Applied Chemistry Research Center

Karachi, Pakistan

Applied Chemistry Research Center

Karachi, Pakistan
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Huang Z.-S.,South China University of Technology | Feng H.-L.,Sun Yat Sen University | Zang X.-F.,South China University of Technology | Iqbal Z.,Applied Chemistry Research Center | And 5 more authors.
Journal of Materials Chemistry A | Year: 2014

Four novel D-π-A metal-free organic dyes DTP1-4 containing a dithienopyrrolobenzothiadiazole (DTPBT) unit were synthesized and applied in dye-sensitized solar cells, where DTPBT was employed as a π-spacer for the first time. The photophysical, electrochemical and photovoltaic properties of the dyes were systematically investigated. The dyes DTP1-4 showed broad absorption spectra and high molar extinction coefficient, resulting in high light harvesting efficiency. In addition, the impacts of donors and the thiophene unit as an additional π-spacer were also studied. The results showed that the dye DTP4 with triphenylamine as the donor exhibited better photovoltaic performance than DTP1-3 with phenothiazine as the donor. The linking position of the thiophene unit to the DTPBT unit significantly influenced the photovoltaic performance. A power conversion efficiency of 7.55% with 1 mM CDCA as the co-adsorbent under simulated AM 1.5 G illumination was reached by the DSSC sensitized by the dye DTP4. These results indicate that the DTPBT-based organic dye is a promising candidate for efficient DSSCs. © the Partner Organisations 2014.

Sultana R.,Applied Chemistry Research Center | Gulzar T.,University of Karachi
JAOCS, Journal of the American Oil Chemists' Society | Year: 2012

Adenanthera pavonina L. is indigenous to Pakistan a proximate analysis of the seeds was carried out and a physicochemical characterization of the seed oil and also a quality evaluation of the oil was made. The hexane-extracted oil content of the seed was 13.32 ± 0.55 %. Analysis showed the seed of A. pavonina contained appreciable amounts of protein (22.14 ± 0.78 %). Fiber and ash contents were 3.13 ± 0.64 and 4.53 ± 0.47 %, respectively. Triacylglycerol (97.51 ± 1.12 %) was predominantly present in the seed oil. Unsaponifiable matter (0.95 ± 0.10 %), peroxide value (11.43 ± 0.51 mequiv./kg) and saponification value (196.3 ± 0.87 mg of KOH/g of oil), iodine value (83.73 ± 1.18 g I/100 g oil) are in close agreement with the edible seed oils. α-Tocopherol was the predominant tocopherol 152.33 ± 13.19 mg/kg of oil while sterols are present at a significant level. Linoleic acid (42.97 ± 0.91 %) and oleic acid (17.89 ± 0.54 %) were found predominantly in unsaturated fatty acids while lignoceric acid (20.24 ± 1.12 %) was the predominant one among the saturated fatty acids. Lignoceric acid is rarely found in seed which is an essential nutrient for growth, development and maintenance of the brain. It is concluded that A. pavonina seeds appear to be a potential source of lignoceric acid and linoleic acid. This oil can be utilized in the manufacture of cosmetics, paints, varnishes, soaps, pharmaceutical products, biodiesel and blended formulations. The high protein content revealed that the seeds could be a good source of energy. © 2012 AOCS.

Shafiq M.,Government College University Lahore | Zia-Ur-Rehman M.,Applied Chemistry Research Center | Khan I.U.,Government College University Lahore | Arshad M.N.,Government College University Lahore | Khan S.A.,Qarshi Research International
Journal of the Chilean Chemical Society | Year: 2011

A convenient ultrasound assisted synthesis of new anti-bacterial N-benzylidene-N'-(1-methyl-2, 2-dioxo-2,3-dihydro-1H-2?6-benzo[c][1,2]thiazin-4- ylidene)-hydrazines from methyl anthranilate is reported. Methyl anthranilate was reacted with methane sulfonyl chloride, followed by N-alkylation and subsequent base catalyzed cyclization. Hydrazinolysis of the cyclized products followed by their ultrasound mediated condensations with different benzaldehydes yielded the title compounds. Some of these compounds showed good anti-bacterial activity against Pseudomonas aeruginosa, Salmonella typhimurium and Staphylococcus aureus.

