Preorganized Macrocyclic Dicarboxylic Receptors

Pollex, Rolf; Weber, Edwin; Czugler, Mátyás

doi:10.1007/978-94-011-5288-4_85

Cited by 1 publication

(2 citation statements)

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“…The synthesis of the present exo-functional host compounds (1-3), based on 3,5-disubstituted benzoic ' acid and a building block analogous to diphenyl n:\ethane, follows a design strategy (Scheme 2) that has previously proved to be successful in the formation of new endo-functional cyclophane receptors [14][15][16]. The key step of the synthesis is the ring closure reaction of bis-benzylic dibromide 4 [21] with diphenols 5a-c [22,23] to give the macrocyclic esters 6a-c. High dilution conditions [24,25] and cesium carbonate as the base [26] were used for this process.…”

Section: Synthesismentioning

confidence: 99%

“…In order to improve the endo mode of host behaviour, convergent functional sites such as carbocyclic groups have been incorporated into the cyclophane scaffold [14][15][16]. On the other hand, the construction of highly organized and complex structures using supramolecular synthon strategy [17] is an exciting emergent subfield of supramolecular chemistry [18].…”

Section: Introductionmentioning

confidence: 99%

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New Exo-Functional Cyclophane Hosts. Synthesis and Crystal Structures of Inclusion Compounds

Golbs

Seichter

Weber

et al. 2006

Supramolecular Chemistry

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The new cyclophane type host compounds 1-3, containing rigid aromatic units and two exo-topic carboxylic acid functions, have been synthesized. Crystalline solvent inclusions, involving the dicarboxylic acid hosts and their corresponding ester intermediates 6 (a~c), namely 1-DMSO (1:4), 2-pyridine (1:3), 3-pyridine (1:4), 6a-pyridine (1:2) and 6abenzene (1:2), have been prepared and studied using X-ray diffraction on single-crystals. Moreover, X-ray structure analyses of the solvent-free crystals of the 6 (a, b) intermediates were also carried out for comparison. Cocrystals of the carboxylic hosts 1-3 contained H-bonded 1:2 host-guest associates as building blocks, together with additional space-filling guests, whereas only loosely bounded space-filling solvent molecules were found in the two solid inclusion compounds of the 6a cyclophane ester host. In addition to the mentioned conventional Hbond interactions between carboxylic hosts and their guests, the crystal structures proved to be held together by relatively weak C-H---O bonds besides the ordinary van der Waals' interactions. Packing relations, and the effects of structural variations, guest molecules and anisotropic packing forces on the conformation of the semi-rigid cylcophane ring have been discussed and compared in seven crystal structures.

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