Adaptive chemistry

Lehn, J.-M. From supramolecular chemistry towards constitutional dynamic chemistry and adaptive chemistry. Chem. Soc. Rev. 2007, 36, 151-160. 

We have discussed the basis of an adaptive chemistry, whereby a system acquires the ability to perceive its environment and interact with it in a sensitive way. Under certain conditions, this interaction allows the system to capture the asymmetry of the external environment and translate it into the properties of a spatial pattern or of a rhythm. 

The is-olefin was prepared as a trans-amide bond replacement. A number of compounds incorporating substituents to mimic both natural and unnatural amino acid sidechains were prepared by adapting chemistry developed by Ibuka for the synthesis of Zs-olefin peptide isosteres (see Scheme l).40,41 The key step involved anti-SN2 displacement of vinyl mesylate 8 by boron trifluoride-activated cuprate addition. Compounds containing butyl, propyl, and benzyl substituents at the allylic positions to mimic the aj and sidechains produced potent FTase inhibitors (Table 4). 

Constitutional Dynamic Chemistry Bridge from Supramolecular Chemistry to Adaptive Chemistry... 

Keywords Adaptive chemistry Dynamic networks Dynamic polymers Molecular recognition Multiple dynamics Self-organization Supramolecular chemistry... 

N0rgaard K, Weygand MJ, Kjaer K, Brust M, Bjqmholm T (2004) Adaptive chemistry of bifunctional gold nanoparticles at the air/water interface. A synchrotron X-ray study of giant amphiphiles. Faraday Discuss 125 221-233... 

The challenge is to construct reduced chemistry models which are fast to evaluate, yet which still satisfy the error tolerance Eq. (13). One effective approach to this is the Adaptive Chemistry method (Schwer et al., 2003a, b), where different reduced chemistry models are used under different local reaction conditions. For example, in the 1—d steady premixed flame studied by Oluwole et al. (Oluwole et al., 2006), six different reduced chemistry models were used, and the full chemistry model only had to be used at about 20% of the grid points, Fig. 14. 

Fig. 14. Fraction of the grid points used by various models during a 1-d Adaptive Chemistry simulation of a premixed stoichiometric methane-air flame. The full chemistry model is GRI-Mech 3.0. Reduced models were accurate at about 80% of the grid points.

An example The temperature field computed for a partially-premixed radi-ally-symmetric methane/air flame is shown in Fig. 15. This is the same 4> — 2.464 laminar flame simulated by Bennett et al. (2000). We used the same 217 reaction full chemistry model used by Bennett et al. (2000) to compute the temperature field shown on the left-hand side of Fig. 15. On the left-hand side is shown the temperature field computed using the full chemistry model everywhere. On the right-hand side is shown the temperature field computed by the Adaptive Chemistry method using 13 different reduced models ranging in size from zero reactions to 156 reactions. As guaranteed by the error control... 

For the preparation of a series of glycoluril derivatives bearing a single aromatic sidewall and potentially nucleophilic ureidyl NH groups, we adapted chemistry developed by Nolte and Rebek. Deprotonation of glycoluril 1 with /-BuOK in DMSO followed by the addition of alkylating... 

The algebraic-differential equation system is then solved in much the same manner as for the QSSA approach. Because the formulation of Equation (25) yields for all species, the RCCE is particularly attractive in adaptive chemistry systems. 

Liang, L., Stevens, J.G., Farrell, J.T. (2009). A dynamic adaptive chemistry scheme for reactive flow computations. Proceedings of the Combustion Institute Vol. 32, pp 527-534. 

Schwer,D.A., Lu, P. Green, W.H. (2003). An adaptive chemistry approach to modeling complex kinetics in reacting flows. Combustion and Flame Vol. 133, pp 451-465. 

It is hard to find a topic in supramolecular chemistry that has not been touched, even briefly, by calixarenes or related macrocycles. This justifies the fact that we were compelled to give only a short summary of the properties of classical calixarenes as molecular receptors for ions and neutral molecules or as scaffolds for the construction of multivalent ligands able to interact with biomacromolecules. We believe, indeed, that these two aspects are the most peculiar and remarkable features of calixarenes, on which a variety of other complex supramolecular functions can be built. The future will certainly be bright for this class of synthetic macrocycles as their molecular recognition and scaffolding properties are likely to be exploited in the classical ways and also in novel forms within the framework of the third developing phase of supramolecular chemistry, namely, constitutional dynamic chemistry and adaptive chemistry. ... 

Widening the perspectives, one may consider that the science of flve-dimensional supramolecular materials in general and supramolecular polymer chemistry in particular, as part of dynamic constitutional chemistry [4], will strongly contribute to the emergence and development of adaptive chemistry [47] on the way toward complex matter. 

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