Showing papers by "J. Fraser Stoddart published in 1988"
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TL;DR: In this paper, three chemically modified cyclodextrins have been prepared, characterised by n.m. spectroscopy, and studied for their possible role as piezoelectric crystal coating detectors towards benzene vapour.
Abstract: Three chemically modified cyclodextrins have been prepared, characterised by n.m.r. spectroscopy, and studied for their possible role as piezoelectric crystal coating detectors towards benzene vapour. 2,6-Per-O-methyl-β-cyclodextrin 3-perbenzoate (DMsCD-B7) is not recommended. 2,6-Per-O-(t-butyldimethylsilyl)-α-cyclodextrin (DSαCD) was found to be the best for the ca. 0.08–ca. 400 mg dm–3 range of benzene vapour in air. 2,6-Per-O-allyl-α-cyclodextrin (DAαCD) is a possible alternative. Both detector systems function for > 20 days. The detectors are selective towards benzene vapour over methane, propane, butane, pentane, ethyne, ammonia, nitrobenzene, and toluene. Toluene gives rise to the most serious interference. For the preferred DSαCD sensor, toluene only gives < 20% of the decrease in frequency observed with the corresponding amount of benzene. However, the interference is slightly greater for the DAαCD sensor.
38 citations
TL;DR: In this article, the second sphere coordination of transition metal complexes by chemically modified cyclodextrins was studied using FABMS, which is a facile technique for studying the second-sphere coordination.
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33 citations
TL;DR: In this article, it was shown that receptors 4 − 9, prepared from the readily-synthesised diazadibenzo-30-crown-10 derivative 1, form strong 1:1 molecular inclusion complexes with Diquat, which, although present mainly as the dication, is accompanied by trace amounts of the radical cation.
TL;DR: X-ray crystallography of compound (2) has revealed the presence of edge-to-face interactions between N-tosyl groups and catechol residues in symmetry related molecules in the crystalline state as discussed by the authors.
TL;DR: In this paper, a series of novel polyether analogues of macrocyclic trichothecenes towards alkali metal cations and RNH3+ ions were investigated.
Abstract: As a result of investigating the complexing properties of a series of novel polyether analogues (3)–(9) of macrocyclic trichothecenes towards alkali metal cations and RNH3+ ions, it has been proposed, with supporting evidence from X-ray crystallography on verrucarin A (1) and fast atom bombardment mass spectrometry of complexes involving (1) and the triacetate (10) of baccharinol B4 (11), that the enhanced biological activities of macrocyclic trichothecenes, such as (1) and (11), compared with non-macrocyclic trichoverroids such as (2), may be a consequence of their abilities to bind to NH3+ ionic sites on proteins, particularly those associated with the 60S ribosomes.
TL;DR: X-ray crystallography has established that, in the 1:1 complex formed between [Diquat]2+ and the diazadibenzo-30-crown-10 derivative 5, the noncovalent bonding pattern is similar to that observed previously in [DB30C10]2+.
TL;DR: In this article, le coordinat PMe 3 hydrophobe s'inserant dans l'etroite ouverture de la cyclodextrine.
Abstract: Formation d'un compose d'addition entre le trans-[Pt (PMe 3 )Cl 2 (NH 3 )] et la β-cyclodextrin, le coordinat PMe 3 hydrophobe s'inserant dans l'etroite ouverture de la cyclodextrine
01 Jan 1988
TL;DR: In this article, a macrobicyclic polyether has been designed, synthesised and demonstrated to act as an effective molecular receptor for transition metal cis-diammines, based on these observations, a ditopic receptor was designed for carboplatin and other chemically modified cyclodextrins, used as intermediates for its preparation.
Abstract: Cyclodextrins have been shown to act as second sphere molecular receptors for transition metal complexes bearing hydrophobic ligands. The majority of work has concentrated on ferrocene and its derivatives but other substrates such as chromium arene complexes, allyl palladium complexes, transition metal diene complexes, and the antitumour drug carboplatin, provide adducts of greater variety. Crown ethers also act as second sphere ligands for transition metal complexes bearing ligands with acidic hydrogen atoms, notably ammine ligands. A macrobicyclic polyether has been designed, synthesised and demonstrated to act as an effective molecular receptor for transition metal cis-diammines. On the basis of these observations, a ditopic receptor was designed for carboplatin and the synthesis of this ‘molecular oyster’ and other chemically-modified cyclodextrins, used as intermediates for its preparation, is described.