5,7-Dimethoxy-2-phenyl-4H-chromen-4-one

The asymmetric unit of the title compound, C17H14O4, contains two independent molecules which differ in the relative orientations of the phenyl rings with repect to the essentially planar [maximum deviations of 0.029 (2) and 0.050 (2) angstrom in the two molecules] chromene fused-ring system, forming dihedral angles of 10.3 (5) and 30.86 (5)degrees in the two molecules. The crystal structure is stabilized by weak C-H center dot center dot center dot O and C-H center dot center dot center dot pi interactions, and pi-pi stacking interactions.

Chlorinated Hypoelectronic Dimetallaborane Clusters: Synthesis, Characterization, and Electronic Structures of (eta(5)-C5Me5W)(2)B5HnClm (n=7, m=2 and n=8, m=1)

Pyrolysis of (eta(5)-C5Me5WH3)B4H8, 1, in the presence of excess BHCl2 center dot SMe2 in toluene at 100 degrees C led to the isolation of (eta(5)-C5Me5W)(2)B5H9, 2, and B-Cl inserted (eta(5)-C5Me5W)(2)B5H8Cl, 3, and (eta(5)-C5Me5W)(2)B5H7Cl2, (four isomers). All the Chlorinated tungstaboranes were isolated as red and air and moisture sensitive solids. These new compounds have been characterized in solution by H-1, B-11, C-13 NMR, and the structural types were unequivocally established by crystallographic analysis of compounds 3, 4, and 7. Density functional theory (DFT) calculations were carded out on the model molecules of 3-7 to elucidate the actual electronic structures of these chlorinated species. On grounds of DFT calculations we demonstrated the role of transition metals, bridging hydrogens, and the effect of electrophilic substitution of hydrogens at B-H vertices of metallaborane structures.

Ethyl 2-acetyl-3-(4-chloroanilino)butanoate

The title compound, C14H18ClNO3, adopts an extended conformation, with all of the main chain torsion angles associated with the ester and amino groups trans. In the crystal, inversion dimers linked by pairs of N-H center dot center dot center dot O hydrogen bonds are observed.

N-{1-[(3-Bromopropyl)aminocarbonyl]ethyl}-2-(2-nitrobenzenesulfonamido)propionamide

In the title compound, C15H21BrN4O6S, all three NH groups are involved in intermolecular N-H center dot center dot center dot O interactions which, together with two intermolecular C-H center dot center dot center dot O contacts, lead to a continuous antiparallel beta-sheet structure. There are no pi-pi interactions between molecules, and two C-H center dot center dot center dot pi interactions primarily govern the linkage between sheets.

Ethyl 3-oxo-2-[(4-sulfamoylphenyl)hydrazono]butyrate

In the title compound, C12H15N3O5S, an intramolecular N-H center dot center dot center dot O hydrogen bond between the hydrazine unit and one of the carbonyl groups may influence the molecular conformation. In the crystal structure, intermolecular N-H center dot center dot center dot O hydrogen bonds, including one which is bifurcated, link the molecules into a two-dimensional network.

1,2,3-Trifluorobenzene

In the title compound, C6H3F3, weak electrostatic and dispersive forces between C(delta+)-F(delta-) and H(delta+)-C(delta-) groups are at the borderline of the hydrogen-bond phenomenon and are poorly directional and further deformed in the presence of pi-pi stacking interactions. The molecule lies on a twofold rotation axis. In the crystal structure, one-dimensional tapes are formed via two antidromic C-H center dot center dot center dot F hydrogen bonds. These tapes are, in turn, connected into corrugated two-dimensional sheets by bifurcated C-H center dot center dot center dot F hydrogen bonds. Packing in the third dimension is furnished by pi-pi stacking interactions with a centroid-centroid distance of 3.6362 (14) angstrom.

2-Chloro-3-hydroxymethyl-7,8-dimethylquinoline

All non-H atoms of the title compound, C12H12ClNO, are co-planar (r.m.s. deviation = 0.055 angstrom). The hydroxy H atom is disordered over two positions of equal occupancy. In the crystal, molecules are linked by O-H center dot center dot center dot O hydrogen bonds, generating zigzag chains running along the b axis.

[B4O9H2] Cyclic Borate Units as the Building Unit in a Family of Zinc Borate Structures

A solvothermal reaction of ZnO, boric acid (B(OH)(3)), and aliphatic airlines in a water-pyridine mixture gave four zinc borate phases of different dimensionalities: [Zn(B4O8H2)(C3H10N2)], I (one-dimensional); [Zn(B4O8H2)(C3H10N2)] H2O, II (two-dimensional); [Zn(B5O10H3)(C10H24N4)]center dot H2O, III (two-dimensional): and [Zn-2(B8O15H2)(C3H10N2)(2)], IV (three-dimensional). The structures are formed by the connectivity involving polyborate chains and layers with Zn2+ species. In all the compounds, the amine molecules act its file ligand binding either the same or different zn centers. The formation of two different structures, II and IV, from the same amine by varying the reaction time is noteworthy. Transformation studies on II indicate that the formation of IV. from II, is facile and has been investigated for the first time. Two of file compounds, I and III, exhibit activity for second-order nonlinear optical behavior. The UV exposure of the sample indicates the absorption of all the UV radiation suggesting that the zinc borate compounds could be exploited for UV-blocking applications. The compounds have been characterized by powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, UV-vis, photoluminescence, and NMR studies.

