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1.  N,N′-Di-8-quinolyl-2,2′-(o-phenyl­ene­di­oxy)diacetamide 
In the title compound, C28H22N4O4, the mol­ecule lies on a crystallographic twofold axis. The quinoline ring is essentially planar (give max or rms deviation 0.0186 Å), and the dihedral angle between the quinoline ring and the central benzene ring is 19.1 (4)°. Intra­molecular N—H⋯(N,O) and C—H⋯O hydrogen bonds contribute to the formation of the roughly planar configuration. The crystal packing is stabilized by inter­molecular C—H⋯O hydrogen bonds, and weak π–π inter­actions between the pyridine rings and central benzene rings of the neighboring mol­ecules [centroid–centroid separation = 3.9009 (6) Å].
doi:10.1107/S1600536809041312
PMCID: PMC2971241  PMID: 21578434
2.  Crystal structure of 2-[4-(4-chloro­phen­yl)-1-(4-meth­oxy­phen­yl)-2-oxoazetidin-3-yl]benzo[de]iso­quinoline-1,3-dione dimethyl sulfoxide monosolvate 
In the title solvated compound, C28H19N2O4·C2H6OS, the central β-lactam ring is almost planar (r.m.s. deviation = 0.002 Å). It makes dihedral angles of 1.92 (11), 83.23 (12) and 74.90 (10)° with the meth­oxy- and chloro­phenyl rings and the ring plane of the 1H-benzo[de]iso­quinoline-1,3(2H)-dione group [maximum deviation = 0.089 (1)], respectively. An intra­molecular C—H⋯O hydrogen bond closes an S(6) ring and helps to establish the near coplanarity of the β-lactam and meth­oxy­benzene rings. In the crystal, the components are linked by C—H⋯O hydrogen bonds, C—H⋯π inter­actions and aromatic π–π stacking inter­actions [centroid-to-centroid distances = 3.6166 (10) and 3.7159 (10) Å], resulting in a three-dimensional network, The dimethyl sulfoxide solvent mol­ecule is disordered over two sets of sites in a 0.847 (2):0.153 (2) ratio.
doi:10.1107/S2056989015001425
PMCID: PMC4384601  PMID: 25878867
crystal structure; β-lactam ring; 1H-benzo[de]iso­quinoline-1,3(2H)-dione group; disorder; azetidin-2-ones
3.  5-(4-Chloro­phen­yl)-3-(2,4-dimethyl­thiazol-5-yl)-1,2,4-triazolo[3,4-a]isoquinoline 
In the title mol­ecule, C21H15ClN4S, the triazoloisoquinoline ring system is approximately planar, with an r.m.s. deviation of 0.054 (2) Å and a maximum deviation of 0.098 (2) Å from the mean plane for the triazole ring C atom that is bonded to the thia­zole ring. The thia­zole and benzene rings are twisted by 66.36 (7) and 56.32 (7)°, respectively, with respect to the mean plane of the triazoloisoquinoline ring system. In the crystal structure, mol­ecules are linked by inter­molecular C—H⋯N inter­actions along the a axis. The mol­ecular conformation is stabilized by a weak intra­molecular π–π inter­action involving the thia­zole and benzene rings, with a centroid–centroid distance of 3.6546 (11) Å. In addition, two other intermolecular π–π stacking inter­actions are observed, between the triazole and benzene rings and between the dihydro­pyridine and benzene rings [centroid–centroid distances = 3.6489 (11) and 3.5967 (10) Å, respectively].
doi:10.1107/S160053681001278X
PMCID: PMC2979146  PMID: 21579114
4.  8-{[3-(3-Meth­oxy­phen­yl)-1,2,4-oxa­diazol-5-yl]meth­oxy}quinoline monohydrate 
In the title hydrate, C19H15N3O3·H2O, the three aromatic groups in the quinoline derivative are close to coplanar: the central oxa­diazole fragment makes dihedral angles of 15.7 (2)° with the benzene ring and 5.30 (14)° with the quinoline ring system. In the crystal, the organic mol­ecules are connected with water mol­ecules by pairs of O—H⋯N hydrogen bonds involving the quinoline and oxa­diazole N atoms. The mol­ecules form stacks along the a axis, neighboring mol­ecules within each stack being related by inversion and the shortest distance between the centroids of the oxa­diazole and pyridine rings being 3.500 (2) Å. Mol­ecules from neighboring stacks are linked by weak C—H⋯O hydrogen bonds, forming a three-dimensional structure.
