Papers by Muhammad Danish
Acta Crystallographica Section E Crystallographic Communications, 2015
In the title compound, C9H11NO5S, the O=S=O plane of the sulfonyl group is twisted at a dihedral ... more In the title compound, C9H11NO5S, the O=S=O plane of the sulfonyl group is twisted at a dihedral angle of 52.54 (16)° with respect to the benzene ring. The dihedral angle between the carboxylic acid group and the benzene ring is 49.91 (16)°. In the crystal, C—H...O, N—H...O and O—H...O hydrogen bonds link the molecules into (001) sheets.
Acta Crystallographica Section C Crystal Structure Communications
Acta Crystallographica Section E Crystallographic Communications, 2015
In the title compound, C14H17N3O3, the dihedral angle between the benzene ring and the five-membe... more In the title compound, C14H17N3O3, the dihedral angle between the benzene ring and the five-membered dihydropyrazole ring is 52.26 (9)°. The ethyl ester group is approximately planar (r.m.s. deviation 0.0568 Å) and subtends an angle 67.73 (8)° to the pyrazole ring. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with anR22(10) ring motif. Weaker C—H...O contacts link these dimers into a three-dimensional network of molecules stacked along thea-axis direction. Offset π–π stacking interactions between the benzene rings [centroid-to-centroid distance = 3.8832 (12) Å] further stabilize the crystal packing.
Journal of Chemical Education, 1995
Many times during the sample preparation for NMR studies solid samples form suspension due to low... more Many times during the sample preparation for NMR studies solid samples form suspension due to low solubility in duterated solvents. We developed a technique to get rid of this problem easily. Just tighten the lid on the NMR sample tube and seal it with parafilm. Invert the tube and centrifuge it for five minutes. Now the suspension is collected in
Journal of Chemistry, 2013
This study was designed to evaluate the antioxidant potential ofLoranthus pulverulentus. Stem bar... more This study was designed to evaluate the antioxidant potential ofLoranthus pulverulentus. Stem bark, leaves, and seeds ofLoranthus pulverulentuswere extracted in methanol:water (90 : 10) and partitioned with n-hexane, chloroform, ethyl acetate, and n-butanol successively using partition chromatography. Total phenolic contents and antioxidant potential were checked using standard protocols. Total phenolic contents of all extracts were determined, using Folin–Ciocalteu reagent, and ranged between 151 ± 2.1 and 396 ± 1.6 for stem bark, 137 ± 0.9 and 430 ± 2.2 for, and 39 ± 0.6 and 231 ± 1.7 for seeds. The antioxidant potential of extracts was evaluated; namely, DPPH, FRAP, and total antioxidant models. The ethyl acetate extract of stem-bark, leaves, and seeds showed the highest activity in DPPH (94.5 ± 2.1%, 96.30 ± 0.9%, and 92.30 ± 1.1%, IC5015.9 ± 0.5 μg, 14.5 ± 0.8, and 102.7 ± 1.3, resp.), FRAP (7.7 ± 0.6, 7.5 ± 0.7 and 6.6 ± 0.7, resp.), and total antioxidant (0.95 ± 0.09, 1.19 ± ...
Acta Crystallographica Section C Crystal Structure Communications, 1997
... MN Tahir, D. Ülkü, M. Danish, S. Ali, A. Badshah and M. Mazhar ... The Sn--O bond lengths are... more ... MN Tahir, D. Ülkü, M. Danish, S. Ali, A. Badshah and M. Mazhar ... The Sn--O bond lengths are significantly different [Snl--O1 2.153(2) and Snl-- 02 2.495 (2),4,]. The C--O bonds within the carboxyl group also have different lengths. ...
Acta Crystallographica Section C Crystal Structure Communications, 1997
ABSTRACT The crystal structure of [Sn(C2H5)(2)(C7H5O2S)(2)] contains discrete molecules in which ... more ABSTRACT The crystal structure of [Sn(C2H5)(2)(C7H5O2S)(2)] contains discrete molecules in which hexa-coordinated Sn atoms lie on twofold axes. The Sn atom is coordinated asymmetrically to two symmetry-related propenoates, with Sn-O distances of 2.105 (5) and 2.538 (6) Angstrom, and to two ethyl groups, with Sn-C distances of 2.155 (2) Angstrom.
Analytical Sciences: X-ray Structure Analysis Online, 2007
The title compound, C14H11N3O, is an effect of catalyzing behavior of dibenzyltin dichloride. It ... more The title compound, C14H11N3O, is an effect of catalyzing behavior of dibenzyltin dichloride. It belongs to the space group P21/n with cell parameters a = 13.5510(12), b = 5.8720(13), c = 15.4890(12)Å and β = 109.912(3)˚. The intermolecular C-H•O hydrogen bonds are dominantly effective in stabilizing the crystal structure. The N-H•N intermolecular hydrogen bonds link the molecules.
Polyhedron, 1995
The synthesis and spectroscopic characterization (tH, 13C, 119Sn NMR, ll9mSn M6ssbauer and mass s... more The synthesis and spectroscopic characterization (tH, 13C, 119Sn NMR, ll9mSn M6ssbauer and mass spectrometry) of a series of organotin carboxylates of m-methyl transcinnamic acid are described. Different literature methods have been successfully applied for the qualitative structural characterization of these compounds. Triorganotin carboxylates are essentially penta-coordinate in the solid state with R3SnO 2 geometry, while tetracoordinate in non-coordinating solvents. Diorganotin carboxylates with a 1 : 2 molar ratio (R2SnO : 2HOCOR') are hexa-coordinate as solids, while there is an equilibrium between hexa-and penta-coordinated states in solution. Moreover, compounds with a 1 : 1 molar ratio (R2SnO:HOCOR'), adopt a characteristic tetraorganodicarboxylato distannoxane structural mode. Interesting results have been observed for tricyclohexyltin derivatives and stannoxanes. 2D NMR has been employed for the assignments of protons of high-spin systems.
