Bimolecular interaction

The coefficient Bij characterizes a bimolecular interaction between molecules i and J, and therefore Bij = Bji. Two lands of second virial coefficient arise Bn and By, wherein the subscripts are the same (i =j) and Bij, wherein they are different (i j). The first is a virial coefficient for a pure species the second is a mixture property, called a cross coefficient. Similarly for the third virial coefficients Cm, Cjjj, and are for the pure species and Qy = Cyi = Cjn, and so on, are cross coefficients. 

To explain the observed magnitude of E and other kinetic features of reaction, a homogeneous bimolecular interaction between neighbouring CIO4 ions in the crystal structure was postulated and application of the activated complex theory to this model gave good agreement with the experimental observations. 

Both the onset of binding, when the radioligand is first applied, and offset, when dissociation is promoted, can be studied directly. The relevant kinetic equations relating to the simple bimolecular interaction of ligand with receptor are presented in Chapter 1, Section 1.3. 

To construct the Hill plot (Figure 5.10E), it was assumed that fimax was 0.654 fmol/mg dry wt., the Scatchard value. The slope of the plot is 1.138 with a standard deviation of 0.12, so it would not be unreasonable to suppose % was indeed 1 and so consistent with a simple bimolecular interaction. Figure 5.10B shows a nonlinear least-squares fit of Eq. (5.3) to the specific binding data (giving all points equal weight). The least-squares estimates are 0.676 fmol/mg dry wt. for fimax and... 

The next group of bimolecular interactions (3) shown in Table 1, includes noncontact interactions, in which fluorescence quenching occurs due to radiative and nonradiative excitation energy transfer [1, 2, 13, 25, 26]. Energy transfer from an excited molecule (donor) to another molecule (acceptor), which is chemically different and is not in contact with the donor, may be presented according to the scheme ... 

The rate of complex formation in a bimolecular interaction described in Section 2.1 is simply described by the equation ... 

The data for the ferricenium half-reaction deserve several comments. The Michaelis-Menten kinetics obtained in the UV-vis experiment supports the formation of the GO-ferricenium intermediates postulated in Scheme 5. The ratio k2i)/K which corresponds to the bimolecular interaction of GO(red) with the ferricenium ion, equals ca. 1 x 105 M-1 s 1 (79) and this must be compared with the observed rate constants of 1.4 x 105 M-1 s 1 found for ferrocene using the electrochemical technique under similar conditions (87). 

For this discussion, bioactive peptides will be defined as peptides which interact specifically with a target macromolecular acceptor or are derived from domains involved in a critical protein-protein interaction and, therefore, can compete effectively to mimic or disrupt this bimolecular interaction. Once the structure-activity relationship of a bioactive peptide is revealed, one can identify the termini and/or positions in which introduction of a caging group will be disruptive for target recognition. Alternatively, caging the peptide in an inactive conformation can be accomplished by end-to-end or end-to-side-chain cyclization. 

The photodimerization of cinnamic acid and similar molecules is observed in crystals, but reactions of the same type occur in some polymers as well. Polymers such as polystyrene are made of long, saturated hydrocarbon chains with pendant groups in close contact dangling from the chain these chromophores can then interact in bimolecular photoaddition reactions. Polyvinyl car bazole and its derivatives are important examples of polymers which lead to such bimolecular interactions (e.g. exciplex formation). 

Detailed reaction dynamics not only require that reagents be simple but also that these remain isolated from random external perturbations. Theory can accommodate that condition easily. Experiments have used one of three strategies. (/) Molecules in a gas at low pressure can be taken to be isolated for the short time between collisions. Unimolecular reactions such as photodissociation or isomerization induced by photon absorption can sometimes be studied between collisions. (2) Molecular beams can be produced so that motion is not random. Molecules have a nonzero velocity in one direction and almost zero velocity in perpendicular directions. Not only does this reduce collisions, it also allows bimolecular interactions to be studied in intersecting beams and increases the detail with which unimolecular processes that can be studied, because beams facilitate dozens of refined measurement techniques. 

The most important mode of termination of a radical polymerization is the bimolecular interaction of its reactive centers. Radicals rapidly recombine or disproportionate, and these reactions anihilate the growing ends. On the other hand, neither recombination nor disproportionation takes place in an ionic polymerization, and hence a collision between two ionically growing centers usually does not lead to termination. 

Figure 25.7 Bimolecular interaction analysis-mass spectrometry.

Coke formation is considered, with just cause, to be a malignant side reaction of normal carbonium ions. However, while chain reactions dominate events occurring on the surface, and produce the majority of products, certain less desirable bimolecular events have a finite chance of involving the same carbonium ions in a bimolecular interaction with one another. Of these reactions, most will produce a paraffin and leave carbene/carboid-type species on the surface. This carbene/carboid-type species can produce other products but the most damaging product will be one which remains on the catalyst surface and cannot be desorbed and results in the formation of coke, or remains in a noncoke form but effectively blocks the active sites of the catalyst. 

On the assumption of bimolecular interactions of rigid molecules, Denm depends only on the translational and rotational degrees of freedom of molecules n and m. Let xj, be the six coordinates of molecule a in unit cell n. Using (2.9) with appropriate coefficients eq s, // may be expressed in terms of phonon operators ... 

All the above-mentioned pharmacokinetic-dynamic models are characterized by reversibility of the drug-receptor interaction. In several cases, however, drug action relies on an irreversible bimolecular interaction thus, enzyme inhibitors and chemotherapeutic agents exert their action through irreversible bimolecular interactions with enzymes and cells (bacteria, parasites, viruses), respectively. 

Grubbs WT, Dougherty TP, Heilweil EJ. Bimolecular interactions in (Et)3SiOH base CCl4 hydrogen-bonded solutions studied by deactivation of the free OH-stretch vibration. J Am Chem Soc 1995 117 11989-11992. 

Sawamoto and Higadiimura have continued their investigation of the stop-flow spectroscopic behaviour of the polymerisation of p-methoxystyrene and added triflic acid to the series of catalysts previously tried. Again, they observed the typical absorption around 380 nm, attributed to the protonated monomer and calculated an initiaticm rate constant at 30 °C in ethylene chloride (assuming a bimolecular interaction orders not determined) kj = 5 x 10 s . This value is expectedly much... 

An equilibrium condition between V and VI, however, is also conceivable in the present case, owing to the thermodynamic instability implied in the gem-inal substitution of isopropyl and dimethylamino groupings. The persistence of VI in the reaction medium would give opportunity for a bimolecular interaction in the Michael mode with a second mole of substrate. The ensuing rare fragmentation that liberates the amine portion from VII looks more familiar if one draws it in parallel with the hydrolysis-decarboxylation of a l3-keto ester. 

Jet cooling may reveal weakly fluorescing systems, since some non-radiative decay processes become less efficient in that environment, particularly bimolecular interactions. Thus, exciplexes formed between aromatic molecules acceptors and tertiary amine donors have long been known to fluoresce, whereas under ambient conditions exciplex emission from pairs in which the tertiary amine has been replaced by a secondary of primary amine is rare. Anner and Haas observed exciplex emission from an anthracene-ammonia adduct in a jet [40] and Drescher et al. [41] reported weak exciplex emission from a /i-methylstyrene-diethylamine adduct... 

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