Department of Chemistry, University of Houston, Houston, Texas 77204-5641, USA.
Dalton Trans. 2013 Mar 14;42(10):3571-80. doi: 10.1039/c2dt32715e. Epub 2013 Jan 2.
A mixed-ligand metal-metal bonded diruthenium complex having the formula Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))Cl where ap is the anilinopyridinate anion was synthesized from the reaction of Ru(2)(O(2)CCH(3))(4)Cl and H(2,4,6-(CH(3))(3)ap), after which the isolated product was structurally, spectroscopically and electrochemically characterized. The crystal structure reveals an unusual arrangement of the bridging ligands around the dimetal unit where one ruthenium atom is coordinated to one anilino and two pyridyl nitrogen atoms while the other ruthenium atom is coordinated to one pyridyl and two anilino nitrogen atoms. To our knowledge, Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))Cl is the only example of a mixed-ligand diruthenium complex of the type Ru(2)L(3)(O(2)CCH(3)), where L is an unsymmetrical anionic bridging ligand that has been structurally characterized with a "(2,1)" geometric conformation of the bridging ligands, all others being "(3,0)". The initial Ru(2)(5+) compound in CH(2)Cl(2) or CH(3)CN containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) undergoes up to four one-electron redox processes involving the dimetal unit. The Ru(2)(5+/4+) and Ru(2)(5+/6+) processes were characterized under N(2) using thin-layer UV-visible spectroelectrochemistry and this data is compared to UV-visible spectral changes obtained during similar electrode reactions for related diruthenium compounds having the formula Ru(2)L(4)Cl or Ru(2)L(3)(O(2)CCH(3))Cl where L is an anionic bridging ligand. Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))Cl was also examined by UV-visible and FTIR spectroelectrochemistry under a CO atmosphere and two singly reduced Ru(2)(4+) species, Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))(CO)Cl and Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))(CO) were in situ generated for further characterization. The CO-bound complexes could be further reduced and exhibited additional reductions to their Ru(2)(3+) and Ru(2)(2+) oxidation states.
一种混合配体的金属-金属键合双钌配合物，具有化学式 Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))Cl，其中 ap 是苯胺吡啶酸盐阴离子，是由 Ru(2)(O(2)CCH(3))(4)Cl 和 H(2,4,6-(CH(3))(3)ap)反应合成的，然后对分离得到的产物进行了结构、光谱和电化学表征。晶体结构揭示了桥联配体在二金属单元周围的不寻常排列方式，其中一个钌原子与一个苯胺基和两个吡啶氮原子配位，而另一个钌原子与一个吡啶基和两个苯胺基氮原子配位。据我们所知，Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))Cl 是唯一一种具有 Ru(2)L(3)(O(2)CCH(3))类型的混合配体双钌配合物的实例，其中 L 是一种不对称的桥联阴离子配体，其结构特征为桥联配体的 "(2,1)" 几何构象，而所有其他配体均为 "(3,0)"。在含有 0.1 M 四丁基高氯酸铵 (TBAP) 的 CH(2)Cl(2)或 CH(3)CN 中的初始 Ru(2)(5+)化合物经历了多达四个涉及二金属单元的单电子氧化还原过程。Ru(2)(5+/4+)和 Ru(2)(5+/6+)过程在 N(2)下使用薄层紫外-可见光谱电化学进行了表征，并将该数据与在具有化学式 Ru(2)L(4)Cl 或 Ru(2)L(3)(O(2)CCH(3))Cl 的相关双钌化合物的类似电极反应中获得的紫外-可见光谱变化进行了比较，其中 L 是阴离子桥联配体。Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))Cl 也通过 CO 气氛下的紫外-可见和傅里叶变换光谱电化学进行了检查，并原位生成了两种单还原的 Ru(2)(4+)物种 Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))(CO)Cl和 Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))(CO)，以进行进一步表征。CO 结合的配合物可以进一步还原，并表现出对其 Ru(2)(3+)和 Ru(2)(2+)氧化态的额外还原。
