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198 Topics in Current Chemistry Editorial Board: A. de Meijere KN ...

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142 Y. Aoyama<br />

2.4<br />

Interaction-Supported Channels<br />

When excess such <strong>in</strong>teractions are available, the sheets can be held together via<br />

<strong>in</strong>tersheet <strong>in</strong>teractions. 2,4-Diam<strong>in</strong>otriaz<strong>in</strong>e can form a hydrogen-bon<strong>de</strong>d tape<br />

motif. A tetraphenylmethane <strong>de</strong>rivative of this heterocycle 35 [54] forms a 2D<br />

net 36 via hydrogen bond<strong>in</strong>g of a well known type 37 (Fig. 10). The sheets are<br />

then l<strong>in</strong>ked via another set of hydrogen bond<strong>in</strong>g to give a 3D molecular polymer<br />

38. One am<strong>in</strong>o group not participat<strong>in</strong>g <strong>in</strong> the network formation is used to hook<br />

the guest molecules <strong>in</strong> the large cavity (11.8 Å diameter for the free space). All<br />

the hydrogen bond<strong>in</strong>g capacity of the diam<strong>in</strong>otriaz<strong>in</strong>e r<strong>in</strong>g is thus fulfilled hierarchically,<br />

i.e. formation of a sheet, stack of the sheets, and guest b<strong>in</strong>d<strong>in</strong>g (see<br />

also the article by R.E. Melén<strong>de</strong>z and A.D. Hamilton <strong>in</strong> this volume).<br />

Another example is a tetraresorc<strong>in</strong>ol <strong>de</strong>rivative of porphyr<strong>in</strong>. The correspond<strong>in</strong>g<br />

diresorc<strong>in</strong>ol <strong>de</strong>rivative 39 affords a hydrogen-bon<strong>de</strong>d (O-H◊◊◊O-H) 2D net<br />

(40 for the top view of the sheet <strong>in</strong> Fig. 11) [55] similar to that (31 <strong>in</strong> Fig. 9) for<br />

36<br />

35<br />

37<br />

Fig. 10. 2D net (36) formed by 35 and <strong>in</strong>tersheet hydrogen bond<strong>in</strong>g to form layered 3D net (38)<br />

38

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