Synthesis of a Poly(3-dodecylthiophene) Bearing Aniline Groups for the Covalent Functionalization of Carbon Nanotubes

The functionalization of carbon nanotubes by polymers necessitates two steps, first their modification by oxidizing them or by covalently attaching small compounds to them, then the growth of the polymer chains from these anchors or their grafting onto them. In order to better control the process and the rate of functionalization, we develop polymers able to covalently react with the carbon nanotubes by their side chains in one step. We describe the synthesis of a copolymer of dodecylthiophene and its analogue bearing an aniline group at the end of the dodecyl side chain. This copolymer can functionalize single-walled carbon nanotubes (SWNTs) non-covalently and disperse more SWNTs than its hexyl analogues. UV-Vis and fluorescence spectroscopies show that in these non-covalent hybrids, the polymer forms p-stacked aggregates on the SWNTs. The non-covalent hybrids can be transformed into covalent ones by diazonium coupling. In these covalent hybrids the polymer is no longer p-stacked. According to Raman spectroscopy, the conformation of the poly(3-hexylthiophene) backbone is more ordered in the non-covalent hybrids than in the covalent ones.

Substituent Effects on Absorption Spectra of 7-Amino-4-Hydroxynaphthalene-2- Sulfonic Acid Based Dyes

The synthesis of dyes derived from coupling 7-amino-4-hydroxynaphthalene-2-sulfonic acid (a diazonium salt) with different coupling agents (phenol, p-nitrophenol, vanillin and salicylic acid) respectively yielded four different dyes namely; Dye A, 4-hydroxy-7-((2- hydroxyphenyl)diazenyl)naphthalene-2-sulfonicAcid, Dye B, 4-hydroxy-7-((2-hydroxy-5- nitrophenyl)diazenyl)-4-hydroxynaphthalene-2-sulfonic Acid, Dye C, 7-((2-formyl-5-hydroxy-4-methoxyphenyl)diazenyl)-4- hydroxy naphthalene-2-sulfonic Acid and Dye D, 2-hydroxy-6-((5-hydroxy-7-sulfonaphthalene-2-yl)diazenyl)benzoic Acid. The wavelengths of maximum absorption of the dyes were determined in different solvents; water, DMF, ethanol and acetone, their λmax was between 510-600nm. The synthesized dyes were characterized using IR and their melting points determined. The dyes were applied on wool and silk and the effect of pH, time, temperature on the %exhaustion for both fabrics was determined. The optimum pH for absorption of the dyes on both fabrics was 3 & 5, optimum time 50, 75 & 90 minutes and optimum temperature75 and 90oC depending on the dye and type of fabric. The Fastness (wash, rub and light) properties of the dyes were also assessed. Keywords: Diazonium, coupling, exhaustion, fastness

Diazonium-functionalized thin films from the spontaneous reaction of p-phenylenebis(diazonium) salts

Salts of the diazonium coupling agent <i>p</i>-phenylenebis(diazonium) form diazonium-terminated conjugated thin films on a variety of conductive and nonconductive surfaces by spontaneous reaction of the coupling agent with the surface. The resulting diazonium-bearing surface can be reacted with various organic and inorganic nucleophiles to form a functionalized surface. These surfaces have been characterized with voltammetry, XPS, infrared and Raman spectroscopy, and atomic force microscopy. Substrates that can be conveniently and quickly modified with this process include ordinary glass, gold, and an intact, fully assembled commercial screen-printed carbon electrode. The scope and convenience of this process makes it promising for practical surface modification.

Diazonium-functionalized thin films from the spontaneous reaction of p-phenylenebis(diazonium) salts

Salts of the diazonium coupling agent <i>p</i>-phenylenebis(diazonium) form diazonium-terminated conjugated thin films on a variety of conductive and nonconductive surfaces by spontaneous reaction of the coupling agent with the surface. The resulting diazonium-bearing surface can be reacted with various organic and inorganic nucleophiles to form a functionalized surface. These surfaces have been characterized with voltammetry, XPS, infrared and Raman spectroscopy, and atomic force microscopy. Substrates that can be conveniently and quickly modified with this process include ordinary glass, gold, and an intact, fully assembled commercial screen-printed carbon electrode. The scope and convenience of this process makes it promising for practical surface modification.

Diazonium-functionalized thin films from the spontaneous reaction of p-phenylenebis(diazonium) salts

Salts of the diazonium coupling agent <i>p</i>-phenylenebis(diazonium) form diazonium-terminated conjugated thin films on a variety of conductive and nonconductive surfaces by spontaneous reaction of the coupling agent with the surface. The resulting diazonium-bearing surface can be reacted with various organic and inorganic nucleophiles to form a functionalized surface. These surfaces have been characterized with voltammetry, XPS, infrared and Raman spectroscopy, and atomic force microscopy. Substrates that can be conveniently and quickly modified with this process include ordinary glass, gold, and an intact, fully assembled commercial screen-printed carbon electrode. The scope and convenience of this process makes it promising for practical surface modification.

Antibacterial Drug Releasing Materials by Post-Polymerization Surface Modification

Functional materials are available by the post-polymerization surface modification of diverse polymers in a three-step process mediated, firstly, by carbene insertion chemistry, secondly, by diazonium coupling, and thirdly by modification with a remotely tethered spiropyran unit, and these materials may be used for the reversible binding and release of Penicillin V. Surface loading densities of up to 0.19[Formula: see text]mmol/g polymer are achievable, leading to materials with higher loading densities and release behavior relative to unmodified controls, and observable antibacterial biocidal activity.

Synthesis and Characterization of a Series of 1-Aryl-4-[Aryldiazenyl]-piperazines. Part II1. 1-Aryl-4-(2-Aryl-1-Diazenyl)-piperazines with Fluoro-, chloro-, Methyl-, Cyano- and Acetyl Substituents in The 1-Aryl Group

This paper reports the synthesis and characterization of eight series of 1-aryl-4-(2-aryl-1-diazenyl)-piperazines (12 to 19). Several series of these triazenes have been synthesized by the diazotization of a primary arylamine followed by diazonium coupling with a secondary arylpiperazine . The arylpiperazines used in this study are: 1-phenylpiperazine, 1-(4-fluorophenyl-)piperazine, 1-(4-chlorophenyl-)piperazine, 1-(3,4-dichlorophenyl-)piperazine, 1-(2-methylphenyl-)-piperazine, 1-(4-acetophenyl-)-piperazine, 1-(2-pyridyl-)piperazine and 2-cyanophenylpiperazine. These new triazenes (series 12-19) have been identified with a cocktail of contemporary spectroscopic techniques, notably infra-red and nuclear magnetic spectroscopy, supported by high resolution electron ionization mass spectrometry.