Structural chemistry and guest inclusion of a new supramolecular material showing sensitivity to organic solvent vapors

Abstract

Clathrate formation—the formation of crystalline inclusion compounds—is one approach to chemical sensing of vapors and gases. The synthesis of a new diol host compound is described and absorptive clathrate formation and thermal clathrate decomposition are reported for acetone as the guest. It is shown that the sorptive uptake of a guest vapor by the crystalline host compound is not merely surface adsorption but true clathrate formation, involving a solid‐state transformation. It is suggested that the use of the host as a chemical sensor is not far off.

Synthesis and solvent sorption characteristics of new types of tartaric acid, lactic acid and TADDOL derived receptor compounds

“…A rather complex behaviour regarding the resonances of the aromatic protons is observed for the TADDOLs 1ce6c showing such multiplets in the 1 H and a large number of signals in the 13 C NMR spectra being difficult to assign. This, however, is in line with a previous finding obtained for closely related TADDOLs 27 providing evidence that a seven-membered ring is formed by an intramolecular hydrogen bond between the two neighbouring OH groups leading to a complex stereochemical environment.…”

“…Also the acetals 12e14 (aec) show this splitting of the ethyl groups due to the diastereotopic property of the methylene protons. In the 13 C NMR of the tartaric acid and ester derivatives, the methine carbons of the asymmetric centres, the respective carboxylic carbons, and also the carbons of the ethyl groups of the esters appear as two different signals.…”

“…10 Thus, unlike the hydrogen bond stabilised networks with the molecules showing outward functional groups, the molecular structures of this specific clathrate host feature endo-oriented functional groups; being in a rather difficult situation of forming a stable crystal lattice that promotes the uptake of solvent as a correction. 11 Prototype compounds having this attribute, which can be used for sensor application, involve particular dihydroxy substituted biphenyls 12,13 and roofshaped molecules, 14 bulkily modified structures of lactic acid, 15,16 or specific derivatives of tartaric acid, 17,18 the latter being called TADDOLs. 19 Here we report on a series of new tartaric acids (1ae6a) and lactic acid derived compounds (7ae11a) including, aside from specific TADDOLs (3ce6c), a particular new type of bis-TADDOLs (1c, 2c).…”

“…MS (ESI): m/z¼381.06 [MÀH] À . 1 H NMR (DMSO-d 6 , 500 MHz): d¼4.79 (d, 1H, CH, 3 J HH ¼3.80); 4.95 (d, 1H, CH, 3 J HH ¼3.80); 6.05 (s, 1H, CH, acetal); 7.66 (s, 4H, aryl-H); 7.69 (d, 2H, aryl-H, 3 J HH ¼8.20); 7.98 (d, 2H, aryl-H, 3 J HH ¼8.20); 13.35 (br, s, 3H, COOH);13 C NMR (DMSO-d 6 , 125 MHz): d¼76.81, 77.34 (CH); 89.43, 91.63 (C^C); 104.69 (CH, acetal); 123.25, 126.48, 127.89, 129.69, 130.80, 131.61, 131.73, 137.07 (aryl-C); 166.78 (ArCOOH), 170.71, 171.13 (CHCOOH). IR (cm À1 , KBr): 3072 (OH); 2214 (C^C); 1733 (C] O); 1609, 1562, 1518 (C]C, Ar); 1220, 1125, 1103 (acetal).…”

“…HH ¼7.15); 4.31 (q, 2H, CH 2 , 3 J HH ¼7.15); 4.37 (q, 2H, CH 2 , 3 J HH ¼7.15); 4.42 (q, 2H, CH 2 , HH ¼7.15); 4.87 (d, 1H, CH, 3 J HH ¼4.00); 4.98 (d, 1H, CH, 3 J HH ¼4.00); 6.20 (s, 1H, CH, acetal); 7.61e7.63 (m, 6H, aryl-H); 8.05 (d, 2H, aryl-H, HH ¼8.10);13 C NMR (CDCl 3 , 125 MHz): d¼14.07, 14.15, 14.30 (CH 3 ); 61.12, 62.09, 62.10 (CH 2 ); 77.41, 77.70 (CH); 89.47, 91.79 (C^C); 106.17 (CH, acetal); 124.33, 127.28, 127.64, 129.47, 130.02, 131.51, 131.70, 136.05 (aryl-C); 166.02, 168.95, 169.48 (COOEt). IR (cm À1 , KBr): 2214 (C^C); 1761 (C]O); 1606, 1562; 1521 (C]C, Ar); 1220, 1116, 1100 (acetal).…”