Bis(molecular tube)s:  Supramolecular Assembly of Complexes of Organoselenium-Bridged β-Cyclodextrins with Platinum(IV)

Abstract

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

Polymeric Rotaxane Constructed from the Inclusion Complex of β‐Cyclodextrin and 4,4′‐Dipyridine by Coordination with Nickel(II) Ions

“…The opposite ICD signals observed between 1 and 2 indicate that not only do the DPD molecules still lie in the cavity of bCDs after the formation of 2, but also that the DPD moiety of 2 may become more acclivitous in the cavity of b-CDs after coordination of Ni II ions. The powder X-ray diffraction patterns [8,23] of b-CD, DPD, 1, and 2 were obtained using a Rigaku D/max-2500 diffractometer with CuKa radiation. The diffractogram of b-CDs shows a characteristic reflection at 2q = 12.48(d = 7.…”

“…[7] We recently showed that the resulting complex formed from an organoseleniumbridged b-CD dimer and a platinum ion could be fabricated into bis(molecular tube)s through formation of a pesudorotaxane with poly(propylene glycol), and the bridged bis(bcyclodextrin)s and calix [4]arene derivatives could also form nanometer-sized linear aggregations by simple host-guest inclusion complexation. [8][9][10] Molecular semiconductors can also be exploited for organic electronics and single molecules can be manipulated and incorporated into nano-engineered devices at a supramolecular level by threading a chargetransport macromolecule. [11][12][13][14][15] However, higher order polymeric rotaxanes fabricated by metal-ion binding to the inclusion complexes formed between CDs and aromatic molecules have not been investigated so far.…”

Secondary assembly mechanism of cyclodextrin based on LiNTf2@β-CD system

“…The results of their further study on the size effect of the homologues of the a,x-diphenylpolyenes series, with two, three, and four double bonds, on the formation of nanotubes with c-CD indicated that the length of guest molecule is a key factor in the course of nanotube formation [5]. Liu et al focused on the artificial design of CD nanotubes induced by different CD derivatives and metal ions through the metal-ligand coordination [6][7][8].…”

Fabrication of cyclodextrins-procainamide supramolecular self-assembly: Shape-shifting of nanosheet into microtubular structure

“…S3). The detailed structural characteristic of such kind of microtubes formed from rods of CD nanotubes have been often reported (Liu et al, 2001;Liu, Wang, Liang, & Zhang, 2004;Miyake et al, 2003). Recently some researchers reported that a linear structure was obtained from ␤-CD inclusion complex by encapsulating linear guest molecule through the intra and intermolecular hydrogen bonding as well as the intradimer -interactions, whereas the wave-type structure was observed other than the linear structure due to the non-linear molecular structure of the guest molecule.…”