboryl)pyrrole-1-carboxylate 
In the title compound, C9H14BNO4, the carbonyl and boronic acid groups are essentially coplanar with the pyrrole ring and the boronic acid group has an exo-endo conformation. The exo-oriented OH is engaged in an intra­molecular O—H⋯O inter­action, while the endo-oriented one is involved in inter­molecular hydrogen bonding to form centrosymmetric dimers. A supra­molecular assembly is achieved through inter­actions involving the tert-butyl groups, forming infinite chains along the crystallographic b axis. There are, in addition, face-to-face and center-to-edge stacking inter­actions [distance between the pyrrole ring centroid and an N atom from a neighbouring mol­ecule = 3.369 (8) Å].
PMCID: PMC2961599  PMID: 21202573
3.  4,4′-[Ethylenebis(nitrilomethylidyne)]dibenzonitrile 
The mol­ecule of the title Schiff base compound, C18H14N4, lies across a crystallographic inversion centre and adopts an E configuration with respect to the azomethine (C=N) bonds. The imino groups are coplanar with the aromatic rings with a maximum deviation of 0.1574 (12) Å for the N atom. Within the mol­ecule, the planar units are parallel, but extend in opposite directions from the dimethyl­ene bridge. In the crystal structure, pairs of inter­molecular C—H⋯N hydrogen bonds link neighbouring mol­ecules into centrosymmetric dimers with R 2 2(10) ring motifs. An inter­esting feature of the crystal structure is the short inter­molecular C⋯C inter­action with a distance of 3.3821 (13) Å, which is shorter than the sum of the van der Waals radius of a carbon atom.
PMCID: PMC2969074  PMID: 21582425
4.  (2,6-Bis{5-amino-3-tert-butyl-4-[(3-methyl-1,2,4-thia­diazol-5-yl)diazen­yl]-1H-pyrazol-1-yl}-4-oxo-1,4-dihydro-1,3,5-triazin-1-ido)methanol(phenol)sodium phenol tetra­solvate 
The title compound, [Na(C23H28N17OS2)(CH3OH)(C6H5OH)]·4C6H5OH, is a five-coordinate NaI complex. The Na+ cation is bound to three N atoms of the triazinide ligand, two from each pyrazole ring and one from the central deprotonated triazine ring system. O atoms from a methanol and a phenol mol­ecule complete the five-coordinate NaN3O2 coordination environment. The asymmetric unit also includes three complete and two half phenol mol­ecules, four of which are hydrogen bonded to the N atoms of the thia­diazole ring. Two of the phenol solvent mol­ecules are disordered over two discrete inversion centres. The triazinide ligand is essentially planar (mean deviation from the least-squares plane = 0.0524 Å), with the methyl groups of the tert-butyl substituents on the pyrazole rings located above and below the plane. The planarity of this system is further assisted by the formation of four intra­molecular N—H⋯N hydrogen bonds between the N—H bonds of both amino groups on the pyrazole rings and the N atoms of the triazine ring and also from each of the adjacent diazene (–N=N–) bonds. The highly polar mol­ecules are stacked along the a axis through the central Na atom sandwiched by two kinds of alternating inter­molecular hydrogen bonds: O(carbon­yl)⋯H—O(methanol)/Na/O—H(phenol)⋯O(carbon­yl). These inter­actions form two polymer chains per mol­ecule.
PMCID: PMC2983962  PMID: 21580548
5.  Methyl 2-(tert-but­oxy­carbonyl­amino)-1,3-thia­zole-5-carboxyl­ate 
The title compound, C10H14N2O4S, was synthesized by the reaction of methyl 2-amino­thia­zole-5-carboxyl­ate and di-tert-butyl carbonate. In this structure, the thia­zole ring is planar (mean deviation = 0.0011 Å). Two weak intra­molecular C—H⋯O hydrogen bonds are formed between two of the methyl groups and one carbonyl O atom, resulting in the formation of two twisted six-membered rings. Inter­molecular N—H⋯N hydrogen bonds link the mol­ecules to form centrosymmetric dimeric units, and the hydrogen-bond scheme is completed by inter­molecular C—H⋯O contacts.
