Tetrakis(2,6-diisopropylphenyl)diphosphine and related compounds : an electrochemical and EPR spectroscopic study of radical cations

xix, 172 leaves : ill (some col.) ; 29 cmIn this thesis the synthesis and full characterization of a new bulky diphosphine, tetrakis-(2,6-diisopropylphenyl)diphosphine, are described. This compound displays facile oxidation and a thorough investigation of its redox properties has been studied by combining solution electrochemical techniques such as cyclic voltammetry (CV) and rotating disk electrode (RDE) voltammetry, with spectroscopic methods such as electron paramagnetic resonance (EPR) and Simultaneous Electrochemical Electron Paramagnetic Resonance (SEEPR) spectroscopy over a wide temperature range. Density functional theory (DFT) calculations were carried out to aid in structural characterization of the radical cation that is produced and to provide computed hyperfine splitting (HFS) constants for comparison with experimental results. For comparison to this species with bulky aromatic substituents, similar studies were conducted that have identified the previously unreported radical cation of tetrakis-tert-butyldiphosphine with a bulky aliphatic substituent that provides even higher steric pressure than the 2,6-diisopropylphenyl group. DFT calculations are reported, as is full characterization with fluid and frozen-solution EPR spectroscopy. Further CV and EPR (SEEPR) studies are reported that led to the identification of radical cations of tris(2,6-diisopropylphenyl)arsine and bis(2,4,6-triisopropylphenyl)(2,6-diisopropylphenyl)phosphine. DFT calculations are reported, as is full characterization with fluid and frozen-solution EPR spectroscopy

Novel thiol-ene hybrid coating for metal protection

Published: 7 April 2016A novel hybrid anticorrosion coating with dual network of inorganic (Si–O–Si) and organic bonds (C–S–C) was prepared on metal through an in situ sol-gel and thiol-ene click reaction. This novel interfacial thin film coating incorporates (3-mercaptopropyl) trimethoxysilane (MPTS) and 1,4-di(vinylimidazolium) butane bisbromide based polymerizable ionic liquid (PIL) to form a thiol-ene based photo-polymerized film, which on subsequent sol-gel reaction forms a thin hybrid interfacial layer on metal surface. On top of this PIL hybrid film, a self-assembled nanophase particle (SNAP) coating was employed to prepare a multilayer thin film coating for better corrosion protection and barrier performance. The novel PIL hybrid film was characterised for structure and properties using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The corrosion protection performance of the multilayer coating was examined using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results reveal that this novel double layer coating on metal offers excellent protection against corrosion and has remarkably improved the barrier effect of the coating.Mona Taghaviksih, Surya Subianto, Naba Kumar Dutta and Namita Roy Choudhur

Bis(tert-butyldimethylsilyl)(2,6-diisopropylphenyl)phosphane: the first structure of an organophosphane with two tert-butyldimethylsily (TBDMS) substituents

Sherpa Romeo green journalYe

Polymeric ionic liquid nanoparticle emulsions as a corrosion inhibitor in anticorrosion coatings

In this contribution, we report the facile preparation of cross-linked polymerizable ionic liquid (PIL)-based nanoparticles via thiol–ene photopolymerization in a miniemulsion. The synthesized PIL nanoparticles with a diameter of about 200 nm were fully characterized with regard to their chemical structures, morphologies, and properties using different techniques, such as Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. To gain an in-depth understanding of the physical and morphological structures of the PIL nanoparticles in an emulsion, small-angle neutron scattering and ultra-small-angle neutron scattering were used. Neutron scattering studies revealed valuable information regarding the formation of cylindrical ionic micelles in the spherical nanoparticles, which is a unique property of this system. Furthermore, the PIL nanoparticle emulsion was utilized as an inhibitor in a self-assembled nanophase particle (SNAP) coating. The corrosion protection ability of the resultant coating was examined using potentiodynamic polarization and electrochemical impedance spectroscopy. The results show that the PIL nanoparticle emulsion in the SNAP coating acts as an inhibitor of corrosion and is promising for fabricating advanced coatings with improved barrier function and corrosion protection.Mona Taghavikish, Surya Subianto, Naba Kumar Dutta, Liliana de Campo, Jitendra P. Mata, Christine Rehm, and Namita Roy Choudhur

