Goze Christine, Leiggener Claudia, Liu Shi-Xia, Sanguinet Lionel, Levillain Eric, Hauser Andreas, Decurtins Silvio
Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012 Bern, Switzerland.
Chemphyschem. 2007 Jul 16;8(10):1504-12. doi: 10.1002/cphc.200700066.
Three ruthenium(II) polypyridine complexes of general formula Ru(bpy)(3-n)(TTF-dppz)n2 (n=1-3, bpy=2,2'-bipyridine), with one, two or three redox-active TTF-dppz (4',5'-bis(propylthio)tetrathiafulvenyl[i]dipyrido[3,2-a:2',3'-c]phenazine) ligands, were synthesised and fully characterised. Their electrochemical and photophysical properties are reported together with those of the reference compounds Ru(bpy)32, Ru(dppz)32 and Ru(bpy)2(dppz)2 and the free TTF-dppz ligand. All three complexes show intraligand charge-transfer (ILCT) fluorescence of the TTF-dppz ligand. Remarkably, the complex with n=1 exhibits luminescence from the Ru(2+)-->dppz metal-to-ligand charge-transfer ((3)MLCT) state, whereas for the other two complexes, a radiationless pathway via electron transfer from a second TTF-dppz ligand quenches the (3)MLCT luminescence. The TTF fragments as electron donors thus induce a ligand-to-ligand charge-separated (LLCS) state of the form TTF-dppz- -Ru(2+)-dppz-TTF(+). The lifetime of this LLCS state is approximately 2.3 micros, which is four orders of magnitude longer than that of 0.4 ns for the ILCT state, because recombination of charges on two different ligands is substantially slower.
合成并全面表征了通式为Ru(bpy)(3 - n)(TTF - dppz)n2（n = 1 - 3，bpy = 2,2'-联吡啶）的三种钌(II)多吡啶配合物，它们分别含有一个、两个或三个氧化还原活性的TTF - dppz（4',5'-双(丙硫基)四硫富瓦烯基二吡啶并[3,2 - a:2',3'- c]吩嗪）配体。报告了它们与参考化合物Ru(bpy)32、Ru(dppz)32、Ru(bpy)2(dppz)2以及游离TTF - dppz配体的电化学和光物理性质。所有三种配合物均显示出TTF - dppz配体的配体内电荷转移（ILCT）荧光。值得注意的是，n = 1的配合物表现出从Ru(2+)→dppz的金属到配体电荷转移（(3)MLCT）态的发光，而对于另外两种配合物，通过从第二个TTF - dppz配体进行电子转移的无辐射途径淬灭了(3)MLCT发光。因此，作为电子供体的TTF片段诱导形成了形式为TTF - dppz--Ru(2+)-dppz - TTF(+)的配体到配体电荷分离（LLCS）态。这种LLCS态的寿命约为2.3微秒，比ILCT态的0.4纳秒长四个数量级，因为两个不同配体上电荷的复合要慢得多。
