Carcerands host-guest complexes

Carceplexes and hemicarceplexes, host-guest complexes in which carcerands and hemicarcerands, in particular those including heterocyclic fragments, are hosts 99CRV931. 

Tunstad LM et al (1989) Host-guest complexation 48. Octol building blocks for cavitands and carcerands. J Org Chem 54 1305-1312... 

A key issue in such studies is the timescale of the measurement. Remember that the total binding energy for a host-guest complex is much less than a covalent bond energy in all but the most exceptional cases (see Section 4.3.3 on carcerands and carceplexes for exceptions). As a result, under most conditions, the complex is constantly forming and breaking up. These are dynamic systems. To emphasize this, we show in Eq. 4.27 an alternative way to represent Kj and as a ratio of rate constants. These expressions make sense. A tight bind-... 

Cram DJ, Karbach S, Kim YH, Baczynskyj L, Marti K, Sampson RM, Kalleymeyn GW (1988) Host-guest complexation. 47. Carcerands and carcaplexes, the first closed molecular container compounds. J Am Chem Soc 110(8) 2554-2560... 

Warmuth [34] when they adopted NPC for the analysis of supermolecules, such as hemicarcerplexes. Hemicarcerplexes are complexes formed with hemi-carcerand host and guest molecules. As shown in Figure 5-6, hemicarcerands possess a very hydrophobic structure with molecular weight over 2000 and is insoluble in protic solvents. A normal-phase HPLC method was developed using a silica column with dichloromethane and diethylether as the mobile-phase system. The authors demonstrate that the chromatographic retention of hemicarcerplexes is mainly dominated by its size. Furthermore, a linear relationship between the logarithmic retention factor and the size of the hemicarcerplexes was observed for linear guest molecules independent of their polarity. 

Host inolecules may be broadly classified into two main types those that form molecular complexes by fitting convex guests into the concave cavity of the host (examples include cyclodextrins, cyclophanes. calixar-enes, cycloveratrylenes, and various carcerands ) and those that form lattice inclusion compounds by packing in such a manner as to leave cavities, channels, or layers in the crystal structure so as to accommodate various guest... 

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