Amines cations

Collectors Fitting into Fattice Cavities. Lattice site fitting of collectors at sohd walls has been invoked as a means of explaining the selective behavior of amines (cationic coUectors) as reagents in the flotation-separation of soluble salt minerals such as KCl and NaCl (22). 

ION-SELECTIVE ELECTRODES REVERSIBLE TO PHYSIOLOGICALLY ACTIVE AMINE CATIONS THE MAIN WAYS FOR CONTROLLING POTENTIOMETRIC SELECTIVITY... 

The primary, secondary, and tertiary aliphatic amines do not form simple addition complex ions with bare transition metal ions. Only Ag+ reacts with MeNH2 to form a simple addition product [AgMeNH2]+ (107). The Pb+ ion also forms addition products, [PbMeNH2]+ and [Pb(MeNH2)2]+, with methylamine (143). Other bare transition metal ions (144) react with amines via removal of one hydrogen to form the metal hydride and the amine cation with one hydrogen removed [RR N]+. 

Ingemann, S. Hammerum, S. Derrick, P.J. Secondary Hydrogen Isotope Effects on Simple Cleavage Reactions in the Gas Phase The a-Cleavage of Tertiary Amine Cation Radicals. J. Am. Chem. Soc. 1988, 770,3869-3873. 

Goto et al. (2004) measured the reaction kinetics of one-electron oxidation of A -methyl-p-anisidine in AN. In the electrode process, oxidation was performed at the platinum disk-shaped anode, in the chemical process, by means of the tris(p-bromophenyl)amine cation-radical. In both the cases, after one-electron oxidation, dimerization took place leading to the formation of the dye variamine blue. According to the kinetic data, the mechanism of this dye formation is different in the electrode and chemical processes (see Scheme 2.34). Namely, in the electrode oxidation, the cation-radical appears to be surrounded by a huge amount of the initial (nonoxidized) A-methyl-p-anisidine... 

The attack of monomeric cation-radical of aniline on oligomeric amine cation-radical leads to chain growth. The chain growth can also proceed as copolymerization of two oligomeric species (Scheme 4.33). 

The linear polymerization of Scheme 7.15 represents an unusual case of diazoacetophenone oxidation. For instance, on the action of copper oxide, diazoacetophenone gives ketocarbene, which is involved in typical carbene reactions such as dimerization, addition to olefins, and insertion in the 0-H bonds of alcohols. If the amine cation-radical is used as an oxidant instead of copper oxide, only the polymer is formed. The ketocarbene was not observed despite careful searches (Jones 1981). 

The photolysis of donor-acceptor systems provides unique synthetic opportunities. Direct irradiation of the donor-acceptor systems, such as systems containing arene and amine components, leads to intramolecular electron transfer, that is, to amine cation-radical and arene anion-radical moieties. After generation, these moieties undergo cyclization reactions providing efficient synthetic routes to fV-heterocycles with a variety of ring sizes. Thus, direct irradiation of secondary amino-ethyl and aminopropyl stilbenes leads to benzazepines in improved yields (Hintz et al. 1996). As known, benzazepines are used in medicine as antidepressants. Scheme 7.44 illustrates ion-radical cyclization with the formation of benzazepine derivative (65% yield). 

Here pn is 1,2-diaminopropane and bn is 2,3-diaminobutane. Decomposition of the amine cation radicals obtained by photooxidation of the ligands en, bn, and pn have been discussed by Moeller. The products of Co(en)33+ photolysis can be satisfactorily explained by postulating that carbon-carbon bondbreaking is the principal step in decomposition of the cation radical H2NCH2CH2NH2t.58 Presuming a similar mechanism to obtain in photoreduction of Co(pn)33+, there are then two possible reaction pathways leading to different products. 

Intermolecular a-dimer cations are known for thioethers but dimeric amine cation species are not well characterized in solution. However, an example was detected in a zeohte the confinement in the narrow channels and the restricted diffusion favor interaction between the two entities. 

Using this method, the dimerization reactions of short lived methyl-diphenylamine and diphenylamine radical cations are successfully investigated61. In this study tris(4-bromophenyl)amine cation radical (TBPA,+) was used as 1 . Oyama et al.,94 used tris(2,4-dibromophenyl)amine (TDBPA) as the reaction initiator (M,+) and spectroscopically detected anthracene derivative cation radicals in acetonitrile using the ESTF method. This approach holds good potential for evaluation of the reactivities of short lived cation radicals. 

The Effects of Complexing Agents. Cai et al.66 replaced the sodium counterion of MX-DNA with various aliphatic amine cations, e.g. spermine cation, and alkyltrimethylammonium cation as well as polymeric amine cations, such as poly-L-lysine and polyethylenimine to vary the separation between DNA duplexes. The radiation-produced electrons from the complexing agents readily transfer to the more electron affinic DNA. 

There is no evidence for ground state charge-transfer complex formation between stilbenes and neutral amines. Amine cations and dications are powerful electron acceptors and can form ground state complexes in which t-1 serves as the electron donor. Complex formation between t-1 and the organic dication methyl viologen is responsible for quenching of the fluorescence of surfactant stilbenes in organized assemblies (112). 

Kayser and Young also examined the fate of the semireduced dye radical (36). In the absence of a monomer, they report that the dye and the amine are completely regenerated if the amine was an arylamine or DABCO. However, for other aliphatic amine quenchers complete back electron transfer to regenerate starting materials does not occur. Instead, permanent photo-bleaching of the dye resulted. The intermediate MB- decays by a second-order process thought to involve a-amino radicals produced from the amine cation radical ... 

Excess ground state MB deprotonates the amine cation radical (eq. 11) to afford the a-amino radical. Bimolecular coupling with MB- yields a reduced, leuco dye eq. 12. 

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