The modular synthesis of a defined, rigid molecular spoked wheel structure with the sum formula C1878H2682 and a diameter of about 12 nm is described. The attached 96 dodecyl side chains provide the solubility of the 25 260 Da compound in common organic solvents. At the octanoic acid/highly oriented pyrolytic graphite interface, the molecules self-assemble to form an ordered 2D lattice, which is investigated by scanning tunneling microscopy, displaying their structure with submolecular resolution.

ether phase decanted. The precipitate was washed several times with ether and finally dried to give the deprotected product as a white powder (13 mg. 91 %). The reductive amination was carried out using a modification of a published procedure [13]. In a typical experiment, the protected peptide la (10 pmol) was dissolved in 2 mL of a 10: 1 mixture of 0.1 M phosphate buffer (pH 6.0) and CH3CN. To this peptide solution were added the carbohydrate (200 pmol) dissolved in 2 mL of the Same buffer and sodium cyanoborohydride (200 pmol) as a solid. The mixture was stirred at room temperature and progress of the coupling reaction monltored by analytical HPLC. The glycopeptides were purified by semipreparative HPLC and characterized by ESI-MS. syntheses solid-phase[l] I.

Alkyl- and alkoxy-substituted p-phenylene–butadiynylene tetramers, obtained via a stepwise synthesis, are polymerized under Glaser coupling conditions. The fractionation of the oligomers by recycling gel permeation chromatography (recGPC) yields three sets of monodisperse oligo­(p-phenylene–butadiynylene)­s (OPBs) with degrees of polymerization n = 4, 8, 12, ..., 60. Subsequent GPC analysis of these oligomers provides three sets of size- and substituent-dependent conversion factors that quantify the overestimation of the oligomer molecular weight when a polystyrene (PS) calibrated GPC system is used for the data analysis. Scanning tunneling microscopy (STM) of representative oligomers at the solid/liquid interface visualizes the monodispersity, the length-dependent rigidity, and their assembling behavior.

We discuss the intriguing photophysics of a giant molecular spoked wheel of π-conjugated arylene-alkynylene chromophores on the single-molecule level. This "molecular mesoscopic" structure, CH, shows fast switching between the 12 identical chromophores since the fluorescence is unpolarised but only one chromophore emits at a time.

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