Molecular structure of crude beeswax studied by solid-state 13C NMR

Abstract 13C Solid-state NMR experiments were performed to investigate the structure of beeswax in the native state (crude beeswax) for the first time. From quantitative direct polarization 13C MAS NMR spectrum, it was found that the fraction of internal-chain methylene (int-(CH2)) component compared to other components of crude beeswax was over 95%. The line shape of the int-(CH2) carbon resonance region was comprehensively analyzed in terms of NMR chemical shift. The 13C broad peak component covering from 31 to 35ppm corresponds to int-(CH2) carbons with trans conformation in crystalline domains, whereas the sharp signal at 30.3 ppm corresponds to gauche conformation in the non-crystalline domain. From peak deconvolution of the aliphatic region, it was found that over 85% of the int-(CH2) has a crystal structure and several kinds of molecular packing for int-(CH2), at least three, exist in the crystalline domain. NMR nuclear magnetic resonance int-(CH2) internal-chain methylene CP cross-polarization MAS magic angle spinning

[1]  D. Grant,et al.  13C NMR Chemical Shifts of the Triclinic and Monoclinic Crystal forms of Valinomycin , 2004, Journal of biomolecular NMR.

[2]  T. Asakura,et al.  Structural role of tyrosine in Bombyx mori silk fibroin, studied by solid‐state NMR and molecular mechanics on a model peptide prepared as silk I and II , 2004, Magnetic resonance in chemistry : MRC.

[3]  N. Al-Waili.  Topical application of natural honey, beeswax and olive oil mixture for atopic dermatitis or psoriasis: partially controlled, single-blinded study. , 2003, Complementary therapies in medicine.

[4]  T. Asakura,et al.  Structure and dynamics in the amorphous region of natural rubber observed under uniaxial deformation monitored with solid-state 13C NMR , 2003 .

[5]  Chenhua Zhao,et al.  Determination of distance of intra-molecular hydrogen bonding in (Ala-Gly)15 with silk I form after removal of the effect of MAS frequency in REDOR experiment. , 2003, Journal of magnetic resonance.

[6]  M. Waelkens,et al.  Mass spectrometric methods prove the use of beeswax and ruminant fat in late Roman cooking pots. , 2002, Journal of chromatography. A.

[7]  C. Cren-olivé,et al.  Characterization of archaeological beeswax by electron ionization and electrospray ionization mass spectrometry. , 2002, Analytical chemistry.

[8]  T. Yamane,et al.  Determination of intermolecular distance for a model peptide of Bombyx mori silk fibroin, GAGAG, with rotational echo double resonance. , 2002, Biopolymers.

[9]  T. Asakura,et al.  Change in the structure of poly(tetramethylene succinate) under tensile stress monitored with solid state 13C NMR , 2002 .

[10]  M. Mariya,et al.  Creating a yield stress in liquid oils by the addition of crystallisable modifiers , 2002 .

[11]  T. Yamane,et al.  Structure ofBombyx mori silk fibroin before spinning in solid state studied with wide angle x-ray scattering and13C cross-polarization/magic angle spinning NMR , 2001 .

[12]  K. Yoshizawa,et al.  Dynamics of the tyrosine side chain in Bombyx mori and Samia cynthia ricini silk fibroin studied by solid state 2H NMR , 1999 .

[13]  K. Yoshizawa,et al.  Hydrogen-bonding structure of serine side chains in Bombyx mori and Samia cynthia ricini silk fibroin determined by solid-state 2H NMR , 1999 .

[14]  Takuro Ito,et al.  Structure of Alanine and Glycine Residues of Samia cynthia ricini Silk Fibers Studied with Solid-State 15N and 13C NMR , 1999 .

[15]  D. Dorset.  Development of lamellar structures in natural waxes - an electron diffraction investigation , 1999 .

[16]  H. Egelhaaf,et al.  Investigating the Selectivity of Triacontyl Interphases. , 1998, Angewandte Chemie.

[17]  D L Dorset,et al.  The crystal structure of waxes. , 1995, Acta crystallographica. Section B, Structural science.

[18]  I. Ando,et al.  Structural studies of n-octadecanol by variable-temperature solid-state high-resolution 13C NMR spectroscopy , 1993 .

[19]  I. Basson,et al.  An investigation of the structures and molecular dynamics of natural waxes. I. Beeswax , 1988 .

[20]  I. Basson,et al.  An investigation of the structures and molecular dynamics of natural waxes. II. Carnauba wax , 1988 .

[21]  Hisaya Sato,et al.  13C NMR chemical shift and crystal structure of paraffins and polyethylene as studied by solid state NMR , 1985 .

[22]  A. Tonelli,et al.  Carbon-13 NMR chemical shifts and the microstructure of polymers , 1981 .

[23]  A. P. Tulloch,et al.  Canadian beeswax: Analytical values and composition of hydrocarbons, free acids and long chain esters , 1972 .

[24]  T. Yamane,et al.  Structure of Bombyx mori silk fibroin before spinning in solid state studied with wide angle x-ray scattering and (13)C cross-polarization/magic angle spinning NMR. , 2001, Biopolymers.

[25]  I Basson,et al.  An investigation of the structures and molecular dynamics of natural waxes. I. Beeswax , 1988 .

[26]  Sidney M. Hecht,et al.  Structural Studies of , 1979 .