Infrared spectra of crystalline polysaccharides. V. Chitin

Pearson, F. G.; Marchessault, R. H.; Liang, Changhao

doi:10.1002/pol.1960.1204314109

Cited by 317 publications

(169 citation statements)

References 11 publications

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“…5 The first two bands are very similar to those observed in both chitin (20) and cellulose I1 (21 ), so that on the basis of its strong parallel dichroism the peak at 3462 cm-' may be assigned to the 0(3+H stretching mode. In the structure proposed for mannan, the 0(6+H does not take part in any inter-molecular hydrogen-bond and it is, therefore, to be expected that the stretching vibration would be of high frequency.…”

Section: Infrared Spectroscopysupporting

confidence: 51%

The Crystalline Structure of Poly-β,D(1→4′)mannose: Mannan I

Nieduszynski¹,

Marchessault²

1972

Can. J. Chem.

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The crystallographic structure of mannan I has been examined by X-ray fiber diffraction, polarized i.r. spectroscopy, and computer chain-packing methods. The combination of X-ray intensity data and the chain packing analyses have shown that the overall number of permissible structures is very limited so that van der Waals' forces play a major role in packing. It was concluded that the chain senses are anti-parallel. The interpretation of the polarized i.r. spectra in the OH stretching region is in line with the presence of an intra-molecular hydrogen-bond between O(3). . .0(5'). The awkward "knobby" shape of the mannan molecule, largely a result of the axial disposition of O(2 j H , lends itself to a close packing mainly determined by van der Waals' forces. The considerable similarity between X-ray and i.r. data from mannans and glucomannans would indicate that structural conclusions about the former might relate to the latter.La structure cristallographique du mannan I a ete reexaminee par la diffraction aux rayons-x de fibre, par la spectroscopie i.r. en lumitre polarisee et par les methodes de calcul d'entassement des chaines dans la maille. La combinaison des donntes sur l'intensitk des rayons-x et les analyses des chaines compactes, ont montrb que le nombre global de structures permises est trts limit6 de sorte que les forces de van der Waals jouent un r6le majeur dans I'entassement. On a conclu a I'antiparalltlisme des directions des chaines. L'interpretation du spectre i.r. polarise, dans la region #elongation du OH, est conforme la presence d'une liaison hydrogknq intramolCculaire entre O(3). . .0(5'). La forme "noueuse et disgracieuse" de la molBcule de Mannan, en grande partie due a la disposition axiale de O(2)-H, se pr&te elle-m&me a un tassement serrk, determine surtout par les forces de van der Waals. La grande similitude dans les donnees des rayons-x et de 1'i.r. entre les mannans et les glucomannans, indiquerait que les conclusions sur les structures du premier seraient likes au second.

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Section: Infrared Spectroscopysupporting

confidence: 51%

The Crystalline Structure of Poly-β,D(1→4′)mannose: Mannan I

Nieduszynski¹,

Marchessault²

1972

Can. J. Chem.

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“…The band a t higher frequency has previously (22)(23)(24) been attributed to the a~nide I vibration. On the other hand, the band a t 1 626 cm-1 has been assigned to a C=N stretching vibration (22), an overtone or combination mode (23), an amide C=O group hydrogen-bonded t o an Of-I group (21), or the C=O group of a rotational isomer of the aminoacetyl group (22), or has been coinpletely ignored (25). The present evidence strongly indicates that these two bands are in fact both due to amide I vibrations, but correspond to two different classes of amide groups.…”

Section: Tlze Chitin Bands At 1 626 and 1 656 Cm-imentioning

confidence: 94%

“…The present results indicate that even much less drastic treatment, such as boiling in pure water, may produce extensive changes. The inacrostructure of chitin, as previously isolated (21)(22)(23)(24)(25)(26)(27), may therefore be an artifact formed in the process of isolation. In particular, the so-called a-, @-, and y-types oi chitin, isolated from some organisms and reported to have different X-ray diffraction patterns and infrared spectra (34,43,44), may be unrelated to the native state of chitin in these organisms.…”

Section: State Of Chitin In Natz~rementioning

confidence: 98%

“…The X-ray diffraction pattern of chitin, on the other hand, is obtained exclusively from the more highly ordered regions of the polysaccharide, which need not be representative of the bulk of the sample. Because of these limitations, previous conclusions about the macrostructure of chitin derived from X-ray diffraction and infrared studies (21)(22)(23)(24)(25)(26)(27) For personal use only.…”