doi:10.1107/S1600536813010271
PMCID: PMC3648286  PMID: 23723906
5.  6-[3-(p-Tolyl­sulfonyl­amino)­prop­yl]diquino­thia­zine1  
In the title mol­ecule {systematic name: N-[3-(diquino[3,2-b;2′,3′-e][1,4]thia­zin-6-yl)prop­yl]-4-methyl­benzene­sulfon­amide}, C28H24N4O2S2, the penta­cyclic system is relatively planar [maximum deviation from the mean plane = 0.242 (1) Å]. The dihedral angle between two quinoline ring systems is 8.23 (2)° and that between the two halves of the 1,4-thia­zine ring is 5.68 (3)°. The conformation adopted by the 3-(p-tolyl­sulfonyl­amino)­propyl substituent allows for the formation of an intra­molecular N—H⋯N hydrogen bond and places the benzene ring of this substituent above one of the quinoline fragments of the penta­cyclic system. In the crystal, mol­ecules are arranged via π–π stacking inter­actions into (0-11) layers [centroid–centroid distances = 3.981 (1)–4.320 (1) Å for the rings in the penta­cyclic system and 3.645 (1) Å for the tolyl benzene rings]. In addition, mol­ecules are involved in weak C—H⋯O, which connect the layers, and C—H⋯S hydrogen bonds. The title compound shows promising anti­cancer activity against renal cancer cell line UO-31.
doi:10.1107/S1600536813013950
PMCID: PMC3685109  PMID: 23795128
6.  Bis(8-hy­droxy-2-methyl­quinolinium) bis­(pyridine-2,6-dicarboxyl­ato)cuprate(II) methanol monosolvate monohydrate 
The title compound, (C10H10NO)2[Cu(C7H3NO4)2]·CH3OH·H2O was prepared by the reaction of copper(II) nitrate hexa­hydrate, 8-hy­droxy-2-methyl­quinoline, and pyridine-2,6-dicarb­oxy­lic acid in a 1:2:2 molar ratio in an aqueous solution. The geometry of the resulting CuN2O4 coordination can be described as distorted octa­hedral. In the crystal, there are several inter­molecular O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds. An intra­molecular N—H⋯O hydrogen bond occurs in one of the cations. Considerable π–π stacking inter­actions are also observed between the aromatic rings of the cations, with centroid–centroid distances of 3.4567 (13), 3.5342 (14), 3.6941 (14) and 3.4568 (13) Å. These non-covalent inter­actions connect the components, forming a three-dimensional supra­molecular structure.
doi:10.1107/S160053681100674X
PMCID: PMC3052026  PMID: 21522300
7.  Crystal structures of di­chlorido­palladium(II), -platinum(II) and -rhodium(III) complexes containing 8-(di­phenyl­phosphan­yl)quinoline 
8-(Di­phenyl­phosphan­yl)quinoline (Ph2Pqn) acts as an asymmetric bidentate ligand to form a planar five-membered chelate ring in the di­chlorido­palladium(II) and -platinum(II) complexes, (SP-4)-[MCl2(Ph2Pqn)] (M = Pd or Pt), as well as in the di­chlorido­rhodium(III) complex, (OC-6-32)-[RhCl2(Ph2Pqn)2]PF6.
