Crystal structure of a methanol solvate of a macrocycle bearing two flexible side-arms.

Di-tert-butyl N,N'-{[13,15,28,30,31,33-hexa-ethyl-3,10,18,25,32,34-hexa-aza-penta-cyclo-[25.3.1.15,8.112,16.120,23]tetra-triaconta-1(31),3,5,7,9,12(33),13,15,18,20,22,24,27,29-tetra-deca-ene-14,29-di-yl]bis-(methyl-ene)}dicarbamate methanol disolvate, C52H72N8O4·2CH3OH, was found to crystallize in the space group P21/c with one half of the macrocycle (host) and one mol-ecule of solvent (guest) in the asymmetric unit of the cell, i.e. the host mol-ecule is located on a crystallographic symmetry center. Within the 1:2 host-guest complex, the solvent mol-ecules are accommodated in the host cavity and held in their positions by O-H⋯N and N-H⋯O bonds, thus forming ring synthons of graph set R 2 2(7). The connection of the 1:2 host-guest complexes is accomplished by C-H⋯O, C-H⋯N and C-H⋯π inter-actions, which create a three-dimensional supra-molecular network.

Carbohydrate receptors combining both a macrocyclic building block and flexible side arms as recognition units: binding properties of compounds with CH2OH groups as side arms.

New representatives of compounds combining both a macrocyclic building block and two flexible side arms as recognition units were prepared and their binding properties toward selected carbohydrates were evaluated. The aim of this study was to examine the effects of the replacement of the heterocycle-bearing side arms by smaller units, such as hydroxy groups, on the binding capability. The design of this type of receptor was inspired by the participation of the side chain hydroxy group of serine and threonine in the biorecognition of carbohydrates. Such structural modifications enable the recognition of structure-activity relationships, which are of high importance in the development of carbohydrate receptors with predictable binding strength and selectivity.