Switchable N-pyridyl-thiourea/urea acyclic and macrocyclic compounds as anion receptors

This thesis is concerned with the synthesis of acyclic and macrocyclic N-pyridyl thiourea/urea based receptors and their tendency to switch their conformations upon protonation and subsequent binding of an anionic guest.  Chapter 1 is an introduction of the basic principles of supramolecular chemistry.  Chapter 2 describes the synthesis of neutral and protonated acyclic N-pyridyl-N-phenyl thiourea receptors. Chapter 3 describes the synthesis of neutral and protonated acyclic N-pyridyl-N-phenyl urea receptors, which showed similar conformations to their analogous neutral and protonated thioureas.  Protonated ureas bind chloride by strong 1:1 and 1:2 binding modes, but are deprotonated with acetate anion.  Unlike the protonated thiourea receptors, protonated ureas formed precipitation of phosphate complexes when treated with dihydrogen phosphate as confirmed by X-ray crystal structure analysis.  On the other hand, NMR studies of the neutral ureas revealed their tendency to form weak to moderate complexes with halide and acetate anions. Chapter 4 describes the unsuccessful attempts to synthesise N-pyridyl-thiourea-based macrocycles and the successful synthesis of an N-pyridyl-urea-based macrocycle.  The structural study of this macrocycle revealed its tendency to adopt a non-binding conformation.  However, structural and NMR studies of protonated urea-based macrocycles were not performed due to low solubility of the salt in a range of solvents and attempted solubilisation in DMSO led to deprotonation of the salt giving back the neutral macrocycle.</p

Chemical Detection of the Toxicity of Nanoparticles of Metals and Metal Oxides

The wide applications of nanoparticles increased the demand for their risk assessment, a number of studies on the diverse effects of nanoparticles on various systems have been published. This review provides an overview of the mechanisms of cellular uptake of nanoparticles (NPs) and the advanced toxicological studies of the nanoparticles of metals and metal oxides on various systems (in-vitro and in-vivo)

Switchable N-pyridyl-thiourea/urea acyclic and macrocyclic compounds as anion receptors

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Towards Effective Environmental Sustainability Reporting in the Large Industrial Sector of Bahrain

The industrial sector plays a vital role in economic development; therefore, there is a necessity to integrate sustainability into industrial development to maintain the economy and avoid any degradation impacts on the environment, and thereafter on society. Thus, do Bahraini companies have sustainability reports and if so, are these reports based on GRI guidelines? Has the status of their sustainability reports been analyzed? This research aims to examine the sustainability reports of companies by analyzing the status of sustainability aspects in their materiality matrices to assist in identifying and prioritizing the most significant sustainability issues for advancement in their future reporting and to improve their environmental performance. This study employs a content analysis approach and analyzes 11 reports from the period 2016–2020 for three companies in Bahrain’s large industrial sector. The study reveals that the companies using materiality analysis in their reporting benefit from better monitoring and measuring of their environmental performance, and from implementing SDGs. Furthermore, the study indicates that the utilization of a materiality matrix as a reporting tool can define and improve report contents by considering stakeholders’ views, consequently, improving the quality of the sustainability reports. The study concludes by proposing a set of recommendations

Environmentally Friendly Polyvinyl Alcohol&minus;Alginate/Bentonite Semi-Interpenetrating Polymer Network Nanocomposite Hydrogel Beads as an Efficient Adsorbent for the Removal of Methylene Blue from Aqueous Solution

Hazardous chemicals like toxic organic dyes are very harmful to the environment and their removal is quite challenging. Therefore there is a necessity to develop techniques, which are environment friendly, cost-effective and easily available in nature for water purification and remediation. The present research work is focused on the development` and characterization of the ecofriendly semi-interpenetrating polymer network (semi-IPN) nanocomposite hydrogels composed of polyvinyl alcohol (PVA) and alginate (Alg) hydrogel beads incorporating natural bentonite (Bent) clay as a beneficial adsorbent for the removal of toxic methylene blue (MB) from aqueous solution. PVA&minus;Alg/Bent nanocomposite hydrogel beads with different Bent content (0, 10, 20, and 30 wt%) were synthesized via external ionic gelation method. The designed porous and steady structure beads were characterized by the use of Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM). The performance of the beads as MB adsorbents was investigated by treating aqueous solutions in batch mode. The experimental results indicated that the incorporation of Bent (30 wt%) in the nanocomposite formulation sustained the porous structure, preserved water uptake, and increased MB removal efficiency by 230% compared to empty beads. Designed beads possessed higher affinity to MB at high pH 8, 30 &deg;C, and fitted well to pseudo-second-order kinetic model with a high correlation coefficient. Moreover, the designed beads had good stability and reusability as they exhibited excellent removal efficiency (90%) after six consecutive adsorption-desorption cycles. The adsorption process was found be combination of both monolayer adsorption on homogeneous surface and multilayer adsorption on heterogeneous surface. The maximum adsorption capacity of the designed beads system as calculated by Langmuir isotherm was found to be 51.34 mg/g, which is in good agreement with the reported clay-related adsorbents. The designed semi-IPN PVA&minus;Alg/Bent nanocomposite hydrogel beads demonstrated good adsorbent properties and could be potentially used for MB removal from polluted water

In vitro study of the interaction of heregulin-functionalized magnetic-optical nanorods with MCF7 and MDA-MB- 231 cells

Multifunctional nanoparticles that actively target specific cells are promising tools for cancer diagnosis and therapy. In this article we review the synthesis and surface chemistry of Fe–Au nanorods and their characterization using microscopy. The diameter of the rods used in this study was selected to be 150–200 nm so that they did not enter the cells. The 80 nm-long Au tips of the nanorods were functionalized with heregulin (HRG), and the micron-long Fe portion was coated with a poly(ethylene glycol) monolayer to minimize non-specific interactions. Nanorods functionalized with HRG were found to preferentially bind to MCF7 cells that express high levels of the receptor tyrosine-protein kinase ErbB2/3. Magnetic tweezers measurements were used to characterize the kinetic properties of the bond between the HRG on the rods and ErbB2/3 on the surface of the cells. The strong magnetization of Fe–Au nanorods makes them excellent candidates for in-vitro and in-vivo imaging, and magnetic therapeutic applications targeting cancer cells in circulation.Science Foundation IrelandErasmus Mundus Gulf Countries Postdoctoral FellowshipMarie Curie Intra-European Fellowshi