【摘要】 <正> 前文报道了用拉曼光谱证明2,2′-乙撑二氧基-双-（1,2-氧硼杂环戊烷）具有环状和网络状结构的两种互变异构体,分别由1,2-氧硼杂环戊烷基的环呼吸振动谱带(897m^-1)和OBO变形振动谱带(821cm^-1)所表征。在15～100℃之间,互变异构平衡符合Van’t Hoff方程,即ln K_c～-1/T为直线。两种互变异构体之间的热焓差ΔH⁰=6.03×10³J/mol。本文报道用拉曼光谱研究2,2′-烷撑二氧基的链结构对2,2′-烷撑二氧基-双-（1,2-氧硼杂环戊烷）类化合物互变异构化的影响。更多还原

【Abstract】 The effect of structure of 2, 2’-alkylenedioxy chain on tautomerism of 2, 2’-alkyienedioxy-bis-1, 2-oxaborolane has been studied. When the chain is—O（CH₂）₂O—,as in compound 1, both cyclic （1a） and network-like （1b） structures exist. However, only cyclic and no network-like structure exists, when the number of carbon are 3, 4 and 5 in—O（CH₂）_nO—chain. Chain branching effects the tautomerism notably. With a CH₃ or CH₂Cl substituent in 2, 2’-ethylenedioxy group, the compounds also show tautomeric isomerism with cyclic （5a） and network-like （5b） structures. But with one methyl substituent on each carbon atom, only cyclic but no network-like form exists. The presence of CH₃ and CH₂Cl substituent in 5 and 6 respectively retards the rate of tautomerio equilibrium with changing temperature. In 15～34℃（or 27～45℃） temperature range, the tautomerio equilibrium is still consistent with the Van’t Hoff equation. The CH₃ （or CH₂Cl） substitution caused enthalpy difference with an increase of about 1.97 （or 1.76）×10³J/mol. The tautomeric equilibrium is not consistent with Van’t Hoff equation when the temperature is higher than 34（or 45）℃. It indicates that the entropy is not constant but is a function of temperature.更多还原