PMCID: PMC3007983  PMID: 21588688
6.  N-(4-tert-Butyl­benz­yl)phthalimide 
The mol­ecule of the title compound [systematic name: 2-(4-tert-butyl­benz­yl)isoindoline-1,3-dione], C19H19NO2, is V-shaped with a dihedral angle of 74.15 (7)° between the mean planes of the phthalimide unit and the benzene ring. The methyl groups of the tert-butyl substituent are disordered over two sets of positions, with an occupancy ratio of 0.700 (4):0.300 (4). In the crystal, inter­molecular C—H⋯O hydrogen bonds link adjacent mol­ecules into centrosymmetric dimers. An additional weak C—H⋯O contact, together with weak C—H⋯π and π–π inter­actions [centroid–centroid distance = 3.961 (2) Å] generate a three-dimensional network.
PMCID: PMC2977282  PMID: 21583486
7.  2-(N-Phenyl­methane­sulfonamido)­ethyl 1H-pyrrole-2-carboxyl­ate 
In the title compound, C14H16N2O4S, the eth­oxy­carbonyl group is nearly planar, with an r.m.s. deviation of 0.0067 Å, and is almost coplanar with the pyrrole ring [dihedral angle = 5.81 (15)°], whereas it is inclined at a dihedral angle of 61.90 (13)° to the phenyl ring. The dihedral angle between the pyrrole and phenyl rings is 56.15 (13)°. In the crystal, centrosymmetrically related mol­ecules are linked into dimers by pairs of N—H⋯O hydrogen bonds, forming rings of R 2 2(10) graph-set motif. The dimers are further connected by weak inter­molecular C—H⋯O hydrogen bonds and C—H⋯π inter­actions, forming layers parallel to the bc plane.
PMCID: PMC3089296  PMID: 21754438
8.  1-(2-Chloro-5-nitro­phen­yl)-3-(2,2-di­methyl­propion­yl)thio­urea 
With the exception of the C atoms of two of the methyl groups of the tert-butyl substituent, all of the non-H atoms of the title compound, C12H14ClN3O3S, lie on a mirror plane. The 2-chloro-5-nitro­phenyl and 2,2-dimethyl­propionyl substituents are, respectively, cis and trans relative to the thio­carbonyl S atom across the two C—N bonds. Intra­molecular N—H⋯O and C—H⋯S hydrogen bonds form S(6) ring motifs, also in the mirror plane. Despite the presence of two N—H subsituents, no inter­molecular hydrogen bonds are observed in the crystal structure. Weak π–π contacts [centroid–centroid distances of 4.2903 (17) Å] involving adjacent aromatic rings link the mol­ecules in a head-to-tail fashion above and below the mol­ecular plane.
