Donor-acceptor architecture

Fischer carbenes have been used as electron acceptors in a variety of donor-acceptor architectures. Values of /3= 16 and 34 x 10 ° esu were reported for 139 and 140 (Figure 13), respectively. A number of species with amino rather... 

S. J. Chen, A New Conjugated Polymer with Donor-Acceptor Architectures Based on Alternating 1,4-Divinyl-2,5-Dioctyloxybenzene and 5,8-(2,3-Dipyridyl)-Quinoxaline Synthesis, Characterization, and Photoinduced Charge Transfer. Express Polym. Lett. 2012,6,454-464. 

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... 

Figure 43 Liquid crystalline coronene derivative and perylene diimide used to produce self-organized donor/acceptor architectures for organic solar cells. °...

Some semiconducting organic CT complexes of mixed-stack architecture exhibit the rather unusual neutral-to-ionic (N-I) phase transition upon variation of an external variable of parameter hyperspace, such as P or r. The transition manifests itself by a change of q and a dimerization distortion with the formation of donor-acceptor dimers along the stacking axis in the I-phase. 

Fig. 3 Contemporary organic solar cell devices are based on donor/acceptor heterojunction device architectures, (a) Energy level diagram, (b) Planar heterojunction conligmation. (c) Bulk heterojunction configuration...

In summary, the ground-state features of exTTF-oPPE -Cgo prove the electron donor/acceptor character in these architectures and we should move on to the characterization of the excited state features, which revealed remarkable charge-transfer processes in these systems. 

Figure 16.4 Principle of the PCT (photoinduced charge transfer), chemically driven, luminescent molecular sensor based on the donor-spacer-acceptor architecture, (a) Binding of analyte trigger to the donor (green) moiety results in hypsochromic shift of absorption (emission) band (b) binding of the same analyte to the acceptor moiety (red) results in bathochro-mic shift of corresponding transition...

P-donor ligands usually form phosphorus-metal bonds with a main group or transition metal that are essentially covalent and in which the phosphorus is the lone pair donor. Despite the vast number of complexes prepared, often with elaborate architecture, the nature of the phosphorus-metal bond remains elusive and controversial, in particular, for transition metals. The simple statement of the bond as a neutral donor-acceptor complex has been elaborated by identifying the many contributing factors. We will discuss the steric factor and the electronic component of the P-M bond separately. The separation of the electronic component into a and n factors is a formal exercise, the reality being Synergic Bonding, wherein these electronic factors are mutually dependent. 

Ravikanth et al <03T6131> have reported meso- orp-furyl porphyrins with N3S and N2S2 cores 58-62. Porphyrins have generated a lot of interest as they can be good acceptors for efficient energy transfer in donor-acceptor type architectures. 

Another type of hydrogen bond involves 7i-facial interactions of the type illustrated in Figure 2.5.As an approximation, such arrangements can be considered to bear a relationship to both a classical donor-acceptor hydrogen bond as well as to a n-n bonded system (see below). Interactions of this type tend to be quite weak (1-5 kJ mol" ). However, they often act in a co-operative manner with other intermolecular interactions such that, for example, they help to dictate a precise orientation within a given supramolecular architecture. 

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