Electrophore

Kaess, A, Mathis, C Chromatogr Electrophor Symp Int 4th, %6, Ann Arbor Science Publishers, Michigan 1968... 

Qnadroni, M., et al., 1996. Analy.sis of global re.spon.ses by protein and peptide fingerprinting of protein.s i.solated by two-dimensional electrophore-.sis. Application to snlfate-starvation re.sponse of Escherichia coli. European Journal of Biochemistry 239 773-781. This paper de.scribes the n.se of tandem MS in the analysis of protein.s in cell extracts. 

The proposed mechanism for the conversion of the furanone 118 to the spiro-cyclic lactones 119 and 120 involves electron transfer to the a -unsaturated methyl ester electrophore to generate an anion radical 118 which cyclizes on the /3-carbon of the furanone. The resulting radical anion 121 acquires a proton, giving rise to the neutral radical 122, which undergoes successive electron transfer and protonation to afford the lactones 119 and 120 (Scheme 38) (91T383). 

A. J. Tomlinson and S. Nayloi, Enlianced peifoitnance membrane preconcentiation-capU-laiy electrophoresis-mass specti ometiy (niPC-CE-MS) in conjunction with transient isota-chophoi esis for analysis of peptide mixtures , 7. Capillary Electrophor. 2 225 - 233 (1995). 

A. J. Tomlinson, E. M. Benson, R. R Oda, W. D. Braddock, B. E. Riggs, J. A. Katzmann and S. Naylor, Novel modifications and clinical applications of preconcentration-cap-illaiy electi ophoi esis-mass specti ometiy , 7. Capillary Electrophor. 2 97-104 (1995). 

Electron donor-acceptor complexes, electron transfer in the thermal and photochemical activation of, in organic and organometallic reactions, 29, 185 Electron spin resonance, identification of organic free radicals, 1, 284 Electron spin resonance, studies of short-lived organic radicals, 5, 23 Electron storage and transfer in organic redox systems with multiple electrophores, 28, 1... 

Redox systems, organic, with multiple electrophores, electron storage and transfer in, 28,1... 

Electron Storage and Transfer in Organic Redox Systems with Multiple Electrophores... 

ORGANIC REDOX SYSTEMS WITH MULTIPLE ELECTROPHORES... 

The common feature of compounds [5]-[15] is that the electrophoric units are linked by saturated spacers, thus establishing only weak electronic (through-bond or through-space) interaction of the Tt-systems. In contrast, the binaphthyl [16], the biperylenyl [17] and the bianthryl [18] as well as the structurally related homologues [19], [20] and [21] allow for a direct 7r,7r-interaction of the subunits it will be shown, however, that for both steric and electronic reasons the inter-ring conjugation can be weak and thus lead to electronically independent redox groups in a similar fashion as in [5]-[15]. 

These structural factors are relevant for the redox-activity of bis- and oligo-electrophoric systems and for the reorganization energy associated with intramolecular electron hopping. 

Accordingly, dianthryl compounds with a close proximity, such as [6] and even [18], are capable of accepting four electrons although an appreciable electrostatic repulsion is built up (Becker et al., 1991 Huber and Mullen, 1980). When considering the question of how a bis-electrophore accommodates the extra charge it is important to note that, for example, the tetra-anion of di(9-anthryl)ethane [6] adopts an anti-conformation with respect to the central C—C bond, thus minimizing the electrostatic repulsion (Huber et al., 1983). 

It is straightforward in the charging of a layered electrophore to increase the interplane distance of the -layers and thus to relax the resulting Coulombic strain this approach is discussed for the doubly layered annulenes [14], In this particular case, a stable tetra-anion is available which can be characterized by a highly resolved H-nmr spectrum (Irmen et al., 1984). 

The situation is even more complicated when a tris-electrophoric system is charged. The first question is which subunit will be charged initially. Then, if a dianion with the two electrons in separate electrophores has been formed, the charges can reside either on neighbouring electrophores or on those allowing the greatest possible distance between charges (see Fig. 1). 

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