Hydrogen bonding in supramolecular chemistry

It is obvious that these molecular systems can be prepared specially or can form spontaneously as self-assemblies when hydrogen or dihydrogen bonds dictate the processes of molecular aggregation. The latter is particularly importaut in supramolecular chemistry and crystal engineering, where the primary attention is focused on mastering weak intermolecular interactions [1]. 

It should be noted that the word complex , often used in supramolecular chemistry, is not very specific. It is applied to charge-transfer complexes like the one formed by 21 with 22 [30] as well as to coordination complexes consisting of one or more atoms or ions with n ligands like K2[Pt(N02)4]. The same name complex also covers the Whitesides hydrogen bonded systems [10] shown in Figure 1.1 and inclusion complexes of 4 embedded in 5. Thus the term complex without any adjective has no specificity and can be applied to any type of molecular associates. 

Why has hydrogen bonding been described as the masterkey interaction in supramolecular chemistry Make a list of features that distinguish hydrogen bonding from other non-covalent interactions. 

Sethi, A. R., Welton, T., Dynamic supramolecular chemistry The role of hydrogen bonding in controlling the selectivity of Diels-Alder reactions in room-temperature ionic liquids, Ionic Liquids, 2002, 818, 41-246. 

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