Thermodynamic Aspects of Thermal Decomposition and Charge-Transfer-Induced Chemiluminescent Decomposition for Bicyclic Dioxetanes Bearing a 4-(Benzothiazol-2-yl)-3-hydroxyphenyl Moiety
作者:Masatoshi Tanimura、Nobuko Watanabe、Hisako K. Ijuin、Masakatsu Matsumoto
DOI:10.1021/jo100449m
日期:2010.6.4
Uncatalyzed thermal decomposition (TD) and charge-transfer-induced decomposition (CTID) of dioxetanes were investigated to determine their thermodynamic characteristics. The dioxetanes examined were a series of 1-[4-(benzothiazol-2-yl)-3-hydroxyphenyl]-4,4-dimethyl-2,6,7-trioxabicyclo[3.2.0]heptanes, 1a−d, bearing an alkyl substituent R, e.g., methyl, ethyl, isopropyl, or tert-butyl, at the 5-position
研究了二氧环乙烷的未催化热分解(TD)和电荷转移诱导的分解(CTID),以确定它们的热力学特性。所检查的二恶丁环是一系列1- [4-(苯并噻唑-2-基)-3-羟苯基] -4,4-二甲基-2,6,7-三恶双环[3.2.0]庚烷,1a - d,带有在5位上有一个烷基取代基R,例如甲基,乙基,异丙基或叔丁基,和一个母体二氧杂环丁烷1e,R = H。对1a - d进行X射线单晶分析。激活的两个自由能,Δ ģ ⧧ TD和Δ ģ ⧧ CTID,在为了增加图1A ≤图1b < 1C < 1D。的自由能差ΔΔ ģ ⧧ =Δ ģ ⧧ TD - Δ ģ ⧧ CTID是约 27 kJ mol -1而不考虑取代基R。但是,使用塔夫脱(Taft)双取代参数表明CTID对取代基R的极性比TD更敏感。熵术语用于CTID,Δ小号⧧ CTID,从零的顺序降低至较大的负值叔丁基,异丙基,乙基和甲基,而Δ小号⧧ TD未显示出同样的倾向。