The catenane layers, in turn, are held together by van der Waals interactions and two intermolecular hydrogen bonds between each catenane and its nearest neighbors in the layers above and below (Fig. 3). The interlayer hydrogen bonds are formed between the amide hydrogen atoms of the inverted amide groups and the carbonyl groups of the cisoid isophthaloyldiamide units. The remaining amide hydrogen atoms and carbonyl groups (NS' and 0 2 ; N5 and 02') appear, by the positioning of the heavy atoms, to be connected through an unusual hydrogen bonding architecture in which the amide proton either binds to the n-cloud of the O=C bond or binds in a nonlinear arrangement to the oxygen atom. Since the H atoms are not resolved in the structure, these two possibilities cannot currently be distinguished.The X-ray crystal structure supports the proposal that the driving force for catenane formation is hydrogen bonding between the newly formed 1,3-diamide units and carbonyl groups on the acid chloride or other intermediates. The stacking of the electron-rich xylylene and electron-poor isophthaloyl rings may also play a supporting role.
In the mannerfirst introduced with the Stoddart catenanes, the formation of new functionalgroups in this reaction controls the self-assembly of a topologicully complex product.[31The following communication ["] shows that 1 is not an isolated example of a [2]catenane, but rather the simplest of a diverse family of catenanes derived in one step from aromatic 1,3-dicarbonyl compounds and benzylic diamines. Self-assembly processes currently provide the only viable route to these kinds of topologically complex molecules which exhibit, in both solution and the solid state, a range of structural and dynamic properties not available to topologically trivial molecules. Experimental Procedure[' ' 1 To a stirred solution of triethylamine (1.19 g, 18.9 mmol) in anhydrous chloroform (130mL, stabilized with amylenes not ethanol) [19] under argon were added 3 (0.87 g, 4.3 mmol) in anhydrous chloroform (130 mL) and 4 (0.58 g, 4.3 mmol) in anhydrous chloroform (130 mL) simultaneously, over 30 min by means of motordriven syringe pumps. The mixture was allowed to stir for about 12 h and then filtered. The filtrate was washed with 1 M aqueous hydrochloric acid (3 x 200 mL). then 5 % aqueous sodium hydroxide (3 x 200 mL), and finally water (3 x 200 mL). The organic layer WAS then dried over anhydrous magnesium sulfate and concentrated under reduced pressure to afford 0.23 g (20.1 %)of [2]catenane 1. M.p. 31 5 "C (decomp); 'HNMR (300 MHz. [DJDMSO): 6 = 4.01 (br. s, 16H, CH,), 6.75 (br. s, 16H, p-xylyl H), 7.50 (t, J,. = Js, = 8 Hz, 4H, isophthaloyl 5-H), 7.88 (dd, J4. = 8 Hz, J2.4 = 1 Hz, 8H, isophthaloyl 4-H and 6-H), 8.05 (d, J2.& = 1 Hz. 4H, isophthaloyl 2-H), 8.62 (s, 8H, CONH); "C NMR (75 MHz, [DJDMSO): 6 = 46. 98, 130.03, 130.81, 132.40, 133.78, 138.40, 141.35, 168.94; FAB-MS (mNBA matrix): m/z 1065 [ ( M + H)+], 533 [(M/2 + H)+]. The precipitate from the reaction contains polymers, larger macrocycles, and ca...