A Metal Alkynyl Molecular Wire with PN ligands: Synthesis, Isomerization, Physical Properties and Single-Molecule Conductance
A Metal Alkynyl Molecular Wire with PN ligands: Synthesis, Isomerization, Physical Properties and Single-Molecule Conductance
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DOI：
10.1016/j.ica.2022.121211
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发表时间：
2022-09
影响因子：
2.8
通讯作者：
Yuya Tanaka;A. Okamoto;S. Fujii;T. Nishino;M. Akita
中科院分区：
文献类型：
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作者：
Yuya Tanaka;A. Okamoto;S. Fujii;T. Nishino;M. Akita
作为有机金属分子线的新候选材料，我们设计了钌反式二（炔基）分子线1h，反式钌（PN）2(C≡CC≡C- h)2，具有两种混合膦-吡啶支撑配体（PN: 2-二苯基膦甲基化-6-甲基吡啶）。虽然可能有两种具有正反构型的立体异构体，但三异丙基硅基丁二基前体syn1tip和syn1h的立体异构体是通过直接和立体选择的方式制备的。电化学分析表明，与双（二膦）类似物相比，syn- 1tips2具有几乎可逆的氧化还原波，其电位发生了阴极位移。tms,trans-Ru(dppe)2(C≡CC≡C- sime3)2。密度泛函理论（DFT）研究支持1和2的电子结构相似，HOMOs接近金电极的费米能级。Au-syn-1-Au（Au: gold电极）的stm破断结测量显示，其单分子电导率高达1.9 × 10-2G0，与Au-2-Au相当。基于dft -非平衡格林函数方法的计算也支持实验结果。值得注意的是，分子连接点au -syn-1- aucn可以由syn- 1h通过C-H活化和Au-C键的形成而不需要任何预功能化，而双（二膦）类似物2h则需要末端金功能化。
As new candidates for organometallic molecular wires, we designed a rutheniumtrans-di(alkynyl) molecular wire1H,trans-Ru(PN)2(C≡CC≡C-H)2, with the two mixed phosphine-pyridine supporting ligands (PN: 2-diphenylphosphinomethyl-6-methylpyridine). While two stereo-isomers with thesynandanticonfigurations were possible, thesynisomers of triisopropylsilylbutadiynyl precursorssyn-1TIPSandsyn-1Hwere prepared in direct and stereo-selective manners. Electrochemical analysis ofsyn-1TIPSrevealed a virtually reversible redox wave with the potential cathodically shifted compared to that of the bis(diphosphine) analogue2TMS,trans-Ru(dppe)2(C≡CC≡C-SiMe3)2. The density functional theoretical (DFT) study supports the similarity of the electronic structures of1and2with the HOMOs being close to the Fermi energy level of gold electrodes. STM-break junction measurements ofAu-syn-1-Au(Au: gold electrode) revealed high single-molecule conductance (1.9 × 10–2G0), which is comparable to that ofAu-2-Au. Calculations on the basis of the DFT-non equilibrium Green’s function method also support the experimental results. Notably, the molecular junctionAu-syn-1-Aucan be formed fromsyn-1Hthrough C-H activation and formation of Au-C bonds without any pre-functionalization in contrast to the bis(diphosphine) analogue2H, which requires terminal gold functionalization.