3- propyl-4,4 -bipyridinium

Di(N-fluoro-propyl bipyridinium)-butylene [(F(CH2)3BiPy)2(CH2)4] + C3oH3gF2N4 490.63... 

Bipyridinium, poly(iV-vinylbenzyl-iV -n-propyl)-in photochemical hydrogen production from water, 6, 505... 

In accordance with the above, three different 4,4 -bipyridinium dications of type 28 with R = H, CH or were prepared as their (di-)hexafluorophosphate salts. Heating of an acetonitrile solution of each of these with four mole equivalents of bis-/ -phenylene-34-crown-10 for 10 days at 60 °C led to isolation of the corresponding rotaxanes in 52, 45 and 47% yields, respectively. When the concentration of the crown was doubled, the yield of the first product increased to 87%. Significantly, when the size of the stopper was increased such that R corresponded to wo-propyl, it was no longer possible to synthesise the corresponding product by this procedure at a preparatively useful rate namely, the rate of formation was inhibited by around ten-fold. 

PVBV and PVAV quenched [Ru(bipy)3] with rate constants fcq = 2.7x10 and 3.1 x 10 mol dm s- respectively, with fcb = L8 x 10 moP dm s in both cases. In the presence of EDTA, the yield of PVBV on photolysis was 6.3% and in the presence of colloidal platinum (protected by the in situ polymer), the hydrogen yield was only 5% of that observed for an equivalent system containing MV " in place of PVBV " and with the Pt supported by carbowax 20M. Matsuo and coworkers " examined poly(N-vinylbenzyl-lV -n-propyl-4,4 -bipyridinium) (PVIOO " ) in conjunction with [Ru(bipy)3] " and the results are collected in Table 9. The quenching... 

A-fluoro-propyl-4,4 -bipyridinium bis((trifluoromethyl)sulfonyl)imide... 

Highlights of research results from the chemical derivatization of n-type semiconductors with (1,1 -ferrocenediyl)dimethylsilane, , and its dichloro analogue, II, and from the derivatization of p-type semiconductors with N,N -bis[3-trimethoxysilyl)-propyl]-4,4 -bipyridinium dibromide, III are presented. Research shows that molecular derivatization with II can be used to suppress photo-anodic corrosion of n-type Si derivatization of p-type Si with III can be used to improve photoreduction kinetics for horseheart ferricyto-chrome c derivatization of p-type Si with III followed by incorporation of Pt(0) improves photoelectrochemical H2 production efficiency. Strongly interacting reagents can alter semicon-ductor/electrolyte interface energetics and surface state distributions as illustrated by n-type WS2/I-interactions and by differing etch procedures for n-type CdTe. 

The first results have been reported of the synthesis of l,T-bis[3-(trimethoxysilyl)propyl]-4,4 -bipyridinium bromide and of its use in the de-rivatization of Pt or p-type Si electrodes. In the dark, p-type Si is blocking to reduction but illumination with light of greater energy than the band gap results in reduction of the surface-confined reagent. This surface will reduce a variety of species such as Fe(f/ -CjH5)2 in MeCN, or [Ru(NH3)g] in water, and is... 

Copolymers of vinyl viologens, such as N-vinylbenzyl-N -alkyl and benzyl and N-(x-mefliacroyloxy)propyl-N -propyl-4,4 -bipyridinium dihalides and polar aprotic comonomers, such as N- vinyl-2-pyrrolydone or N.N dimethylacrylamide exhibit a strong color formation upon irradiation. One such copolymer can be illustrated as follows ... 

Kelaidopoulou A, Kokkinidis G, Coutouli-Argyropoulou E (1998) Electrochemical behavior of N-methyl-N-(3-indol-l-yl-propyl)-4,4 -bipyridinium. Anodic polymerization and redox properties of the viologen unit of monomer and polymer film. Electrochim Acta 43 987-997... 

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