Cryptands hemispherands

Scheme 1 Typical examples of phosphorylated cryptands A [12, 13], B [14, 15], C [16], macrocycle [17], hemispherand [18], and cavitand [19]...

As stated above, systematic names of macrocyclic host molecules were absurdly complicated for routine discussions [22]. Therefore Vogtle proposed the name coronand for crown ethers, and that of coronates for their complexes while cryptand complexes were called cryptates . The corresponding noncyclic analogues are podands such as 64 [23] and podates, respectively. The cumbersome name podando-coronands (and correspondingly podando-coronates ) was proposed for lariat ethers [24] having at least one sidearm like 65. Examples of hemispherands 66 [25], cavitands 25 [26] and those of some other hosts are discussed in Chapter 7 in some detail, whilst the exceptional stability of fragile guests 4 [2a] and 67 [27] in the hemicarcerand 5 cavity are discussed in Chapters 1 and Section 7.3. 

Hemispherands (11) are by nature only partially preorganized for complexation, depending on their structural characteristics.30 129 132 Addition of hydrocarbon-based bridges, which essentially converts the monocycles to bicyclic systems, serves to provide a more rigid structural framework as in the cryptands.132... 

Cross-fertilisation between the crown ethers (or, more generally, corands), cryptands, spherands and podands has produced an enormous range of hybrid hosts such as cryptaspherands and hemispherands, many exhibiting all the useful features of the parent materials (Figure 3.16). 

Fig. 4 Representatives of typical cyclophane host families calixarene (21), resorcinarene (22), cavitands (23, 24), cdrcerand (25). hemicarcerand (26), crown ether (27), cryptand (28), spherand (29). and hemispherand (30)...

Similar to the hemispherands are the cryptahemispherands. Instead of a corand part, there is a cryptand part the rest of the host again is a highly preorganized spherand unit. Cryptahemi spherand 13 binds Na" as a seven-... 

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