Electron donor-acceptor stack

Table 7 Effective electronic donor-acceptor coupling (in eV) mediated by of nucleobase pairs obtained with an effective Hamiltonian various r-stacks...

The generalization of the Hiickel model (1) to a donor-acceptor stack is through a site energy, ep = (—1)PA, that lowers the energy of electrons on odd-numbered D sites for A > 0. In principle we have different on-site U in (3) for donors and acceptors, but a single U is usually assumed. The Coulomb terms in (4) now have zp = 2 and 0 at odd and even sites, respectively, because neutral D and A require two and no electrons. The complete basis for a stack is identical to the PPP basis... 

Pi-stacking and electron donor-acceptor interactions have also been extensively used for designing host-guest complexes in a predictable manner [8]. 

Electron donor-acceptor (EDA) stacks have been accessed by Percec et al. [90] using partially fluorinated dendrons (Fig. 14) to form LC columnar phases. The self-assembly of the dendrons is primarily driven by phase segregation of the fluorinated chains and the aromatic units. Functionalization of the dendrons at their apex with either an aromatic electroactive donor (29a) or an acceptor (29b) group yields LC columnar structures, further aided by the additional interaction between the aromatic units, which have optoelec-... 

We discuss the interaction of a partially filled electronic conduction band in a segregated donor-acceptor stack system with libra-tional modes of the solid. The orientational Peierls instability predicted by us earlier leads to the formation of chiral charge density waves, which interact and phase-lock below the metal-insulator transition via the Coulomb interaction. The effect of the resulting order on the physical properties of the system and the implications for the understanding of the recent neutron scattering data for the occurrence of several transitions in TTF-TCNQ will be discussed. 

Chen and coworkers hypothesized that n-n stacking may also be modulated by n -electron donor-acceptor interactions." Under this theory, pristine, jr-electron-rich CNTs adsorb r-electron-poor nitroaromatic compounds more strongly than nonpolar aromatic compounds, and the adsorption affinity increases with an increasing number of nitro groups. 

Figure 3. Schematic representation of thermotropic mesophases based on charge-transfer induced formation of intercalated donor-acceptor stacks Ncoi nematic columnar and Colh columnar hexagonal ordered mesophase (see footnote 1 in Sec. 3 commenting on the nomenclature of such columnar mesophases). electron donor, electron acceptor.

Single-Stack Donor. Ion-radical salts can also be formed from electron donors such as tetrathiafulvalene (TTE) or TMPD (N,N,N N-tetramethyl- phenylene diamine) with inorganic acceptors such as halogens. The resulting stmcture of compounds such as TTE(A)... 

Charge-transfer adducts are formed with the gold(I) trimers [Au3(MeN=COR)3] (R = Me, Et), which act as electron donors, and organic electron acceptors as nitro-9-fluorenes. The structures of these adducts involve mixed stacks in which the gold trimers and the planar nitro-fluorenes are interleaved.3130 No luminescence has been observed from these solid charge-transfer adducts, which is not surprising since the luminescence of [Au3(MeN=COR)3] is a property that is associated with the supramolecular organization in the solid. 

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