PMCID: PMC2977335  PMID: 21583450
9.  Eight 7-benzyl-3-tert-butyl-1-phenyl­pyrazolo[3,4-d]oxazines, encompassing structures containing no inter­molecular hydrogen bonds, and hydrogen-bonded structures in one, two or three dimensions 
7-Benzyl-3-tert-butyl-1-phenyl-6,7-dihydro-1H,4H-pyrazolo[3,4-d][1,3]oxazine, C22H25N3O, (I), and 3-tert-butyl-7-(4-methyl­benz­yl)-1-phenyl-6,7-dihydro-1H,4H-pyrazolo[3,4-d][1,3]oxazine, C23H27N3O, (II), are isomorphous in the space group P21, and mol­ecules are linked into chains by C—H⋯O hydrogen bonds. In each of 3-tert-butyl-7-(4-methoxy­benz­yl)-1-phenyl-6,7-dihydro-1H,4H-pyrazolo[3,4-d][1,3]oxazine, C23H27N3O2, (III), which has cell dimensions rather similar to those of (I) and (II), also in P21, and 3-tert-butyl-1-phenyl-7-[4-(trifluoro­meth­yl)benz­yl]-6,7-dihydro-1H,4H-pyrazolo[3,4-d][1,3]oxazine, C23H24F3N3O, (IV), there are no direction-specific inter­actions between the mol­ecules. In 3-tert-butyl-7-(4-nitro­benz­yl)-1-phenyl-6,7-dihydro-1H,4H-pyrazolo[3,4-d][1,3]oxazine, C22H24N4O3, (V), a combination of C—H⋯O and C—H⋯N hydrogen bonds links the mol­ecules into complex sheets. There are no direction-specific inter­actions between the mol­ecules of 3-tert-butyl-7-(2,3-dimethoxy­benz­yl)-1-phenyl-6,7-dihydro-1H,4H-pyrazolo[3,4-d][1,3]oxazine, C24H29N3O3, (VI), but a three-dimensional framework is formed in 3-tert-butyl-7-(3,4-methyl­enedioxy­benz­yl)-1-phenyl-6,7-dihydro-1H,4H-pyrazolo[3,4-d][1,3]oxazine, C23H25N3O3, (VII), by a combination of C—H⋯O, C—H⋯N and C—H⋯π(arene) hydrogen bonds, while a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds links the mol­ecules of 3-tert-butyl-1-phenyl-7-(3,4,5-trimethoxy­benz­yl)-6,7-dihydro-1H,4H-pyrazolo[3,4-d][1,3]oxazine, C25H31N3O4, (VIII), into complex sheets. In each compound, the oxazine ring adopts a half-chair conformation, while the orientations of the pendent phenyl and tert-butyl substituents relative to the pyrazolo[3,4-d]oxazine unit are all very similar.
PMCID: PMC2720151  PMID: 19652329
10.  3,3′-Di-tert-butyl-1,1′-[1,3-phenyl­enebis(methyl­ene)]diurea 
The title compound, C18H30N4O2, contains two tert-butyl urea groups, each connected to a benzene ring though a methyl­ene group. One of the groups occupies a position almost normal to the aromatic plane with a C—N—C—C torsion angle of −94.4 (4)°, while the other is considerably twisted from the ring with a C—N—C—C torsion angle of −136.1 (4)°. In the crystal, pairs of mol­ecules are connected to each other, forming centrosymmetric dimers in which two NH groups of one mol­ecule act as hydrogen-bond donors to one carbonyl O atom of the other mol­ecule. The dimers are linked into sheets parallel to (100) by N—H⋯O hydrogen bonds involving the remaining N—H and C=O groups.
PMCID: PMC2983681  PMID: 21580407
11.  2-Amino-5-methyl­pyridinium 1H-pyrazole-3,5-dicarboxyl­ate trihydrate 
In the title compound, 2C6H9N2 +·C5H2N2O4 2−·3H2O, the 1H-pyrazole-3,5-dicarboxyl­ate anion is close to planar [maximum deviation = 0.208 (1) Å]. The two distinct 2-amino-5-methyl­pyridinium cations are also almost planar, with maximum deviations of 0.018 (2) and 0.014 (2) Å. In the crystal, pairs of inter­molecular N—H⋯O and O—H⋯O hydrogen bonds connect neighbouring mol­ecules into dimers, generating R 2 2(8) and R 2 4(8) ring motifs, respectively. Further inter­molecular N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network.
