Computational and Experimental Studies of the Effect of Substituents on the Singlet−Triplet Energy Gap in Phenyl(carbomethoxy)carbene
作者:C. Michael Geise、Yuhong Wang、Olena Mykhaylova、Brian T. Frink、John P. Toscano、Christopher M. Hadad
DOI:10.1021/jo0255330
日期:2002.5.1
The effect of aromatic substitution on the singlet-triplet energy gap in substituted phenyl(carbomethoxy)carbene (X-Ph-C-CO(2)CH(3), PCC) has been explored by time-resolved infrared (TRIR) spectroscopy and gas-phase computational methods. The ground state of para-substituted PCC is calculated to change from the triplet state in p-NO(2)-PCC (Delta G(ST) = 6.1 kcal/mol) to the singlet state in p-NH(2)-PCC
通过时间分辨红外(TRIR)光谱研究了芳香族取代对取代苯基(羰甲氧基)卡宾(X-Ph-C-CO(2)CH(3),PCC)中的单重态-三重态能隙的影响气相计算方法。计算对位取代PCC的基态,使其从p-NO(2)-PCC中的三重态(Delta G(ST)= 6.1 kcal / mol)变为p-NH(2)-PCC中的单重态(ΔG(ST)=-2.8kcal / mol)。pN(CH(3))(2)-PCC(应具有类似于p-NH(2)-PCC的电子特性)和母体PCC的TRIR光谱中没有溶剂扰动,这与它们的基态一致>与下一个可用电子状态相比,+ /-2 kcal / mol,与计算结果一致。在p-OCH(3)-PCC和p-CH(3)-PCC的TRIR光谱中观察到溶剂扰动,表明它们的基态与下一个可用电子态相比<+/- 1 kcal / mol。这与我们的计算结果一致,该计算结果预测,与Delta相比,p