Chemically Initiated Electron Exchange Luminescence of Silyloxyaryl‐Substituted Spiroadamantyl Dioxetanes: Kinetics and Excited State Yields
Chemically Initiated Electron Exchange Luminescence of Silyloxyaryl‐Substituted Spiroadamantyl Dioxetanes: Kinetics and Excited State Yields
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甲硅烷氧基芳基取代的螺金刚二氧杂环丁烷的化学引发电子交换发光：动力学和激发态产率
DOI：
10.1111/j.1751-1097.1996.tb03070.x
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发表时间：
1996
影响因子：
3.3
通讯作者：
W. Adam*
中科院分区：
文献类型：
--
作者：
A. Trofimov;K. Mielke;R. F. Vasil'ev;W. Adam*
本文研究了热稳定的硅氧芳基取代的螺烷基二氧杂环己烷1a、b在氟化物诱导下的分解动力学，以及这种化学引发的电子交换发光(CIEEL)激发态的形成。确定了两个与氟浓度有关的闪光和发光的极限动力学区域，第一个在高氟浓度下，第二个在低[F-]触发下，其详细的动力学分析提供了在乙腈和二甲基亚砜中脱保护的二氧六环2a，b裂解的速率常数，并且化学发光测量了CIEEL和酚酸盐4(CIEEL发射体)的激发产率。螺烷基二氧杂环己烷中的氯代取代不影响脱保护步骤K2，但使脱保护二氧杂环己烷2的裂解速度快约五倍，而两种二氧杂环己烷的化学激发产率相同。采用AM1组态相互作用计算方法，在显式考虑乙腈为溶剂的条件下(自洽反应场法)，计算了苯酚4分子的第一激发态、单重态和三重态的能量。CIEEL发射体酚4的第一激发态具有π，π*特征，这是由π类分子轨道和较大的单、三重态能隙所揭示的。在二氧杂环己烷1a，b裂解过程中，激发态酚4的单线态和三线态的化学激发都是可行的，但实验测定的高的单线态激发产率表明，在氟离子引发的CIEEL过程中，苯酚4的单线态优先占据。
Abstract— The kinetics of the fluoride‐induced decomposition of the thermally stable silyloxyaryl‐substituted spiroadamantyl dioxetanes 1a,b and the excited state formation of this chemically initiated electron exchange luminescence (CIEEL) have been investigated. Two limiting kinetic regimes flash and glow have been identified, which depend on the fluoride concentration, the first at high, the second at low [F‐] triggering, whose detailed kinetic analysis affords the rate constants for the deprotected dioxetanes 2a,b cleavage in acetonitrile and dimethyl sulfoxide and chemiluminescence measurements the CIEEL and phen‐olate 4 (CIEEL emitter) excitation yields. Chloro‐substi‐tution in the spiroadamantyl dioxetane does not affect the deprotection step k2 but leads to a ca five‐fold faster cleavage of the deprotected dioxetane 2, while the chemiexcitation yield is the same for both dioxetanes. The energies of the first excited singlet and triplet states of the emitting phenolate 4 were estimated by AM1 configuration interaction calculations with explicit consideration of acetonitrile as solvent (self‐consistent reaction field approach). The first excited singlet and triplet state of the CIEEL emitter phenolate 4 possess π,π* character, as suggested by the π‐type molecular orbitals and the large singlet‐triplet energy gap. The chemiexcitation of both singlet and triplet states of the excited phenolate 4 is feasible during the dioxetanes 1a,b cleavage, but the experimentally determined high singlet excitation yields suggest that preferentially the phenolate 4 singlet state is populated in the fluoride ion‐triggered CIEEL process.