Mechanisms in the photocatalytic breakdown of persistent pharmaceutical and pesticide molecules over TiO-based photocatalysts: A review.

Titanium dioxide (TiO) based photocatalysts have been widely used as a photocatalyst for the degradation of various persistent organic compounds in water and air. The degradation mechanism involves the generation of highly reactive oxygen species, such as hydroxyl radicals, which react with organic compounds to break down their chemical bonds and ultimately mineralize them into harmless products. In the case of pharmaceutical and pesticide molecules, TiOand modified TiOphotocatalysis effectively degrade a wide range of compounds, including antibiotics, pesticides, and herbicides.

Photocatalytic performance and interaction mechanism of reverse micelle synthesized Cu-TiO nanomaterials towards levofloxacin under visible LED light.

The degradation performance of Cu-TiO nanomaterials towards levofloxacin (LFX) antibiotic was investigated under an environmentally benign visible LED light source. Cu-TiO nanomaterials were prepared using the reverse micelle sol-gel method with different copper content ranging from 0.25 to 1.

Thermoresponsive liquid crystalline formulation of Exemestane: Design and structural characterization.

Exemestane (EXE), a drug used for the treatment of breast cancer, has limited aqueous solubility of 0.08 mg/mL and log P∼ 4.22.

Mechanism of organic pollutants sorption from aqueous solution by cationic tunable organoclays.

A variety of quaternary ammonium salts with different carbon chain lengths were used to modify and convert montmorillonite clay to organoclays. The surface modification attributing to the wettability was investigated using various techniques. The zeta-potential values of all clays showed pH dependency.

Quality by Design approach for an in situ gelling microemulsion of Lorazepam via intranasal route.

The present study illustrates the application of the concept of Quality by Design for development, optimization and evaluation of Lorazepam loaded microemulsion containing ion responsive In situ gelator gellan gum and carbopol 934. A novel approach involving interactions between surfactant and polymer was employed to achieve controlled drug release and reduced mucociliary clearance. Microemulsion formulated using preliminary solubility study and pseudo ternary phase diagrams showed significantly improved solubilization capacity of Lorazepam with 54.

Novel strategy involving surfactant-polymer combinations for enhanced stability of aqueous teflon dispersions.

Among various polymers, the Teflon surface possesses extreme hydrophobicity (low surface energy), which is of great interest to both industry and academia. In this report, we discuss the stability of aqueous Teflon dispersions (particle size range of 100-3000 nm) formulated by a novel strategy that involves distinct combinations of surfactant and polymer mixtures for dispersion stabilization. As a first step, the hydrophobic Teflon particles were wetted using a range of surfactants (ionic, Triton, Brij, Tween, and Pluronic series) bearing different hydrophobic-lipophilic balance (HLB) and further characterized by contact angle and liquid penetration in packed powder measurements.

Controlling wettability and hydrophobicity of organoclays modified with quaternary ammonium surfactants.

The montmorillonite clays were modified with quaternary ammonium salts (QASs) having different alkyl chain lengths and a benzyl substitute group. The modified organoclays were characterized by different analytical techniques. The wettability and hydrophilicity/hydrophobicity of the modified clays was evaluated using water or oil penetration (adsorption) and contact angle measurements.

Dimerization of aromatic ureido pyrimidinedione derivatives: observation of an unexpected tautomer in the solid state.

Ureido pyrimidinedione derivatives with phenyl, 1-naphthyl and 2-naphthyl substituents form stable dimers via quadruple hydrogen bonding, but the 1-naphthyl derivative presents an unexpected tautomer in the solid state.

Physicochemical and photophysical studies on porphyrin-based donor-acceptor systems: effect of redox potentials on ultrafast electron-transfer dynamics.

We report new polychromophoric complexes, where different porphyrin (P) derivatives are covalently coupled to a redox active Mo center, MoL*(NO)Cl(X) (L* is the face-capping tridentate ligand tris(3,5-dimethylpyrazolyl) hydroborate and X is a phenoxide/pyridyl/amido derivative of porphyrin). The luminescence quantum yields of the bichromophoric systems (1, 2, and 5) were found to be an order of magnitude less than those of their respective porphyrin precursors. Transient absorption measurements revealed the formation of the porphyrin radical cation species (P(.

Controlling structure from the bottom-up: structural and optical properties of layer-by-layer assembled palladium coordination-based multilayers.

Layer-by-layer assembly of two palladium coordination-based multilayers on silicon and glass substrates is presented. The new assemblies consist of rigid-rod chromophores connected by terminal pyridine moieties to palladium centers. Both colloidal palladium and PdCl2(PhCN)2 were used in order to determine the effect of the metal complex precursor on multilayer structure and optical properties.

Site affinity effects upon charge injection into siloxane-based monolayers.