The crystal structures of di­chlorido­palladium(II), -platinum(II) and -rhodium(III) complexes containing 8-(di­phenyl­phosphan­yl)quinoline, (SP-4)-[PdCl2(C21H16NP)], (1) [systematic name: di­chlor­ido­(8-di­phenyl­phosphanyl­quinoline)­palladium(II)], (SP-4)-[PtCl2(C21H16NP)]·CH2Cl2, (2) [systematic name: di­chlorido­(8-di­phenyl­phos­phanyl­quinoline)­platinum(II) dichlorometh­ane monosolvate], and (OC-6–32)-[RhCl2(C21H16NP)2]PF6·0.5CH2Cl2·0.5CH3OH, (3) [systematic name: cis-di­chlor­ido­bis­(8-di­phenyl­phosphanyl­quinoline)­rhodium(III) hexa­fluorido­phos­phate di­chloro­methane/­methanol hemisolvate] are reported. In these complexes, the phosphanyl­quinoline acts as a bidentate ligand, forming a planar asymmetrical five-membered chelate ring. The palladium(II) and platinum(II) complex mol­ecules in (1) and (2), respectively, show a typical square-planar coordination geometry and form a dimeric structure through an inter­molecular π–π stacking inter­action between the quinolyl rings. The centroid–centroid distances between the stacked six-membered rings in (1) and (2) are 3.633 (2) and 3.644 (2) Å, respectively. The cationic rhodium(III) complex in (3) has a cis(Cl),cis(P),cis(N) (OC-6–32) configuration of the ligands, in which two kinds of intra­molecular π–π stacking inter­actions are observed: between the quinolyl and phenyl rings and between two phenyl rings, the centroid–centroid distances being 3.458 (2) and 3.717 (2) Å, respectively. The PF6 − anion in (3) is rotationally disordered, the site occupancies of each F atom being 0.613 (14) and 0.387 (14). The CH2Cl2 and CH3OH solvent mol­ecules are also disordered and equal site occupancies of 0.5 are assumed.
doi:10.1107/S2056989015006076
PMCID: PMC4420072  PMID: 25995852
crystal structure; 8-quinolylphos­phane; stacking inter­action; geometrical structure; trans influence
8.  Ethyl 8-meth­oxy-4-oxo-1,4-di­hydro­quinoline-3-carboxyl­ate 
In the title compound, C13H13NO4, the asymmetric unit contains four independent mol­ecules, each exhibiting an intra­molecular N—H⋯O hydrogen bond. The ethyl group in one of the four mol­ecules is disordered, with a refined occupancy ratio of 0.295 (16):0.705 (16). A face-to-face stacking inter­action is found between the benzene rings of the quinoline units of two of the mol­ecules [centroid–centroid distance = 3.541 (2) Å], which are sandwiched by the other two mol­ecules through N—H⋯O hydrogen bonding. In the crystal, the sandwiched mol­ecules are assembled via stacking inter­actions along the b-axis direction with their translation-symmetry equivalents [centroid–centroid distance = 3.529 (2) Å], and are further linked through N—H⋯O hydrogen bonding. The other two mol­ecules are linked via stacking inter­actions with their inversion-symmetry equivalents [centroid–centroid distances = 3.512 (3) and 3.716 (4) Å] and via N—H⋯O hydrogen bonding.
doi:10.1107/S1600536814011854
PMCID: PMC4051033  PMID: 24940288
9.  N-[2-(4-Methyl-2-quinol­yl)phen­yl]acetamide: a P1 structure with Z = 4 
The title compound, C18H16N2O, crystallizes in the triclinic space group P1, with four independent mol­ecules in the asymmetric unit wherein two mol­ecules have an irregular -ac, -ac, +ap conformation (ap, antiperiplanar; ac, anticlinal), while the other mol­ecules exhibit a different, +ac, +ac, +ap conformation. The planar (r.m.s. deviation = 0.006 Å in each of the four molecules) quinoline ring systems of the four mol­ecules are oriented at dihedral angles of 32.8 (2), 33.4 (2), 31.7 (2) and 32.3 (2)° with respect to the benzene rings. Intra­molecular N—H⋯N inter­actions occur in all four independent mol­ecules. The crystal packing is stabilized by inter­molecular N—H⋯O and C—H⋯O hydrogen bonds, and are further consolidated by C—H⋯π and π–π stacking inter­actions [centroid–centroid distances = 3.728 (3), 3.722 (3), 3.758 (3) and 3.705 (3) Å].
doi:10.1107/S1600536810027650
PMCID: PMC3007511  PMID: 21588351
10.  Crystal structure of bis­(2,2′-bi­pyridine)[N′-(quino­lin-2-ylmethylidene)pyridine-2-carbohydrazide]ruthenium(II) bis(tetra­fluorido­borate) di­chloro­methane tris­olvate 
2-Picolinoylhydrazone with a 2-quinolyl substituent on the imine-C atom coordinates in the neutral Z form to a RuII(bpy)2 fragment via the amide-O and imine-N atoms, affording a planar five-membered chelate ring, and its hydrazone N—H group forms an intra­molecular hydrogen bond with the uncoordinating quinoline-N atom.
