Synthesis of poly(4-vinyl pyridine-b-methyl methacrylate) by MAMA-SG1 initiated sequential polymerization and formation of metal loaded block copolymer inverse micelles

Well-defined poly(4-vinylpyridine) (P4VP) was synthesised by nitroxide-mediated radical polymerization using the BlocBuilder MAMA-SG1. The controlled character of the polymerization was confirmed by kinetic measurements and linear increase of the molar mass with monomer conversion. Poly(4-vinylpyridine) terminated with SG1 was then used as macroinitiator and chain extended to form poly(4-vinylpyridine-b-methyl methacrylate) and poly(4-vinylpyridine-b-(methyl methacrylate-co-styrene)) block copolymers. These block copolymers spontaneously organized into spherical inverse micelles in THF with critical micelle concentrations of 0.1 mg/mL for poly(4VP₁₉₀-b-MMA₉₁) and 0.01 mg/mL for poly(4VP₁₉₀-b-(MMA₅₇-co-S₁₈)) and sizes of 70 and 130 nm (DLS), respectively. The inverse micelles were loaded with copper(II)acetate leading to a slight increase in micelle size. The uniform structure of the inverse micelles was confirmed by FeSEM images, while the presence of copper in the micelle core was established by energy-dispersive X-ray spectroscopy (EDX) and FTIR spectroscopy.     

Determination of the singlet state lifetime of dissolved nitrous oxide from high field relaxation measurements

Longitudinal spin relaxation due to modulation of dipolar interactions often limits the development of hyperpolarized magnetic tracers. Recently, it has been demonstrated that transferring spin order to a singlet state significantly increases the polarization lifetimes in systems where nitrous oxide is dissolved in a liquid solvent. Additionally, previous studies have suggested that the longitudinal relaxation of nitrous oxide is largely dominated by the spin-rotation interaction. Models of spin-relaxation under Brownian motion nai?vely predict the angular momentum reorienting correlation time of the spin rotation interaction to be inversely proportional to the viscosity of the solution. This dependence implies the singlet lifetime can be lengthened by increasing the dissolving solvent's viscosity-an extension which is not observed. Our work formulates a model which describes the relaxation of nitrous oxide dissolved in various solvents. We investigate the effect of altering the temperature of the solvent, as well as the effect of varying solute-solvent interactions on the singlet state as well as the longitudinal polarization lifetime. We predict the singlet lifetime for nitrous oxide dissolved in several solvents by fitting rotational and angular momentum correlation times measured at high magnetic field, and relate singlet relaxation to translational diffusion constants.     

Reductive Coupling of Carbonyl Compounds to Pinacols with Zinc in THF-Saturated Aqueous Ammonium Chloride

Summary.  In the presence of metallic zinc, aldehydes and ketones experience reductive coupling in tetrahydrofuran-saturated aqueous ammonium chloride (5:3) to afford the corresponding pinacols in moderate to high yields. Received October 23, 2000. Accepted (revised) December 12, 2000     

Synthesis and Crystal Structure of a new O,N Lithium Coordination Polymer

The reaction of 4‐Amino‐6‐methyl‐1, 2, 4‐triazine‐3(2H)‐thione‐5‐one (HAMTTO) with n‐butyl lithium in dimethoxyethane (DME) gives the complex [Li(DME)(AMTTO)] ( 1 ). 1 was characterized by elemental analysis, IR‐ and mass‐spectrometry and an X‐ray structure analysis [space group P2₁/n, Z = 4, lattice dimensions at —80 °C: a = 867.6(1), b = 1721.5(2), c = 931.8(1) pm, β = 112.81(1)°, R₁ = 0.0315. The complex is a coordination polymer along [001] with a zig‐zag arrangement.     

TBHP/R4N+X– promoted hydroaroylation of dialkyl azodicarboxylates with methyl arenes,aldehydes, aryl methanols and arylmethyl chlorides

Efficient TBHP/R₄N⁺X^– promoted hydroaroylations of dialkyl azo-1,2-dicarboxylates with methyl arenes, aldehydes, aryl methanols and arylmethyl chlorides are described. These oxidation/oxygenation and hydroaroylation processes were carried out by tert-butyl hydroperoxide as terminal oxidant/oxygen source, and were catalyzed by tetrabutylammonium bromide and tricaprylmethylammonium chloride as the driving force. During this investigation, all these hydroaroylating sources were found to be highly efficient reagents without the need of any transition-metal.     

Detection of hippuric acid: A glue solvent metabolite,using a mobile test kit

Many testing kits for screening common drugs are widely used in Malaysia, such as the dip strip urine drug testing kit which is specified for detecting drug in abuser. However, currently there is no specific testing kit for screening urine samples to detect glue abusers. This research is dedicated to develop a specific color test method to emphasize the screening for glue abusers, known as G.S. Kit. It contains benzenesulphonyl chloride, pyridine and distilled water. The urine sample is mixed with pyridine and benzenesulphonyl chloride and followed by distilled water. A positive result will be in the form of a color reaction from yellow to red. This novel G.S. Kit would be quite useful for the screening and detection of glue sniffing and toluene abusing qualitatively, as a way of helping National Anti Drug Agency, Department of Education and Royal Police of Malaysia in preventing glue sniffing from becoming a social pandemic.