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1.  Crystal structure of 8-hy­droxy­quinoline: a new monoclinic polymorph 
In an attempt to grow 8-hy­droxy­quinoline–acetamino­phen co-crystals from equimolar amounts of conformers in a chloro­form–ethanol solvent mixture at room temperature, the title compound, C9H7NO, was obtained. The mol­ecule is planar, with the hy­droxy H atom forming an intra­molecular O—H⋯N hydrogen bond. In the crystal, mol­ecules form centrosymmetric dimers via two O—H⋯N hydrogen bonds. Thus, the hy­droxy H atoms are involved in bifurcated O—H⋯N hydrogen bonds, leading to the formation of a central planar four-membered N2H2 ring. The dimers are bound by inter­molecular π–π stacking [the shortest C⋯C distance is 3.2997 (17) Å] and C—H⋯π inter­actions into a three-dimensional framework. The crystal grown represents a new monoclinic polymorph in the space group P21/n. The mol­ecular structure of the present monoclinic polymorph is very similar to that of the ortho­rhom­bic polymorph (space group Fdd2) studied previously [Roychowdhury et al. (1978 ▶). Acta Cryst. B34, 1047–1048; Banerjee & Saha (1986 ▶). Acta Cryst. C42, 1408–1411]. The structures of the two polymorphs are distinguished by the different geometries of the hydrogen-bonded dimers, which in the crystal of the ortho­rhom­bic polymorph possess twofold axis symmetry, with the central N2H2 ring adopting a butterfly conformation.
doi:10.1107/S1600536814016110
PMCID: PMC4186174  PMID: 25309256
8-hy­droxy­quinoline; hydrogen bonds; polymorphism; crystal structure
2.  2-Methyl-N-p-tolyl­benzamide: a second monoclinic polymorph 
The title compound, C15H15NO, (I), is a polymorph of the structure (II) reported by Gowda et al. [Acta Cryst. (2008), E64, o1494]. Compound (II) crystalllizes in the space group C2/c (Z = 8), whereas the title compound occurs in space group P21/c (Z = 4). The two mol­ecular structures differ slightly in the relative orientations of their central amide group with respect to the benzoyl ring [dihedral angles of 55.99 (7) for (I) and 59.96 (11)° for (II)] and in the inclination of the benzoyl and aniline rings [88.67 (8) for (I) and 81.44 (5)° for (II)]. In the crystal structure of (I), mol­ecules are linked by N—H⋯O hydrogen bonds, forming C(4) chains, which are augmented by weak C—H⋯O inter­actions. The structure is further stabilized by C—H⋯π contacts involving both of the aromatic rings.
doi:10.1107/S1600536810010378
PMCID: PMC2983768  PMID: 21580722
3.  2-Chloro-N-(4-meth­oxy­phen­yl)benzamide 
In the title compound, C14H12ClNO2, the chloro- and meth­oxy-substituted benzene rings are close to orthogonal [dihedral angle = 79.20 (3)°]. These rings also make angles of 45.9 (3) and 33.5 (3)° with the amide –CONH– unit. The meth­oxy substituent lies close to the meth­oxy­benzene ring plane, with a maximum deviation of 0.142 (3) Å for the methyl C atom. The N—H bond is anti to the 2-chloro substituent of the aniline ring. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds form C(4) chains augmented by a weak C—H⋯O inter­action involving an ortho H atom of the meth­oxy benzene ring that generates an R 2 1(6) motif. The chains stack the mol­ecules into columns down the b axis. Adjacent columns are linked by additional C—H⋯O and C—H⋯π contacts, generating a three-dimensional network.
doi:10.1107/S1600536810043035
PMCID: PMC3009019  PMID: 21589131
4.  1,3-Bis(2-chloro­phen­yl)thio­urea: a monoclinic polymorph 
The title compound, C13H10Cl2N2S, represents a monoclinic polymorph of the previously reported ortho­rhom­bic form [Ramnathan et al. (1996 ▶). Acta Cryst. C52, 134–136]. The mol­ecule is twisted with the dihedral angle between the benzene rings being 55.37 (7)°. The N—H atoms are syn to each other, which contrasts their anti disposition in the ortho­rhom­bic form. In the crystal, mol­ecules assemble into zigzag chains along the c axis via N—H⋯S hydrogen bonds. Chains are connected into layers via C—H⋯Cl inter­actions, and these stack along the a axis.