The title compound, [Ru(C10H8N2)2(C16H12N4O)](BF4)2·3CH2Cl2, crystallizes with one complex dication, two BF4 − counter-anions and three di­chloro­methane solvent mol­ecules in the asymmetric unit. The central RuII atom adopts a distorted octa­hedral coordination sphere with two 2,2′-bi­pyridine (bpy) and one quinoline-2-carbaldehyde (pyridine-2-carbon­yl)hydrazone (HL) ligand. The hydrazone ligand has a Z form and coordinates to the RuII atom via the amide-O and imine-N atoms, affording a planar five-membered chelate ring, while its pyridine-N and quinoline-N donor atoms in the substituents are non-coordinating. The hydrazone N—H group forms an intra­molecular hydrogen bond with the quinoline-N atom. In the crystal, the quinoline moiety of HL shows the shortest π–π stacking inter­action with the pyridine substituent of HL in a neighbouring complex, the centroid-to-centroid distance being 3.793 (3) Å.
doi:10.1107/S2056989015000122
PMCID: PMC4384626  PMID: 25878803
crystal structure; picolinolylhydrazone; intra­molecular hydrogen bonding; ruthenium(II) polypyridyl complex.
11.  (E)-3-[4-(Dimethyl­amino)­phen­yl]-1-(2-methyl-4-phenyl­quinolin-3-yl)prop-2-en-1-one 0.7-hydrate 
In the title compound, C27H24N2O·0.7H2O, the quinoline ring system is approximately planar, with a maximum deviation of 0.011 (1) Å, and forms dihedral angles of 74.70 (4) and 80.14 (4)° with the phenyl and benzene rings, respectively. In the crystal, the mol­ecules are linked to the water mol­ecules via inter­molecular O—H⋯N hydrogen bonds and further stabilized by C—H⋯π inter­actions involving the centroid of the benzene ring of the quinoline group. This benzene ring is observed to form a π–π inter­action with an adjacent pyridine ring [centroid–centroid distance = 3.7120 (6) Å].
doi:10.1107/S1600536811019088
PMCID: PMC3120557  PMID: 21754884
12.  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.
doi:10.1107/S1600536811005411
PMCID: PMC3052057  PMID: 21522403
13.  (E)-1-[(Diphenyl­amino)meth­yl]-4-(4-fluoro­benzyl­ideneamino)-3-[1-(4-iso­butyl­phen­yl)eth­yl]-1H-1,2,4-triazole-5(4H)-thione 
The title 1,2,4-triazole compound, C34H34FN5S, exists in a trans configuration with respect to the acyclic C=N bond. An intra­molecular C—H⋯S contact generates a six-membered ring, producing an S(6) ring motif. The essentially planar 1,2,4-triazole ring [maximum deviation 0.008 (1) Å] is inclined at 21.43 (5) and 83.03 (6)°, respectively, with respect to the flurophenyl unit and the isobutyl-substituted benzene ring. The diphenyl­amino unit is not planar, as indicated by the dihedral angle between two phenyl rings of 76.95 (6)°. The crystal structure is stabilized by C—H⋯π and π–π [centroid–centroid distance = 3.6169 (6) Å] inter­actions; mol­ecules are stacked along the b axis.
doi:10.1107/S1600536809052039
PMCID: PMC2980061  PMID: 21580181
14.  Ethyl 7-oxo-7H-benzo[de]imidazo[5,1-a]iso­quinoline-11-carboxyl­ate–tri­fluoro­acetic acid (1/1) 
The structure of the title tri­fluoro­acetic acid adduct, C17H12N2O3·C2HF3O2, contains a tri­fluoro­acetic acid mol­ecule hydrogen bonded to the imine N atom of the imidazole ring of a nearly planar four-fused-ring system (r.m.s. deviatiation = 0.013 Å). The carb­oxy­lic acid group of the triflouro­acetic acid mol­ecule is twisted with respect to the mean plane of the four-fused-ring sytem by 75.9 (2)°. A short intra­molecular C—H⋯O hydrogen bond occurs. In the crystal, the adduct mol­ecules are arranged into stacks along the b axis via π–π inter­actions between imidazole rings and between imidazole and one of the benzene rings [centroid–centroid distances 3.352 (2) and 3.485 (2) Å, respectively]. Molecules are linked via C—H⋯O hydrogen bonds, forming an alternating polymeric head-to-head/tail-to-tail stepped chain approximately along the a-axis direction and tilted on an axis bisecting the b and c axes.