Section: Fig 3 T H E Infrared Absorption Spectrum O F Chitan (A) Anmentioning

confidence: 99%

“…and u~it11 other reagents causes a siinultaneous appearance of the new band a t 1 636 cm-l, and a decrease in the intensity a t 1 626 cm-l. (c) Reprecipitation of chitin froin hydrochloric acid causes an intensification of the band a t 1656 cin-', with a corresponding decrease a t 1 626 cm-l. (d) The band a t 1 626 cin-I has been observed to disappear inore rapidly than does the band a t 1 656 cin-I on progressive deacetylation and during nitration (21). (e) The two bands differ in their relative intensities and dichroisnl in different preparations of chitin (10,(21)(22)(23)(24)34).…”

Section: Tlze Chitin Bands At 1 626 and 1 656 Cm-imentioning

confidence: 99%

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STUDIES ON CHITAN (β-(1 → 4)-LINKED 2-ACETAMIDO-2-DEOXY-D-GLUCAN) FIBERS OF THE DIATOM THALASSIOSIRA FLUVIATILIS HUSTEDT: II. PROTON MAGNETIC RESONANCE, INFRARED, AND X-RAY STUDIES

Falk¹,

Smith²,

McLachlan³

et al. 1966

Can. J. Chem.

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ABSTR.4CrrThe estracellular fibers attached to the diatom Tkalasszosirafluz~iatilis have been shown to be pure 0-(1 -, 4)-linked 2-acetamido-2-deosy-D-glucan. This polysaccharide \\-as given the systematic trivial name chitan to distinguish it f r o~n chitin, which is not a chemically distinct species and which has a radically different X-ray diffraction pattern and infrared spectrun~. Proton magnetic resonance studies on the acid hydrolysis of chitan have established that the hydrolysis occurred in three distinct steps: (a) the degradation of the polysaccharide to smaller polymeric units, (b) the prod~lction of N-acetylglucosarnine from the latter, and ( c ) the conversion of iV-acetylgl~icosamii~e into gl~~cosarnine and acetic acid. X-ray and infrared studies have shown that chitan has a different macrostructure frorn that of arthropod chitin. Chitan is completely crystalline and can beconverted irreversibly into a form indistinguishable from that of chitin by treatment with hot aqueous lithium thiocyanate. Boiling chitan in \\rater converts it into a second crystalline modification, possibly a hydrate, which can be reconverted into the starting material by drying i n vaczro. The exceptioilally sharp infrared spectrum of chitan allows a more ~lneq~iivocal assignment of a number of bands common t o chitan and chitin, and provides information about the nat~lre of the bands a t 1 6 2 6 and 1 6 5 6 cm-I in the spectr~lrn of chitin. The correlation of the bands in the region of 840 to 890 cm-1 with the configuration a t the anomeric center of glycopyranose derivatives is discussed.

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Synthesis, properties, and permeation of solutes through hydrogels based on poly(ethylene glycol)-co-poly(lactones) diacrylate macromers and chitosan

Cho

Kim

Lee

et al. 1999

J. Appl. Polym. Sci.

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Triblock copolymers from poly(ethylene glycol) (PEG) and D,L-lactide or -caprolactone were synthesized to prepare semi-interpenetrating polymer networks (semi-IPNs) with chitosan by ultraviolet (UV) irradiation method. Then, the solute permeation through these semi-IPNs hydrogels were investigated. The structures of semi-IPNs were confirmed by Fourier transform infrared (FTIR) spectroscopy and wide-angle X-ray diffractometer (WAXD). The equilibrium water content (EWC) of these hydrogels was in the range of 67-75%. The crystallinity, thermal properties, and mechanical properties of semi-IPNs hydrogels were studied. All the hydrogels revealed a remarkable decrease in crystallinity as compared with the PEG macromer itself. The tensile strengths of semi-IPNs hydrogels in a dry state were rather high, but those of hydrogels in a wet state decreased drastically. The permeabilities of solutes of hydrogels followed the swelling behaviors and were regulated by solute size.

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Infrared spectra of crystalline polysaccharides. V. Chitin

Cited by 317 publications

References 11 publications

The Crystalline Structure of Poly-β,D(1→4′)mannose: Mannan I

The Crystalline Structure of Poly-β,D(1→4′)mannose: Mannan I

STUDIES ON CHITAN (β-(1 → 4)-LINKED 2-ACETAMIDO-2-DEOXY-D-GLUCAN) FIBERS OF THE DIATOM THALASSIOSIRA FLUVIATILIS HUSTEDT: II. PROTON MAGNETIC RESONANCE, INFRARED, AND X-RAY STUDIES

Synthesis, properties, and permeation of solutes through hydrogels based on poly(ethylene glycol)-co-poly(lactones) diacrylate macromers and chitosan

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