PMCID: PMC3008987  PMID: 21589058
12.  Poly[tetra­deca­aqua­tetra­kis­(μ3-1H-imidazole-4,5-dicarboxyl­ato)tetra-μ3-sulfato-cobalt(II)hexa­gadolinium(III)] 
The asymmetric unit of the title compound, [CoGd6(C5H2N2O4)4(SO4)6(H2O)14]n, contains a CoII ion (site symmetry ), three GdIII ions, two imidazole-4,5-dicarboxyl­ate ligands, three SO4 2− anions, and seven coordinated water mol­ecules. The CoII ion is six-coordinated by two O atoms from water mol­ecules, two O atoms and two N atoms from two imidazole-4,5-dicarboxyl­ate ligands, giving a slightly distorted octa­hedral geometry. The GdIII ions exhibit three types of coordination environments. One Gd ion is eight-coordinated in a bicapped trigonal–prismatic geometry by four O atoms from two imidazole-4,5-dicarboxyl­ate ligands, two O atoms from two SO4 2− anions and two coordinated water mol­ecules. The other Gd ions are nine-coordinated in a tricapped trigonal–prismatic geometry; one of these Gd ions is bonded to four O atoms from two imidazole-4,5-dicarboxyl­ate ligands, three O atoms from three SO4 2− anions and two water O atoms and the other Gd ion is coordinated by one O atom and one N atom from one imidazole-4, 5-dicarboxyl­ate ligand, five O atoms from three SO4 2− anions as well as two coordinated water mol­ecules. These metal coordination units are connected by bridging imidazole-4,5-dicarboxyl­ate and sulfate ligands, generating a three-dimensional network. The crystal structure is further stabilized by N—H⋯O, O—H⋯O, and C—H⋯O hydrogen-bonding inter­actions between water mol­ecules, SO4 2− anions, and imidazole-4,5-dicarboxyl­ate ligands.
PMCID: PMC3212143  PMID: 22090845
13.  Bis[triaqua­(1H-1,2,4-triazole-3,5-dicarboxyl­ato-κ2 O 3,N 4)copper(II)] di-μ-aqua-bis­[diaqua­(1H-1,2,4-triazole-3,5-dicarboxyl­ato-κ2 O 3,N 4)copper(II)] 
In the title compound, [Cu(C4HN3O4)(H2O)3]2[Cu2(C4HN3O4)2(H2O)6], both monomeric and dimeric mol­ecules are present in the solid state. In the monomeric compound, the CuII atom is five-coordinated in a square-pyramidal configuration by one O atom and one N atom from one 1H-1,2,4-triazole-3,5-dicarboxyl­ate (TZDCA2−) ligand and three O atoms from water mol­ecules. In the centrosymmetric binuclear complex, each CuII atom is six-coordinated in an octa­hedral geometry by one O atom and one N atom from one TZDCA2− ligand and four O atoms from water mol­ecules, two of which bridge the CuII atoms. In the structure, there are intra­molecular O—H⋯O and N—H⋯O hydrogen bonds, and in the crystal, inter­molecular O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds link symmetry-related mol­ecules, forming a three-dimensional supra­molecular structure.
PMCID: PMC2977176  PMID: 21583383
14.  N-{2-[(4S)-4-tert-Butyl-4,5-dihydro-1,3-oxazol-2-yl]phen­yl}-5,6-diphenyl-1,2,4-triazin-3-amine 
The title compound, C28H27N5O, was synthesized using palladium cross-coupling amination of 3-bromo-5,6-diphenyl-1,2,4-triazine with 2-[(4S)-4-tert-butyl-4,5-dihydro-1,3-oxazol-2-yl]aniline. The oxazoline ring is almost planar, with a maximum atomic deviation of 0.023 (5) Å. The phenyl rings make dihedral angles of 29.0 (1) and 54.6 (1)° with the triazine ring while the benzene ring makes a dihedral angle of 0.6 (1)° with the oxazoline ring. The conformation of the mol­ecule is influenced by strong intra­molecular N—H⋯N and weak C—H⋯N hydrogen bonds. In the crystal, screw-axis related mol­ecules are linked into supra­molecular chains by inter­molecular C—H⋯O hydrogen bonds. π–π stacking is observed between the oxazoline and triazine rings of adjacent mol­ecules, with a centroid–centroid distance of 3.749 (2) Å.
