Effect of alkali metal ions

Sousa LR, Larson JM (1977) Crown ether model systems for the study of photoexcited state response to geometrically oriented perturbers. The effect of alkali metal ions on emission from naphthalene derivatives. J Am Chem Soc 99 307-310... 

Niaura and Jakubenas [124] have studied the effect of alkali metal ions on the SERS spectra of phosphate anions adsorbed at Ag electrodes. The formation of ion pairs at the interface has been confirmed. 

Chen, X., Shao, Z.Z., Knight, D.P., and Vollrath, F. "Conformation transition of silk protein membranes monitored by time-resolved FTIR spectroscopy Effect of alkali metal ions on Nephila spidroin membrane". Acta Chimica Sinica 60(12), 2203-2208 (2002c). 

Bhattacharya has also studied the effect of alkali metal ions on glucose uptake in rat hemidiaphragms and accumulation of D-xylose in the intact diaphragm in the absence of insulin. He finds that uptake of glucose and accumulation of xylose are highest with Li+ ions and follow the order Li+ > Na+ > K+ = Rb+ > Cs+, which is the same as the order of these ions in the so-called lyotropic or Hofmeister series. 

Bush ME, Forbes MW, Jockusch RA, Oomens J, Polfer NC, Saykally RJ, Williams ER (2007) Infrared spectroscopy of cationized lysine and epsilon-N-methyllysine in the gas phase effects of alkali-metal ion size and proton affinity on zwitterion stability. J Phys Chem A 111 7753-7760... 

A detailed investigation of the effects of alkali-metal ions on the oxidation of A/ -propyl-l,4-dihydronicotinamide, PNAH, by [Fe(CN)6] ,... 

The effect of alkali metal ions, notably potassium, seems to be on the latter process. The shape of the Pulver-Vefzar curves (71) suggests this possibility. Farmer and Jones (19) note that the maximum stimulation by potassium occurs when fermcuitation has proceeded only to a slight extent. ... 

Whittam, R., 1962b, Directional effects of alkali metal ions on adenosine triphosphate hydrolysis in erythrocyte ghosts. Nature 196 134. 

Watase, M., Nishinaii, K. Effect of alkali metal ions on the viscoelasticity of concentrated kappa-carrageenan and agarose gels. Rheol. Acta 21(3), 318-324 (1982)... 

Takenaka S, Tanaka T, Funabiki T, Yoshida S (1998) Effect of alkali-metal ion addition to silica-supported molybdenum oxide on photocatalysis photooxidation of propane and propene, and photo-assisted metathesis of propene. J Chem Soc Faraday Trans 94 695-700... 

The NH2 groups can be diazotized and reduced in the presence of thiosulphates and different metal ions. The effect of some metal ions, namely Fe ", Sn, Cu +, and Co on the graft yield of cotton modified with aryl diazonium groups via its reaction with 2,4-dichloro-6-(p-nitroaniline)-5-triazine in the presence of alkali and followed by reduction of nitro group was studied [4]. 

The reaction product SiF4 would be gaseous, but it reacts with two HF to Si I7 and two protons and stays in solution [Mellj. The solubility of Si 17, which is in the order of mol 1 1 is significantly reduced in the presence of alkali metal ions. Especially for Rb, K or Cs, a micrometer thick, insoluble layer of metal hexafluoro-silicate may be formed on the electrode surface [Hal2j. The divalent electrochemical dissolution reaction is dominant during PS formation. The effects of the reaction products SiFg and H2 on pore growth are discussed in Section 9.5. 

Similar effects of the cation of the supporting electrolyte occur, to a greater or lesser extent, in the reductions of alkali and alkaline earth metal ions in basic aprotic solvents [26a]. In dimethylacetamide (DMA), the reductions of alkaline earth metal ions are electrochemically masked by Et4N+. In DMF and DMSO, the reversibility of the reductions of alkali and alkaline earth metal ions decreases with the decrease in the cationic size of the supporting electrolyte. This effect is apparent from the kinetic data in Table 8.3, which were obtained by Baranski and Fawcett [23 b] for the reductions of alkali metal ions in DMF. 

The bouquet -type compounds 114 and 115 and related molecules thus form functional ion transfer entities. Further studies are required to ascertain the mechanism of transport and the effects of parameters such as membrane composition, nature of alkali metal ions and concentration of bouquet molecules on the transport rate in order to better describe the mode of action of these compounds. Ion transport by bouquet -type molecules related to 114 and bearing lateral macrocyclic units has been investigated [8.188]. 

The salen-Ni(II) complex 39a derived from (lR,2R)-[N,N -bis(2 -hydroxybenzyl-idene)]-l,2-diaminocyclohexane was also equally effective (Table 7.3, entry 4). In contrast to earlier reports on salen-metal complexes, where the introduction of a bulky tert- butyl substituent increased enantioselectivity [31], the use of complex 39b exhibited a significant decrease in enantioselectivity (entry 5). The presence of a bulky tert-butyl group obstructed the chelation of alkali metal ions by phenolic oxygen atoms. A dramatic increase in selectivity could be achieved when nickel was replaced with copper, and a salen-Cu(II) complex 39c afforded 85% ee (entry 6). Although screening of other bases or 50% NaOH were not advantageous, the use of 3 equiv. NaOH improved the enantiomeric excess to 92% (entry 9) and after recrystallization of a-methylphenylalanine optical purity was increased to 98% ee. 

This reaction is accompanied by complete combustion into water and carbon dioxide. The only selective catalyst known is based on silver. This catalyst was known as early as the 1930s and has been continuously improved since then in a rather empirical way. It has been discovered that the catalyst may be promoted by the addition of alkali metal ions. Moreover, the presence of chlorine has a beneficial effect (cf. Fig. 5.11) [94]. Chlorine has to be added continuously because it disappears from the surface by reacting to give chlorinated ethane. It is sufficient to mix 10-40 ppm chlorine with the feed. The feed consists of a mixture of... 

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