EVIDENCE FOR DISSOCIATIVE PHOTOSUBSTITUTION REACTIONS OF [RU(TRPY)(BPY)(NCCH3)]2+ - CRYSTAL AND MOLECULAR-STRUCTURE OF [RU(TRPY)(BPY)(PY)](PF6)2.(CH3)2CO
EVIDENCE FOR DISSOCIATIVE PHOTOSUBSTITUTION REACTIONS OF [RU(TRPY)(BPY)(NCCH3)]2+ - CRYSTAL AND MOLECULAR-STRUCTURE OF [RU(TRPY)(BPY)(PY)](PF6)2.(CH3)2CO
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DOI：
10.1021/ic00004a013
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发表时间：
1991-02-20
影响因子：
4.6
通讯作者：
MCMILLIN, DR
中科院分区：
文献类型：
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作者：
HECKER, CR;FANWICK, PE;MCMILLIN, DR
在乙腈和适当的亲核剂存在下，配合物[Ru(Trpy)(Bpy)(NCCH3)]2+在金属-配体吸收带体系中发生配体取代反应。(符号trpy表示2，2‘：6’，2“-联吡啶，而bpy表示2，2‘-联吡啶。)在25℃温度下，吡啶、4-苯基吡啶和2-甲基吡啶的1.0M溶液中乙腈配体的置换量子产率分别为0.0013(1)、0.0013(1)和0.0026(5)。没有观察到Os(II)类似物的光化学，所有的发现都可以根据涉及反应3d-d态的解离反应机理来理解。从低于约180K发射的3CT状态访问3D-D状态。从发射寿命的温度依赖关系的测量中，3D-D状态的布居势垒大约为1500 cm-1。最后，用衍射仪测定了[Ru(Trpy)(Bpy)(Py)](Pf6)2.(CH3)2CO的晶体结构。该化合物在一个三斜晶胞中以两个独立的公式单元结晶。空间群为P1BAR，每个单位单元(Z=4)有四个公式，a=13.150(1)埃，b=14.927(1)埃，c=19.771(2)埃，α=102.840(9)度，β=91.655(8)度，伽马=91.655(8)度。结构用全矩阵最小二乘法求解，最后一步精化后，R=0.055，配位球内存在配位空间应变，配位不对称，Ru-N键长相差约0.04埃。这种内部应变可能解释了为什么我们不能用标准方法制备2-甲基吡啶类似物。
In acetonitrile and in the presence of appropriate nucleophiles, the complex [Ru(trpy)(bpy)(NCCH3)]2+ undergoes a ligand substitution reaction when irradiated into the metal-to-ligand absorption band system. (The symbol trpy denotes 2,2':6',2"-terpyridine, and bpy denotes 2,2'-bipyridine.) At 25-degrees-C quantum yields for displacement of the acetonitrile ligand are 0.0013 (1), 0.0013 (1), and 0.0026 (5) for 1.0 M solutions of pyridine, 4-phenylpyridine, and 2-methylpyridine, respectively. No photochemistry is observed for the osmium(II) analogue, and all findings can be understood in terms of a dissociative reaction mechanism involving a reactive 3d-d state. The 3d-d state is accessed from a 3CT state, which is emissive below ca. 180 K. From measurements of the temperature dependence of the emission lifetime, the barrier to population of the 3d-d state is approximately 1500 cm-1. Finally, the crystal structure of [Ru(trpy)(bpy)(py)](PF6)2.(CH3)2CO has been determined with a diffractometer. The compound crystallizes with two independent formula units in a triclinic unit cell. The space group is P1BAR, and there are four formulas per unit cell (Z = 4) with a = 13.150 (1) angstrom, b = 14.927 (1) angstrom, c = 19.771 (2) angstrom, alpha = 102.840 (9)-degrees, beta = 91.655 (8)-degrees, and gamma = 103.371 (8)-degrees. The structure was solved by the full-matrix least-squares method, and after the final stage of refinement, R = 0.055 There is evidence of interligand steric strain within the coordination sphere, and the bpy ligand is coordinated asymmetrically with a difference in Ru-N bond lengths of about 0.04 angstrom. The internal strain probably explains why we have been unable to prepare the 2-methylpyridine analogue by standard methods.