Charge transfer structures

These charge-transfer structures have been studied [4] in terms a very limited number of END trajectories to model vibrational induced electron tiansfer. An electronic 3-21G-1- basis for Li [53] and 3-21G for FI [54] was used. The equilibrium structure has the geometry with a long Li(2)—FI bond (3.45561 a.u.) and a short Li(l)—H bond (3.09017 a.u.). It was first established that only the Li—H bond stietching modes will promote election transfer, and then initial conditions were chosen such that the long bond was stretched and the short bond compressed by the same (%) amount. The small ensemble of six trajectories with 5.6, 10, 13, 15, 18, and 20% initial change in equilibrium bond lengths are sufficient to illustrate the approach. 

Copolymers composed of electron-donating and electron-withdrawing units are considered to have intramolecular charge transfer structure.41 These copolymers show absorption bands at wavelengths longer than those of the corresponding homopolymers (Fig. 9.2). 

When the reaction is well-established as a radical one it is still possible to find explanations of polar substituent effects, usually in terms of ion-radical intermediates, dipole-dipole repulsion, solvation, or charge-transfer structures like those postulated for -complexes.488 Reac-... 

M. Matsumi, K. Naka, and Y. Chujo, ir-Conjugated poly(cyclodiborazane)s with intramolecular charge transferred structure, Macromolecules, 33 3956-3957, 2000. 

Variable charge-transfer structures of nitrosonium-EDA complexes leading to thermal and photo-induced electron transfer 224... 

Axial and oblique structures of EDA complexes with diatomic acceptors 225 Charge-transfer in weak and strong aromatic EDA complexes 226 Charge-transfer structures of aromatic complexes with the nitrosonium cation 228... 

CHARGE-TRANSFER STRUCTURES OF AROMATIC COMPLEXES WITH THE NITROSONIUM CATION... 

When sodium lignosulfonate or sulfur lignin are compounded, for instance, with iodine or bromine, complexes supposedly form (16-17). These systems are conductors with mixed ionic and electronic nature. Presumably they are charge transfer complexes, since the electronic conductivity predominates (18-19). These compounded materials form charge transfer structures (20). Water is supposed to introduce ionic conductivity to the system. Impurities affect conductivity, too (21). In any case, the main models of conductivity are probably based on the band model and/or the hopping model. 

C. Charge-Transfer Structures of Bis(arene)iron(II) Acceptors with... 

The ionic charge transfer structures involve the double bond coupling at meta positions occuring three times in contrast to ortho and para bonds, where 7r-electron perfect spin... 

The band around 260 nm has been assigned by Nagakura and co-workers [ 12] as being produced in ca, 6% by the internal charge-transfer structure. 

Maeda K, Kashiwabara T, Tokuyama M, Mechanism of the chemiluminescence of lucigenin. 2. The charge-transfer structure of lucigenin and reduction of by electron transfer from nucleophiles. Bull Chem Soc Jpn 1977 50 473-81. 

Dicyano compoimds undergo poly(cyclodiborazanes) (19), which have proven relatively stable towards air and thermal oxidation (eq. 19) (77-79). Some examples have been prepared where the dicyano compound allows for incorporation of a charge transferred structure (80). These exhibit extended r-conjugation through the cycloborazane unit. 

Recently, a series of chemical substances called functional dyes have attracted considerable attention. Because such dyes have long conjugated pi-electron systems and in many cases possess intramolecular charge transfer structures, functional dyes are expected to show interesting optical and electronic properties. Among functional dyes, phthalocyanine compounds have been extensively investigated because of their excellent physical, chemical and coloristic properties, as mentioned above. For example, about 1000 related US patents, published from 1990 onwards, are retrievable from the World Patent Index data base of Derwent, and more than 30 % of these are classified in such non-colorant applications as electrophotography, catalysis, and infrared radiation absorption. 

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