Agricultural waste as a source for the production of silica nanoparticles.

The major interest of the paper deals with the extraction of silica from four natural sources such as rice husk, bamboo leaves, sugarcane bagasse and groundnut shell. These waste materials in large quantities can create a serious environmental problem. Hence, there is a need to adopt proper strategy to reduce the waste. In the present investigation, all the waste materials are subjected to moisture removal in a hot plate and sintered at 900°C for 7 h. The sintered powder was treated with 1 M NaOH to form sodium silicate and then with 6M H2SO4 to precipitate silica. The prepared silica powders were characterized by FT-IR, XRD and SEM-EDAX analysis. The silica recovered from different sources was found to vary between 52% and 78%. Magnesium substituted silica was formed from the groundnut waste and further treatment is required to precipitate silica.

Fungus-mediated biosynthesis and characterization of TiO2 nanoparticles and their activity against pathogenic bacteria.

In the present study, the biosynthesis of TiO(2) nanoparticles (TiO(2) NPs) was achieved by a novel, biodegradable and convenient procedure using Aspergillus flavus as a reducing and capping agent. Research on new, simple, rapid, eco-friendly and cheaper methods has been initiated. TiO(2) NPs were characterized by FTIR, XRD, AFM, SEM and TEM studies. The X-ray diffraction showed the presence of increased amount of TiO(2) NPs which can state by the presence of peaks at rutile peaks at 100, 002, 100 and anatase forms at 101 respectively. SEM observations revealed that synthesized TiO(2) NPs were spherical, oval in shape; individual nanoparticles as well as a few aggregate having the size of 62-74 nm. AFM shows crystallization temperature was seen on the roughness of the surface of TiO(2). The Minimum inhibitory concentration value for the synthesized TiO(2) NPs was found to be 40 µg ml(-1) for Escherichia coli, which was corresponding to the value of well diffusion test. This is the first report on antimicrobial activity of fungus-mediated synthesized TiO(2) NPs, which was proved to be a good novel antibacterial material.

2-Chloro-8-methyl-3-[(pyrimidin-4-yl-oxy)meth-yl]quinoline.

In the title compound, C(15)H(12)ClN(3)O, the quinoline ring system is essentially planar, with a maximum deviation of 0.017 (1) Å. The crystal packing is stabilized by π-π stacking inter-actions between the quinoline rings of adjacent mol-ecule, with a centroid-centroid distance of 3.5913 (8) Å. A weak C-H⋯π contact is also observed between mol-ecules.

1-[(2-Chloro-8-methyl-quinolin-3-yl)-meth-yl]pyridin-2(1H)-one.

In the title compound, C(16)H(13)ClN(2)O, the quinoline ring system is approximately planar [maximum deviation 0.021 (2) Å] and forms a dihedral angle of 85.93 (6)° with the pyridone ring. Inter-molecular C-H⋯O hydrogen bonding, together with weak C-H⋯π and π-π inter-actions [centroid-to-centroid distances 3.5533 (9) and 3.7793 (9) Å], characterize the crystal structure.

N-[4-Chloro-2-(2-chlorobenzoyl)phenyl]acetamide.

In the title compound, C(15)H(11)Cl(2)NO(2), the dihedral angle between the two benzene rings is 74.83 (5)°. The N-bound and terminal benzene rings are inclined at dihedral angles of 4.09 (10) and 78.38 (9)°, respectively, to the mean plane through the acetamide group. Intra-molecular C-H⋯O and N-H⋯O hydrogen bonds both generate S(6) rings.

Methyl 1-methyl-1H-1,2,3-triazole-4-carboxyl-ate.

The title mol-ecule, C(5)H(7)N(3)O(2), has an almost planar conformation, with a maximum deviation of 0.043 (3) Å, except for the methyl H atoms. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into layers parallel to the bc plane. Inter-molecular π-π stacking inter-actions [centroid-centroid distances = 3.685 (2) and 3.697 (2) Å] are observed between the parallel triazole rings.

3-tert-Butyl-1H-isochromene-1-thione.