Submolecular electrical information is successfully derived by applying element-specific, chemically resolved electrical measurements to a covalently bound stilbazole-based monolayer on a silicon substrate. Pronounced affinity effects are found in the response of adjacent atomic sites to external charge injection, accompanied by intramolecular polarization variations. These noncontact electrical read-out capabilities may provide a first entry toward the realization of organic devices based on submolecular electrical units.

Strategies for electrooptic film fabrication. Influence of pyrrole-pyridine-based dibranched chromophore architecture on covalent self-assembly, thin-film microstructure, and nonlinear optical response.

The new dibranched, heterocyclic "push-pull" chromophores bis{1-(pyridin-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane (1), 1-(pyrid-4-yl)-2-(N-methyl-5-formylpyrrol-2-yl)ethylene (2), {1-(N-methylpyridinium-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}{(1-(pyridin-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane (3), N-methyl-2-[1-(N-methylpyrid-4-yl)ethen-2-yl]-5-[pyrid-4-yl]ethen-2-yl]pyrrole iodide (4), bis{1-(N-methyl-4-pyridinio)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane iodide (5), and N-methyl-2,5-[1-(N-methylpyrid-4-yl)ethen-2-yl]pyrrole iodide (6) have been synthesized and characterized. The neutral (1 and 2) and monomethyl salts (3 and 4) undergo chemisorptive reaction with iodobenzyl-functionalized surfaces to afford chromophore monolayers SA-1/SA-2 and SA-3/SA-4, respectively. Molecular structures and other physicochemical properties have been defined by (1)H NMR, optical spectroscopy, and XRD.

Mixed-ligand complexes of ruthenium(II) containing new photoactive or electroactive ligands: synthesis, spectral characterization and DNA interactions.

Mixed-ligand ruthenium(II) complexes of three photoactive ligands, viz., (E)-1-[2-(4-methyl-2-pyridyl)-4-pyridyl]-2-(1-naphthyl)-1-ethene (mppne), (E)-1-(9-anthryl)-2-[2-(4-methyl-2-pyridyl)-4-pyridyl]-1-ethene (mppae) and (E)-1-[2-(4-methyl-2-pyridyl)-4-pyridyl]-2-(1-pyrenyl)-1-ethene (mpppe), in which a 2,2'-bipyridyl unit is linked via an ethylinic linkage to either a naphthalene, an anthracene or a pyrene chromophore and three electroactive ligands, viz., 4-(4-pyridyl)-1,2-benzenediol (catpy), 5,6-dihydroxy-1,10-phenanthroline (catphen) and 1,2-benzenediol (cat), were synthesized in good to moderate yields.

A comparative Langmuir-Blodgett study on a set of covalently linked porphyrin-based amphiphiles: a detailed atomic force microscopic study.

A set of covalently linked phenyl-amidophenyl-substituted porphyrin amphiphiles with n-C15H31 tails have been synthesized and completely characterized. These amphiphiles form good Langmuir-Blodgett (LB) films at the air/water interface. Mean molecular areas for the series were measured from the isotherms and found to increase as the number of aliphatic chains increased from one to four.

Synthesis, characterization, physicochemical, and photophysical studies of redox switchable NIR dye derived from a ruthenium-dioxolene-porphyrin system.

Newly synthesized semi-quinone derivatives of the ruthenium polypyridyl, covalently linked to a porphyrin core, show very high epsilon values (59,000-83,500 M(-1)cm(-1)) for the absorption band in the near infrared (NIR) region of the spectrum. Further, complexes 1-4 show an interesting reversible electrochromic behavior as a function of the redox state of the coordinated dioxolene functionality, and a switching phenomenon between bleaching and the restoration of the NIR peak could be achieved electrochemically. Thus, complexes 1-4 could be ideal candidate materials for NIR-active electrochromic devices.

Redox switchable NIR dye derived from ruthenium-dioxolene-porphyrin systems.

Newly synthesised Ru(bp)2(sq)(+)-derivatives, covalently linked to a porphyrin-core, show very high epsilon values in the NIR region; which exhibit fast on/off switching depending on the redox state of the coordinated dioxolene functionality.

β-Cyclodextrin-Assisted Intervalence Charge Transfer in Mixed-Valent [2]Rotaxane Complexes Having Metal Centers Linked by an Interrupted π-Electron System.

Fe to Ru electron transfer is initiated by the inclusion of saturated bridging ligands into the β-cyclodextrin (CD) cavity of [2]rotaxane complexes and is observed as an intervalence charge transfer (IVCT) band in the electronic spectra. The rotaxanes are synthesized by using Ru and Fe complexes as stoppers, β-CD as the cyclic molecular head, and 4,4'-bipyridine derivatives with interrupted π-electron system as the bridging ligand between the metal centers.