Crystal Structure of <i>Valonia</i> Cellulose Iβ

Finkenstadt, Victoria L.; Millane, Rick P.

doi:10.1021/ma9804895

Cited by 108 publications

(89 citation statements)

References 28 publications

(77 reference statements)

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“…6b). This is consistent with previous reports showing no hint of inter-sheet O-HÁÁÁO hydrogen bonds, and cellulose sheets held together by C-HÁÁÁO bonds and hydrophobic interactions (Finkenstadt and Millane 1998;Nishiyama et al 2002;Claffey and Blackwell 1976). The length between the (donor) C4-H in the center chain and O2 (accepter) in the corner chain is predicted to remain constant at 2.491 Å as stress is applied along the x 3 direction (Table 4).…”

Section: Structural Evolution With Stress Along the X 3 Directionsupporting

confidence: 92%

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Modeling of negative Poisson’s ratio (auxetic) crystalline cellulose Iβ

Yao

Alderson²,

Alderson

2016

Cellulose

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Energy minimizations for unstretched and stretched cellulose models using an all-atom empirical force field (molecular mechanics) have been performed to investigate the mechanism for auxetic (negative Poisson's ratio) response in crystalline cellulose I b from kraft cooked Norway spruce. An initial investigation to identify an appropriate force field led to a study of the structure and elastic constants from models employing the CVFF force field. Negative values of on-axis Poisson's ratios m 31 and m 13 in the x 1 -x 3 plane containing the chain direction (x 3 ) were realized in energy minimizations employing a stress perpendicular to the hydrogen-bonded cellobiose sheets to simulate swelling in this direction due to the kraft cooking process. Energy minimizations of structural evolution due to stretching along the x 3 chain direction of the 'swollen' (kraft cooked) model identified chain rotation about the chain axis combined with inextensible secondary bonds as the most likely mechanism for auxetic response.

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Section: Structural Evolution With Stress Along the X 3 Directionsupporting

confidence: 92%

“…Matthews et al (2006) note that Nishiyama's structure is in good agreement with the structure derived earlier by Finkenstadt and Millane (1998). The cellobiose repeat units are bonded by covalent bonds along each chain.…”

Section: Introductionsupporting

confidence: 81%

Modeling of negative Poisson’s ratio (auxetic) crystalline cellulose Iβ

Yao

Alderson²,

Alderson

2016

Cellulose

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“…9, a) shows four cross-peaks diagnostic for HÀC(1)/OH interactions, but none for OH/OH interactions. The cross-peaks between HÀC(1a) and HO(3b), between HÀC(1b) and HO(3b'), and between HÀC(1b') and HO(3c) are consistent with the orientation of HO(3b), HO(3b'), and HO(3c) dictated 11 ) The cross-peak in a ROESY spectrum may arise from a true ROE or from relayed ROEs, such as TOCSY/ ROE and exchange/ROE [47]. The ROESY spectrum of a three by the interresidue O(3b)ÀH´´´O(5a), O(3b')ÀH´´´O(5b), and O(3c)ÀH´´´O(5b') H-bonds (Fig.…”

supporting

confidence: 55%

Oligosaccharide Analogues of Polysaccharides, Part 20 , NMR Analysis of Templated Cellodextrins Possessing Two Parallel Chains: A Mimic for Cellulose I?

Bernet

Vasella

2000

HCA

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Für Albert, den Meister des Komplexen an sich Naphthalene-1-ethanol and naphthalene-1,8-diethanol carrying one or two glycosidically bonded cellodextrin chains, T-x and T-x-x, resp. (x 1 ± 4, 8) were analyzed by NMR spectroscopy. For solutions in (D 6 )DMSO and (D 5 )pyridine, analysis was based on a comparison of chemical shifts, coupling constants, temperature dependence of OH signals, and ROESY spectra of the singly and doubly substituted T-x and T-x-x. The characteristic strong intrachain inter-residue O(3)ÀH´´´O(5') H-bond of celluloses was detected in the singly and doubly substituted naphthalenes. Also detected was a weakly persistent flip-flop H-bond between HO(2') and HO(6). Weak interchain interactions were, however, observed only for the units closest to the link of T-x-x in (D 6 )DMSO and for parallel units of T-1-1 and T-3-3 in (D 5 )pyridine. Interchain interactions in T-x-x are stronger in (D 5 )pyridine than in (D 6 )DMSO and decrease with increasing distance from the link. The solidstate CP/MAS 13 C-NMR spectra of T-x-x were compared with those of T-x and of celluloses. The spectrum of T-8 and, surprisingly, also of T-8-8 strongly resembles that of cellulose II and not that of cellulose I b , evidencing that a flexible template possessing parallel cellodextrin chains does not impose sufficient constraints on the structure of supramolecular assemblies to mimic cellulose I b , but leads to a valuable mimic of cellulose II.Introduction. ± There are at least four polymorphs of celluloses, namely cellulose I ± IV [2 ± 4]. The two most common polymorphs are cellulose I, the native form, and cellulose II, the mercerised or regenerated form. Cellulose II is the most stable polymorph. There are two allomorphs of cellulose I. Cellulose I a predominates in algal celluloses [5] [6] and cellulose I b in plant celluloses. Cellulose I b is more stable than cellulose I a [7]. Common to all celluloses is the 4 C 1 conformation of all 1,4-linked b-dglucopyranosyl moieties and the intrachain inter-residue O(3)ÀH´´´O(5') H-bond 2 ). Alternating glucopyranosyl units are rotated by ca. 1808 relative to each other; thus, cellobiosyl moieties are the repeating unit of celluloses. Current three-dimensional structures of celluloses are mainly based on limited X-ray-diffraction data of polycrystalline samples (a few tens of reflections) and computer modeling. Additional models for cellulose II are derived from the crystal structure of b-cellotetraose hemihydrate and from a neutron-diffraction analysis of deuteriated cellulose II fibres (see below).

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“…Based on the X-ray diffraction data for specimens from the sea algae Valonia ventricosa, native cellulose I was first said to have a triclinic crystal structure of parallel chains [14] but later work showed by solid state NMR spectroscopy that cellulose I can be subdivided into cellulose I and cellulose I [15][16], where the I is dominating in bacteria and algae and I is dominating in higher plants. Recent work on X-ray and neutron diffraction data suggests that only cellulose I is truly triclinic, while the I form is monoclinic [17]. Cellulose I can easily and irreversible transform into the monoclinic cellulose II by regeneration or alkali treatment, suggesting that the cellulose II is the more stable allomorph [18].…”

Section: Cellulose Morphologymentioning

confidence: 99%