PMCID: PMC3052057  PMID: 21522403
15.  (2E,4E,6E)-3-Methyl-7-(pyren-1-yl)octa-2,4,6-trienoic acid 
The title compound, C25H20O2, was synthesized by a Wittig reaction between triphen­yl[1-(pyren-1-yl)eth­yl]phospho­nium bromide and ethyl (2E,4E)-3-methyl-6-oxohexa-2,4-dienoate, in the presence of n-butyl lithium, followed by saponification. It was obtained pure in the all-trans configuration following crystallization from ethyl acetate. The asymmetric unit contains two independent mol­ecules (A and B), which are arranged almost parallel to each other within the crystal structure. The triene chain is not coplanar with the pyrene ring system, forming dihedral angles of 52.8 (1) and 42.2 (1)° for mol­ecules A and B, respectively. Inter­molecular hydrogen bonds between the carboxyl groups of the mol­ecules link them into centrosymmetric pairs, AA and BB, each with the R 2 2(8) graph-set motif.
PMCID: PMC2970380  PMID: 21578017
16.  3,4-Dibromo-2,5-bis­[(dieth­oxy­phosphor­yl)meth­yl]-1-phenyl­sulfonyl-1H-pyrrole 
In the title compound, C20H29Br2NO8P2S, the pyrrole ring is essentially planar, with a maximum deviation of 0.013 (3) Å for a C atom. The pyrrole ring is almost orthogonal to the sulfonyl-bound phenyl ring, with a dihedral angle 88.5 (2)°. Both P atoms exhibit distorted tetra­hedral configurations with O—P—O angles widened and O—P—C angles narrowed from the ideal tetra­hedral value. In the crystal, mol­ecules are linked into centrosymmetric dimers via C—H⋯O inter­actions, resulting in R 2 2(10) graph-set motifs which are further consolidated by R 2 2(13) graph-set ring motifs via C—H⋯O inter­actions, further resulting in chains of mol­ecules running parallel to the c axis; a phosphono O atom is involved in bifurcated hydrogen bonding. All the eth­oxy groups are disordered over two positions each with unequal site-occupancy factors.
PMCID: PMC3200636  PMID: 22064776
17.  A series of N-(2-phenyl­ethyl)nitro­aniline derivatives as precursors for slow and sustained nitric oxide release agents 
A series of N-(2-phenyl­ethyl)nitro­aniline derivatives is presented, demonstrating that modest changes in the functional groups cause significant differences in mol­ecular conformation, inter­molecular inter­actions and packing.
2,4-Di­nitro-N-(2-phenyl­ethyl)aniline, C14H13N3O4, (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 ethyl C—C bond leads to the phenyl and aniline rings being essentially parallel. Mol­ecules are linked into dimers by inter­molecular N—H⋯O hydrogen bonds, such that each amine H atom participates in a three-centre inter­action with two nitro O atoms. Though the dimers pack so that the arene rings of adjacent mol­ecules are parallel, the rings are staggered and π–π inter­actions do not appear to be favoured. 4,6-Di­nitro-N,N′-bis­(2-phenyl­ethyl)benzene-1,3-di­amine, C22H22N4O4, (II), differs from (I) in the presence of a second 2-phenyl­ethyl­amine group on the substituted ring. Compound (II) also crystallizes with one unique mol­ecule in the asymmetric unit. Both amine groups are involved in intra­molecular N—H⋯O hydrogen bonds with adjacent nitro groups. Although one ethyl group adopts an anti conformation as in (I), the other is gauche, with the result that the pendant phenyl rings are not parallel. The amine group that is part of the gauche conformation participates in a three-centre N—H⋯O hydrogen bond with the nitro group of a neighbouring mol­ecule, leading to dimers as in (I). The other amine H atom does not form any inter­molecular hydrogen bonds. The packing leads to separations of ca 3.4 Å of the parallel anti phenyl and amino­benzene rings. 2-Cyano-4-nitro-N-(2-phenyl­ethyl)aniline, C15H13N3O2, (III), differs from (I) only in having a cyano group in place of the 2-nitro group. The absence of the adjacent nitro group eliminates the intra­molecular N—H⋯O hydrogen bond. Mol­ecules of (III) adopt the same anti conformation about the ethyl group as in (I), but crystallize in the higher-symmetry monoclinic space group P21/n. The mol­ecules are linked into dimers via N—H⋯N amine–cyano hydrogen bonds, while the nitro groups are not involved in any N—H⋯O inter­actions. Owing to the different symmetry, the mol­ecules pack in a herringbone pattern with fewer face-to-face inter­actions between the rings. The closest such inter­actions are about 3.5 Å between rings that are largely slipped past one another. 4-Methyl­sulfonyl-2-nitro-N-(2-phenyl­ethyl)aniline, C15H16N2O4S, (IV), differs from (I) in having a methyl­sulfonyl group in place of the 4-nitro group. The intra­molecular N—H⋯O hydrogen bond is present as in (I). However, unlike (I), the conformation about the ethyl group is gauche, so the two arene rings are nearly per­pen­dicular rather than parallel. The packing is significantly different from the other three structures in that there are no inter­molecular hydrogen bonds involving the N—H groups. The mol­ecules are arranged in tetra­gonal columns running along the c axis, with the aniline rings mostly parallel and separated by ca 3.7 Å. Taken together, these structures demonstrate that modest changes in functional groups cause significant differences in mol­ecular conformation, inter­molecular inter­actions and packing.