Arshad M.N.,Government College University Lahore | Khan I.U.,Government College University Lahore | Zia-Ur-Rehman M.,Applied Chemistry Research Center | Shafiq M.,Government College University Lahore
Asian Journal of Chemistry | Year: 2011

An easy synthesis of a series of N-alkyl-1,2-benzothiazine-1,1-dioxide derivatives from commercially available saccharine is reported in order to explore their antioxidant potential. The newly synthesized compounds were characterized by spectroscopic techniques (FT-IR, NMR, MS) and single crystal X-ray diffraction analyses. All the synthesized compounds were screened for their DPPH and FRAP analyses to determine their antioxidant activity.

Ahmad M.,Applied Chemistry Research Center | Ahmad M.,University of Punjab | Siddiqui H.L.,University of Punjab | Zia-ur-Rehman M.,Applied Chemistry Research Center | Parvez M.,University of Calgary
European Journal of Medicinal Chemistry | Year: 2010

A series of potential anti-oxidant and anti-bacterial N′-arylmethylidene-2-(3,4-dimethyl-5,5-dioxidopyrazolo[4,3-c][1,2]benzothiazin-2(4H)-yl)acetohydrazides was synthesized in a facile way starting from commercially available saccharine. 3,4-Dimethyl-2,4-dihydropyrazolo[4,3-c][1,2]benzothiazine 5,5-dioxide was obtained by ring expansion of 2-(2-oxopropyl)-1,2-benzisothiazol-3(2H)-one 1,1-dioxide followed by N-methylation and cyclization with hydrazine using ultrasonic irradiation. N-alkylation of the cyclized product with methyl chloroacetate followed by its reaction with hydrazine and subsequent ultrasonic mediated condensations with aromatic aldehydes afforded the title compounds. All the synthesized compounds were subjected to the preliminary evaluation for their anti-oxidant and anti-bacterial activities. © 2009 Elsevier Masson SAS. All rights reserved.

Ahmad N.,University of Punjab | Zia-Ur-Rehman M.,Applied Chemistry Research Center | Siddiqui H.L.,University of Punjab | Ullah M.F.,University of Punjab | Parvez M.,University of Calgary
European Journal of Medicinal Chemistry | Year: 2011

A series of 4-hydroxy-N′-[1-phenylethylidene]-2H/2-methyl, 1,2-benzothiazine-3-carbohydrazide 1,1-dioxides was synthesized from commercially available sodium saccharin. Base catalyzed ring expansion of methyl (1,1-dioxido-3-oxo-1,2-benzisothiazol-2(3H)-yl)acetate followed by ultrasound mediated hydrazinolysis and subsequent reaction with 1-phenylethanones under the influence of microwaves yielded the title compounds. Besides, microwave assisted synthesis of 1,4-dihydropyrazolo[4,3-c][1,2]benzothiazin-3-ol 5,5-dioxide and 4-methyl-1,4-dihydropyrazolo[4,3-c][1,2]benzothiazin-3-ol 5,5-dioxide is also discussed. Most of the synthesized compounds were found to possess moderate to significant anti-microbial (anti-bacterial and anti-fungal) activities. It is found that compounds with greater lipophilicity (N-methyl analogues) possessed higher anti-bacterial activities. © 2011 Elsevier Masson SAS.

Ahmed K.,Applied Chemistry Research Center | Nizami S.S.,University of Karachi | Raza N.Z.,Applied Chemistry Research Center
Journal of Industrial and Engineering Chemistry | Year: 2013

This paper discusses an extensive overview of characterization of marble sludge (MS) with carbon black (CB) and rice husk derived silica (RHS) in hybrid natural rubber (NR) composite. Cure characteristics, mechanical and swelling properties of MS/CB and MS/RHS hybrid NR composite were investigated. As CB and RHS content increases in weight ratio of MS/CB and MS/RHS a decrease in scorch and cure time and increase in the torque, tensile, tear, modulus, hardness, crosslink density were observed, while elongation at break and swelling coefficient decreased. The aging behavior of corresponding hybrid composite materials was also evaluated at two different temperatures. © 2012 The Korean Society of Industrial and Engineering Chemistry.

