Zareen Zuhra

Synthesis, Structure, and Photoluminescence of Color-Tunable and White-Light-Emitting Lanthanide Metal–Organic Open Frameworks Composed of AlMo6(OH)6O183– Polyanion and Nicotinate

A series of isostructural compounds Na(HL)(CH3COO)Ln(Al(OH)6Mo6O18)(H2O)6·10H2O [L = nicotinate; Ln = Eu (1), Tb (2)] and Na(HL)(CH3COO)EumTbnLa1-m-n(AlMo6(OH)6O18)(H2O)6·10H2O (3-8, L = nicotinate), wherein Anderson-type polyanions AlMo6(OH)6O183- as basic inorganic building blocks are connected by Eu(CH3COO)(HL)(H2O)3]24+ and [Na2(H2O)8]2+ cations, resulting in formation of three-dimensional lanthanide metal-organic open frameworks, were synthesized successfully with AlCl3·6H2O, Na2MoO4·2H2O, nicotinic acid, and lanthanide nitrates as starting materials. The compounds were characterized by UV-vis, IR, elemental analysis, powder XRD, and TG-DTA measurements. The single-crystal structures of compounds 1 and 2 show that the two compounds display three-dimensional open frameworks with 1D channels along the b and c axes. Investigation of the energy transfer mechanism indicated that the organic nicotinate ligand can transfer energy efficiently to Tb3+ rather than Eu3+. The influence of the POM moiety on the fluorescence of the compounds is also studied. Compounds 1-8 exhibit tunable luminescence color, and emitting of white light was realized through adjusting the molar ratio of Eu:Tb:La within the compounds.

Ferrocene-Based Bioactive Bimetallic Thiourea Complexes: Synthesis and Spectroscopic Studies

Bioactive 1,1′-(4,4′-di-ferrocenyl)di-phenyl thiourea and various metal complexes of this ligand have been successfully synthesized and characterized by using physicoanalytical techniques such as FT-IR and multinuclear (1H and 13C) NMR spectroscopy along with melting point and elemental analyses. The interaction of the synthesized compounds with DNA has been investigated by using cyclic voltammetric and viscometric measurements. The intercalation of the complexes into the double helix structure of DNA is presumably occurring. Viscosity measurements of the complexes have shown that there is a change in length and this is regarded as the least ambiguous and the most critical test of the binding model in solution. The relative potential of the complexes as anti-bacterial, antifungal, and inhibition agents against the enzyme, alkaline phosphatase EC 3.1.3.1, has also been assessed and the complexes were found to be active inhibitors.

A facile synthesis, structural morphology and fluorescent properties of cross-linked poly(cyclotriphosphazene-co-1,3,5-tri(4-hydroxyphenyl)benzene) hybrid copolymer microspheres

The ever increasing growth and interest in the field of material science for the production of functionalized polymer microspheres with tunable size is of pivotal importance. This research describes the one pot method for the facile synthesis of fluorescent active poly[cyclotriphosphazene-co-1,3,5-tri(4-hydroxyphenyl)benzene] (PCTHB) microspheres with the desired structural morphology obtained by the reaction of 1,3,5-tri(4-hydroxyphenyl)benzene (HPB) with hexachlorocyclotriphosphazene (HCCP) through the precipitation polymerization. The sizes of the microspheres can be tuned by changing the amount of both the cross linkers in a calculated molar ratio. The mean diameter of the microspheres varies in the range of 0.5–1.1 μm. The morphology and structure of PCTHB microspheres were characterized by FT-IR, solid state 31P NMR, SEM, EDX-mapping and TEM analyses. A mechanism for the preparation of PCTHB microspheres has been proposed, in which HPB plays a crucial role, as its presence gives the final desired shape to the microspheres. The concentration of HBP beyond 2 mM has produced irregular morphology of the microspheres. Room-temperature photoluminescence spectra of the PCTHB microspheres reveal a strong emission peak at 372 nm. These fluorescent polymer PCTHB microspheres can be developed with great ease as compared to those with the aid of quantum dots and dyes. Due to these superior properties and novelty of our synthesized material, it can be used as a potential biomaterial for several applications such as diagnostics, photocatalysis, biological imaging, organic or inorganic analysis, and light emitting diodes.

Necessity of calcination in the preparation of phosphotungstic acid@TiO2 composites. A case study on the facile sol–gel synthesis of nanospheres and their superior performance in catalytic oxi-desulfurization

Calcination is considered to be a key step in the process of preparation of titanium dioxide based catalysts; however, it consumes a lot of energy. We describe unequivocally here for the first time that high-energy consuming calcination is a surplus process in the preparation of phosphotungstic acid@titanium dioxide (PW12@TiO2) catalysts with various loadings of phosphotungstic acid (10–40 wt%) for oxidative catalytic reactions. To prove this, a case study on the preparation of PW12@TiO2 nanospheres via the sol–gel procedure is discussed here. The structure and morphology of the nanospheres were characterized by FT-IR, FT-Raman, BET XRD, ICP and SEM analyses. Oxidative desulfurization of a model oil composed of 350 ppmwS dibenzothiophene (DBT) in n-octane was investigated using these nanospheres. The results showed that both calcinated and un-calcinated-PW12@TiO2 nanospheres exhibited almost parallel yet excellent oxidative desulfurization performances in the model oil. The 350 ppmwS of sulfur content in 20 mL of n-octane was dropped down to 2.4 and 2.6 ppmwS within 2 hours at 60 °C using 70 mg of calcinated and un-calcinated-PW12@TiO2 nanospheres with 30 wt% PW12 loading, respectively. The high desulfurization efficiency of the catalyst remained unchanged even after the regeneration of the catalyst ten times. This excellent desulfurization performance makes the as-prepared composite without calcination treatment a promising catalyst in practical oxidative desulfurization processes.

Layer-by-layer assembly of Cu3(BTC)2 on chitosan non-woven fabrics: a promising haemostatic decontaminant composite material against sulfur mustard

Cu3(BTC)2 (H3BTC = 1,3,5-benzenetricarboxylic acid) was anchored onto the surface of carboxymethylated chitosan non-woven fabrics by a controllable layer-by-layer technique in alternating solution baths of Cu(OAc)2·H2O and H3BTC solutions, and the resulting [Cu3(BTC)2]n@chitosan non-woven fabric composite materials (n = number of alternate deposition cycles) were thoroughly characterized. The results showed that the composite materials not only exhibited excellent decontamination ability against sulfur mustard (HD), with an enhanced degradation rate of HD with increasing n, but also possessed remarkable haemostasis performance. The degradation efficiency of sulfur mustard by [Cu3(BTC)2]4@chitosan was found to be much higher than that of pristine [Cu3(BTC)2]4. The inherent haemostatic capabilities of the chitosan non-woven fabrics were not affected by the growth of Cu3(BTC)2 on the surface of chitosan. Oral and histological toxicity examinations of the pristine Cu3(BTC)2 sample showed that damage and toxicity in the viscera of mice was very low, even if the intra-gastric administration dose of Cu3(BTC)2 reached a very high level (50 mg of Cu3(BTC)2 per kg of mouse). The results have shown that the as-prepared composite can be used safely as a promising haemostatic decontaminant with good recyclability against sulfur mustard.