Neutral-molecule binding

and Cram, J. M., Container Molecules and their Guests, The 

Cavitand A molecular host that has an enforced concave surface, producing a cavity. 

Caviplex The term given to the complex between a cavitand and a guest molecule. 

A cyclophane is a compound that has a MANCUDE ring system, that is to say, a MAximium number of NonCUmulative DoublE bonds, or assemblies of MANCUDE ring systems. 

Cyclophanes contain atoms and /or saturated or unsaturated chains as alternate components of larger ring systems (cf. compounds 2.117a and 2.117b). 

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Although it is not surprising that anions have a rather high affinity for protons, it is also found that neutral molecules bind protons with the release of energy. Table 9.3 shows the proton affinities for some neutral molecules having simple structures. 

Restraints can facilitate docking a substrate molecule to a binding site. Restraints can also facilitate the interaction of two molecules in solution. In both cases, it is unlikely that two different neutral molecules would come into van der Waals contact with each other without the use of restraints. 

Urographic contrast agents are contrast agents which possess the characteristics of very little enteral absotp-tion, almost no protein binding or uptake into cells, an extracellular (interstitial) distribution and glomerular filtration. These pharmacokinetics are due to very little interaction with the organism, resulting in very low toxicity, preferably nonionic (neutral) molecules. 

There is not a unique binding site for all sorts of xenobiotics, but the compounds are intercalated in such a way into the membrane that they interact most favourably with the membrane components and with least perturbation. Some compounds, such as hydrophobic and neutral molecules, are actually dissolved in the membrane interior, whereas others exhibit more specific interactions in the polar region of the membrane. In general, interaction of the xenobiotics with the head groups leads to a stronger perturbation of the bilayer than intercalation in the membrane core [170]. 

See also Supramolecular architectures Supramolecular assemblies anion binding in, 24 43-47 binding neutral molecules in, 24 47-49 bottom-up nanoscale fabrication in, 24 61 cation binding in, 24 40-43 current and anticipated applications for, 24 52... 

Inhibitors that bind to free virus particles have been little investigated in the past with the notable exception of rhinoviruses, where a number of quite potent molecules bind to the external protein of the virus and hence inhibit latter stages of virus uncoating. Possibly the only compound known at present, apart from disinfectants, that could affect the virus stability is A1-721, a mixture of neutral... 

Positively charged stopcocks can be plugged in the zeolite channels by ion exchange, whereas neutral stopcocks can be added by dehydration of the zeolite channels and adsorption from a nonaqueous solution or from the gas phase. The zeolite s external surface consists of a coat and a base. These two surfaces differ in a number of properties so that the interactions can be tuned. For MFI- and FAU-type zeolites, as an example, it was reported that guest molecules bind to the holes on the external surface much more strongly than on the framework between the holes [38,39]. 

In aqueous solutions, the high negative surface charge of a zeolite must be neutralized by binding counterions, such as Na+, K+, and Ca +. The distribution of zeolite pore size can be modified, such that small molecules are included in the pores those too large to diffuse into the pores are excluded. Structure types are named by a three-letter lUPAC code, based in part on the name of the zeolite first used to identify the specific type. They are also classified by pore size, framework density, and/or symmetry. 

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