Heterometallic CeIII–FeIII–salicylate networks : models for corrosion mitigation of steel surfaces by the ′Green′ inhibitor, Ce(salicylate)3

The syntheses and structures of the novel Ce–Fe bimetallic complexes [{Fe(sal)₂(bpy)}₂Ce(NO₃)(H₂O)₃]·EtOH and [{Fe(sal)₂(bpy)}₄Ce₂(H₂O)₁₁][salH]₂·EtOH·3H₂O (salH₂ = salicylic acid) suggest Fe³⁺–sal²⁻ units and Ce–OC(R)O–Fe bridging contribute to the formation of corrosion inhibitive layers on steel surfaces exposed to [Ce(salH)₃(H₂O)].

ATR characterisation of synergistic corrosion inhibition of mild steel surfaces by cerium salicylate

The nature of deposits on mild steel surfaces formed by exposure to corrosive and inhibiting solutions has been examined by attenuated total reflectance spectroscopy. For cerium-based inhibitors, e.g. CeCl₃ the formation of cerium-containing coatings was detected whilst the cerium carboxylate Ce(sal)₃ (sal=salicylate), which combines the Ce³⁺ with the known organic inhibitor sal⁻, was shown to involve substantial deposition of both cerium and a salicylate species. These results, combined with corrosion inhibition data for the respective inhibitor compounds clearly indicate a synergistic corrosion mechanism for Ce(sal)₃ which underpins the improved performance of this corrosion inhibitor in comparison to the individual components (i.e. Na(sal) or CeCl₃).

Modifying the bitterness of selected oral pharmaceuticals with cation and anion series of salts

Purpose. NaCl has proven to be an effective bitterness inhibitor, but the reason remains unclear. The purpose of this study was to examine the influence of a variety of cations and anions on the bitterness of selected oral pharmaceuticals and bitter taste stimuli: pseudoephedrine, ranitidine, acetaminophen, quinine, and urea.
Method. Human psychophysical taste evaluation using a whole mouth exposure procedure was used.
Results. The cations (all associated with the acetate anion) inhibited bitterness when mixed with pharmaceutical solutions to varying degrees. The sodium cation significantly (P < 0.003) inhibited bitterness of the pharmaceuticals more than the other cations. The anions (all associated with the sodium cation) also inhibited bitterness to varying degrees. With the exception of salicylate, the glutamate and adenosine monophosphate anions significantly (P < 0.001) inhibited bitterness of the pharmaceuticals more than the other anions. Also, there were several specific inhibitory interactions between ammonium, sodium and salicylate and certain pharmaceuticals.
Conclusions. We conclude that sodium was the most successful cation and glutamate and AMP were the most successful anions at inhibiting bitterness. Structure forming and breaking properties of ions, as predicted by the Hofmeister series, and other physical-chemical ion properties failed to significantly predict bitterness inhibition.

Design of multiligand inhibitors for the swine flu H1N1 neuraminidase binding site

Viral neuraminidase inhibitors such as oseltamivir and zanamivir prevent early virus multiplication by blocking sialic acid cleavage on host cells. These drugs are effective for the treatment of a variety of influenza subtypes, including swine flu (H1N1). The binding site for these drugs is well established and they were designed based on computational docking studies. We show here that some common natural products have moderate inhibitory activity for H1N1 neuraminidase under docking studies. Significantly, docking studies using AutoDock for biligand and triligand forms of these compounds (camphor, menthol, and methyl salicylate linked via methylene bridges) indicate that they may bind in combination with high affinity to the H1N1 neuraminidase active site. These results also indicate that chemically linked biligands and triligands of these natural products could provide a new class of drug leads for the prevention and treatment of influenza. This study also highlights the need for a multiligand docking algorithm to understand better the mode of action of natural products, wherein multiple active ingredients are present.

Novel imidazolinium ionic liquids and organic salts

The preparation and physical properties of a novel family of ionic liquids and organic salts based on the imidazolinium cation are described, and compared with their imidazolium analogues in some cases. Ionic liquids were obtained with the triflate, formate and salicylate anions, while > 100 °C melting points were observed with acetate and several other benzoate derivatives. The triflate salt was less ion-conductive than the corresponding imidazolium salt, but less so than expected on the basis of its viscosity, suggesting a contribution from proton conductivity. The electrochemical window of the imidazolinium was slightly extended in the reductive direction, due to the lower proton activity produced by the cation in this case. Imidazolinium salts are also known to exhibit anti-corrosion properties and hence a preliminary study of this property is also reported; 2-methylimidazolinium 4-hydroxycinnamate was found to show strong anodic corrosion inhibition on mild steel.