Size‐ and Structure‐Selective Noncovalent Recognition of Saccharides by Tetraethyl and Tetraphenyl Resorcinarenes in the Gas Phase

Theoretical and experimental gas-phase studies of carbohydrates show that their hydroxyl groups are located in homodromic partial rings that resemble cooperative hydrogen bonds, albeit with long H…O distances and small O-H…O angles. On the other hand, anecdotal experience with disaccharide crystal structures suggested that these clockwise 'c' or counter-clockwise (reverse 'r') sequences are not prevalent in the crystalline state. The situation was clarified with quantum mechanics calculations in vacuum and in continuum solvation, as well as Atoms-In-Molecules analyses. From the experimental side, the Cambridge Structural Database was searched. Geometric criteria for these sequences were developed. A criterion based on 120°ranges of hydroxyl orientations accepted 4% of sequences as having 'c,c' or 'r,r' orientations instead of the 7% expected based on chance. Criteria based on an O-H…O angle [ 90°a nd a 90°lower limit of the absolute value of the H-O-C…H improper torsion accepted 7.0% of the 358 sequences as 'c,c' or 'r,r'. Highly variable orientation of the hydroxyl groups in crystals was seen to depend mostly on strong inter-residue or intermolecular hydrogen bonds. That lack of specific orientation in general for the crystal structures was supported by the solvated calculations that showed very little variation in the energy when one of the hydroxyl groups in 1,2-dihydroxycyclohexane was rotated. The vacuum calculations found the energy to vary with rotation by more than 4 kcal/mol, confirming the gas-phase experiments and calculations on more complicated molecules. Molecules examined in some detail include scyllo inositol and native and methylated cellobiose.

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“…It is the proton donor to both an excellent Fig. 9 Crystalline b-cellobiose in its neat crystal structure (CELLOB04, Kalenius et al 2008 …”

Section: Methyl B-cellobiosidementioning

confidence: 99%

“…9, CSD refcode CELLOB04, Kalenius et al 2008 nearly trans to the methine hydrogen with a torsion angle of 172.6°. Its distance to O4 0 is 3.23 Å and its disqualifying O-H…O angle is 57.4°(not shown).…”

Section: B-cellobiosementioning

confidence: 99%

Hydroxyl orientations in cellobiose and other polyhydroxyl compounds: modeling versus experiment

French

Csonka

2011

Cellulose

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“…1(b) and 1(c)). Cellobiose is a disaccharide with amphiphilic properties that is known to form non‐covalent complexes with lipophilic compounds 39, 40. As can be seen in Fig.…”

Section: Resultsmentioning

confidence: 99%

Electrospray ionization mass spectrometry studies of cyclodextrin‐carboxylate ion inclusion complexes

Mohamed

Wilson

Headley³

et al. 2009

Rapid Comm Mass Spectrometry

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Aqueous solutions containing simple model aliphatic and alicyclic carboxylic acids (surrogates 1-4) were studied using negative ion electrospray mass spectrometry (ESI-MS) in the presence and absence of alpha-, beta-, and gamma-cyclodextrin. Molecular ions were detected corresponding to the parent carboxylic acids and complexed forms of the carboxylic acids; the latter corresponding to non-covalent inclusion complexes formed between carboxylic acid and cyclodextrin compounds (e.g., beta-CD, alpha-CD, and gamma-CD). The formation of 1:1 non-covalent inclusion cyclodextrin-carboxylic complexes and non-inclusion forms of the cellobiose-carboxylic acid compounds was also observed.Aqueous solutions of Syncrude-derived mixtures of aliphatic and alicyclic carboxylic acids (i.e. naphthenic acids; NAs) were similarly studied using ESI-MS, as outlined above. Molecular ions corresponding to the formation of CD-NAs inclusion complexes were observed whereas 1:1 non-inclusion forms of the cellobiose-NAs complexes were not detected. The ESI-MS results provide evidence for some measure of inclusion selectivity according to the 'size-fit' of the host and guest molecules (according to carbon number) and the hydrogen deficiency (z-series) of the naphthenic acid compounds. The relative abundances of the molecular ions of the CD-carboxylate anion adducts provide strong support for differing complex stability in aqueous solution. In general, the 1:1 complex stability according to hydrogen deficiency (z-series) of naphthenic acids may be attributed to the nature of the cavity size of the cyclodextrin host compounds and the relative lipophilicity of the guest.

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“…Cellobiose crystals belong to monoclinic system (space group P2 1 , Z = 2, a = 5.0633 Å, b = 13.017 Å, c = 10.9499 Å, β = 90.811º) [21]. In the monoclinic crystals, the two-fold rotation or inversion axis coincides with one of the three magnetic axes [22].…”

Section: Crystal Symmetrymentioning

confidence: 99%

Single-crystal NMR approach for determining chemical shift tensors from powder samples via magnetically oriented microcrystal arrays

Song

Kusumi

Kimura

et al. 2015

Journal of Magnetic Resonance

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Size‐ and Structure‐Selective Noncovalent Recognition of Saccharides by Tetraethyl and Tetraphenyl Resorcinarenes in the Gas Phase

Cited by 31 publications

References 50 publications

Hydroxyl orientations in cellobiose and other polyhydroxyl compounds: modeling versus experiment

Hydroxyl orientations in cellobiose and other polyhydroxyl compounds: modeling versus experiment

Electrospray ionization mass spectrometry studies of cyclodextrin‐carboxylate ion inclusion complexes

Single-crystal NMR approach for determining chemical shift tensors from powder samples via magnetically oriented microcrystal arrays

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