The title compound, C(13)H(14)OS, crystallizes with two independent mol-ecules in the asymmetric unit. The unit cell contains three voids of 197 Å(3), but the residual electron density (highest peak = 0.24 e Å(-3) and deepest hole = -0.18 e Å(-3)) in the difference Fourier map suggests no solvent mol-ecule occupies this void. The crystal structure is stabilized by π-π inter-actions between the isocoumarin ring systems, with centroid-centroid distances of 3.6793 (14) and 3.6566 (15) Å.

1-[(2-Chloro-7,8-dimethyl-quinolin-3-yl)meth-yl]pyridin-2(1H)-one.

In the title compound, C(17)H(15)ClN(2)O, the quinoline ring system is nearly planar, with a maximum deviation from the mean plane of 0.074 (2) Å, and makes a dihedral angle of 81.03 (7)° with the pyridone ring. The crystal packing is stabilized by π-π stacking inter-actions between the pyridone and benzene rings of the quinoline ring system [centroid-centroid distance = 3.6754 (10) Å]. Furthermore, weak inter-molecular C-H⋯O hydrogen bonding links mol-ecules into supra-molecular chains along [001].

1-[(2-Chloro-7-methyl-3-quinol-yl)meth-yl]pyridin-2(1H)-one.

In the title compound, C(16)H(13)ClN(2)O, the quinoline ring system is essentially planar, with a maximum deviation of 0.021 (2) Å. The pyridone ring is oriented at a dihedral angle of 85.93 (6)° with respect to the quinoline ring system. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules along the b axis. Weak π-π stacking inter-actions [centroid-centroid distances = 3.7218 (9) and 3.6083 (9) Å] are also observed.

Ethyl 6-chloro-2-[(2-chloro-7,8-dimethyl-quinolin-3-yl)meth-oxy]-4-phenyl-quinoline-3-carboxyl-ate.

In the title compound, C(30)H(24)Cl(2)N(2)O(3), the two quinoline ring systems are almost planar [maximum deviations = 0.029 (2) and 0.018 (3) Å] and the dihedral angle between them is 4.17 (8)°. The dihedral angle between the phenyl ring and its attached quinoline ring is 69.06 (13)°. The packing is stabilized by C-H⋯O, C-H⋯N, weak π-π stacking [centroid-centroid distances = 3.7985 (16) and 3.7662 (17) Å] and C-H⋯π inter-actions.

(2-Chloro-8-meth-oxy-quinolin-3-yl)methanol monohydrate.

In the title compound, C(11)H(10)ClNO(2)·H(2)O, the organic mol-ecule is roughly planar (r.m.s. deviation = 0.074 Å). In the crystal structure, molecues are linked by O-H⋯O and O-H⋯N hydrogen bonds and weak C-H⋯π and π-π inter-actions [centroid-centroid distance = 3.578 (3) Å] consolidate the packing. A short Cl⋯O contact [3.147 (3) Å] is also observed.

(2-Chloro-8-methyl-quinolin-3-yl)methanol.

The mol-ecule of title compound, C(11)H(10)ClNO, is close to being planar (r.m.s deviation for the non-H atoms = 0.017 Å). In the crystal, mol-ecules inter-act by way of O-H⋯O hydrogen bonds, generating C(2) chains propagating in [010]. The crystal structure is consolidated by C-H⋯π inter-actions and aromatic π-π stacking inter-actions [centroid-centroid distance = 3.661 (2) Å].

(2-Chloro-6-methyl-quinolin-3-yl)methanol.

The title compound, C(11)H(10)ClNO, is close to being planar (r.m.s deviation for the non-H atoms = 0.026 Å). In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, generating C(2) chains, and weak C-H⋯π inter-actions and aromatic π-π stacking inter-actions [centroid-centroid distance = 3.713 (3) Å] help to consolidate the structure.

3-[(2-Chloro-6-methyl-quinolin-3-yl)meth-yl]quinazolin-4(3H)-one.