doi:10.1107/S1600536811041894
PMCID: PMC3247371  PMID: 22219989
5.  An ortho­rhom­bic polymorph of 5-[(4-methyl­phen­yl)diazen­yl]salicylaldehyde 
The title compound, C14H12N2O2, is an ortho­rhom­bic polymorph of the previously reported monoclinic form [Bakir et al. (2005 ▶). Acta Cryst. E61, o1611–o1613]. The dihedral angle between the aromatic rings is 4.32 (13)°. The mol­ecular structures of the two polymorphs, including short intra­molecular O—H⋯O hydrogen bonds between the the hydr­oxy and keto groups, are quite similar but their crystal packings are distinct. Unlike the monoclinic form, in which centrosymmetrically related hydr­oxy and keto groups form {⋯H⋯O}2 synthons via weak O—H⋯O contacts, leading to dimeric aggregates, in the ortho­rhom­bic form, the hydrogen bonding between these groups leads to the formation of supra­molecular chains orientated along the a axis.
doi:10.1107/S1600536809046868
PMCID: PMC2971774  PMID: 21578791
6.  N-(4-Chloro­phen­yl)benzamide 
The structure of the title compound, C13H10ClNO, resembles those of N-phen­ylbenzamide, N-(2-chloro­phenyl)­benzamide and other benzanilides, with similar bond parameters. The amide group –NHCO– makes a dihedral angle of 29.95 (9)° with the benzoyl ring, while the benzoyl and aniline rings form a dihedral angle of 60.76 (3)°. The structure shows both intra- and inter­molecular hydrogen bonding. The mol­ecules are linked by N—H⋯O hydrogen bonds into chains running along the [100] direction.
doi:10.1107/S1600536808008155
PMCID: PMC2961007  PMID: 21202156
7.  2-Chloro-N-(3,4-dimethyl­phen­yl)benzamide 
In the title compound, C15H14ClNO, the conformation of the N—H bond is anti to the meta-methyl group in the aniline ring, while that of the C=O bond is anti to the ortho-chloro group in the benzoyl ring. The mean planes through the two benzene rings make a dihedral angle of 80.8 (2)°. In the crystal, mol­ecules are linked by inter­molecular N—H⋯O hydrogen bonds, forming column-like chains along the b axis.
doi:10.1107/S1600536811027267
PMCID: PMC3213471  PMID: 22091050
8.  N-(2-Chloro­phen­yl)-2-methyl­benzamide 
In the structure of the title compound (N2CP2MBA), C14H12ClNO, the conformations of the N—H and C=O bonds are trans to each other. Furthermore, the conformation of the N—H bond is syn to the ortho-chloro group in the aniline ring and the C=O bond is syn to the ortho-methyl substituent in the benzoyl ring, similar to what is observed in 2-chloro-N-(2-chloro­phen­yl)benzamide and 2-methyl-N-phenyl­benzamide. The amide group makes almost the same dihedral angles of 41.2 (14) and 42.2 (13)° with the aniline and benzoyl rings, respectively, while the dihedral angle between the benzoyl and aniline rings is only 7.4 (3)°. The mol­ecules in N2CP2MBA are packed into chains through N—H⋯O hydrogen bonds.
doi:10.1107/S1600536808020229
PMCID: PMC2962055  PMID: 21203140
9.  2-Chloro-N-(2,3-dimethyl­phen­yl)benzamide 
In the title compound, C15H14ClNO, the N—H and C=O bonds in the amide group are anti to each other. The amide group is inclined at 60.3 (1)° to the chloro-substituted benzoyl ring and at 59.2 (1)° to the dimethyl-substituted aniline ring. The mean planes through the two benzene rings make a dihedral angle of 7.7 (1)°. In the crystal structure, mol­ecules are linked by inter­molecular N—H⋯O hydrogen bonds, forming chains along [010].
doi:10.1107/S1600536810024943
PMCID: PMC3007441  PMID: 21588231
10.  A third polymorph of 1,4-bis­(1H-benzimid­azol-2-yl)benzene 
The title compound, C20H14N4, is a new polymorph of the previously reported structures, which were ortho­rhom­bic, space group Pbca [Bei et al. (2000). Acta Cryst. C56, 718–719] and monoclinic, space group P21/c [Dudd et al. (2003). Green Chem. 5, 187–192]. The asymmetric unit consists of two independent mol­ecules in which the dihedral angels between the central benzene ring and the outer benzimidazole ring systems are 16.81 (10) and 14.23 (10)° in one molecule and 26.09 (10) and 37.29 (10)° in the other. In the crystal, mol­ecules are linked by N—H⋯N and C—H⋯N hydrogen bonds into a tape running along the c-axis direction.
