Selective Pseudo-Rotaxane Type Complex Formation of Zinc(II) (t-butylatedtetraphenyl) porphyrin-Viologen Linked Compounds with tri-O-methyl-β-Cyclodextrin

Morozumi, Tatsuya; Sato, Nao; Nakamura, Hiroshi

doi:10.1007/s10847-006-9075-4

Cited by 3 publications

(2 citation statements)

References 33 publications

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“…The thread 2 2+ was designed (Scheme 1) to possess a bipyridinium moiety at its center, along with two additional biphenyl “stations” [36] which would have a lower affinity for the cyclodextrin cavity, with the future aim of developing a controllable molecular machine [19–25]. The choice of building the linear component with two degenerate “stations” flanking the central bipyridinium one was made to avoid the formation of topological isomers deriving from the formation of a pseudorotaxane-like complex between a cyclodextrin and an unsymmetrical guest [14,30,37–41]. The cyclodextrin chosen to probe the threading tendency of 2 2+ was heptakis-2,6-di- O -methyl-3- O -acetyl-β-cyclodextrin [34,42] ( 1 , see Figure 1), which had been previously investigated and found to form stable complexes with bipyridinium cations in acetonitrile or acetone [32,34].…”

Section: Resultsmentioning

confidence: 99%

“…In this respect, taking advantage of the development of efficient methods for exhaustive and selective functionalization [27–29], a number of papers have appeared in recent years on the construction of supramolecular structures composed of chemically-modified CDs and viologen derivatives [9,30–33]. In particular, cyclodextrins bearing acyl groups on the secondary face can efficiently yield inclusion complexes in polar organic media (acetonitrile, acetone) where a dicationic bipyridinium moiety is tightly bound owing to carbonyl oxygen-cation interactions.…”

Section: Introductionmentioning

confidence: 99%

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Threading Cyclodextrins in Chloroform: A [2]Pseudorotaxane

Gattuso

Gargiulli

Parisi

2007

IJMS

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Threading Cyclodextrins in Chloroform: A [2]Pseudorotaxane

Gattuso

Gargiulli

Parisi

2007

IJMS

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Synthesis and Redox-Driven Chiroptically Switching Properties of Viologen-Containing Optically Active Polymer with Main-Chain Axial Chirality

et al. 2008

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A novel type of redox-based chiroptically switching polymer was prepared by grafting electrochromic viologens onto side chains of a 1,1′-binaphthyl-6,6′-diyl-based optically active conjugated polymer. The resulting polymer exhibited much larger mean residue optical rotation ([m]D 20 = −3308°) than the molar rotation of the corresponding model compound (R)-BBEBPP ([ϕ]D 20 = +384°) and an intense negative CD signal in the absorption band of the polymer backbone, indicating a secondary chirality of the main chain. The viologen-grafting ratio was determined to be ∼50% by proton NMR and thermogravimetric analysis, which corresponds to a predominant polymer structure with one viologen on each repeat unit. Due to the presence of viologen groups, the polymer exhibited a distinctive color change from light yellow to dark blue upon electrochemical or chemical reduction of cationic viologens (V2+) to radical cations (V+·). Correspondingly, the CD spectrum of P4 (V+·) showed two new positive Cotton effects in the absorption bands of V+· at 404 and 520 nm. In comparison with the small molecular model compound that exhibited stronger negative Cotton effects in absorption bands of V+·, P4 (V+·) has a quite different CD pattern, which was attributed to a different exciton coupling mechanism between the two. By taking advantage of the pronounced changes in the CD spectrum of P4 before and after reduction (e.g., [θ] from measuring nearly 0 to 1.2 × 104 deg cm2 dmol−1 at 404 nm or 5.9 × 103 deg cm2 dmol−1 at 520 nm), redox-driven chiroptically switching properties of P4 was probed in a DMF solution using tin as the reducing agent. After five redox cycles, no deterioration of the sample solution was observed and good reversibility in CD signals was demonstrated.

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Chiroptically Active Photonics Polymers: Synthesis and Chiroptically Switching Properties of Helical Polyacetylene Bearing Electrochromic Viologens in the Side Chains

2009

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Toward near-infrared chiroptically active photonics polymers, a new type of optically active polyacetylene bearing l-alanine and electrochromic viologen in the side chains was prepared and carefully studied for the chiroptical properties. The resulting polymer exhibited much larger optical rotation ([m]25 D = −1310°, DMF) than the model compound ([φ]25 D = 201°, DMF) as well as a strong negative circular dichroism (CD) signal attributable to backbone absorption, indicating the formation of a single-handed helical structure of the polymer main chain. The content of viologen in the polymer was determined to be >70 mol % relative to the repeat unit by NMR and X-ray photoelectron spectrscopy. Because of the chiral perturbation of the helical main chain, the viologens in the side chains are asymmetrically positioned and interacted to yield a new strong negative CD band at long wavelengths (i.e., 450−800 nm) upon reduction to radical cations. The intensity of this CD signal could be easily switched between nearly 0 and −1.0 × 104 deg cm2 dmol−1 by redox cycles, which could be repeated for five times without incurring any deterioration of the sample solution. The rotatory strength of the CD signal was calculated to be 1.3 × 10−40 esu2 cm2 according to Moffitt and Moscowitz’s equation, which should contribute nontrivially to the chiroptical properties of the polymer at the near-infrared spectral region.

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Selective Pseudo-Rotaxane Type Complex Formation of Zinc(II) (t-butylatedtetraphenyl) porphyrin-Viologen Linked Compounds with tri-O-methyl-β-Cyclodextrin

Cited by 3 publications

References 33 publications

Threading Cyclodextrins in Chloroform: A [2]Pseudorotaxane

Threading Cyclodextrins in Chloroform: A [2]Pseudorotaxane

Synthesis and Redox-Driven Chiroptically Switching Properties of Viologen-Containing Optically Active Polymer with Main-Chain Axial Chirality

Chiroptically Active Photonics Polymers: Synthesis and Chiroptically Switching Properties of Helical Polyacetylene Bearing Electrochromic Viologens in the Side Chains

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