PMCID: PMC3818095  PMID: 24192194
crystal structure; N-(2-phenyl­ethyl)nitro­aniline derivatives; secondary amines; nitric oxide release agents
18.  5,11,17,23-Tetra-tert-butyl-25,26,27,28-tetra­kis[2-(2-chloro­ethoxy)eth­oxy]-2,8,14,20-tetra­sulfonyl­calix[4]arene 
Mol­ecules of the title compound, C56H76Cl4O16S4, have crystallographic C 2 symmetry and adopt a 1,3-alternate conformation where the four –OCH2CH2OCH2CH2Cl groups are located alternately above and below the virtual plane (R) defined by the four bridging S atoms. The dihedral angles between the plane (R) and the phenolic rings are 72.85 (7) and 74.57 (7)°. An unusual 24-membered macrocyclic ring is formed in the crystal structure with an array of eight intra­molecular C—H⋯O hydrogen bonds between the ether arm H atoms and the sulfonyl O atoms. In the supra­molecular structure, the mol­ecular components are linked into infinite zigzag one-dimensional chains by a combination of four inter­molecular C—H⋯O hydrogen bonds, forming R 2 2(13), R 2 2(16), R 2 2(21) and R 2 2(26) ring motifs. These chains are augmented into a wave-like two-dimensional network by weak C⋯O inter­actions. One tert-butyl group shows rotational disorder, and one CH2CH2Cl group is disordered over two orientations; the site-occupation factors are 0.756 (6) and 0.244 (6) for the two tert-butyl groups, and 0.808 (3) and 0.192 (3) for the two CH2CH2Cl units.
PMCID: PMC2968348  PMID: 21581981
19.  2-n-Butyl-6-chloro-1-(2,4-dimethyl­phenyl­sulfon­yl)-1H-benzimidazole–2-n-butyl-5-chloro-1-(2,4-dimethyl­phenyl­sulfon­yl)-1H-benzimidazole (0.759/0.241) 
The title compound, 0.759C19H21ClN2O2S·0.241C19H21ClN2O2S, was synthesized by aryl­sulfonyl­ation of 2-n-butyl-5-chloro-1H-benzimidazole in the presence of triethyl­amine. The crystal structure is composed of two mol­ecules, 2-n-butyl-6-chloro-1-(2,4-dimethylphenyl­sulfon­yl)-1H-benzimidazole and 1-(2,4-dimethylphenyl­sulfon­yl)-2-n-butyl-5-chloro-1H-benz­imidazole, in the refined ratio of 0.759 (4):0.241 (4) disordered at the same position in the unit cell. The mol­ecule has three essentially planar fragments viz. benzimidazole, dimethyl­benzene and n-butyl (r.m.s. deviations of 0.009, 0.024 and 0.003 Å, respectively). The angle between the benzimidazole and dimethyl­benzene fragments is 86.0 (1)°. In the crystal, pairs of inter­molecular C—H⋯π inter­actions form centrosymmetrical dimers, which are linked by weak inter­molecular C—H⋯O hydrogen bonds.