Emerging Corrosion Inhibitors for Interfacial Coating

Corrosion is a deterioration of a metal due to reaction with environment. The use of corrosion inhibitors is one of the most effective ways of protecting metal surfaces against corrosion. Their effectiveness is related to the chemical composition, their molecular structures and affinities for adsorption on the metal surface. This review focuses on the potential of ionic liquid, polyionic liquid (PIL) and graphene as promising corrosion inhibitors in emerging coatings due to their remarkable properties and various embedment or fabrication strategies. The review begins with a precise description of the synthesis, characterization and structure-property-performance relationship of such inhibitors for anti-corrosion coatings. It establishes a platform for the formation of new generation of PIL based coatings and shows that PIL corrosion inhibitors with various heteroatoms in different form can be employed for corrosion protection with higher barrier properties and protection of metal surface. However, such study is still in its infancy and there is significant scope to further develop new structures of PIL based corrosion inhibitors and coatings and study their behaviour in protection of metals. Besides, it is identified that the combination of ionic liquid, PIL and graphene could possibly contribute to the development of the ultimate corrosion inhibitor based coating

Facile Fabrication of Polymerizable Ionic Liquid Based-Gel Beads via Thiol-ene Chemistry

Multipurpose gel beads prepared from natural or synthetic polymers have received significant attention in various applications such as drug delivery, coatings, and electrolytes because of their versatility and unique performance as micro-and nanocontainers.1 However, comparatively little work has been done on poly(ionic liquid)-based materials despite their unique ionic characteristics. Thus, in this contribution we report the facile preparation of polymerizable ionic liquid-based gel beads using thiol-ene click chemistry. This novel system incorporates pentaerythritol tetra (3-mercaptopropionate) (PETKMP) and 1,4-di(vinylimidazolium) butane bisbromide in a thiol-ene-based photopolymerization to fabricate the gel beads. Their chemical structure, thermal and mechanical properties have been investigated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The gel beads possess low T<inf>g</inf> and their ionic functionalities attribute self-healing properties and their ability to uptake small molecules or organic compounds offers their potential use as pH sensing material and macrocontainers

Effect of polymerized ionic liquid based gel inhibitor on electrochemical performance of self-assembled nanophase coating

The corrosion process is a surface reaction that can be controlled by the addition of corrosion inhibitors, which adsorb on the reacting metal surface. The inhibitors could be applied to a metal surface in many different ways. In this contribution, influence of polymerized ionic liquid (PIL) was examined on inhibition performance of a coating using carbon steel samples. The PIL was loaded in self-assembled nanophase particle (SNAP) coating and the inhibition behaviour was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy and scanning kelvin probe techniques. The inhibition efficiency of the coating increases with the addition of PIL as observed from potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. In addition, scanning kelvin probe (SKP) measurement provides further understanding on the strong interfacial properties of the modified coating compared to that of the SNAP

Effect of polymerized ionic liquid based gel inhibitor on electrochemical performance of self-assembled nanophase coating

The corrosion process is a surface reaction that can be controlled by the addition of corrosion inhibitors, which adsorb on the reacting metal surface. The inhibitors could be applied to a metal surface in many different ways. In this contribution, influence of polymerized ionic liquid (PIL) was examined on inhibition performance of a coating using carbon steel samples. The PIL was loaded in self-assembled nanophase particle (SNAP) coating and the inhibition behaviour was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy and scanning kelvin probe techniques. The inhibition efficiency of the coating increases with the addition of PIL as observed from potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. In addition, scanning kelvin probe (SKP) measurement provides further understanding on the strong interfacial properties of the modified coating compared to that of the SNAP.Mona Taghavikish, Surya Subianto, Namita Roy Choudhury, Naba Kumar Dutt