doi:10.1107/S1600536813013834
PMCID: PMC3685112  PMID: 23795131
15.  Crystal structure of 2-[(3S,4S)-4-(anthracen-9-yl)-1-(4-meth­oxy­phen­yl)-2-oxoazetidin-3-yl]-2-aza-2H-phenalene-1,3-dione unknown solvate 
The central β-lactam ring of the title compound, C36H24N2O4, is almost planar (r.m.s. deviation = 0.003 Å) and makes dihedral angles of 17.17 (19), 89.76 (17) and 78.44 (17)° with the benzene ring, the anthracene ring (r.m.s. deviation = 0.003 Å) and the 1H-benzo[de]iso­quinoline-1,3(2H)-dione moiety, which is nearly planar [maximum deviation = 0.098 (2) Å], respectively. The mol­ecular structure is stabilized by an intra­molecular C—H⋯N hydrogen bond. In the crystal, mol­ecules are linked via C—H⋯π and π–π stacking inter­actions [centroid–centroid distances = 3.5270 (19) and 3.779 (2) Å], forming a three-dimensional structure. A region of disordered electron density, probably disordered solvent mol­ecules, was treated with the SQUEEZE procedure in PLATON [Spek (2015 ▶). Acta Cryst. C71, 9–18], which indicated a solvent cavity of 322 Å3 containing approximately 91 electrons. Their formula mass and unit-cell characteristics were not taken into account during the refinement.
doi:10.1107/S2056989015002959
PMCID: PMC4350708  PMID: 25844239
crystal structure; β-lactam ring; 2-azetidinone; anthracene; intra­molecular C—H⋯N hydrogen bond; C—H⋯π inter­actions; π–π stacking inter­actions
16.  6-(3,5-Dimethyl­benz­yl)-5-ethyl-1-[(2-phenyl­eth­oxy)meth­yl]pyrimidine-2,4(1H,3H)dione 
In the title pyrimidine derivative, C24H28N2O3, the uracil unit is essentially planar with an r.m.s. deviation of 0.0054 (1) Å for the eight non-H atoms. The pyrimidine ring is tilted by a dihedral angle of 77.08 (7)° with respect to the aromatic ring of the 3,5-dimethyl­benzyl substituent, whereas it is nearly parallel to the benzene ring of the pheneth­oxy­methyl unit, with a dihedral angle of 8.17 (8)°. An intra­molecular C—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked by a pair of amide–uracil N—H⋯O hydrogen bonds into an inversion R 2 2(8) dimer. These dimers are stacked along the b axis through π–π inter­actions with a centroid–centroid distance of 3.9517 (8) Å. Weak C—H⋯π inter­actions are also present.
doi:10.1107/S1600536812009841
PMCID: PMC3343994  PMID: 22589903
17.  2-(1H-Benzimidazol-2-yl)phenol 
The title mol­ecule, C13H10N2O, is essentially planar, the maximum deviation from the plane of the non-H atoms being 0.016 (2) Å. The imidazole ring makes a dihedral angle of 0.37 (13)° with the attached benzene ring. An intra­molecular O—H⋯N hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked through N—H⋯O hydrogen bonds, forming chains propagating in [001]. The crystal packing also features four π–π stacking inter­actions involving the imidazole ring, fused benzene ring and attached benzene ring system [centroid–centroid distances = 3.6106 (17), 3.6108 (17), 3.6666 (17) and 3.6668 (17) Å].
doi:10.1107/S1600536814001366
PMCID: PMC3998336  PMID: 24764897
18.  Quinoline-2-carbonitrile 
In the title compound, C10H6N2, the mol­ecule is almost planar, with an r.m.s. deviation of 0.014 Å. The dihedral angle between the aromatic rings is 1.28 (16)°. In the crystal, mol­ecules are stacked along the a axis by way of weak aromatic π–π stacking inter­actions between the benzene and pyridine rings of adjacent mol­ecules [centroid–centroid separation = 3.7943 (19) Å].
