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The shaping of a calix(7)ar- ene macrocycle into cone-like structure 3, through exhaustive alkylation of doubly bridged calix(7)arene derivative 2 with bulky groups, has been investi- gated. Conformational details about the structure adopted by calix(7)arene derivative 3 in solution have been ob- tained by using chemical shift surface maps, as previously reported by our group. Thus, chemical shift contour plots indicated that 3 adopted a cone- shaped structure in solution analogous to that adopted by the known p-tert-bu- tylcalix(7)arene heptacarboxylic acid derivative 4. Interestingly, the X-ray structure of derivative 3 showed a high degree of similarity to the theoretical structure, which confirmed the validity of the contour plots method. The pre- organized calix(7)arene host 3 showed interesting recognition abilities toward both organic and alkali cations. In fact, an unprecedented endo-cavity com- plexation of linear and branched alkyl ammonium cations with a larger cal- ix(7)arene host was evidenced. A com- parable affinity for branched tBuNH3 + and linear nBuNH3 + guests was ob

This work is funded by the EPSRC A series of eight 1-halo-8-(alkylchalcogeno)naphthalene derivatives ( 1 – 8 ; halogen=Br, I; alkylchalcogen=SEt, SPh, SePh, TePh) containing a halogen and a chalcogen atom occupying the peri positions have been prepared and fully characterised by using X-ray crystallography, multinuclear NMR spectroscopy, IR spectroscopy and MS. Naphthalene distortion due to non-covalent substituent interactions was studied as a function of the bulk of the interacting chalcogen atoms and the size and nature of the alkyl group attached to them. X-ray data for 1 , 2 , 4 and 5 – 8 were compared. Molecular structures were analysed in terms of naphthalene ring torsions, peri-atom displacement, splay angle magnitude, X⋅⋅⋅E interactions, aromatic ring orientations and quasi-linear X⋅⋅⋅EC arrangements. A general increase in the X⋅⋅⋅E distance was observed for molecules that contain bulkier atoms at the peri positions. The I⋅⋅⋅S distance of 4 is comparable with the I⋅⋅⋅Te distance of 8 , and is ascribed to a stronger lone pair–lone pair repulsion due to the presence of an axial S(naphthyl) ring conformation. Density functional theory (B3LYP) calculations performed on 5 – 8 revealed Wiberg bond index values of 0.05–0.08, which indicate minor interactions taking place between the non-bonded atoms in these compounds. Postprint