doi:10.1107/S1600536814011179
PMCID: PMC4051014  PMID: 24940273
11.  N-(3-Chloro­phen­yl)benzamide 
The conformation of the N—H bond in the structure of the title compound (N3CPBA), C13H10ClNO, is anti to the meta chloro substituent in the aniline benzene ring, similar to that observed with respect to the ortho chloro substituent in N-(2-chloro­phen­yl)benzamide (N2CPBA) and meta chloro substituent in N-(3,4-dichloro­phen­yl)benzamide (N34DCPBA), but in contrast to the syn conformation observed with respect to both the ortho and the meta chloro substituents in N-(2,3-dichloro­phen­yl)benzamide (N23DCPBA). The bond parameters in N3CPBA are similar to those in N-phenyl­benzamide, N2CPBA, N23DCPBA, N34DCPBA and other benzanilides. The amide group –NHCO– makes a dihedral angle of 18.2 (2)° with the benzoyl ring, while the dihedral angle between the two benzene rings is 61.0 (1)°. The mol­ecules are linked into chains along the b axis by N—H⋯O hydrogen bonds.
doi:10.1107/S1600536808001311
PMCID: PMC2960316  PMID: 21201488
12.  A monoclinic polymorph of 1-(4-chloro­phen­yl)-3-(4-methoxy­phen­yl)prop-2-en-1-one 
The crystal structure of the title compound, C16H13ClO2 (II), (space group P21/c,) is a polymorph of the structure, (I), reported by Harrison, Yathirajan, Sarojini, Narayana & Indira [Acta Cryst. (2006), E62, o1647–o1649] in the ortho­rhom­bic space group Pna21. The dihedral angle between the mean planes of the 4-chloro- and 4-meth­oxy-substituted benzene rings is 52.9 (1)° in (II) compared to 21.82 (6)° for polymorph (I). The dihedral angles between the mean planes of the prop-2-en-1-one group and those of the 4-chloro­phenyl and 4-methoxy­phenyl rings are 23.3 (3) and 33.7 (1)°, respectively. in (II). The corresponding values are 17.7 (1) and 6.0 (3)°, respectively, in polymorph (I). In the crystal, weak C—H⋯π inter­actions are observed.
doi:10.1107/S1600536809054956
PMCID: PMC2979778  PMID: 21579708
13.  2-Chloro-N-(3-chloro­phen­yl)benzamide 
In the structure of the the title compound, C13H9Cl2NO, the N—H and C=O groups are mutually trans. Furthermore, the conformation of the C=O group is syn to the ortho-chloro group in the benzoyl ring, while the N—H bond is anti to the meta-chloro group in the aniline ring. The amide group forms dihedral angles of 89.11 (19) and 22.58 (37)°, respectively, with the benzoyl and aniline rings, while the benzoyl and aniline rings form a dihedral angle of 69.74 (14)°. The mol­ecules are linked into infinite chains through inter­molecular N—H⋯O hydrogen bonds.
doi:10.1107/S1600536808018102
PMCID: PMC2961659  PMID: 21202929
14.  A new polymorph of N-(2-{N′-[(1E)-2-hy­droxy­benzyl­idene]hydrazinecarbon­yl}phen­yl)benzamide 
The title compound, C21H17N3O3, is a new polymorph of an already published structure [Shashidhar et al. (2006 ▶). Acta Cryst. E62, o4473–o4475]. The previously reported structure crystallizes in the monoclinic space group C2/c, whereas the structure reported here is in the tetra­gonal space group I41/a. The bond lengths and angles are similar in both structures. The mol­ecule adopts an extended conformation via intra­molecular N—H⋯O and O—H⋯N hydrogen bonds; the terminal phenyl ring and the hy­droxy­lphenyl ring are twisted with respect to the central benzene ring by 44.43 (7) and 21.99 (8)°, respectively. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, weak C—H⋯O hydrogen bonds and weak C—H⋯π inter­actions into a three-dimensional supra­molecular network.
doi:10.1107/S1600536814010010
PMCID: PMC4051047  PMID: 24940232
15.  4-Chloro-N-(2,6-dichloro­phen­yl)benzamide 
The title compound, C13H8Cl3NO, crystallizes with four mol­ecules in the asymmetric unit. In the mol­ecular structure, the conformations of the central amide –CONH group show a wide range of dihedral angles with respect to the attached aromatic rings (benzoyl and anilino). The dihedral angles between the amide group and the benzoyl ring are 8.1 (3), 4.3 (3), 27.8 (1) and 32.7 (2)° in the four mol­ecules. The amide group is twisted out of the plane of the anilino ring, as shown by the dihedral angles of 85.4 (1), 74.3 (1), 88.1 (1) and 77.6 (1)° in the four mol­ecules. The aromatic rings are oriented at dihedral angles of 86.6 (1), 78.0 (1), 60.3 (1) and 69.8 (1)° in the four mol­ecules. The crystal structure is stabilized via inter­molecular N—H⋯O hydrogen bonds, aromatic aromatic inter­actions, short Cl⋯Cl contacts and C—H⋯Cl hydrogen bonds. Inter­molecular hydrogen bonds connect the mol­ecules into two distinct chains running along the c axis of the crystal. One mol­ecule forms an inversion dimer in which the main inter­actions are π–π stacking [centroid–centroid distances = 3.749 (1) and 3.760 (1) Å] and a short Cl⋯Cl contact of 3.408 (1) Å.
