Conformational effects in molecular tectons containing protonated benzimidazole cations

Kübel-pollak, Anita; Matthews, Craig J.; Verdan, Simon; Bocquet, Bernard; Melich, Xavier; Williams, Alan F.; Lavergnat, Francine; Morgantini, Pierre-Yves; Bérnardinelli, Gerald

doi:10.1039/b602468h

Cited by 10 publications

(9 citation statements)

References 25 publications

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“…mation of bis-benzimidazolonium cations 22 and shown that methylation at the nitrogen atom modifies the conformation. More specifically, when R is methyl (Scheme 4) the dihedral angle χ 1 is influenced and R′ influences χ 3 .…”

Section: Crystal Structuresmentioning

confidence: 99%

“…It is well known from previous work using benzimidazoles that the dissociable proton can couple with redox processes at the metal [16][17][18][19][20] and methylation can prevent this. 21 However, alkylation at the nitrogen also affects the conformation of the ligand 22 and it therefore seemed interesting to see if this modified the binding of the ligand to the cubane. Finally we show that aryl carboxylates can replace the DPP − anion and undergo intramolecular stacking interactions.…”

Section: Introductionmentioning

confidence: 99%

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Helicity inversion and redox chemistry of chiral manganese(ii) cubanes

et al. 2014

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The chiral ligand S-1,2-bis(1H-benzimidazol-2-yl)ethanol, 1, reacts with manganese(II) salts to form cubanes which readily undergo oxidation reactions leading either to a tetranuclear manganese(II,III) mixed valence complex 4 or to a tetranuclear complex of ligand 5 where the secondary alcohol has been oxidised to an enolate. N-methylation of ligand 1 slows the oxidation reaction and stable manganese(II) cubanes may be isolated. The fully methylated ligand 2 gives a cubane of opposite helicity to that found previously for 1 with cobalt. The inversion may be explained by conformational analysis. Cyclic voltammetry suggests that the manganese cubanes reported here are insufficiently robust to store oxidising equivalents as in the oxygen evolving system of photosystem II.

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Section: Crystal Structuresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Helicity inversion and redox chemistry of chiral manganese(ii) cubanes

et al. 2014

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“…In fact the D2 of 2.926(2) Å for ACN2 is much shorter than that found in the case of type IV lone pair⋯π contacts in six membered heteroaromatic compounds as reported by Reedijk et al25 Our own CSD search for type IV N⋯imidazole and imidazolium derivatives show that there are 277 structures containing at least one RCuN molecule and one imidazole or imidazolium ring. Out of these, 38 (13.7%) exhibit at least one lone pair⋯π interaction (D < 4 Å) and the minimum distance was found to be 3.189 Å 26. This makes this interaction in the present case the strongest to date.The crystal structure of the probe molecule shows stacking down the b axis.…”

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confidence: 61%

A catalytic chemodosimetric approach for detection of nanomolar cyanide ions in water, blood serum and live cell imaging

et al. 2015

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Naphthimidazolium based monocationic chemodosimeters CD-1 and CD-2 undergo cyanide mediated catalytic transformation in the presence of cyanide ions (0.01% to 1% of CD-1/CD-2 concentrations) with a turnover number from 70 to 360. These chemodosimeters can detect as low as 0.5 nM and 1 nM cyanide ions under nearly physiological conditions (HEPES buffer-DMSO (5%), pH 7.4). The structures of CD-1 and its cyanide induced hydrolyzed product 4 have been confirmed by single crystal X-ray crystallography. CD-1 can also be used for the determination of 2 nM cyanide in the presence of blood serum. CD-1 and CD-2 also find applications in live cell imaging of 10 nM cyanide ions in rat brain C6 glioma cells. To the best of our knowledge, this is the first report where high sensitivity towards cyanide ions has been achieved through catalytic hydrolysis of the fluorescent chemodosimeter.

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“…The non‐coordinated benzimidazole of ligand 4 is protonated, and shows a stacking interaction with a coordinated benzimidazole of the complex generated by the twofold screw axis along a . We have previously established the strong tendency of benzimidazole cations to give stacking interactions[16b], but this is the first time we have observed a stack between a protonated and a coordinated benzimidazole. The chains along the a ‐axis are linked by hydrogen bonding along the c ‐axis.…”

Section: Resultsmentioning

confidence: 99%