Main Group Metal Chemistry, 1996
Synthesis and multinuclear studies of stannoxane of 3-(2-thiophenyl)-2-propenoic acid have been p... more Synthesis and multinuclear studies of stannoxane of 3-(2-thiophenyl)-2-propenoic acid have been performed. Crystal structure of bis[(3-(2-thiophenyl)-2-propenoato)dimethyltin]oxide is presented. The unit cell is triclinic with space group PI, Z=2. Out of 3050 reflections, 2273 were unique with I > 2σ(7). The thiophene ring SI, C5, C6, C7 and C4 is staggered with an other ring containing Sla, C5a, C6a, C7a and C4a which describes the ring twist under the impact of radiation leading to disorder in the structural refinement. Of particular interest is the mode of 05 interactions. It forms an intra-molecular contact with Sn atom of the same molecule while an inter-molecular interaction with Sn atom of a symmetry related unit in the lattice. These intra-and inter-molecular interactions result in the formation of an infinite one dimensional polymer.
Heteroatom Chemistry, 1997
Organotin compounds with the general formula R 2 (X)SnL (where RסMe, Et, n-Bu, Ph; Lסthe tran... more Organotin compounds with the general formula R 2 (X)SnL (where RסMe, Et, n-Bu, Ph; Lסthe trans-3-(2-furanyl)-2-propenoate anion or the trans-3-(3methylphenyl)-2-propenoate anion; and XסCl) have been prepared by redistribution reactions between the R 2 SnL 2 and R 2 SnX 2 compounds. These compounds were characterized by elemental analyses and various spectroscopic techniques such as 1 H, 13 C, 119 Sn NMR, Mass, Mö ssbauer, and IR spectroscopies. On the basis of these spectroscopic data, it is suggested that these compounds adopt the cis-R 2 (X)SnO 2 geometry.
Heteroatom Chemistry, 1996
The mechanism of the fluxional process occurring in dimeric tetraorganodicarboxylato stannoxanes ... more The mechanism of the fluxional process occurring in dimeric tetraorganodicarboxylato stannoxanes is pre-sented on the basis of multinuclear NMR studies car-ried out in noncoordinating solvents. This fluxional process is a consequence of rapid migration of car-boxylate ...
Geochimica et Cosmochimica Acta, 2011
The western Himalaya, Karakoram and Tibet are known to be heterogeneous with regard to Pb isotope... more The western Himalaya, Karakoram and Tibet are known to be heterogeneous with regard to Pb isotope compositions in K-feldspars, which allows this system to be used as a sediment provenance tool. We used secondary ion mass spectrometry to measure the isotopic character of silt and sand-sized grains from the modern Sutlej and Chenab Rivers, together with Thar Desert sands, in order to constrain their origin. The rivers show a clear Himalayan provenance, contrasting with grains from the Indus Suture Zone, but with overlap to known Karakoram compositions. The desert dunes commonly show 207 Pb/ 204 Pb and 206 Pb/ 204 Pb values that are much higher than those seen in the rivers, most consistent with erosion from Nanga Parbat. This implies at least some origin from the trunk Indus, probably reworked by summer monsoon winds from the SW, a hypothesis supported by bulk Nd and U-Pb zircon dating. Further data collected from Holocene and Pleistocene sands shows that filled and abandoned channels on the western edge of the Thar Desert were sourced from Himalayan rivers before and at 6-8 ka, but that after that time the proportion of high isotopic ratio grains rose, indicating increased contribution from the Thar Desert dunes prior to $4.5 ka when flow ceased entirely. This may be linked to climatic drying, northward expansion of the Thar Desert, or changes in drainage style including regional capture, channel abandonment, or active local Thar tributaries. Our data further show a Himalayan river channel east of the present Indus, close to the delta, in the Nara River valley during the middle Holocene. While this cannot be distinguished from the Indus it is not heavily contaminated by reworking from the desert. The Pb system shows some use as a provenance tool, but is not effective at demonstrating whether these Nara sediments represent a Ghaggar-Hakra stream independent from the Indus. Our study highlights an important role for eolian reworking of floodplain sediments in arid rivers such as the Indus.
Acta Crystallographica Section E Structure Reports Online, 2012
In the title compound, C 14 H 21 NO 4 S, the O-SO angle is 120.06 (11) , with the S atom adopting... more In the title compound, C 14 H 21 NO 4 S, the O-SO angle is 120.06 (11) , with the S atom adopting a distorted tetrahedral geometry. In the crystal, N-HÁ Á ÁO hydrogen bonds connect the molecules along the a axis, generating an infinite chain. The disordered C atoms of the isobutyl group were refined with the CC distances restrained to 1.52 (1) Å and the occupancy ratio refined to 0.504 (3):0.496 (3).
Acta Crystallographica Section E Structure Reports Online, 2009
Acta Crystallographica Section E Structure Reports Online, 2011
Acta Crystallographica Section E Structure Reports Online, 2009
Acta Crystallographica Section E Structure Reports Online, 2009
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Papers by Muhammad Danish