Da-Bin Qin

Regioselective asymmetric stereoablative O-alkylation of α-nitrophosphonates via o-azaxylylene intermediates generated in situ from 3-bromooxindoles

Enantioselective O-alkylation of α-nitrophosphonates was reported for the first time. A series of optically active 3,3-disubstituted oxindoles was prepared via a less exploited organocatalyzed stereoablative reaction of 3-bromooxindoles.

Bis[1-benzyl-3-(4-methyl-phen-yl)imidazol-2-yl-idene]silver(I) hexa-fluorido-phosphate.

The title silver N-heterocyclic carbene compound, [Ag(C17H16N2)2]PF6, crystallizes as a mononuclear salt. The two imidazole rings, which are almost coplanar [maximum deviation from the least squares plane of 0.05 (2) Å], are linked by the Ag atom with a C—Ag—C angle of 178.60 (9)°. In the crystal, C—H⋯F hydrogen bonds, weak π–π interactions [centroid–centroid distances = 3.921 (1) and 3.813 (3) Å] and C—H⋯π interactions lead to a supermolecular structure.

Diacetonitrile­(3-{2-[8-(2-bromo­eth­oxy)-9,10-dioxoanthracen-1-yl­oxy]eth­yl}-1-(2-pyridyl­meth­yl)imidazolium)silver(I) bis­(hexa­fluorido­phosphate)

The title compound, [Ag(C27H23BrN3O4)(CH3CN)2](PF6)2, is a mononuclear salt species in which the silver(I) atom is coordinated by one ligand and two acetonitrile molecules and exhibits a distorted T-shaped coordination. The asymmetric unit contains one independent cation and two independent hexafluoridophosphate anions, one of which is disordered over two positions in a 0.756 (11):0.244 (11) ratio. Weak π–π interactions between the anthraquinone ring systems [centroid–centroid distance = 3.676 (3) Å], intermolecular Ag–π interactions [Cg⋯Ag = 3.405 Å] and C—H⋯π interactions between pairs of adjacent molecules are observed.

N-Phenyl­anthranilic anhydride

The complete molecule of the title compound, C26H20N2O3, is generated by crystallographic twofold symmetry, with the central O atom lying on the rotation axis. The conformation is stabilized by an intramolecular N—H⋯O hydrogen bond. The dihedral angle between the inner and outer aromatic ring planes is 61.12 (5)°.

9,10-Bis{2-[1-(2-pyridylmeth-yl)imidazolium-3-yl]eth-oxy}anthracene bis(hexa-fluoridophosphate).

The cation of the title compound, C36H34N6O2 2+·2PF6 −, lies across a crystallographic inversion centre. The imidazole and pyridine rings form dihedral angles of 82.28 (5)° and 11.87 (7)°, respectively, with the anthracene ring system. The crystal packing is stabilized by π–π interactions between the pyridine ring and the central ring of anthracene, with a ring centroid–centroid distance of 3.684 (3) Å. The PF6 − anion is disordered over three different positions with occupancies of 0.284 (6), 0.354 (8) and 0.362 (9).

1-[3-(Anthracen-9-yl)-5-(pyridin-2-yl)-4,5-dihydro-1H-pyrazol-1-yl]ethanone

In the title compound, C24H19N3O, the pyrazoline ring adopts an envelope conformation with the C atom linking to the pyridine ring as the flap. The mean plane of the pyrazoline ring makes dihedral angles of 85.54 (4) and 81.66 (3)° with the pyridine ring and the anthracene ring system, respectively. In the crystal, molecules are linked by C—H⋯O hydrogen bonds. In addition, weak π–π interactions [centroid–centroid distances = 3.695 (3)–3.850 (7) Å] are observed.

3-[(8-But­oxy­quinolin-2-yl)meth­yl]-1-(pyridin-2-ylmeth­yl)-1H-imidazol-3-ium hexa­fluoridophosphate

In the cation of the title compound, C23H25N4O+·PF6 −, the imidazolium ring make dihedral angles of 87.20 (6) and 79.89 (5)° with the pyridine ring and the quinoline system, respectively. In the crystal, C—H⋯F and C—H⋯N hydrogen bonds are observed.

3-Anilino-N-p-tolyl­benzamide

The title compound, C20H18N2O, which crystallizes with two independent molecules (A and B) in the asymmetric unit, is composed of three aromatic rings (I, II and III). The conformation of the two independent molecules is slightly different. The dihedral angles between the central aromatic ring II and rings I and III are 47.13 (9) and 89.36 (9)°, respectively, for molecule A, and 29.60 (9) and 70.72 (9)°, respectively, for molecule B. Rings I and III are inclined to one another by 86.57 (9)° in molecule A, and 64.59 (10)° in molecule B. The molecular structures are stabilized by intramolecular N—H⋯O hydrogen bonds. In the crystal structure, molecules are linked through intermolecular N—H⋯O hydrogen bonds, forming chains propagating in the [010] direction. In addition, a number of C—H⋯π interactions are observed.

3,3′-Dimethyl-1,1′-(methyl­enedi-p-phenyl­ene)diimidazolium bis­(hexa­fluoro­phosphate)

The title N-heterocyclic carbene compound, C21H22N4 2+·2PF6 −, crystallizes as an inversion twin. There are two independent N-heterocyclic carbene dications (A and B) and four independent hexafluorophosphate anions in the asymmetric unit. The cations are L-shaped with the benzene rings being inclined to one another by 88.82 (16)° in cation A and 87.03 (16)° in cation B. The imidazole rings make dihedral angles of 35.7 (2) and 32.83 (18)° with the attached benzene rings in cation A, and 30.14 (19) and 31.96 (18)° in cation B. In the crystal, the cations are linked via C—H⋯F hydrogen bonds, forming a three-dimensional network. π–π interactions involving the benzene and imidazole rings [centroid–centroid distances = 3.602 (2) and 3.723 (2) Å] and C—H⋯π interactions are also present.

1-{2-[2-(1H-Benzimidazol-1-yl)eth-oxy]eth-yl}-1H-benzimidazol-3-ium hexa-fluoro-phosphate.

In the title salt, C18H19N4O+·PF6 −, the dihedral angle between the benzimidazolium and benzimidazole ring systems is 16.24 (2)°. In the cation, a π–π interaction is observed between the imidazolium ring and the benzene ring of the benzimidazole ring system [centroid–centroid distance = 3.5713 (11) Å]. The PF6 − ion is disordered over two sites, with occupancies of 0.895 (2) and 0.105 (2). In the crystal structure, pairs of N—H⋯N hydrogen bonds link the cations, forming centrosymmetric dimers. The dimers are linked via π–π interactions [centroid–centroid distance = 3.5606 (11) Å]. In addition, C—H⋯F hydrogen bonds are observed.