Synthesis and modes of self-assembly are described for the tapered monodendritic molecules 3,4,5-nGi-X of generation i = 1, 2, 3 (see structures below) that contain multiple (CH2)nH alkyl chains on their periphery (n = 12, 14, 16) and a polar group X at the apex (X = COOH, COONa, COOCs, CO(OCH2CH2)3OH). These monodendrons self-assemble into supramolecular cylindrical or spherical dendrimers, which in turn self-organise into p6mm columnar or Pm3n cubic thermotropic liquid crystals, respectively. The two principal ways of affecting the self-assembly of these compounds by means of their molecular architecture are: a) by changing the width of the wide (aliphatic) end, and b) by changing the volume at the apex. In the present work a) is controlled through temperature (conformational disorder) and b) is controlled by chaging the generation number i or the size of X, for example, through the choice of metal cation. The single most important geometric parameter of these dendritic building blocks is the molecular solid angle (taper angle) alpha; a high alpha leads to spherical and a low alpha to cylindrical supramolecular dendrimers. Furthermore, alpha also determines the equilibrium size of the supramolecular objects; a larger alpha results in a smaller diameter. The unusually strong negative thermal expansion coefficient of the cubic and columnar lattice is attributed to the excess of the increasingly highly tapered molecules being rejected from their parent aggregates and reassembling as new ones. Increasing alpha is also considered to be responsible for the observed thermotropic columnar-cubic transition.

The synthesis of functional aromatic bis(sulfonyl chlorides) containing an acetophenone and two sulfonyl chloride groups, i.e., 3,5-bis[4-(chlorosulfonyl)phenyl]-1-acetophenone (16), 3,5-bis(chlorosulfonyl)-1-acetophenone (17), and 3,5-bis(4-(chlorosulfonyl)phenyloxy)-1-acetophenone (18) via a sequence of reactions, involving in the last step the quantitative oxidative chlorination of S-(aryl)- N,N'-diethylthiocarbamate, alkyl- or benzyl thiophenyl groups as masked nonreactive precursors to sulfonyl chlorides is described. A related sequence of reactions was used for the synthesis of the aromatic trisulfonyl chloride 1,1,1-tris(4-chlorosulfonylphenyl)ethane (24). 4-(Chlorosulfonyl)phenoxyacetic acid, 2,2-bis[[[4-(chlorosulfonyl)phenoxyacetyl]oxy]methyl]-1,3-propanediyl ester (27), 5,11,17,23-tetrakis(chlorosulfonyl)-25,26,27,28-tetrakis(ethoxycarbonylmethoxy)calix[4]arene (38), 5,11,17,23,29,35-hexakis(chlorosulfonyl)-37,38,39,40,41,42-hexakis(ethoxycarbonylmethoxy)calix[6]arene (39), 5,11,17,23,29,35,41,47-octakis(chlorosulfonyl)-49,50,51,52,53,54,55,56-octakis(ethoxycarbonylmethoxy)calix[8]arene (40), 5,11,17,23-tetrakis(tert-butyl)-25,26,27,28-tetrakis(chlorosulfonyl phenoxyacetoxy)calix[4]arene (44), 5,11,17,23,29,35-hexakis(tert-butyl)-37,38,39,40,41,42-hexakis(chlorosulfonylphenoxyacetoxy)calix[6]arene (45), and 5,11,17,23,29,35,41,47-octakis(tert-butyl)-49,40,51,52,53,54,55,56-octakis(chlorosulfonylphenoxyacetoxy)calix[8]arene (46) were synthesized by two different multistep reaction procedures, the last step of both methods consisting of the chlorosulfonation of compounds containing suitable activated aromatic positions. 2,4,6-Tris(chlorosulfonyl)aniline (47) was obtained by the chlorosulfonation of aniline. The conformation of two series of multisulfonyl chlorides i.e., 38, 39, 40 and 44, 45, 46, was investigated by (1)H NMR spectroscopy. The masked nonreactive precursor states of the functional aromatic multisulfonyl chlorides and the aromatic multisulfonyl chlorides reported here represent the main starting building blocks required in a new synthetic strategy elaborated for the preparation of dendritic and other complex organic molecules.

The synthesis of 2-[3,4-bis(n-alkan-1-yloxy)phenyl]-2-oxazolines with alkan = octan, decan, dodecan, and tridecan is presented. Their living cationic ring opening polymerization produces cylindrical macromolecules that self-organize in a hexagonal columnar two-dimensional phase. The structural analysis of these polymers was carried out by a combination of techniques including differential scanning calorimetry, thermal optical polarized microscopy, X-ray diffraction, transmission electron microscopy, electron diffraction, scanning force microscopy, and atomic force microscopy (AFM). The diameter of these cylindrical macromolecules ranges from 33 to 44 A, and therefore they represent the simplest cylindrical macromolecules that can be directly visualized by AFM on a surface. Preliminary experiments have demonstrated the use of these cylindrical macromolecules as models to investigate the creation of two-dimensional and three-dimensional order via direct visualization and thus they represent the simplest nonbiological systems that mimic the role played by the complexes of nucleic acids with proteins in structural analysis by direct visualization.

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Linear polymers with monodendron side groups adsorb on highly oriented pyrolytic graphite (HOPG) in a remarkably regular pattern. The wormlike molecules have been depicted individually by scanning force microscopy with their long axis aligned according to the 3-fold symmetry of HOPG. The positional and orientational order of the adsorbed molecules is explained by the specific interaction of the alkyl substituents of the monodendrons with the HOPG surface. Direct evidence of the epitaxial adsorption was found by scanning tunneling microscopy of monolayers of the monomeric dendrons on HOPG. Ordering depended on the number of the alkoxy substitutes on the monodendrons. If the substitution of the monodendrons by the alkoxy groups was too dense, regular adsorption of the alkyl tails was impeded.