An approach to the design of molecular solids. The ureylene dicarboxylic acids

A rational design of molecular materials

“…Our approach is based upon a library of functional groups that reliably assemble into one-dimensional hydrogen-bonded a-networks, each is characterized by a specific intermolecular repeat distance. [18][19][20] Our prototypical group is the disubstituted urea functionality. Such ureas form a pair of hydrogen bonds in a very reliable and reproducible manner.…”

Influence of structure on the kinetics of assembly of cyclic dipeptides into supramolecular tapes

“…With amides serving to link molecules via hydrogen bonds, a variety of supramolecular structures (Fig. 4) have been assembled that are described as capsules and spheres, 3,26,27 channels, 8,9,28,29 helices, 11,30 ribbons or tapes, 10,31-38 rods, 39 rosettes, 40,41 sheets or layers 17,28,29,36,[42][43][44][45][46][47][48][49][50][51][52] and tubes. 16,[53][54][55] …”

Urea and Thiourea Derivatives as Low Molecular‐Mass Organogelators

“…[3][4][5][6]12] By contrast, we are unaware of inclusion complexes in which N-alkyl or N,N'-dialkyl ureas serve as the hosts. However, N,N'-disubstituted ureas, in which the substituents are more complex than an n-alkyl chain, can form a-networks (i.e., with one degree of translational symmetry [13] ), [14,15] and some of these have been shown to lead to gels [16,17] with organic liquids and water. [18][19][20][21][22][23][24][25][26][27][28][29] Among the latter, few contain only one urea moiety.…”