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Treatment of phenylcalix[4]resorcinarene 1 with dipropylamine and paraformaldehyde leads to the formation of a deep cleft cavitand 2, in which the cavity is extended by a collar of exquisite intramolecular donor-acceptor hydrogen bonding networks which all proceed in the same direction around the upper rim imparting chirality on the individual cavitands; the amine groups involvement in intramolecular hydrogen bonding draws the N-alkyl substituents inward to form an encapsulating 'hood' over an included CH2CI2 guest molecule.In the early 1980s Cram coined the term 'cavitand' to describe synthetic molecules possessing an enforced cavity132 of a size large enough to accommodate other molecules, atoms or ions. Calix[4]resorcinarenes (e.g. 1) are conformationally mobile macrocycles generally possessing ephemeral rather than permanent cavities. However, bridging the hydroxy groups of adjacent aromatic rings of such structures with covalent linkages of one or two atoms leads to rigid, bowl-shaped receptors capable of forming supramolecular complexes with many different guest species.3-5We have recently prepared a new class of extended deep cleft cavitands (e.g. 2) where the rigidity of the cavity is enforced by non-covalent forces, namely donor-acceptor hydrogen bonding networks.6 Here we report the solid-state of 2 which confirms both the geometry of the cavity and the nature of the hydrogen-bonding network. Included in each cavitand is a molecule of methylene chloride. One of the hydrogen atoms of the included methylene chloride points directly toward the centre of the aromatic ring of one of the resorcinal units of the calixarene, forming a strong rc-arene...H bond (C--.ring centroid 3.68 A) which stabilises the host-guest complex. Also clathrated in the structure is an equal number of well ordered acetone molecules which are located outside the calix[4]resorcinarene cavities and not hydrogen bonded to any other molecules. Fig. 1 shows the solid-state structure of 2 from a side and top view with both included methylene chloride and clathrated acetone.The aminomethylated phenylcalix[ 41resorcinarene 2 was prepared by condensation of 1 with dipropylamine and formaldehyde (Scheme 1) .t The tetra-substituted Mannich base was recrystallised from a 1: 1 solution of methylene chloride and acetone to give colourless single crystals suitable for study by X-ray crystallography$ and which proved to be a 1 : 1 : 1 clathrated inclusion complex of 2, methylene chloride and acetone. Ph 1 li R = Pr Scheme 1 The synthesis of the aminomethylated calix[4]resorcinarene 2. Reagents and conditions: i, CH20, dipropylamine.

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