Molecular Recognition Studies on Supramolecular Systems. 32.¹ Molecular Recognition of Dyes by Organoselenium-Bridged Bis(β-cyclodextrin)s

Abstract

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.

Synthesis, Structure, and Glutathione Peroxidase‐Like Activity of Amino Acid Containing Ebselen Analogues and Diaryl Diselenides

“…This finding corroborates the observations of Młochowski et al., where they have used the acid chloride method instead of the DCC coupling reaction for the synthesis of 20 a 17. This observation is also consistent with that of Liu et al., where they synthesized organoselenium‐bridged bis(β‐cyclodextrin)s from 45 through a DCC coupling reaction 42. Even the active ester 48 (synthesized from compound 45 by using DCC coupling) was found to be unreactive towards the amino acids under similar reaction conditions and only the starting material was recovered from each reaction.…”

Induced‐Fit Recognition of CCG Trinucleotide Repeats by a Nickel–Chromomycin Complex Resulting in Large‐Scale DNA Deformation

“…Although originally conceived to explain the interactions between enzymes and their substrates, the induced‐fit theory has been widely applied to other chemical systems and is now a key concept in supramolecular chemistry . Interestingly, there are few examples which use the induced fit concept to explain the binding between DNA and small compounds .…”

Cyclodextrin Combinations with Azocompounds

“…Organoselenium bridged -cyclodextrin dimers as specific host molecules were investigated [29]. The authors showed that the "dimeric" molecules ( Figure 8) not only significantly enhance the binding affinity of the parent -cyclodextrin but also remarkably extend its molecular recognition abilities towards different host molecules, including Methyl Orange and Methyl Red.…”