PMCID: PMC3238991  PMID: 22199840
20.  (E)-3-Methyl-4-[(2-oxidoquinolin-1-ium-3-yl)methyl­eneamino]-1H-1,2,4-triazole-5(4H)-thione N,N-dimethyl­formamide solvate 
The title 1,2,4-triazole compound, C13H11N5OS·C3H7NO, crystallizes as a 1:1 dimethyl­formamide (DMF) solvate. The main mol­ecule exists in a trans configuration with respect to the acyclic C=N bond. An intra­molecular C—H⋯S hydrogen bond generates an S(6) ring motif. In the synthesis, a proton is transferred from the O atom of a hydr­oxy group to the quinoline group N atom. The essentially planar triazole ring and quinoline ring system [maximum deviations of 0.001 (2) and 0.013 (2) Å, respectively] form a dihedral angle of 5.86 (9)°. In the crystal structure, mol­ecules of (E)-4-[(2-hydroxy-3-­quinolyl)methyl­eneamino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione are linked into R 2 2(8) centrosymmteric dimers via N—H⋯O hydrogen bonds. These dimers are further linked into an extended three-dimensional structure by the DMF solvent mol­ecules via inter­molecular N—H⋯O and C—H⋯O hydrogen bonds. The crystal structure is consolidated by two different inter­molecular π–π inter­actions [centroid–centroid distances = 3.6593 (12) and 3.6892 (12) Å].
PMCID: PMC2972175  PMID: 21578940
21.  Diaqua­(2,2′-bipyridine-5,5′-dicarboxyl­ato-κ2 N,N′)(ethyl­enediamine-κ2 N,N′)copper(II) 2.5-hydrate 
In the mol­ecule of the title compound, [Cu(C12H6N2O4)(C2H8N2)(H2O)2]·2.5H2O, the CuII atom is six-coordinated in a distorted octa­hedral configuration by two N atoms from a 2,2′-bipyridine-5,5′-dicarboxyl­ate anion, two N atoms from ethyl­enediamine and two O atoms from two water mol­ecules. There are also two and a half water mol­ecules in the asymmetric unit. The planar five-membered ring is nearly coplanar with the adjacent pyridine rings, while the other five-membered ring adopts a twisted conformation, probably due to hydrogen bonding. In the crystal structure, intra- and inter­molecular N—H⋯O and O—H⋯O hydrogen bonds link the mol­ecules.
PMCID: PMC2959425  PMID: 21201030
22.  4-(sec-Butyl­amino)-3-nitro­benzoic acid 
The asymmetric unit of title compound, C11H14N2O4, consists of two crystallographically independent mol­ecules (A and B). In each, intra­molecular N—H⋯O hydrogen bonds generate S(6) ring motifs. The mean plane of the nitro group forms dihedral angles of 4.5 (3) and 0.5 (3)° with the benzene ring in mol­ecules A and B, respectively. In mol­ecule A, there is disorder of the butyl­amino group which corresponds to an approximate 180° rotation about the N—C(H) bond, forming two sites with refined occupancies of 0.722 (6) and 0.278 (6). Mol­ecule B is similarly disordered but in addition there is further rotational disorder about the C(H)—C(H2) bond giving a ratio of occupancies for three components of 0.42:0.35:0.23. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link mol­ecules into centrosymmetric dimers generating R 2 2(8) ring motifs. The crystal structure is also stabilized by weak inter­molecular C—H⋯O inter­actions.