doi:10.1107/S160053680902265X
PMCID: PMC2969447  PMID: 21582902
16.  A second ortho­rhom­bic polymorph of 2-(pyridin-4-ylmeth­oxy)phenol 
The crystal structure of the title compound, C12H11NO2, represents a new ortho­rhom­bic polymorph II of the previously reported ortho­rhom­bic form I [Zhang et al. (2009 ▶) Acta Cryst. E65, o3160]. In polymorph II, the six-membered rings form a dihedral angle of 13.8 (1)° [71.6 (1)° in I], and O—H⋯N hydrogen bonds link mol­ecules into chains along [100], whereas the crystal structure of I features hydrogen-bonded centrosymmetric dimers.
doi:10.1107/S1600536812014067
PMCID: PMC3344498  PMID: 22590260
17.  2-Chloro-N-(2,6-dichloro­phen­yl)benzamide 
In the structure of the title compound (N26DCP2CBA), C13H8Cl3NO, the conformations of N—H and C=O bonds in the amide group are trans to each other, similar to that observed in N-(2,6-dichloro­phen­yl)benzamide, 2-chloro-N-phenyl­benzamide, 2-chloro-N-(2-chloro­phen­yl)benzamide and 2-chloro-N-(2,3-dichloro­phen­yl)benzamide with similar bond parameters. Furthermore, the position of the amide O atom is syn to the ortho-chloro group in the benzoyl ring. The amide group makes a dihedral angle of 59.8 (1)° with the benzoyl ring, while the benzoyl and aniline rings make a dihedral angle of 8.1 (2)°. The mol­ecules are linked by N—H⋯O hydrogen bonds into infinite chains running along the b axis.
doi:10.1107/S1600536808021223
PMCID: PMC2962123  PMID: 21203205
18.  Second monoclinic polymorph of 4-[(1H-benzimidazol-1-yl)meth­yl]benzoic acid 
Recently, we reported the first monoclinic [Kuai & Cheng (2011). Acta Cryst., E67, o2787] and the ortho­rhom­bic polymorph [Kuai & Cheng (2011). Acta Cryst., E67, o3014] of the title compound, C15H12N2O2. Another monoclinic polymorph was obtained accidentally by the hydro­thermal reaction of the title compound with manganese chloride in the presence of potassium hydroxide at 413 K. The asymmetric unit consists of four independent mol­ecules. In the crystal, O—H⋯N hydrogen bonds link the independent mol­ecules into four separate chains parallel to the b axis.
doi:10.1107/S1600536811045983
PMCID: PMC3238873  PMID: 22199726
19.  Dicyclo­hexyl­ammonium thio­cyanate: monoclinic polymorph 
The title salt, C12H24N+·NCS−, represents a monoclinic polymorph of the previously reported ortho­rhom­bic form [Khawar Rauf et al. (2008 ▶). Acta Cryst. E64, o366]. Two independent formula units comprise the asymmetric unit with the major difference in their mol­ecular structures relating to the relative dispositions of the cyclo­hexyl rings [dihedral angles = 79.88 (6) and 67.72 (5)°]. Further, the independent anions form distinctive patterns of hydrogen-bonding inter­actions, i.e. 2 × N—H⋯N versus N—H⋯N and N—H⋯S. The resulting supra­molecular architecture is a supra­molecular chain along the c axis based on a square-wave topology.
doi:10.1107/S1600536811040001
PMCID: PMC3247581  PMID: 22219886
20.  N-(4-Chloro­phen­yl)-2-methyl­benzamide 
In the structure of the title compound, C14H12ClNO, the N—H and C=O bonds are trans to each other. Furthermore, the C=O bond is syn to the ortho-methyl group in the benzoyl ring, similar to what is observed in 2-methyl-N-(4-methyl­phen­yl)benzamide and 2-methyl-N-phenyl­benzamide. The amide linkage (–NHCO–) makes dihedral angles of 36.9 (7) and 46.4 (5)° with the aniline and benzoyl rings, respectively, while the dihedral angle between the benzoyl and aniline rings is 83.1 (1)°. In the crystal structure, mol­ecules form chains running along the b axis through N—H⋯O hydrogen bonds.