doi:10.1107/S1600536810033118
PMCID: PMC3008022  PMID: 21588729
19.  Crystal structure of di­chlorido­{N 1-phenyl-N 4-[(quinolin-2-yl-κN)methylidene]benzene-1,4-diamine-κN 4}mercury(II) 
In the mononuclear title complex, [HgCl2(C22H17N3)], synthesized from the quinoline-derived Schiff base N 1-phenyl-N 4-[(quinolin-2-yl)methyl­idene]benzene-1,4-di­amine (PQMBD) and HgCl2, the coordination sphere around the Hg2+ atom is distorted tetra­hedral, comprising two Cl atoms [Hg—Cl = 2.3487 (14) and 2.4490 (15) Å] and two N atom donors from the PQMBD ligand, viz. the quinolyl and the imine N atom [Hg—N = 2.270 (4) and 2.346 (4) Å, respectively]. The dihedral angle between the two benzene rings attached to the amino group is 43.7 (3)°. In the crystal, N—H⋯Cl and C—H⋯Cl hydrogen bonds, as well as π–π stacking inter­actions between one phenyl ring and the pyridine ring of the quinoline moiety of an adjacent mol­ecule [centroid-to-centroid separation = 3.617 (4) Å] are observed, resulting in a three-dimensional network.
doi:10.1107/S2056989015001620
PMCID: PMC4384595  PMID: 25878849
crystal structure; Schiff base; mercury(II) complex; N—H⋯Cl and C—H⋯Cl hydrogen bonding; π–π stacking inter­actions
20.  Diaqua­bis[4-(dimethyl­amino)benzoato](isonicotinamide)zinc(II) 
The mol­ecule of the title ZnII complex, [Zn(C9H10NO2)2(C6H6N2O)(H2O)2], contains two 4-(dimethyl­amino)benzoate (DMAB) ligands, one isonicotinamide (INA) ligand and two water mol­ecules; one of the DMAB ions acts as a bidentate ligand while the other and INA are monodentate ligands. The four O atoms in the equatorial plane around the Zn atom form a distorted square-planar arrangement, while the distorted octa­hedral coordination is completed by the N atom of the INA ligand and the O atom of the water mol­ecule in the axial positions. Intra­molecular C—H⋯O hydrogen bonding results in the formation of a six-membered ring adopting an envelope conformation. The dihedral angle between the carboxyl groups and the adjacent benzene rings are 4.87 (16) and 2.2 (2)°, while the two benzene rings are oriented at a dihedral angle of 65.13 (8)°. The dihedral angle between the benzene and pyridine rings are 11.47 (7) and 74.83 (8)°, respectively. In the crystal structure, inter­molecular O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds link the mol­ecules into a supra­molecular structure. π–π contacts between the pyridine and benzene rings and between the benzene rings [centroid–centroid distances = 3.695 (1) and 3.841 (1) Å, respectively] further stabilize the structure. Weak inter­molecular C—H⋯π inter­actions are also present.
doi:10.1107/S1600536809017620
PMCID: PMC2969605  PMID: 21583016
21.  6-(4-Chloro­phen­yl)-3-methyl­imidazo[2,1-b]thia­zole 
In the title compound, C12H9ClN2S, the imidazo[2,1-b]thia­zole fragment is planar (r.m.s. deviation = 0.003 Å), and the benzene ring is twisted slightly [by 5.65 (6)°] relative to this moiety. In the crystal, mol­ecules are linked by π–π stacking inter­actions into columns along [010]. The mol­ecules within the columns are arranged alternatively by their planar rotation of 180°. Thus, in the columns, there are the two types of π–π stacking inter­actions, namely, (i) between two imidazo[2,1-b]thia­zole fragments [inter­planar distance = 3.351 (2) Å] and (ii) between an imidazo[2,1-b]thia­zole fragment and the phenyl ring [inter­planar distance = 3.410 (5) Å]. There are no short contacts between the columns.
