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141.
Muhammad Imran Malik Tooba Mahboob Shakil Ahmed 《Analytical and bioanalytical chemistry》2014,406(25):6311-6317
Poly(2-vinylpyridine)s (P2VPs) are important polymers with extensive applications in modern day material science. P2VP is an exceptional case for liquid chromatography because of certain polar interactions with most of the stationary phases. In the present study, we established the critical adsorption point (CAP) of P2VP for the first time. The effectiveness of the method is demonstrated by analyses of blends and block copolymers of P2VP and PMMA. The CAP of PMMA is established for determination of molar mass of P2VP component of above mentioned blends and block copolymers. The methods successfully demonstrate the separation of both types of homopolymers from the rest of the samples in conjunction with the determination of molar mass distribution of noncritical block or component. Graphical Abstract
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142.
Muhammad Tariq Saqib Ali Muhammad Nawaz Tahir Nasir Khalid Jafir Hussain Shirazi 《Journal of the Iranian Chemical Society》2014,11(3):839-846
A series of six organotin(IV) carboxylates [Me2SnL2] (1), [n-Bu2SnL2] (2), [n-Oct2SnL2] (3), [Me3SnL] (4), n-Bu3SnL (5) and [Ph3SnL] (6), where L = 3-(4-cyanophenyl) acrylic acid have been synthesized and characterized by elemental analysis, FT-IR and NMR (1H, 13C). The complex (4) was also analyzed by single crystal X-ray analysis which showed distorted trigonal bipyramidal geometry with polymeric bridging behavior. The complexes 1–6 were screened for antimicrobial activities and cytotoxicity. The results showed significant activity with few exceptions. The catalytic activity of complexes was assessed in transesterification reaction of Brassica campestris oil (triglycerides) to produce biodiesel (fatty acid methyl esters). The results showed that triorganotin(IV) complexes exhibited good catalytic activity than their di-analogues. 相似文献
143.
Yetkin Gök Senem Akkoç Mehmet Akkurt Muhammad Nawaz Tahir 《Journal of the Iranian Chemical Society》2014,11(6):1767-1774
The nine new heteroaryl-substituted imidazolidinium (1a–c), pyrimidinium (2a–c) and diazepinium (3a–c) salts as N-heterocyclic carbene (NHC) precursors were synthesized in good yields and entirely characterized using elemental analyses and conventional spectroscopic methods. In situ formed complexes from heterocyclic salts (1–3), Pd(OAc)2 and in the presence of KOBu t as a base were tested as catalysts for the Mizoroki–Heck coupling reaction in an aqueous media and very high yields were achieved. 1,3-Di(5-methylthiophen-2-ylmethyl)pyrimidinium hexafluorophosphate salt (2b) was structurally characterized by single-crystal X-ray diffraction. In the 2b compound (C16H21N2S2)+[PF6]?, the terminal thiophene rings are twisted with a dihedral angle of 72.8(3)°. In the pyrimidine ring, the three successive C atoms between the N atoms are disordered over two positions [occupancy ratio 0.753(12):0.247(12)]. In the crystal, neighboring molecules are linked by C–H…F hydrogen bonds, running along the b axis. 相似文献
144.
Zia‐ur‐ Rehman Muhammad Moazzam Naseer Afzal Shah Saqib Ali Auke Meetsma 《Heteroatom Chemistry》2015,26(2):123-133
A fascinating ligand, 4‐formylpiperazinium 4‐formylpiperazine‐1‐carbodithioate (L‐salt) has been reacted with two electronically and sterically different trimethyltin(IV) chloride and triphenyltin(IV) chloride. The complexes 1 and 2 were characterized by elemental analysis, spectroscopic techniques, and X‐ray single crystal analysis. The latter technique confirmed the polymeric and monomeric nature of 1 and 2 , respectively. Both 1 and 2 showed intriguing molecular packing properties in the solid state. However, the packing of 1 is more interesting and unique where one‐dimensional polymer chains self assemble in two‐over‐two saltire‐shaped fashion to provide an overall multilayered structure. The different behavior of L toward two different tin(IV) compounds can be attributed to different electronic and steric environments around metal center. 相似文献
145.