PMCID: PMC2969477  PMID: 21582841
23.  1-(4-Methyl­benz­yl)-2-(4-methyl­phen­yl)-1H-benzimidazole 
The title compound, C22H20N2, crystallizes with two independent mol­ecules (A and B) in the asymmetric unit. The benzimidazole units are almost planar [maximum deviations = 0.0161 (8) Å for A and 0.0276 (8) Å for B]. The dihedral angles between the benzimidazole unit and the benzene rings of the 4-methyl­benzyl and 4-methyl­phenyl groups are 76.64 (3) and 46.87 (4)°, respectively, in mol­ecule A. The corresponding values in mol­ecule B are 86.31 (2) and 39.14 (4)°. The dihedral angles between the planes of the two benzene rings are 73.73 (3) and 80.69 (4)° in mol­ecules A and B, respectively. Pairs of weak inter­molecular C—H⋯N hydrogen bonds link B mol­ecules, forming centrosymmetric dimers with R 2 2(8) ring motifs. There are no significant corresponding inter­actions involving the A mol­ecules.
PMCID: PMC3239139  PMID: 22199987
24.  (E)-2-[1-(1-Benzothio­phen-2-yl)ethyl­idene]-N-phenyl­hydrazinecarboxamide 
The title compound, C17H15N3OS, crystallizes with two unique mol­ecules, denoted 1 and 2, in the asymmetric unit. The two mol­ecules are closely similar and overlay with an r.m.s. deviation of 0.053 Å. Both mol­ecules adopt E configurations with respect to the C=N bonds. The dihedral angles between the benzothio­phene groups and N-bound phenyl rings are 36.36 (9)° for mol­ecule 1 and 29.71 (9)° for mol­ecule 2. The C=N—NH—C(O)NH ethyl­idene–hydrazinecarboxamide units are also reasonably planar, with r.m.s. deviations of 0.061 and 0.056 Å, respectively, for the two mol­ecules. The methyl substituents lie 0.338 (3) and 0.396 (3) Å, respectively, from these planes. The C=N—NH—C(O)NH planes are inclined to the phenyl rings at 13.65 (11) and 15.56 (11)°, respectively, in mol­ecules 1 and 2. This conformation is enhanced by weak intra­molecular C—H⋯O hydrogen bonds between ortho-H atoms of the two phenyl rings and the carbonyl O atoms, which generate S(6) rings in each mol­ecule. In the crystal, pairs of mol­ecules are linked by pairs of inter­molecular N—H⋯O hydrogen bonds into dimers. Alternating dimers are further inter­connected by weak C—H⋯O contacts into zigzag rows along b. The rows are stacked along a by C—H⋯π contacts involving the benzene ring from molecule 2 and the thiophene ring from molecule 1 of adjacent benzothio­phene units.
PMCID: PMC3201294  PMID: 22058789
25.  N-(4-Meth­oxy­phen­yl)-6-methyl-2-phenyl-5-{[4-(tri­fluoro­meth­yl)anilino]meth­yl}pyrimidin-4-amine 
The title compound, C26H23F3N4O, crystallizes with two symmetry-independent mol­ecules in the asymmetric unit, denoted A and B, which differ mainly in the rotation of the meth­oxy­phenyl ring. The –CF3 group of mol­ecule B is disordered by rotation, with the F atoms split over two sets of sites; the occupancy factor for the major component is 0.853 (4). The dihedral angles between the pyrimidine ring and the attached phenyl, meth­oxy­phenyl and tri­fluoro­methyl­phenyl rings are 8.1 (2), 37.5 (2) and 70.7 (2)°, respectively, in mol­ecule A, and 9.3 (2), 5.3 (2) and 79.7 (2)° in mol­ecule B. An intra­molecular N—H⋯N hydrogen bond occurs in each mol­ecule. In the crystal, two crystallographically independent mol­ecules associate into a dimer via a pair of N—H⋯N hydrogen bonds, with a resulting R 2 2(12) ring motif and π–π stacking inter­actions [centroid–centroid distance = 3.517 (4) Å] between the pyrimidine rings. For the A mol­ecules, there are inter­molecular C—H⋯O hydrogen bonds between an aryl C atom of meth­oxy­phenyl ring and a meth­oxy O atom of an adjacent mol­ecule. A similar inter­action is lacking in the B mol­ecules.
PMCID: PMC3885078  PMID: 24454254

Results 1-25 (274154)