Donor-acceptor molecules interactions

Energy transfer [3,12] between molecules has also been used in the design of optical sensors. Here, an excited molecule (donor) can transfer its electronic energy to another species (acceptor). This process occurs without the appearance of a photon and results from dipole-dipole interaction between the donor-acceptor molecules. The rate depends on the fluorescence quantum yield of the donor, the overlap of the emission spectra of the donor with the absorption of the spectrum of the acceptor, and their relative orientation and distance. It is the overlap of... 

In principle, aliphatic amines may interact as n electron donor molecules towards electron acceptor centres such as aromatic substrates, both homocyclic and heterocyclic, containing electron-withdrawing groups, usually nitro groups. These interactions are mainly electron donor-acceptor (EDA) interactions, in which aromatic amines are considered n or/and tt electron donors. 

The term charge tranter refers to a succession of interactions between two molecules, ranging from very weak donor-acceptor dipolar interactions to interactions that result in the formation of an ion pair, depending on the extent of electron delocalization. Charge transfer (CT) complexes are formed between electron-rich donor molecules and electron-deficient acceptors. Typically, donor molecules are p-electron-rich heterocycles (e.g., furan, pyrrole, thiophene), aromatics with electron-donating substiments, or compounds... 

Figure 20. Schematic diagram of the donor-acceptor site interaction between two molecules of deoxyhemoglobin S with two cyclic peptides designed to mimic the donor site (206).

Second, the interfacial dipole layer may be formed by the polarization of an electronic cloud within the molecules. The vacuum level shift at the interface is proportional to the component of the dipole moment perpendicular to the interface. Since the interaction is much stronger between nearest donor/acceptor molecules, it seems possible to elucidate the factors influencing the formation of the IDL by performing quantum-chemical calculations on just a dimer. 

The S scale was constructed from carefully selected data. Thus, it excluded data for (a) all systems involving any contribution from donor-acceptor specific interactions (donor molecules where only measured in donor solvents and data for ttsolutes were excluded) (b) concentrated solutions of polar molecules in non-polar solvents (which might result in clustering) and (c) polar solvents occurring as rotamers (each rotamer would be solvated in a different way). 

Molecules with Electron Donor-Acceptor Functional Groups. In a similar way, molecules carrying groups which are either Lewis bases (electron donors, D) or Lewis acids (electron acceptors. A) can also interact by sharing the electrons pair, so forming D A charge-transfer (CT) or electron donor-acceptor (EDA) interactions. 

Ko YH, Kim K, Kim E, Kim K. Exclusive formation of 1 1 and 2 2 complexes between cucurbit[8]uril and electron donor-acceptor molecules induced by host-stabilized charge-transfer interactions. Supramol Chem 2007 19 287-93. 

Hydrogen, being a non-polar molecule with weak donor-acceptor properties, interacts only weakly with oxide surfaces. The interaction depends strongly on the... 

Example If a drug molecule interacts with a receptor molecule through hydrogen bonds, then yon might restrain the distance between the donor and acceptor atoms involved in the hydrogen bonds. During a molecular dynamics simulation, these atoms would slay near an ideal value, while the rest of the molecular system fully relaxes. 

Morokuma K 1977. Why Do Molecules Interact The Origin of Electron Donor-Acceptor Complexes, Hydrogen Bonding, and Proton Affinity. Accounts of Chemical Research 10 294-300. 

For electron movement to occur, the donor and acceptor molecules must approach so that the donor HOMO and acceptor LUMO can interact. For example, the LUMO of singlet methylene is a 2p atomic orbital on carbon that is perpendicular to the molecular plane. Donors must approach methylene in a way that allows interaction of the donor HOMO with the 2p orbital. 

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