A series of bimetallic complexes has been prepared in which an octadentate DOTA-monoamide pocket containing a bound lanthanide ion is linked covalently to a ReI or RuII bipyridyl unit via an alkyl spacer group. The transition metal chromophores incorporated in this way act as effective sensitisers for lanthanide-centred luminescence. The rate and efficiency of energy transfer are dependent upon the nature of the spacer group, and upon the nature of the lanthanide acceptor. For the RuNd diad, there is a long rise-time associated with the energy-transfer step, such that energy transfer is rate determining in H2O, but not in D2O. The results also lead us to suggest that energy transfer may precede formation of the 3M(Ru/Re)L(bpy)CT state and may be a competitive deactivation pathway for the precursor state (1M(Ru/Re)L(bpy)CT).
制备了一系列双
金属配合物,其中含有结合的
镧系离子的八齿 DOTA-单酰胺袋通过烷基间隔基团与 ReI 或 RuII 联
吡啶基单元共价连接。以这种方式掺入的过渡
金属发色团充当以
镧系元素为中心的发光的有效敏化剂。能量转移的速率和效率取决于间隔基团的性质以及
镧系元素受体的性质。对于 RuNd 二元组,存在与能量转移步骤相关的较长上升时间,因此能量转移在
H2O 中决定速率,但在 D2O 中则不然。结果还使我们认为能量转移可能先于 3M(Ru/Re)L(bpy)CT 态的形成,并且可能是前体态 (1M(Ru/Re)L(bpy)CT 的竞争性失活途径)。