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Search Results: 1 - 10 of 760 matches for " Aminul Huq Mirza "
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Some Novel Schiff Bases from Pyruvic Acid with Amines Containing N & S Donor Atoms: Synthesis, Spectral Studies and X-Ray Crystal Structures  [PDF]
Abdul Azim Jambol, Malai Haniti Sheikh Abdul Hamid, Aminul Huq Mirza, Md. Shafiqul Islam, Mohammad Rezaul Karim
International Journal of Organic Chemistry (IJOC) , 2017, DOI: 10.4236/ijoc.2017.71005
Abstract: Four Schiff bases, from pyruvic acid (1) with amines containing N and S donor atoms, thiocarbohydrazide (2, 61%), 2-methyl-3-thiosemicarbazide (3, 26%), S-benzyldithiocarbazate (4, 51%) and S-n-octyldithiocarbazate (5, 63%) have been successfully synthesized. The conventional method was used and a series of novel linear and cyclic Schiff bases were obtained with or without catalyst. All the Schiff bases were fully characterized by CHN elemental analysis, FT-IR, 1H & 13C NMR, EI-MS and two of the Schiff bases were further characterized by X-ray crystallographic structure analysis. Compound 2 crystallizes in the triclinic space group P-1 and unit cell dimensions are: a = 4.1777(8), b = 5.9538(11), c = 13.458(3) Å, α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0439. Compound 3 crystallizes in the orthorhombic space group P n a 2(1) and unit cell dimensions are: a = 5.5992(2), b = 11.3962(5), c = 10.6473(5), α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0285. Compounds 2 and 3 were obtained as cyclic Schiff bases which are triazine derivatives.
(1E,2E)-1,2-Bis(2,3,4-trimethoxybenzylidene)hydrazine
Malai Haniti S. A. Hamid,Mohammad Akbar Ali,Aminul Huq Mirza,Gan Ai Len
Acta Crystallographica Section E , 2010, DOI: 10.1107/s160053681003518x
Abstract: The title compound, C20H24N2O6, was obtained as an unexpected product by the reaction of hydrazinium dithiocarbazate with 2,3,4-trimethoxybenzaldehyde in refluxing ethanol. The molecule lies on a center of inversion. The crystal packing is stabilized by weak intermolecular C—H...O interactions.
4-(Prop-2-yn-1-yloxy)benzene-1,2-dicarbonitrile
Yee Jan Chin,Ai Ling Tan,Franz L. Wimmer,Aminul Huq Mirza
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812028309
Abstract: In the title compound, C11H6N2O, the complete molecule is generated by the application of crystallographic twofold symmetry (the molecule is disordered about this axis). The prop-2-yn-1-yl residue is slightly twisted out of the plane of the benzene ring [C—O—C—C torsion angle = 173.1 (3)°] and is orientated away from the nitrile substituents. In the crystal, supramolecular chains along the a axis, arising from C—H...N interactions, are connected into stacks along the c axis by π–π interactions between the benzene rings [centroid–centroid distance = 3.6978 (6) = length of the c axis].
4,5-Diphenoxybenzene-1,2-dicarbonitrile
Chuan Ching Foo,Ai Ling Tan,Franz L. Wimmer,Aminul Huq Mirza
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812004060
Abstract: In the title compound, C20H12N2O2, the phenyl and benzene rings are mutually perpendicular, with the dihedral angle between the phenyl rings being 87.92 (16)° and those formed between the phenyl rings and the benzene rings being 73.68 (15) and 84.65 (15)°. Helical supramolecular chains along [010], mediated by C—H...N interactions, are found in the crystal structure.
Generalized Chung-Feller Theorems for Lattice Paths (Thesis)
Aminul Huq
Mathematics , 2009,
Abstract: In this thesis we develop generalized versions of the Chung-Feller theorem for lattice paths constrained in the half plane. The beautiful cycle method which was developed by Devoretzky and Motzkin as a means to prove the ballot problem is modified and applied to generalize the classical Chung-Feller theorem. We use Lagrange inversion to derive the generalized formulas. For the generating function proof we study various ways of decomposing lattice paths. We also show some results related to equidistribution properties in terms of Narayana and Catalan generating functions. We then develop generalized Chung-Feller theorems for Motzkin and Schroeder paths. Finally we study generalized paths and the analogue of the Chung-Feller theorem for them.
Compositions of Graphs Revisited
Aminul Huq
Mathematics , 2007,
Abstract: The idea of graph compositions, which was introduced by A. Knopfmacher and M. E. Mays, generalizes both ordinary compositions of positive integers and partitions of finite sets. In their original paper they developed formulas, generating functions, and recurrence relations for composition counting functions for several families of graphs. Here we show that some of the results involving compositions of bipartite graphs can be derived more easily using exponential generating functions.
Antibacterial Activities of New Schiff Bases and Intermediate Silyl Compounds Synthesized from 5-Substituted-1,10-phenanthroline- 2,9-dialdehyde  [PDF]
Zinia Jaman, Mohammad R. Karim, Korsi Dumenyo, Aminul H. Mirza
Advances in Microbiology (AiM) , 2014, DOI: 10.4236/aim.2014.415124
Abstract: Schiff bases are known to possess anticancer, antibacterial, antifungal, antitubercular, anti-inflammatory, antimicrobial and antimalarial properties. In this paper antibacterial studies against variety of plants and human pathogenic bacteria with eight newly synthesized Schiff bases and several intermediate silyl compounds have been reported. The antibacterial activities of the synthesized compounds were primarily determined by paper disc diffusion method. The minimum inhibitory concentration (MIC) of each compound was also determined by tube dilution process. Seven different human pathogenic bacteria and eighteen different plant pathogenic bacteria were used for the antibacterial activity studies. While all synthesized compounds have shown significant antibacterial activity, one intermediate silyl compound has shown remarkably high antibacterial property. 5-substituted derivatives have shown relatively higher activity than non-substituted compounds. Polar substituent which increases hydrophilicity may have a positive impact on the antibacterial property.
Cooperative learning and peer evaluation: the effect of free riders on team performance and the relationship between course performance and peer evaluation
Molly J. Dingel,Wei Wei,Aminul Huq
The Journal of Scholarship of Teaching and Learning , 2013,
Abstract: Cooperative learning has gained popularity in higher educational settings. However, assigning grades fairly to all team members in a way that rewards them for their contributions remains challenging. In this paper, we ask whether having free riders on a team lowers the quality of submitted work, and whether students’ course performance correlates with peer evaluations. In an introductory sociology course, 101 students were grouped into 20 teams; each team completed a set of three papers. Students were evaluated by the quality of work submitted and peer evaluations. For statistical analysis, we organized the teams into one of three groups, among which we compared average paper grades: group one contained teams with free riders, group two contained teams that may have free riders, and group three contained teams with no free riders. We found that teams with free riders did not submit significantly lower quality work than teams without free riders. We also statistically analyzed the relationship between student course performance and their peer evaluation, and found that students’ performance in the course showed little correlation with their peer evaluations. Our results indicate that free riders do not depress the grades of non-free rider students. We also found that students’ peer evaluations do not correlate with their course performance, a finding which warrants further research.
Synthesis and Structure of Dimeric Copper (I) Complex from Bis[(2,2’)-dimethyl 2,2’-(1,10-phenanthroline-2,9-diyl) bis(methan-1-yl-1-ylidene)-bis(hydrazinecarbo dithioate)]  [PDF]
Md. Arifuzzaman, Tasneem A. Siddiquee, Mohammad R. Karim, Aminul H. Mirza, Mohamad A. Ali
Crystal Structure Theory and Applications (CSTA) , 2013, DOI: 10.4236/csta.2013.24022
Abstract:

