Modulation of Lifetimes and Diastereomeric Discrimination in Triplet-Excited Substituted Butane-1,4-diones through Intramolecular Charge-Transfer Quenching
作者:J. N. Moorthy、S. L. Monahan、R. B. Sunoj、J. Chandrasekhar、C. Bohne
DOI:10.1021/ja9818708
日期:1999.4.1
lifetimes have been determined for the diastereomers of a broad set of butane-1,4-dione derivatives (1−3). A remarkable dependence of lifetimes on conformational preferences is revealed in that the lifetimes are shorter for the meso diastereomers of 1−3 than those for the racemic ones. The intramolecular β-phenyl quenching is promoted in the case of meso diastereomers by virtue of the gauche relationship
已经确定了一组广泛的丁烷-1,4-二酮衍生物 (1-3) 的非对映异构体的三重寿命。寿命对构象偏好的显着依赖性表明,1-3 的内消旋非对映异构体的寿命比外消旋非对映异构体的寿命短。在内消旋非对映异构体的情况下,分子内 β-苯基猝灭由于受激发的羰基和 β-芳基环之间的关系而被促进,而外消旋非对映异构体中最低能量构象(H-反)的远端排列阻止这样的停用。通过化合物 2 的内观非对映异构体的三重态寿命与 β-苯环上的取代基性质的相关性,表明分子内 β-苯基猝灭中涉及电荷转移。