In order to extend stepwise photochromism to more metal-coordination systems for multicolors and multistates, a new photochromic dithienylethene-ethynylthiophene (L1o) was synthesized to design head–head coupled symmetric ruthenium(II) complex trans-Ru(dppe)₂(L1o)₂ (1oo) and head-shoulder coupled asymmetric ruthenium(II) complex trans-Ru(dppe)₂(L1o)(L2o) (2oo). However, upon irradiation under UV light, 1oo only converts to 1co without the observation of dually ring-closed species 1cc, and only the dually ring-closed species 2cc is observed without the detection of the mixed ring-open/closed species 2co and 2oc, implying that it is difficult to achieve substantial stepwise photochromic process of 1oo-2oo → 1co-2oc/2co→1cc-2cc due to the rapid intramolecular energy transfer in 1co and the absence of electronic communication between two dithienylethene units in 2oo. The photochemical processes are well demonstrated and explained by NMR, UV–vis, electrochemical, as well as time-dependent density functional theory (TD-DFT) computational studies.

为了将逐步的光致变色作用扩展到更多的金属配位体系，以实现多色和多态，合成了一种新的光致变色二噻吩基乙烯-乙炔基噻吩（L1o），设计了头-头耦合对称钌（II）复合反式Ru（dppe）₂（Lpp）。₂（1oo）和头肩偶联的不对称钌（II）络合物反Ru（dppe）₂（L1o）（L2o）（2oo）。但是，在紫外线照射下，1oo只能转换为1co，而没有观察到双闭环物种1 cc和只有双闭环物种2 cc没有检测到所述混合环打开/关闭物种的观察2CO和20C中，这意味着它是难以实现的实质逐步光致变色过程1OO-2OO →林前-20C中/ 2CO→1CC-2 CC由于快速的分子内能量转印在林前，并在两个dithienylethene单元之间不存在电子通信的2OO。通过NMR，UV-vis，电化学以及随时间变化的密度泛函理论（TD-DFT）计算研究，可以很好地说明和解释光化学过程。