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The ureaÈcarboxylate interaction is introduced as a potentially general motif for the control of solid-state packing patterns. We show that simple phenylurea carboxylate derivatives can form extended hydrogen-bonded ribbons in the crystal in which the zig-zag shape of the aggregate is controlled by the relative orientation of the two substituents about the phenyl core. We also show that an alternative type of aggregation may occur in solution involving the formation of cyclic aggregates. Again, the size and stability of the aggregate is dependent on the substitution pattern of the monomer.

The ability of surfactant aggregate−H2O interfaces to control the regioselectivity of Diels−Alder reactions has been investigated. Cycloadditions of surfactant 1,3-dienes 2-[[3-(dimethyldodecylsilyl)-1,3-butadien-2-yl]thio]-N,N,N-trimethyl-1-ethanaminium iodide (1a) and 6-[[3-(dimethyloctylsilyl)-1,3-butadien-2-yl]thio]-N,N,N-trimethyl-1-hexanaminium iodide (1b) with surfactant dienophiles (E)-2-[[[2-(dodecoxycarbonyl)ethenyl]carbonyl]oxy]-N,N,N-trimethyl-1-ethanaminium iodide (2a) and (E)-6-[[[2-(octoxycarbonyl)ethenyl]carbonyl]oxy]-N,N,N-trimethyl-1-hexanaminium bromide (2b) within their aqueous mixed micelles have been performed at 25(35) °C. The cycloaddition of 1a and 2a gave a 30:1 ratio of trans-1-[(2-trimethylammonio)ethylthio]-2-(dimethyldodecylsilyl)-4-(dodecoxycarbonyl)-5-[(2-trimethylammonio)ethoxycarbonyl]-1-cyclohexene dihalide (15a) and trans-1-[(2-trimethylammonio)ethylthio]-2-(dimethyldodecylsilyl)-4-[(2-trimethylammonio)ethoxycarbonyl]-5-(dodecoxycarbonyl)-1-cyclohexene dihalide (16a), respectively, and that of 1b and 2b a 6.6:1 ratio of trans-1-[(6-trimethylammonio)hexylthio]-2-(dimethyloctylsilyl)-4-(octoxycarbonyl)-5-[6-(trimethylammonio)hexoxycarbonyl]-1-cyclohexene dihalide (15b) and trans-1-[(6-trimethylammonio)hexylthio]-2-(dimethyloctylsilyl)-4-[6-(trimethylammonio)hexoxycarbonyl]-5-(octoxycarbonyl)-1-cyclohexene dihalide (16b), respectively. The excess of 15 over 16 is consistent with the reaction of 1 and 2 within mixed aggregates in their preferred orientations at the aggregate−H2O interface. The greater regioselectivity obtained in the reaction of 1a and 2a is ascribed to the shorter tether between their reactive functional groups and quaternary ammonium headgroups. A monolayer study of 15a and 16a was also performed.

Theory, operation, and application of the MSB-1 balance, a new type of magnetic susceptibility balance.