【摘 要】
：
After the geometry optimization at B3LYP/6-31+G(d,p) level, the calculations of the NMR chemical shifts of a series of stilbene analogues were carried out by me
【机 构】
：
Department of Chemistry
【基金项目】
：
Supported by the Scientific Research Foundation of Department of Education of Yunnan Province, China
论文部分内容阅读
After the geometry optimization at B3LYP/6-31+G(d,p) level, the calculations of the NMR chemical shifts of a series of stilbene analogues were carried out by means of Gauge Including Atomic Orbitals(GIAO) method at HF/6-31+G(d) level and B3LYP/6-311G+(2d,p) level, respectively. The 13C NMR chemical shifts calculated at both HF/6-31+G(d) and B3LYP/6-31+G(d,p) levels are in agreement with the observed values. By virtue of a series of linear correction equations(δpred. =a+bδcalcd.) of the 13C chemical shifts, accurate prediction of 13C chemical shifts was achieved for the new stilbene compounds. For the 13C NMR chemical shifts calculated at HF/6-31+G(d) level, the linear correlation of δpred. with δexptl. is excellent, and the square of correlation coefficient, r2, is 0.9985. The maximum absolute difference between δpred. and δexptl., Δδ, is 2.3, and the root-mean-square error between δpred. and δexptl. is 0.98. In the meantime, for those obtained at B3LYP/6-31+G(d,p) level, the linear correlation of δpred. with δexptl. is also excellent, and the square of correlation coefficient, r2, is up to 0.9987. The maximum absolute difference between δpred. and δexptl., Δδ, is 2.2, and the root-mean-square error between δpred. and δexptl. is only 0.88.
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