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.
The resorcinarene 1 4 ,1 6 ,5 4 ,5 6 -tetrahydroxy-2,4,6,8-tetramethyl-3 4 ,3 6 ,7 4 ,7 6 -tetra(p-toluene sulfonyl-oxy)-1,3,5,7(1,3)-tetrabenzenacyclooctaphane hereafter referred to as C1TS is the host of our new study on inclusion chemistry. We have formed several host-guest compounds with various volatile amines, namely: Ethylamine (bp: 17°C), Propylamine (bp: 33-34°C) and Isopropylamine (bp: 48°C). The low boiling points of these solvents allowed us to work on kinetics of enclathration of the host with guest vapour.We have formed the complex C1TS×5Propylamine. Thermal analysis (Thermal Gravimetry and Differential Scanning Calorimetry) have been carried out and the results were correlated with the crystal structure. The inclusion compound crystallize in the monoclinic crystal system in the space group P2 1 /n and has Z=2 and H:G=5. One guest contained in the cavity of the resorcinarene is disordered about the 2-fold axis; the four other guests are outside the cavity and hydrogen bonded to the host molecule via the hydroxyl groups.The kinetics of enclathration of the host with guest vapour has been studied using an automated magnetic suspension balance and the experiments were carried out under isothermal conditions. The results were modeled as following first order kinetics.
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