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Hydrogen Bonding Effects on the 13C NMR Chemical Shift Tensors of Some Amino Acids in the Solid State

✍ Scribed by Guang Zheng; Liming Wang; Jianzhi Hu; Xiaodong Zhang; Lianfang Shen; Chaohui Ye; Graham A. Webb

Publisher: John Wiley and Sons
Year: 1997
Tongue: English
Weight: 164 KB
Volume: 35
Category: Article
ISSN: 0749-1581
DOI: 10.1002/(sici)1097-458x(199709)35:9<606::aid-omr124>3.0.co;2-#

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✦ Synopsis

The inÑuence of hydrogen bonding (HB) on the 13C chemical shift tensors in four solid amino acids was studied by the ab initio gauge-included atomic orbital (GIAO) approach. The results of the present calculations were compared with those predicted previously and with the experimentally observed shieldings. The RMS error (without HB) found on comparing the calculated and observed principal components of the shielding tensor for the four carboxyl carbons is 35.3 ppm, whereas when the HB e †ects are included, the RMS error is reduced to 19.6 ppm. This clearly demonstrates the importance of including HB e †ects in the calculation of the 13C shieldings for the carboxyl carbons, especially for the component ; this also agrees with published experimental results. 1997

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