doi:10.1107/S1600536813028833
PMCID: PMC3884351  PMID: 24454127
22.  2,2′-(2,6-Pyridinedi­yl)diquinoline 
The title mol­ecule, C23H15N3, is a terpyridine derivative resulting from the Friedländer annulation between 2,6-diacetyl­pyridine and N,N′-bis­(2-amino­benz­yl)ethyl­ene­di­amine. The asymmetric unit contains one half-mol­ecule, the complete mol­ecule being generated by a mirror plane (one N atom and one C atom lie on the plane). The mol­ecule, although aromatic, is deformed from planarity as a result of crystal packing forces: mol­ecules are stacked along the short c axis, with a short separation of 3.605 (1) Å between the mean planes. The bent mol­ecular shape is reflected in the dihedral angle of 16.10 (5)° between the essentially planar quinoline groups. In addition to π⋯π inter­actions, the crystal structure features weak inter-stack C—H⋯N contacts involving atoms of the central pyridine rings which lie in a common crystallographic m plane.
doi:10.1107/S1600536810006033
PMCID: PMC2983720  PMID: 21580414
23.  2-Hy­droxy-4-(prop-2-yn­yloxy)benz­alde­hyde 
The asymmetric unit of the title compound, C10H8O3, contains two independent mol­ecules, both of which are almost planar (r.m.s deviations for all non-H atoms of 0.044 and 0.053 Å). The dihedral angles between the benzene ring and the prop-1-yne group are 3.47 (1) and 3.07 (1)° in the two mol­ecules, and the prop-1-yne groups adopt extended conformations. In each mol­ecule, an intra­molecular O—H⋯O hydrogen bond involving the OH and aldehyde substituents forms an S(6) ring. In the crystal, mol­ecules are linked into cyclic centrosymmetric dimers via C—H⋯O hydrogen bonds, generating R 2 2(14) ring motifs. The crystal structure is further stabilized by aromatic π–π stacking inter­actions between the benzene rings [centroid–centroid distances = 3.813 (2) and 3.843 (2) Å]
doi:10.1107/S1600536812049598
PMCID: PMC3588223  PMID: 23476445
24.  3,6,8-Tribromo­quinoline 
The title mol­ecule, C9H4Br3N, is almost planar, the maximum deviation being 0.110 (1) Å. The crystal structure is stabilized by weak aromatic π–π inter­actions [centroid–centroid distance = 3.802 (4) Å] between the pyridine and benzene rings of the quinoline ring systems of adjacent mol­ecules.
doi:10.1107/S1600536810045484
PMCID: PMC3011610  PMID: 21589435
25.  Crystal structure of methyl 6-meth­oxy-11-(4-meth­oxy­phen­yl)-16-methyl-14-phenyl-8,12-dioxa-14,15-di­aza­tetra­cyclo­[8.7.0.02,7.013,17]hepta­deca-2(7),3,5,13(17),15-penta­ene-10-carboxyl­ate 
In the title compound, the pyran and pyrone rings adopt slightly distorted half-chair and envelope conformations, respectively. In the crystal, C—H⋯O and π–π inter­actions connect the mol­ecules, forming double layers that stack along the c-axis direction.
In the title compound, C30H28N2O6, the pyran ring adopts a slightly distorted half-chair conformation and the pyrone ring adopts an envelope conformation, with the C atom bearing the carboxyl­ate group as the flap. The pyrazole ring [maximum deviation = 0.002 (2) Å] forms a dihedral angle of 13.2 (1)° with the attached benzene ring. The near-planar atoms of the pyran ring and the pyrazole ring are close to coplanar, the dihedral angles between their mean planes being 6.4 (1)°. The dihedral angle between the pyrone ring and the benzene ring of the chromene unit is 10.7 (1)°. The mol­ecular conformation is stabilized by an intra­molecular C—H⋯O hydrogen bond, which generates an S(6) ring motif. In the crystal, C—H⋯O inter­actions generate supra­molecular chains propagating in [100] and these are connected into double layers that stack along the c-axis direction by weak π–π inter­actions between pyrazole rings [centroid–centroid distance = 3.801 (1) Å].
doi:10.1107/S1600536814017929
PMCID: PMC4186142  PMID: 25309159
crystal structure; conformation; crystal packing; chromene

Results 1-25 (181929)