Donor-acceptor structure

Donor/Acceptor (Structural) Effects on n-Halogen Interactions 3.4.1... 

Transition state has no bonding to H which is therefore in a hydride-like (H ) circumstance. The electron density available for bonding (2 electrons in a formal hydride-transfer reaction) is thus sequestered on H and shared neither by the donor moiety nor the acceptor moiety in the critical state for the identity reactions (rate constant ku). For the acceptor moiety, this corresponds to no change in electron density and for the donor moiety a decrease of unit electron density, as in the equilibrium (Kio) reaction. Thus ku and KiQ respond equally to donor/acceptor structure (d[ln(feii)]/d[ln(Kio)] — +1) and t — 1 — 1 = 0. 

Transition state has unit total bond order to H, as is the case in both reactant and product states. The gain in bond order of the forming bond compensates exactly in the transition state for the loss in bond order of the breaking bond. The gain in electron density in the acceptor moiety for the identity reaction is exactly compensated by the loss in electron density from the donor moiety and ku is independent of donor/acceptor structure (d[ln(feii)]/d[ln(Kio)] — 0). Thus r = 1 — 0 — 1. 

Figure 2. Donor-acceptor structure of the reaction center of Rb. sphaeroides.

Table 14.2. Contributions Co(i), C2(i), C3(f) of the six donor-acceptor structures in the three Slater determinants 4 0. 4 2d i 4 3 built of molecular orbitals at the three reaction stages reactant (R), intermediate (I), and product (P)". The Co(OI > 0.5 are in bold.

For the realization of narrow band gap polymers, a useful synthetic strategy consists in copolymerizing an electron-rich and an electron-poor unit, to obtain a donor-acceptor structure. An example of this alternating donor-acceptor architecture has been reported by Jenekhe [36] with the synthesis of the copolymer PNIBT consisting of an electron-donating dialkoxybithiophene and... 

We would like to know the a, b, c values at various reaction stages, because we could then calculate the coefficients Co, C2 and C3 for the DA as well as for other donor-acceptor structures (e.g., D+A , see below) and deduce what really happens during the reaction. 

Table 14.3. Contributions of the six donor-acceptor structures in the Pq Slater determinant at three different stages (R, I, P) of the reaction [S. Shaik, J. Am. Chem. Soc. 103 (1981) 369Z Adapted with permission from the American Chemical Society. Courtesy of the author.]...

High crystallinity and large surface area are also obtained by incorporating triphenylene and diimide as donor and acceptor building blocks, respectively, in COFs. COFs with large pore dimensions, resulting from variation of the donor-acceptor structure, play an important role in charge transfer and separation in lattices. ... 

Kim E, Kim M, Kim K (2006) Diarylethenes with intramolecultir donor-acceptor structures for... 

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