The convenient preparation of stable aryl-coated zerovalent iron nanoparticles

A novel approach for the in situ synthesis of zerovalent aryl-coated iron nanoparticles (NPs) based on diazonium salt chemistry is proposed. Surface-modified zerovalent iron NPs (ZVI NPs) were prepared by simple chemical reduction of iron(III) chloride aqueous solution followed by in situ modification using water soluble arenediazonium tosylate. The resulting NPs, with average iron core diameter of 21 nm, were coated with a 10 nm thick organic layer to provide long-term protection in air for the highly reactive zerovalent iron core up to 180 °C. The surface-modified iron NPs possess a high grafting density of the aryl group on the NPs surface of 1.23 mmol/g. FTIR spectroscopy, XRD, HRTEM, TGA/DTA, and elemental analysis were performed in order to characterize the resulting material

Conceptual developments of aryldiazonium salts as modifiers for gold colloids and surfaces

International audienceModified colloids and flat surfaces occupy an important place in materials science research due to their widespread applications. Interest in development of modifiers that adhere strongly to surfaces relates to the need for stability under ambient conditions in many applications. In the last 20 years, diazonium salts have evolved as the primary choice for modification of surfaces. The term 'diazonics' has been introduced in the literature to describe "the science and technology of aryldiazonium salt-derived materials". The facile reduction of diazonium salts via chemical or electrochemical processes, irradiation stimuli, or spontaneously, results in efficient modification of gold surfaces. Robust gold-organic nanoparticles and films modified by using diazonium salts are critical in electronics, sensors, medical implants, and materials for power sources. Experimental and theoretical studies suggest that gold-carbon interactions constructed via chemical reactions with diazonium salts are stronger than nondiazonium surface modifiers. This invited feature article summarizes the conceptual development of recent studies of diazonium salts in our laboratories and others with a focus on surface modification of gold nanostructures and flat surfaces, and their applications in nanomedicine engineering, sensors, energy, forensic science, and catalysis

Preparation and X‑ray Structural Study of Dibenziodolium Derivatives

New experimental procedures for the preparation of dibenziodolium salts by oxidative cyclization of 2-iodobiphenyl in the presence of appropriate strong acids are described. Particularly useful is a convenient one-pot synthesis of dibenziodolium hydrogen sulfate from 2-iodobiphenyl using Oxone as an inexpensive and environmentally safe oxidant. Dibenziodolium hydrogen sulfate, bis­(triflyl)­imidate, or triflate can be readily converted to various other dibenziodolium derivatives (chloride, bromide, thiocyanate, azide, cyanide, phenylsulfinate) by anion exchange. Structures of key products have been established by single-crystal X-ray diffraction analysis. Particularly interesting is the X-ray structure of dibenziodolium thiocyanate, which represents the first example of a structurally characterized hypervalent iodine compound with a relatively short iodine–sulfur secondary bond distance

Weak Bonds, Strong Effects: Enhancing the Separation Performance of UiO-66 toward Chlorobenzenes via Halogen Bonding

Halogen bonding (HaB) is a weak interaction that assists in the recognition of nucleophilic molecules. However, HaB elements are currently under-investigated as a part of functional materials in separation science. Herein, we develop a novel approach for introducing HaB elements into UiO-66 to fine-tune the adsorption properties toward chlorobenzenes (CBs). A series of UiO-66 containing various contents of 2-iodoterephtalic acid (I-TA) (0%, 33%, 50%, 67%, and 100%) was prepared, characterized, and applied for the selective removal of CB contaminants from nonchlorinated aromatic analogues that cannot be separated by common distillation. Investigation of the structure-property relationship revealed that the highest adsorption capacity was achieved in the case of UiO-66 loaded with 50% I-TA (UiO-66-Iopt), and this was attributed to the balance between the number of HaB elements and the surface area of the UiO-66 structure. According to density functional theory calculations, the formation of a conjugate between dichlorobenzene and UiO-66-Iopt was more energetically favorable (up to 1.7 kcal/mol) than that of the corresponding conjugate with UiO-66. The formation of HaBs was experimentally verified by UV-vis, Raman, and X-ray photoelectron spectroscopies. To obtain functional materials for separation applications, waste polyethylene terephthalate (PET) was used as a support and feedstock for the surface-assisted growth of UiO-66-Iopt. The as-prepared PET@UiO-66-Iopt exhibited a close-to-perfect selectivity and reusability for the separation of a wide range of CBs from nonchlorinated aromatic analogues.</p