Ethyl 2-acetyl-3-(4-bromoanilino)butanoate

The title compound, C14H18BrNO3, adopts an extended conformation, with all of the main-chain torsion angles associated with the ester and amino groups close to trans. In the crystal, inversion dimers linked by pairs of N-H center dot center dot center dot O hydrogen bonds are observed.

(2-Chlorobenzo[h]quinolin-3-yl)methanol

In the title molecule, C14H10ClNO, all non-H atoms are coplanar (r.m.s deviation = 0.0266 angstrom). In the crystal, symmetry-related molecules are hydrogen bonded via intermolecular O-H center dot center dot center dot O interactions, forming chains along the b axis.

1-[(2-Chloro-7,8-dimethylquinolin-3-yl)methyl]pyridin-2(1H)-one

In the title compound, C17H15ClN2O, the quinoline ring system is nearly planar, with a maximum deviation from the mean plane of 0.074 (2) angstrom, and makes a dihedral angle of 81.03 (7)degrees with the pyridone ring. The crystal packing is stabilized by pi-pi stacking interactions between the pyridone and benzene rings of the quinoline ring system [centroid-centroid distance = 3.6754 (10) angstrom]. Furthermore, weak intermolecular C-H center dot center dot center dot O hydrogen bonding links molecules into supramolecular chains along [001].

Photocytotoxic Lanthanum(III) and Gadolinium(III) Complexes of Phenanthroline Bases Showing Light-Induced DNA Cleavage Activity

Lanthanide complexes of formulation [La(B)(2)(NO3)(3)] (1-3) and [Gd(B)(2)(NO3)(3)] (4-6), where B is a N,N-donor phenanthroline base, namely, 1,10-phenanthroline (phen in 1, 4),dipyrido[3,2-d2',3'-f]quinoxaline (dpq in 2,5) and dipyrido[3,2-a2',3'-c]phenazine (dppz in 3, 6), have been prepared, characterized from physicochemical data, and their photoinduced DNA and protein cleavage activity studied The photocytotoxicity of the dppz complexes 3 and 6 has been studied using HeLa cancer cells. The complexes exhibitligand centered bands in the UV region The dppz complexes show thelowest energy band at 380 nm in N,N-dimethylformamide (DMF) The La(III)complexes are diamagnetic. The Gd(III) complexes (4-6) have magneticmoments that correspond to seven unpaired electrons The complexes are1(.)1 electrolytic in aqueous DMF The dpq and dppz complexes in DMFshow ligand-based reductions. The complexes display moderate binding propensity to calf thymus DNA giving binding constant values in the range of 5.7 x 10(4)-5.8 x 10(5) M-1 with a relative order. 3, 6 (dppz)> 2, 5 (dpq) > 1, 4 (phen) The binding data suggest DNA surface and/or groove binding nature of the complexes. The complexes do not show any hydrolytic cleavage of plasmid supercoiled pUC19 DNA. The dpq and dppz complexes efficiently cleave SC DNA to its nicked circular form onexposure to UV-A light of 365 nm at nanomolar complex concentration. Mechanistic studies reveal the involvement of singlet oxygen (O-1(2)) and hydroxyl radical (HO center dot) as the cleavage active species.The complexes show binding propensity to bovine serum albumin (BSA)protein giving K-BSA values of similar to 10(5) M-1. The dppz complexes 3 and 6 show BSA protein cleavage activity in UV-A light of 365 nm The dppz complexes 3 and 6 exhibit significant photocytotoxicity in HeLa cells giving respective IC50 values of 341 nM and 573 nM in UV-A light of 365 nm for an exposure time of 15 min (IC50 > 100 mu M in dark for both the complexes) Control experiments show significant dark and phototoxicity of the dppz base alone (IC50 = 413 nM in light with 4 h incubation in dark and 116 mu M in dark with 24 h incubation). A significant decrease in the dark toxicity of the dppz base is observedon binding to the lanthanide ions while retaining similar phototoxicity.

4-(5-Phenyl-1,2,4-triazolo[3,4-a]isoquinolin--yl)benzonitrile

In the title molecule, C23H14N4, the triazoloisoquinoline ring system is nearly planar, with an r.m.s. deviation of 0.038 (2) angstrom and a maximum deviation of -0.030 (2) angstrom from the mean plane of the triazole ring C atom which is bonded to the benzene ring. The benzene and phenyl rings are twisted by 57.65 (8) and 53.60 (9)degrees, respectively, with respect to the mean plane of the triazoloisoquinoline ring system. In the crystal structure, molecules are linked by weak aromatic pi-pi interactions [centroid-centroid distance = 3.8074 (12) angstrom]. In addition, the crystal structure exhibits a nonclassical intermolecular C-H center dot center dot center dot N hydrogen bond.

1-[(2-Chloro-3-quinolyl)methyl]indoline-2,3-dione

In the title compound, C18H11ClN2O2, the isatin and 2-chloro-3-methylquinoline units are both almost planar, with r.m.s.deviations of 0.0075 and 0.0086 angstrom, respectively, and the dihedral angle between the mean planes of the two units is 83.13 (7)degrees. In the crystal, a weak intermolecular C-H center dot center dot center dot O interaction links the molecules into chains along the c axis.

2-Chloro-8-methyl-3-[(pyrimidin-4-yloxy)methyl]quinoline

In the title compound, C15H12ClN3O, the quinoline ring system is essentially planar, with a maximum deviation of 0.017 (1) angstrom. The crystal packing is stabilized by pi-pi stacking interactions between the quinoline rings of adjacent molecule, with a centroid-centroid distance of 3.5913 (8) angstrom. Aweak C-H center dot center dot center dot pi contact is also observed between molecules.