| 12-钼磷酸—聚乙烯醇的光电子转移反应 |
| ELECTRON-TRANSFER REACTION OF 12-MOLYBDENUM PHOSPHORIC ACID WITH PVA |
|
| 摘要: 12-钼磷酸—聚乙烯醇体系具有不可逆光致变色的特性.根据X射线光电子能谱、电子自旋共振谱、紫外及可见光谱的测试结果,笔者认为:在PMo12-PVA的光电子转移反应中,PMo12既是氧化剂也是光敏剂.PMo12分子中氧可分成Op、Ob和Ot三种情况.其中Ot可成为光化学的活性位置,它和PVA羟基上的氧均较易被紫外光激活.激活的0t边使周围的一个电荷向金属原子(MoⅥ)转移,边与PVA羟基上被激活的氧作用,电子就由此羟基上的氧向Ot转移,致使体系中部分PMo12与PVA发生二电子或四电子氧化还原反应,形成Mo(Ⅵ、Ⅴ)配合物而变色,同时,PVA分子的部分羟基及该羟基位的碳上脱氢形成羰基而具有酮结构.此外,从Mo(V)的ESR特征信号随时间变化而减弱,但其吸收光谱的吸光度未变,于是推断该光化学反应过程中尚有Mo(Ⅳ)生成,已由XPS谱证实. |
| 关键词: H3[PMo12O40]-PVA 光电子转移反应 |
| 基金项目: |
| Abstract: PMo12 is not only a oxidant but also a photoscnsitizcr in the electron transfer reaction of PMo12-PVA system. The terminal Ot in the octahedral MoO6 of PMo12 is a photochemical active site, the Ot and the oxygen of hydroxylic group of PVA were excited easier by 2537Å(25ω). The Ot intcrrcacted with the excited oxygen of hydroxylic group of PVA while the excited terminal oxygen Ot transferred a negative charge to centric atom(MoⅥ), hence, the electron was transported to Ot from oxygen of hydroxylic group, it induced the part of PMo12 in this system to form two or four electronic reductive coordination compound contained Mo(Ⅵ,Ⅴ), and it caused this system to change colour, simultaneously, for PVA the part of hydroxy and the carbonic situs of that hydroxylic location was dchydrogcnated to form a carbonyl group.Moreover, the ESR character signal of Mo(Ⅴ)weakened with the lapse of time, but the absorbance of absorption spectrum not changed, the deduction that the Mo(Ⅳ)might be formed in the process of this photochemical reaction was confirmed by XPS. |
| Keywords: H3(PMo12O40-PVA photoelectron-transfer reaction |
| 投稿时间：1988-09-01 |
| 摘要点击次数: 1400 |
| 全文下载次数: 1464 |
| 程传煊,苏英草.12-钼磷酸—聚乙烯醇的光电子转移反应[J].无机化学学报,1991,7(2):208-213. |
| 查看全文 查看/发表评论 下载PDF阅读器 |
| Support information: |
|
|
|
|
|
|
