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在B3LYP/6-31G(d,p)水平下优化了4种姜黄素类似物的几何构型,并通过振动分析验证了其构型稳定性。在B3LYP/6-311G(d,p)水平下计算了该类化合物的核磁共振谱,研究结果表明:4种化合物结构共平面性较好,为一较大共轭体系。由于羟基或卤素原子的引入,使Compound-B/C/D中C1均具有较大δ值,而邻位C2和C6的δ值相对较小。而在羰基与碳-碳双键所形成的共轭羰基化合物中,羰基C15的δ值(183)相对于乙醛中的δ值(201)有所减小,C12,17(α碳)的δ值(123)相对减小,而C11,18(β碳)的δ值(144)相对增大。最后,通过线性回归方法,利用相关系数值R研究了~1H-NMRδ值的实验和理论计算值的相关性,结果发现相关性较好,实验值和理论值基本吻合。
The geometrical configurations of four curcumin analogues were optimized at the B3LYP / 6-31G (d, p) level and their configurational stability was verified by vibrational analysis. The NMR spectra of these compounds have been calculated at the B3LYP / 6-311G (d, p) level. The results show that the four compounds have a good coplanarity and a larger conjugate system. Due to the introduction of hydroxyl or halogen atoms, C1 in Compound-B / C / D has a larger value of δ, and the values of δ in adjacent positions C2 and C6 are relatively smaller. In the conjugated carbonyl compound formed by the carbonyl group and the carbon-carbon double bond, the δ value (183) of the carbonyl group C15 is decreased with respect to the δ value (201) in the acetaldehyde and the C12,17 The δ value (123) decreases relatively while the δ value (144) of C11,18 (β carbon) increases relatively. Finally, the correlation between experimental and theoretical calculated values of ~ 1H-NMR δ was studied by linear regression method using the correlation coefficient value R. The results showed that the correlation was good, and the experimental and theoretical values were in good agreement.