Zang X.-F.,South China University of Technology | Huang Z.-S.,South China University of Technology | Wu H.-L.,South China University of Technology | Iqbal Z.,Applied Chemistry Research Center | And 3 more authors.
Journal of Power Sources | Year: 2014

Three types of novel diketopyrrolopyrrole-based organic dyes (Type 1-3) with phenyl unit as an additional π-bridge and triphenylamine or phenothiazine as the donors are designed and synthesized for dye-sensitized solar cells (DSSCs). Type 1 dyes incorporating the donor segment directly to the diketopyrrolopyrrole core lead to a better electron communication between the donor and acceptor, allowing an efficient charge transfer process. Type 2 and Type 3 dyes with a phenyl unit between the donor and diketopyrrolopyrrole unit show lower delocalization of the excited state. Compared with Type 3 dyes, Type 1 dyes exhibit higher conjugated skeleton co planarity and shorter electron transfer distance from the donor to TiO2, resulting in the red-shifts of absorption and promotion of electron injection, respectively. Moreover, the dyes with triphenylamine as the donor display better UV performance and lower trend of aggregation than the dyes with phenothiazine as the donor. Finally, a power conversion efficiency of 8% with chenodeoxycholic acid as the co-absorbant for the DSSC based on Type 1 dyes with triphenylamine is achieved. The results reveal that the donors, the position and number of phenyl unit of the dyes significantly influence the photovoltaic performance of their DSSCs. © 2014 Elsevier B.V. All rights reserved.

Shabbir A.,University of Health Sciences, Lahore | Shabbir A.,COMSATS Institute of Information Technology | Shahzad M.,University of Health Sciences, Lahore | Ali A.,University of Health Sciences, Lahore | Zia-Ur-Rehman M.,Applied Chemistry Research Center
European Journal of Pharmacology | Year: 2014

Benzothiazine and pyrazole derivatives possess anti-inflammatory properties. Previously, synergism of both heterocyclic moieties into a single nucleus has shown to produce biologically active N′-arylmethylidene-2-(3, 4-dimethyl-5,5-dioxidopyrazolo(4,3-c)(1,2)benzothiazin-2(4H)yl)acetohydrazides) compound. Present study investigates the anti-arthritic effect and possible mechanism of 2,4-dihydroxyphenyl derivative (DHP) in Freund¢s complete adjuvant-induced arthritic rat model. Ankle joint histopathology was performed with Hematoxylin & Eosin staining, while serum C-reactive protein (CRP) levels were measured by agglutination method. mRNA expression levels and protein levels of proinflammatory markers were measured by real time reverse transcription polymerase chain reaction and Enzyme linked immunosorbent assay (ELISA), respectively. in vitro Concanavalin A (ConA)-stimulated splenocyte proliferation was also measured by ELISA reader. DHP treatment reduced the macroscopic arthritic score, CRP levels, synovial inflammation, bone erosion and pannus formation. Levels of cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), Prostaglandin-E2 (PGE2), and 5-lipoxygenase (5-LOX), were significantly attenuated by DHP. It also significantly decreased the levels of toll-like receptor 2, nuclear factor-kappaB (NF-KB), and tissue necrosis factor-α (TNF-α) and non-significantly elevated interleukin-4 (IL-4) levels. Piroxicam, used as reference drug, significantly reduced the levels of COX-1, COX-2, PGE2, NF-KB, and TNF-α, but did not show reduction in 5-LOX and toll-like receptor 2 levels. However piroxicam significantly enhanced the levels of IL-4. Both DHP and piroxicam suppressed ConA-stimulated splenocyte proliferation. DHP normalized all altered hematological markers and did not show any sign of hepatotoxicity or nephrotoxicity as determined by alanine transaminase, aspartate aminotransferase, urea, and creatinine levels. Results showed that DHP possesses significant anti-arthritic activity which may be attributed to its immunomodulatory and anti-inflammatory effects. © 2014 Elsevier B.V.

Parveen N.,Quaid-i-Azam University | Nazir R.,Applied Chemistry Research Center | Mazhar M.,University of Malaya
Journal of Thermal Analysis and Calorimetry | Year: 2013

Tris(bipyridine)nickel(II) chloride (1) and bis(bipyridine)nickel(II) chloride (2) pyrolize at heating rate of 50 C/min to a maximum of 450 C for 24 h under an inert atmosphere of flowing argon gas, to yield size-controlled nickel nanoparticles. Thermogravimetric studies of the complexes (1) and (2) and GC-MS analysis of the trapped volatile matter evolved during thermal degradation of the complexes indicate their clean decomposition pathway to zero-valent nickel. Both heating rate and argon gas flow rate affect purity, particle size, and shape of the particles. X-ray powder diffractometry and atomic force microscopy showed the formation of face-centered cubic (fcc) structured nickel particles having particle size in the range of 3.5-5.0 nm. Magnetic susceptibility measurements suggest nickel nanoparticles to be ferromagnetic in nature characterized by particle size-dependent Curie temperature and high coercivity that is comparable to the bulk iron. © 2012 Akadémiai Kiadó, Budapest, Hungary.

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