SYNTHESES, BINDING-PROPERTIES, AND STRUCTURES OF 7 NEW HEMICARCERANDSEACH COMPOSED OF 2 BOWLS BRIDGED BY 3 TETRAMETHYLENEDIOXY GROUPS AND A 4TH UNIQUE LINKAGE

Treatment of 2 mol of the bowl-shaped tetrol 1 (derived originally fro m resorcinol and dihydrocinnamaldehyde) with 3 mol of Ts(6)(CH2)(4)OTs gave diol 2. Eight compounds with different combinations of bridges w ere formed from 2 by treatment with Cs2CO3 and the following reagents in the presence of potential guests to give either free or complexed h emicarcerands as follows: ClCH2Br gave 4; TsO(CH2)(2)OTs gave 5; TsO(C H2)(3)OTs gave 6; MsO(CH2)(4)OMs gave 7, a known system; MsO(CH2)(5)OM s gave 8; 2,3-bis(bromomethyl)quinoxaline gave 9; 1,3-(ClCH2)(2)C6H4 g ave 10; 2,6-bis(chloromethyl)pyridine gave 11. Thirty-six fully charac terized new hemicarceplexes are reported which were prepared either di rectly from diol 2 by the ''sealing in'' of the guest during introduct ion of the fourth bridge, or by guest exchange driven by mass law at 2 5 to 160 degrees C. The guests ranged in size from CHCl3 to 1,2,3-(MeO )(3)C6H3. The incarcerated guests correlated with portal sizes of thei r hosts. Crystal structures of 8.4-MeC(6)H(4)OMe and 10.CHCl3 were det ermined. Changes in chemical shifts in H-1 NMR spectra of incarcerated and free guests are interpreted in terms of their locations in the ho sts' inner phases. The length and nature of the unique host bridge aff ects the chemical shifts of the other bridges. Force field calculation s of structural models for N-methylpyrrolidinone incarcerated in 4-7 w ere made. Approximate half-lives for decomplexation were determined fo r complexes involving the larger hosts and guests. Force-field calcula tions were made of binding energies and activation energies for decomp lexations of models of 7.N-methylpyrrolidinone, 8.N-methylpyrrolidinon e, and 10.N-methylpyrrolidinone. The activation energies for decomplex ation were dissected into intrinsic and constrictive components.