β Scribed by K.H. van Streun; P. Piet; A.L. German
No coin nor oath required. For personal study only.
Almtraet--A photometric method is developed for the determination of the molar mass of 2,4-ionene by attaching a chromophoric moiety to its end-groups. Molar mass determination of these polyelectrolytes by acid-base titration of the amine end-groups is also possible, and confirms the photometric method. The effects of molar mass of 2,4-ionenes on the oxidative coupling of 2-mercaptoethanol (ME) was studied in the presence of cobalt(II)phthalocyanine-tetra-sodium-sulphonate (CoTSPc). Monomeric analogues of 2,4-ionene showed no increase of reaction rate as compared with the polymer-free system. However, relatively low molar mass ionene (M, = 1740) showed a dramatic increase of reaction rate. The reactivity showed an optimum around pH = 8. Saturation kinetics (Michaelis-Menten kinetics) were observed. The calculated turnover number was 3200 sec-t and3600sec 1 for)kl"n= 6600and h,St, = 1740, respectively. The stoichiometry of the reaction was disturbed at low thiol concentration.
π SIMILAR VOLUMES
Because buffers can act as metal ligands, they can effect several reactions necessary for DNA oxidation by ferric iron and thiols, such as iron reduction. Therefore, these reactions were studied in Hepes and phosphate buffers and unbuffered NaCl. Reduction of Fe β«3β¬ by dithiothreitol (DTT) and cyste
The cluster (nBu N) [Fe S (SR) 1, the analogue of the active site of nonheme iron-sulfur p ot 4 $ ins, 4 $atal$zed the oxidation of thiols to disulfides extremely and the llgand effects for the catalytic oxidation were investigated.
## Abstract Polyphenylene oxide (PPO) was prepared via oxidative coupling polymerization of 2,6βdimethylphenol (DMP) catalyzed by copper salt. The ligand was a novel series of random copolymers (PSVP) of styrene and 4βvinylpyridine prepared by reversible additionβfragmentation chain transfer (RAFT)