doi:10.1107/S1600536809002633
PMCID: PMC2968167  PMID: 21581984
21.  An ortho­rhom­bic polymorph of 3,4-di­amino­benzo­nitrile 
The title compound, C7H7N3, is an ortho­rhom­bic polymorph that crystallizes in the space group Pca21. The previously reported monoclinic form [Geiger & Parsons (2013 ▶) Acta Cryst. E69, o452] crystallizes in the space group P21/c (Z = 4). In the crystal, two independent HN—H⋯N C hydrogen bonds link the mol­ecules into chains along the a-glide plane. Two further independent HN—H⋯NH2 hydrogen bonds join the chains, forming a three-dimensional network.
doi:10.1107/S1600536813008489
PMCID: PMC3647854  PMID: 23723820
22.  2-Chloro-N-(3-methyl­phen­yl)benzamide 
In the structure of the title compound, C14H12ClNO, the ortho-Cl atom in the benzoyl ring is positioned syn to the C=O bond, while the meta-methyl group in the aniline ring is positioned anti to the N—H bond. The amide group forms dihedral angles of 60.1 (1) and 22.0 (1)°, respectively, with the benzoyl and aniline rings, while the angle between these rings is 38.7 (1)°. The crystal structure is stabilized by N—H⋯O hydrogen bonds, which give rise to infinite chains running along the c axis.
doi:10.1107/S1600536812005739
PMCID: PMC3295494  PMID: 22412605
23.  A monoclinic polymorph of (R,R)-4,4′-dibromo-2,2′-[cyclo­hexane-1,2-diylbis(nitrilo­methanylyl­idene)]diphenol 
The title compound, C20H20Br2N2O2, a tetra­dentate Schiff base, is the enanti­omerically pure R,R-diastereomer of four possible stereoisomers. The mol­ecular structure reveals two strong intra­molecular O—H⋯N hydrogen bonds between the hy­droxy O atom and the imino N atom, which each generate S(6) rings. In the crystal, mol­ecules are stacked in columns along the a axis; when viewed down the b axis, successive columns are stacked in the opposite direction. The structure reported herein is the monoclinic polymorph of the previously reported ortho­rhom­bic form [Yi & Hu (2009 ▶). Acta Cryst. E65, o2643], in which the complete mol­ecule is generated by a crystallographic twofold axis.
doi:10.1107/S1600536812016376
PMCID: PMC3344566  PMID: 22590328
24.  N-(2,6-Dichloro­phen­yl)benzamide 
The conformation of the N—H and C=O bonds in the structure of the title compound (N26DCPBA), C13H9Cl2NO, are anti to each other, similar to that observed in N-phenyl­benzamide (NPBA), N-(2-chloro­phen­yl)benzamide (N2CPBA), N-(2,3-dichloro­phen­yl)benzamide (N23DCPBA) and other benzanilides. The asymmetric unit of N26DCPBA contains two mol­ecules. The bond parameters in N26DCPBA are similar to those in NPBA, N2CPBA, N23DCPBA and other benzanilides. The amide group, –NHCO–, makes a dihedral angle of 30.8 (1)° with the benzoyl ring in the first mol­ecule and 35.1 (2)° in the second mol­ecule of the asymmetric unit. The dihedral angle between the two benzene rings (benzoyl and aniline) is 56.8 (1)° in the first mol­ecule and 59.1 (1)° in the second mol­ecule. N—H⋯O hydrogen bonds give rise to infinite chains running along the a axis of the crystal structure.
doi:10.1107/S160053680800305X
PMCID: PMC2960174  PMID: 21201559
25.  N-(3,5-Dichloro­phen­yl)benzamide 
The conformation of the H—N—C=O unit in the title compound, C13H9Cl2NO, is trans, similar to the conformation observed in N-(3-chloro­phen­yl)benzamide, N-(2,3-dichloro­phen­yl)benzamide, N-(2,4-dichloro­phen­yl)benzamide, N-(2,6-dichloro­phen­yl)benzamide and N-(3,4-dichloro­phen­yl)benz­amide. The amide group makes dihedral angles of 14.3 (8) and 44.4 (4)° with the benzoyl and aniline rings, respectively, while the benzoyl and aniline rings form a dihedral angle of 58.3 (1)°. The mol­ecules are linked by N—H⋯O hydrogen bonds into infinite chains running along the c axis.
doi:10.1107/S1600536808017017
PMCID: PMC2961786  PMID: 21202878

Results 1-25 (357197)