A semiempirical molecular orbital study on the reaction of an aminopyrazolinyl azo dye with singlet molecular oxygen
A semiempirical molecular orbital study on the reaction of an aminopyrazolinyl azo dye with singlet molecular oxygen
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氨基吡唑啉基偶氮染料与单线态分子氧反应的半经验分子轨道研究
DOI：
10.1016/s0143-7208(98)00038-2
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发表时间：
1999
影响因子：
4.5
通讯作者：
S. Hada
中科院分区：
文献类型：
--
作者：
Z. Morita;S. Hada
采用MO （PM3）半经验计算方法，对氨基唑啉基偶氮染料（黄- 1）和一些羟基偶氮染料与偶氮基单线态分子氧的光化学反应进行了评价。结构优化得到的生成能最小，表明在真空中黄- 1以偶氮形式存在比以腙形式存在更明显。黄- 1的偶氮和腙形式在与单线态氧的烯反应或1,2-环加成反应中具有相似的反应活性。单线态氧加入到腙互变异构体的碳氮双键上，以及偶氮互变异构体吡唑啉环的碳碳双键上，得到相同的终产物，即过氧化氢。染料被单线态氧光氧化的能力取决于染料的性质和偶氮腙的互变异构性。偶氮染料的光氧化性可通过偶氮基团取代羟基化和胺化芳烃的碳原子上的超离域性值来估计。©
Semiempirical MO (PM3) calculations were carried out to evaluate the photochemical reaction with singlet molecular oxygen at the azo group for an aminopyrazolinyl azo dye (Yellow-I) and for some hydroxy azo dyes. Structure optimization to give the minimum energy of formation showed that Yellow-I exists more predominantly in the azo form than the hydrazone one in vacuum. The azo and hydrazone forms of Yellow-I were shown to have similar reactivity in the reaction with singlet oxygen via ene reaction or 1,2-cycloaddition mechanism. Singlet oxygen adds to the carbon–nitrogen double bond of the hydrazone tautomer, as well as to the carbon–carbon double bond in the pyrazoline ring of the azo tautomer to give the same end product, i.e. hydroperoxide. The facility with which a dye is photo-oxidized by singlet oxygen is dependent on the properties of the dye and on the azo-hydrazone tautomerism. The ease of photooxidizability for azo dyes can be estimated by the value of the superdelocalizability at the carbon atoms on which azo groups are substituted for hydroxylated and aminated aromatics. ©