Sadiq‐ur‐Rehman Bilal Ahmad Khan Muhammad Aziz Chaudhary Khawaja Ansar Yasin Saqib Ali 《Heteroatom Chemistry》2015,26(6):417-425
Di‐ and triorganotin(IV) carboxylates, RnSn(OCOC(R2)=CHR1)4–n (n = 2 and 3; R = Me, Et, n‐Bu, Ph; R1 = 3‐CH3O‐4‐OHC6H3, R2 = C6H5) were prepared by reacting the corresponding organotin(IV) chloride with the silver salt of the (E)‐3‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐phenylpropenoic acid. The title compounds were investigated and characterized by elemental analysis, infrared (FT‐IR), multinuclear (1H, 13C, 119Sn) NMR, and mass spectrometry, and possible structures were proposed. The complexes and ligand acid ( HL ) have been evaluated in vitro against various bacteria and fungi. The results noticed during the biocidal activity screenings proved their in vitro biological potential. They were also tested for cytotoxicity. 相似文献
146.
Motivated by the high potential of shape memory alloys (SMA) in several industrial applications, we investigate the material response under cyclic loading. In particular, the focus is set on the modelling of functional fatigue, which results in the deterioration of the specific features of SMA. In fact, functional fatigue restricts SMA in terms of its applicability for real structures and workpieces. This necessitates the development of material models which take this phenomenon into account. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
147.
通过溶剂热反应成功合成出一种新型2D配位聚合物[Tb(1,4-bdc)1.5(phen)(H2O)]n(1)(1,4-H2bdc=对苯二甲酸;phen=菲咯啉)。对其进行了单晶X射线衍射、粉末X射线衍射、红外光谱、元素分析、荧光光谱表征。X射线衍射晶体学分析表明,配合物1结晶于三斜晶系P1空间群,2个相邻的Tb(Ⅲ)离子与4个1,4-bdc2-通过—O—C—O—桥联成双核单元,并进一步通过1,4-bdc2-桥联成二维层状结构。荧光实验证明配合物1可以通过荧光猝灭机制检测Fe3+,Ksv=8.39×103 L·mol-1,检测限为0.017μmol·L-1。 相似文献
148.
Hafiz Muhammad Bilal Ameer Muhammad Faizan Ameer Kaouther Ghachem Muhammad Ali Ahsan Razaq Sami Ullah Khan Muhammad Hamza Lioua Kolsi 《印度化学会志》2022,99(6):100505
The environmental degradation, combined with the continuous depletion of the world's fossil fuel reserves, has forced the search for alternative fuels. This study was performed to investigate the performance of novel biodiesels in the CI engine. The experiments were performed at three different compressions ratios (16:1, 17:1, 18:1) and four loading conditions (25%, 50%, 75%, 100%). Different types of fuels such as jatropha biodiesel (JB), roselle biodiesel (RB), and ternary biodiesel (TB) were prepared and analyzed. The thermal performance of different fuels was analyzed in terms of brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), and exhaust gas temperature (EGT). The emission characteristics such as CO2 emission, NOx emission, and smoke emission were analyzed for all types of fuels. The results of these fuels in the engine were compared with mineral diesel (MD). The BTE was increased with increasing compression ratios and loads for all types of fuels. The BSFC was increased with increasing compression ratios but decreased with increasing loads. The increase in emission of NOx was observed at higher compression ratios and loads. However, the CO2 emission was decreased at higher loads and lower compression ratio. The performance curves achieved with a 20% jatropha biodiesel blend showed results that were approximate to those obtained with pure MD. The comparative analysis between different fuels showed that JB exhibit higher thermal performance as compared to other biodiesels. Therefore, JB can be a better alternative to conventional fuel. 相似文献
149.
Ismail Muhammad Javed Salma Kazim Muhammad Razaq Abdur Hussain Ejaz Attia-tul-Wahab Ali Sajjad Choudhary Muhammad Iqbal 《Chemistry of Natural Compounds》2022,58(4):637-643
Chemistry of Natural Compounds - One new and seven known secondary metabolites 1–8 were isolated, and the nematocidal and insecticidal activities of major compounds from Tanacetum... 相似文献
150.
Two dimensional incompressible steady viscous nano-fluid flow with the impacts of heat generation and porous medium is examined numerically. For this objective Ti6Al4v are taken as nano-particles dispersed in different base fluids such as methanol, engine oil and water. Basically in this study we will compare three different nano-fluids to assess their flow behaviour and thermal performance. The flow model is developed under certain assumptions. The two dimensional non-linear PDEs are converted into non-linear ODEs with suitable transformation. The numerical procedure is adopted to find the results by using Bvp4c technique in MATLAB. Moreover, graphs are generated for various parameters against the temperature and velocity profiles. The fluid behaviour for different parameter is examined on velocity and temperature profile. It is depicted that for high values of volume fraction and curvature parameter nano-particles leads to high velocity and temperature profile. Moreover, velocity profile decreases for permeability parameter, while temperature profile enhances for heat generation parameter. The influence of Nusselt number and skin friction also assessed. The model of entropy generation is also presented. 相似文献