In the title mol-ecule, C(19)H(14)ClN(3)O, the quinoline and quinazoline ring systems form a dihedral angle of 80.75 (4)°. In the crystal, the mol-ecules are linked by pairs of C-H⋯N hydrogen bonds into centrosymmetric dimers, generating R(2) (2)(6) ring motifs. The structure is further stabilized by C-H⋯π inter-actions and π-π stacking inter-actions [centroid-centroid distances = 3.7869 (8) and 3.8490 (8) Å].

1-{6-Chloro-2-[(2-chloro-3-quinol-yl)meth-oxy]-4-phenyl-3-quinol-yl}ethan-1-one.

In the title compound, C(27)H(18)Cl(2)N(2)O(2), the 2-chloro-quinoline and 6-chloro-quinoline rings are almost planar, with maximum deviations from their mean planes of 0.072 (1) and 0.044 (1) Å, respectively, for the Cl atoms. The inter-planar angle between these rings is 14.36 (5)°. The inter-planar angle between the 6-chloro-quinoline and phenyl rings is 66.00 (8)°. In the crystal, mol-ecules are inter-linked by weak C-H⋯O, C-H⋯π and π-π stacking [centroid-centroid distances = 3.7453 (10) and 3.7557 (9) Å] inter-actions.

N-[2-(4-Methyl-2-quinol-yl)phen-yl]acetamide: a P1 structure with Z = 4.

The title compound, C(18)H(16)N(2)O, crystallizes in the triclinic space group P1, with four independent mol-ecules in the asymmetric unit wherein two mol-ecules have an irregular -ac, -ac, +ap conformation (ap, antiperiplanar; ac, anticlinal), while the other mol-ecules exhibit a different, +ac, +ac, +ap conformation. The planar (r.m.s. deviation = 0.006 Šin each of the four molecules) quinoline ring systems of the four mol-ecules 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. Intra-molecular N-H⋯N inter-actions occur in all four independent mol-ecules. The crystal packing is stabilized by inter-molecular N-H⋯O and C-H⋯O hydrogen bonds, and are further consolidated by C-H⋯π and π-π stacking inter-actions [centroid-centroid distances = 3.728 (3), 3.722 (3), 3.758 (3) and 3.705 (3) Å].

1-(3,5-Diethyl-1H-pyrazol-1-yl)-3-phenyl-isoquinoline.

In the title mol-ecule, C(22)H(21)N(3), the isoquinoline ring is almost planar [maximum deviation = 0.046 (1) Å] and makes dihedral angles of 52.01 (4) and 14.61 (4)° with the pyrazole and phenyl rings, respectively. The phenyl ring and the pyrazole ring are twisted by 44.20 (6)° with respect to each other. The terminal C atoms of both of the ethyl groups attached to the pyrazole ring are disordered over two sites with occupancy ratios of 0.164 (7):0.836 (7) and 0.447 (16):0.553 (16). A weak intra-molecular C-H⋯N contact may influence the mol-ecular conformation. The crystal structure is stabilized by C-H⋯π contacts involving the phenyl and pyrazole rings, and by π-π stacking inter-actions involving the pyridine and benzene rings [centroid-centroid distance = 3.5972 (10) Å].

2-Chloro-6-methyl-quinoline-3-carbaldehyde.

The quinolinyl fused-ring of the title compound, C(11)H(8)ClNO, is almost planar (r.m.s. deviation = 0.013 Å); the formyl group is slightly bent out of the plane of the fused ring system [C-C-C-O torsion angle = 13.5 (4)°].

2-Chloro-benzo[h]quinoline-3-carbaldehyde.

The benzo[h]quinolinyl fused-ring of the title compound, C(14)H(8)ClNO, is planar (r.m.s. deviation = 0.016 Å); the formyl group is slightly bent out of the plane [the C-C-C-O torsion angle is 10.7 (4)°].

Ethyl 2,6-dichloro-4-phenyl-quinoline-3-carboxyl-ate.

In the title compound, C(18)H(13)Cl(2)NO(2), the quinoline ring system is almost planar (r.m.s. deviation 0.009 Å), and the phenyl and carboxyl-ate planes are twisted away from it by 59.2 (1) and 65.9 (2)°, respectively.