2-(4-Bromobenzyl)-5,11,17,23-tetra-tert-butyl-25,26,27,28-tetramethoxycalix[4]arene

Abstract

In the title compound, C55H69BrO4, the calixarene mol­ecule displays a ‘partial cone’ conformation bearing the lateral substituent in a sterically favorable equatorial arrangement between two syn-orientated arene units. The crystal packing is stabilized by weak C—H⋯π contacts, involving one tert-butyl group, and π–stacking inter­actions of the lateral bromo­benzene units [centroid–centroid distance = 3.706 (1) Å].

Bridge-Disubstituted Calix[4]arenes in the Rare 1,2-Alternate Conformation: Control of the Inclusion Behavior Depending on the Bridge Substituents

“…The third acetonitrile molecule is enclathrated interstitially between the columns as void filler without any considerable hydrogen bond interaction (Figure 5b,c). Compared to a bridge mono-p-bromobenzyl substituted calixarene in the partial cone conformation, 19 the switch to the 1,2-alternate conformation as observed in 4a offers the advantage in that the higher symmetrical 1,2-alternate conformation promotes the formation of domains of bromobenzyl groups as well as solvent molecules, as illustrated in Figure S1. Remarkably, in contrast to the guest free mono-p-bromobenzyl substituted calixarene, 19 the presence of a second lateral substituent requires a total of three acetonitrile guests, each of them possessing a different feature (Figure 5b).…”