Metal complex, bis[(2,2’)-dimethyl 2,2’-(1,10-phenanthrline-2,9-diyl)bis(methan-1-yl-1-ylidene)-bis(hydrazinecarrbo dithioate)copper(I)], was synthesized from the reaction of Schiff base, (2,2’)-dimethyl 2,2’-(1,10-phenanthroline-2,9-diyl)bis(methan-1-yl-1-ylidene)-bis(hydrazinecarbo dithioate) and CuCl2 at reflux condition in methanol. The copper centers of the complex appear to be reduced. This probably was facilitated by in situ oxidative formation of disulfide bond at the uncomplexed ligand moieties. Single crystal X-ray diffraction analysis reveals the distorted tetrahedral geometry around the copper centers. This compound crystallizes in the triclinic space group, P-1 with crystallographic parameters: a = 10.006(3) ?, b = 13.272(3) ?, c = 22.123(6) ?, α = 85.656(6)°, β = 81.656(6)°, γ = 73.097(5)°, μ = 1.223 mm-1

Synthesis and Characterization of New Schiff Bases Formed by Condensation of 2,9-Phenathroline-1,10-dialdehyde with Sulfur-Containing Amines  [PDF]
Md. Arifuzzaman, Mohammad R. Karim, Tasneem A. Siddiquee, Aminul H. Mirza, Mohamad A. Ali
International Journal of Organic Chemistry (IJOC) , 2013, DOI: 10.4236/ijoc.2013.31009
Abstract:

Four new Schiff bases of 1,10-phenanthroline-2,9-dicarboxaldehyde with sulfur-containing amines such as 2-mercaptoaniline, S-alkyl/aryl dithiocarbazates and thiosemicarbazide have been synthesized and characterized by spectroscopic and X-ray crystallographic techniques. A comparative study of the methods of synthesis has been made using both traditional and microwave techniques. A significant reduction in reaction time has been observed when the microwave method was used. In some of the reactions, the yields also increased significantly.

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