Sciences Chimiques de Rennes, UMR 6226 CNRS, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France.
Chemistry. 2010 Oct 4;16(37):11340-56. doi: 10.1002/chem.201001463.
Conjugated systems based on phospholes and 1,1'-biphospholes bearing 3,4-ethylenedithia bridges have been prepared using the Fagan-Nugent route. The mechanism of this organometallic route leading to intermediate zirconacyclopentadienes has been investigated by using theoretical calculations. This study revealed that the oxidative coupling leading to zirconacyclopentadienes is favored over oxidative addition within the S-C≡C bond both thermodynamically and kinetically. The impact of the presence of the S atoms on the optical and electrochemical behavior of the phospholes and 1,1'-biphospholes has been systematically evaluated both experimentally and theoretically. A comparison with their "all-carbon" analogues is provided. Of particular interest, this comparative study revealed that the introduction of S atoms has an impact on the electronic properties of phosphole-based conjugated systems. A decrease of the HOMO-LUMO separation and a stabilization of the LUMO level were observed. These general trends are also observed with 1,1'-biphospholes exhibiting σ-π conjugation. The P atom of the 3,4-ethylenedithiaphospholes can be selectively oxidized by S(8) or O(2). These P modifications result in a lowering of the HOMO-LUMO separation as well as an increase of the reduction and oxidation potentials. The S atoms of the 3,4-ethylenedithia bridge of the 2,5-phosphole have been oxidized using m-chloroperoxybenzoic acid. The resulting 3,4-ethylenesulfoxide oxophosphole was characterized by an X-ray diffraction study. Experimental and theoretical studies show that this novel chemical manipulation results in an increase of the HOMO-LUMO separation and an important decrease of the LUMO level. The electropolymerization of 2-thienyl-capped 3,4-ethylenedithiathioxophosphole and 1,1'-biphosphole is reported. The impact of the S substituents on the polymer properties is discussed.
基于膦和带有 3,4-亚乙基二硫桥的 1,1'-联膦的共轭体系已通过 Fagan-Nugent 路线制备。通过理论计算研究了导致中间体锆杂环戊二烯的这种有机金属途径的机制。这项研究表明，氧化偶联导致锆杂环戊二烯的反应在热力学和动力学上都优先于 S-C≡C 键的氧化加成。实验和理论系统地评估了 S 原子的存在对膦和 1,1'-联膦的光学和电化学行为的影响，并与它们的“全碳”类似物进行了比较。特别有趣的是，这项比较研究表明，S 原子的引入会影响基于膦的共轭体系的电子性质。观察到 HOMO-LUMO 能隙减小和 LUMO 能级稳定。这些总体趋势也在具有 σ-π 共轭的 1,1'-联膦中观察到。3,4-亚乙基二硫膦的 P 原子可以被 S(8)或 O(2)选择性氧化。这些 P 修饰导致 HOMO-LUMO 能隙降低以及还原和氧化电位增加。2,5-膦的 3,4-亚乙基二硫桥的 S 原子已用过氧苯甲酸氧化。通过 X 射线衍射研究对得到的 3,4-亚乙基砜氧膦进行了表征。实验和理论研究表明，这种新的化学操作导致 HOMO-LUMO 能隙增加和 LUMO 能级显著降低。报道了 2-噻吩基封端的 3,4-亚乙基二硫代硫氧膦和 1,1'-联膦的电聚合。讨论了 S 取代基对聚合物性质的影响。
