A Molecular Approach for Mitigation of Aluminum Pitting based on Films of Zinc(II) and Gallium(III) Metallosurfactants.

The use of metallosurfactants to prevent pitting corrosion of aluminum surfaces is discussed based on the behavior of the metallosurfactants [ZnII (LN2O2 )H2 O] (1) and [GaIII (LN2O3 )] (2). These species were deposited as multilayer Langmuir-Blodgett films and characterized by IR reflection absorption spectroscopy and UV/Vis spectroscopy. Scanning electron microscopy images, potentiodynamic polarization experiments, and electrochemical impedance spectroscopy were used to assess corrosion mitigation. Both metallosurfactants demonstrate superior anticorrosion activity due to the presence of redox-inactive 3d10 metal ions that enhance the structural resistance of the ordered molecular films and limit chloride mobility and electron transfer.

Dendrimer-based Nanoparticle for Dye Sensitized Solar Cells with Improved Efficiency.

Dye sensitized solar cells were fabricated with DyLight680 (DL680) dye and its corresponding europium conjugated dendrimer, DL680-Eu-G5PAMAM, to study the effect of europium on the current and voltage characteristics of the DL680 dye sensitized solar cell. The dye samples were characterized by using Absorption Spectroscopy, Emission Spectroscopy, Fluorescence lifetime and Fourier Transform Infrared measurements. Transmission electron microscopy imaging was carried out on the DL680-Eu-G5PAMAM dye and DL680-Eu-G5PAMAM dye sensitized titanium dioxide nanoparticles to analyze the size of the dye molecules and examine the interaction of the dye with titanium dioxide nanoparticles. The DL680-Eu-G5PAMAM dye sensitized solar cells demonstrated an enhanced solar-to-electric energy conversion of 0.32% under full light illumination (100 mWcm-2, AM 1.5 Global) in comparison with that of DL680 dye sensitized cells which recorded an average solar-to-electric energy conversion of only 0.19%. The improvement of the efficiency could be due to the presence of the europium that enhances the propensity of dye to absorb sunlight.

Observation of current rectification by a new asymmetric iron(iii) surfactant in a eutectic GaIn|LB monolayer|Au sandwich.

In this paper we expand on the search for molecular rectifiers of electrical current and report on a hexacoordinate metallosurfactant [FeIII(LN3O)(OMe)2], where (LN3O)- is the deprotonated form of the new asymmetric ligand 2-((E)-((4,5-bis(2-methoxyethoxy)-2-(((E)-pyridin-2-ylmethylene)amino)phenyl)imino)methyl)-4,6-di-tert-butyl-phenol. This species rectifies current when deposited as a Langmuir-Blodget film in a "EGaIn/Ga2O3|LB|Au" sandwich with rectification ratios ranging from 25 to 300 at 1 Volt.

MRI Monitoring of Cerebral Blood Flow after the Delivery of Nanocombretastatin across the Blood Brain Tumor Barrier.

Introduction of polymeric nanoparticles in cancer therapeutics is widely investigated since nanomedicine often enables the intratumoral delivery of drugs with increased efficacy with minimal side effects. In this study MRI monitoring was employed to study the therapeutic effect of nanocombretastatin (G3-CA4) in an orthotopic glioma model. Water insoluble combretastatin (CA4) was conjugated to a small-sized water soluble G3-succinamic acid PAMAM dendrimer. Nanoconstruct sizes were determined by TEM to be 3 to 5 nm. Intravenous (i.v.) delivery of G3-CA4 in an orthotopic glioma model produced a long-lived ischemia accompanied by necrosis at the core of the tumor but leaving a rim of viable tissue. In contrast, delivery of CA4 alone has no therapeutic effect in an experimental rat model of glioma.

Application of Dendrimer-based Nanoparticles in Glioma Imaging.

Dendritic polymers or dendrimers present an alternate template for the development of nanoparticulate-based drug delivery and imaging systems. The smaller size (~7-12 nm) of dendrimers have the advantage over the other particles, because its smaller size can possibly improve tumor penetration and the inclusion of tumor specific drug release mechanisms. A Paramagnetic Chemical Exchange Saturation Transfer (PARACEST) MRI contrast agent, Eu-DOTA-Gly4 or a clinical relevant Gd-DOTA was conjugated on the surface of a G5 PAMAM dendrimer. To create a dual mode MRI-optical imaging nanoparticle, Dylight680 was also incorporated on the amines surface of a G5 dendrimer. The particle was detected with in vivo MRI in preclinical glioma animal model. Furthermore, noninvasive imaging results were validated with in vivo and ex-vivo optical imaging.

Langmuir-Blodgett films of salophen-based metallosurfactants as surface pretreatment coatings for corrosion mitigation.

Salophen-based metallosurfactants are successfully used as pretreatment LB films for corrosion mitigation in acidic and saline media. Passivation of electron transfer is clearly demonstrated in gold electrodes, while 99.5% iron substrates treated with such films show up to an impressive 30% corrosion mitigation.

Efficient water oxidation with electromodified Langmuir-Blodgett films of procatalytic [Co(III)(N2O3)] metallosurfactants on electrodes.

Electromodified Langmuir-Blodgett films of a phenolate-rich [Co(III)(L(N2O3))H2O] metallosurfactant support water oxidation at an overpotential of 0.5 V. Gradual enhancement of catalytic activity is observed between 1 and 9 deposited layers. Upon application of a potential bias the molecular species rearranges into a catalytic layer that yields estimated turnover numbers of 54 000 ± 1500 h(-1).

The mechanisms of rectification in Au|molecule|Au devices based on Langmuir-Blodgett monolayers of iron(III) and copper(II) surfactants.

Langmuir-Blodgett films of metallosurfactants were used in Au|molecule|Au devices to investigate the mechanisms of current rectification.