A novel supramolecular assembly, bis(molecular tube)s composed of complexes of organoselenium-bridged β-cyclodextrins and platinum(IV) ion, have been fabricated via the pseudorotaxane with poly(propylene glycol) and characterized by 1 H NMR, TEM, and AFM images, etc.Molecular recognition and molecular self-assembly are currently being extensively studied in chemical and biological systems. 1 Recently, Ghadiri et al. 2 reported the construction of open-ended hollow nanotubes based on the self-assembly of cyclic peptide subunits, which display good channelmediated ion-transport activity with rates exceeding 10 7 ions per second, rivaling the performance of many naturally occurring counterparts. Such molecular assemblies should find use in medicine and material science. Nolte and coworkers 3 reported the self-assembling of crown ethersubstituted phthalocyanines into columnar supramolecular architectures having a length of several micrometers. The most interesting applications are in the field of onedimensional transport of energy, charge, and ions. In the meanwhile, Harada et al. 4 reported a molecular tube, composed of cyclodextrin molecules linked by covalent bonds. Ooya et al. 5 reported the synthesis of a similar biodegradable polyrotaxane for the use in drug delivery systems, in which cyclodextrins were used as drug carriers.Here, we report a novel molecular assemblysbis(molecular tube)s of β-cyclodextrin derivatives containing selenium and platinum. It is well-known that some cis-platinum complexes are successful anticancer agents, and organoselenium compounds were suggested as repressors of human immunodeficiency virus (HIV) transcription. 6 Therefore, the nano assembly reported here might have important potential application in drug delivery systems.The assembly was prepared according to the procedures shown in Scheme 1. As shown in Scheme 1, β-cyclodextrin

A series of novel bis(beta-cyclodextrin)s tethered with organoselenium linkers, i.e., 6,6'-(o-phenylene-diseleno)-bridged bis(beta-cyclodextrin) (2), 6,6'-[2,2'-diselenobis(benzoyloxy)]-bridged bis(beta-cyclodextrin) (3), and 6,6'-[2,2'-diselenobis[2-(benzoylamino)ethylamino]]-bridged bis(beta-cyclodextrin) (4), were synthesized from beta-cyclodextrin (1). The inclusion complexation behavior of 1-4 with some dyes, such as 8-anilinonaphthalenesulfonate (ANS), Brilliant Green, Crystal Violet, Tropaeolin OO, Auramine O, and Methyl Orange, was investigated in aqueous phosphate buffer solution (pH 7.20) at 25 degrees C by UV-vis, fluorescence, and circular dichroism spectrometry, as well as fluorescence lifetime measurements. The complex stability constants (Ks) and Gibbs free energy changes (delta Go) for the stoichiometric 1:1 inclusion complexation of 1-4 with the dyes were obtained by the spectrophotometric or spectropolarimetric titrations. The bis(beta-cyclodextrin)s 2-4 showed much higher affinities toward these guest dyes than native beta-cyclodextrin 1 with fairly good molecular selectivities. The cooperative binding abilities of these bis(beta-cyclodextrin)s are discussed from the viewpoints of size/shape-fit interaction, induced-fit concept, and multiple recognition mechanism.