Hafiz Badaruddin Ahmad

Robustness of thioamide dimer synthon, carbon bonding and thioamide–thioamide stacking in ferrocene-based thiosemicarbazones

The role of thioureas in crystal engineering as robust supramolecular synthons is now recognized, but their analogs, namely thiosemicarbazones/N-iminothioureas, have not received the attention they deserve. A series of five structurally related ferrocene-based thiosemicarbazones 1–5 have been designed, synthesized and crystallographically characterized in order to investigate the prevalence of the thioamide dimer synthon and carbon bonding. All of the compounds have shown a general preference for the adoption of the cis, trans conformation about the central thiourea moiety which is ideal for the formation of a dimeric hydrogen-bonded R22(8) {⋯H–N–CS}2 synthon as the building block. Therefore, this dimeric synthon is observed in all of the compounds, with the methyl group particularly set for playing its supportive stabilization role through C–H⋯S and carbon bonding interactions. Carbon bonding has been observed in all of the compounds except compound 2. The centrosymmetrically arranged thioamide protons present in trans conformation through N–H⋯H–C interactions give rise to the formation of tapes of varying topology in all of the compounds except 3, where a staircase arrangement of dimeric molecules is observed. Another notable feature of the crystal packing of 1–5 is the presence of thioamide–thioamide stacking, which has been observed in all five compounds. The prevalence of the thioamide dimer synthon, carbon bonding, and observation of new thioamide–thioamide stacking interactions indicate a much larger role for this class of compounds as a design element in crystal engineering than anticipated so far.

Glucomannan based polyurethanes: A critical short review of recent advances and future perspectives.

Polysaccharides derived from plants are one of the largest groups of natural compounds that offer potentially beneficial functions and properties. Glucomannan, a bioactive polymer belonged to mannan family of polysaccharides is fairly abundant in nature along with superior gelling and film forming properties. Glucomannan and its derivative with several synthetic polymers are used in a biomedical and food sector especially. Polyurethanes (PUs), a commercially useful class of polymers are extensively used in both industry and everyday life because they retain exceptional properties of both plastics and elastomers. This review addresses the properties and applications of glucomannan based materials with the aim to be explored this less attempted polymer further. Furthermore this paper also presents an overview of current status and perspectives of glucomannan based polyurethane materials.

Synthesis and application of alumina supported nano zero valent zinc as adsorbent for the removal of arsenic and nitrate

Arsenic and nitrate are ill-famed environmental pollutants that are responsible for various lethal diseases. Their removal from drinking water is very essential. In present study, newly synthesized alumina supported nano zerovalent zinc (Alumina-nZvZ) has been tested to remove arsenic and nitrate. Quantitative analyses of arsenic have been performed spectrophotometrically and while that of nitrates ions colorimetrically. After optimization of time and amount of adsorbent, Langmuir, Freundlich and D-R isotherms were applied to determine different parameters for the assessment of adsorption. Synthesized samples were characterized by scanning electron microscopy (SEM) to evaluate porosity and void size. Alumina coated with reduced ZnCl2 showed better efficiency for removal of arsenic and nitrate ions. Kinetics of adsorption was evaluated by using pseudo first-order and pseudo second-order rate equations.

Robustness of a thioamide {⋯H–N–CS}2 synthon: synthesis and the effect of substituents on the formation of layered to cage-like supramolecular networks in coumarin–thiosemicarbazone hybrids

The applications of thioureas in crystal engineering have increased dramatically over the past few years. However, their analogs namely N-imino thioureas/thiosemicarbazones are largely ignored, despite the fact that these can be more interesting with respect to crystal engineering applications due to the presence of an additional N-imino moiety. Aiming to highlight their importance in crystal engineering/supramolecular chemistry, three structurally related coumarin–thiosemicarbazone hybrids (3a–3c) have been designed, synthesized and crystallographically characterized. All of the compounds showed a general preference for the adoption of the cis, trans conformation around the central thiourea moiety; a conformation which is ideal for the formation of a dimeric hydrogen-bonded R22(8){⋯H–N–CS}2 synthon as the building block. Therefore, this dimeric synthon is observed in all of the compounds, regardless of the formation of layered to cage-like three dimensional supramolecular networks depending on different substituents. The prevalence of the cis, trans conformation and the robustness of the thioamide dimer synthon in thiosemicarbazones indicate its potential use as a design element in crystal engineering.

Comparative study on calcium, magnesium and cobalt in diabetic and non diabetic patients (males) in Punjab, Pakistan

Minerals are very important because of their important role in the maintenance of human health. Our study was aimed at assessing and comparing the levels of Ca, Mg and Co in the blood samples of diabetic and non diabetic persons (males) of five age groups between one and 75 years. For this purpose, fasting blood samples of diabetic and non diabetic males of selected age groups were collected. The blood samples were centrifuged to get serum. The mineral elements in the serum were analyzed by using atomic absorption spectrophotometer. The results depicted that the diabetic patients had higher mean concentration of Ca (141.47 ppm), Mg (18 ppm) and Co (0.057 ppm) while non diabetic persons had higher mean concentration of Ca (201.33 ppm), Mg (36.15 ppm) and Co (0.047 ppm). Statistical analysis was done by applying Student’s T-test. It can be concluded from the study that the diabetic patients of all five age groups are deficient of Ca, Mg, whereas the concentration of Co is higher in diabetic patients. In the further study physiological parameters along with other inorganic cofactors are being taken into consideration. Key words : Diabetes mellitus, blood serum, Ca, Mg, Co.

Synthesis of some novel adsorbents for antimicrobial activity and removal of arsenic from drinking water

Arsenic contamination in drinking water is alarming for human beings; especially for those people who use ground water directly for drinking purposes. Attempts were made to design adsorbents for the removal of arsenic. Silica gel has been tested as adsorbent for such removal. After optimizing concentration, time and amount of adsorbent, Langmuir, Freundlich and D-R isotherms are drawn to determine different parameters for the evaluation of arsenic adsorption. Kinetics of adsorption is also calculated by using pseudo first order and pseudo second order rate equations. Zerovalent iron and manganese nanoparticles have been coated on silica gel and efficiency of removal of arsenic have been determined. Iron and manganese particles have been stabilized with polyvinyl alcohol (PVA). Similarly mixtures of iron-silver and manganese-silver nanoparticles have been synthesized by stabilizing with PVA, which show better efficiency than individual nanoparticles of iron and manganese coated silica gel. The newly synthesized adsorbents are very much effective for not only arsenic but also for antimicrobial activity. Concentration of arsenic in water has been determined spectrophotometrically using variamine blue as indicator.