The d²-hexahydride complex OsH₆(PⁱPr₃)₂ (1) promotes the activation of C–H bonds of 2,2′-bipyridines and related heterocycles. The study of the same reactions with the deuteride counterpart OsD₆(PⁱPr₃)₂ (1-d) reveals that the activation of the C–H bonds situated in the sterically less hindered positions is kinetically preferred. However, the isolated products are the result of the thermodynamic control of the reactions. Thus, reactions of 1 with 2,2′-bipyridine, 6-phenyl-2,2′-bipyridine, and 6-methyl-2,2′-bipyridine give the “rollover cyclometalation” products OsH₃{κ²-C,N-[C₅(R)H₂N-py]}(PⁱPr₃)₂ (R = H (2), Ph (3), Me (4)), whereas 3,5-dimethyl-6-phenyl-2,2′-bipyridine affords OsH₂{κ³-C,N,C-[C₅H₃N-(Me)₂py-C₅H₄]}(PⁱPr₃)₂ (5), containing a dianionic C,N,C-pincer ligand. The behavior of substrates pyridyl-benzimidazolium and -imidazolium is similar. Reaction of 1 with 3-methyl-1-(6-phenylpyridin-2-yl)-1H-benzimidazolium tetrafluoroborate leads to OsH₃{κ²-C,C-[MeBzim-C₅(Ph)H₂N]}(PⁱPr₃)₂ (6), bearing an anionic C_py,C_NHC-chelate. On the other hand, 3-methyl-1-(6-phenylpyridin-2-yl)-1H-imidazolium tetrafluoroborate yields [OsH₂{κ³-C,N,C-(MeIm-py-C₆H₄)}(PⁱPr₃)₂]BF₄ (7), containing a monoanionic C,N,C-pincer with a NHC-unit coordinated in an abnormal fashion. The reactivity pattern of these substrates is also observed with the d⁴-iridium-pentahydride IrH₅(PⁱPr₃)₂ (8), which has generated IrH₂{κ²-C,N-[C₅(R)H₂N-py]}(PⁱPr₃)₂ (R = H, (9), Ph (10)) and IrH{κ³-C,N,C-[C₅H₃N-(Me₂)py-C₅H₄]}(PⁱPr₃)₂ (11). The osmium(IV)–carbon bonds display a higher degree of covalency than the iridium(III)–carbon bonds. In contrast to 2, the metalated carbon atom of 9 undergoes the addition of a proton of methanol to give [IrH₂{κ²-N,N-(bipy)}(PⁱPr₃)₂]BF₄ (12).

中文翻译：

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2和铱促进的2，2'-联吡啶和相关杂环的CH键活化：动力学和热力学偏好

该d ² -hexahydride复杂OSH ₆（P^我镨₃）₂（1）促进的2,2'-联吡啶和相关的杂环C-H键活化。对与氘代对应物OsD ₆（P ⁱ Pr ₃）₂（1 - d）进行的相同反应的研究表明，在空间上受阻位置上的C–H键的活化在动力学上是优选的。但是，分离出的产物是反应热力学控制的结果。因此，反应1与2,2'-联吡啶，6-苯基-2,2'-联吡啶，和6-甲基-2,2'-联吡啶，得到“翻转环金属化”产品OSH ₃ {κ ² - Ç，ñ - [C ₅（R）H ₂ N-py]}（P ⁱ Pr ₃）₂（R = H（2），Ph（3），Me（4）），而3,5-二甲基-6-苯基-2,2 '联吡啶，得到OSH ₂ {κ ³ - ç，ñ，ç - [C ₅ H ^ ₃ N-（Me）的₂ PY-C ₅ H ^ ₄]}（P ⁱ Pr ₃）₂（5），含有双阴离子C，N，C-钳位配体。底物吡啶基-苯并咪唑鎓和-咪唑鎓的行为相似。的反应1与3-甲基-1-（6-苯基吡啶-2-基）-1 ħ -benzimidazolium四氟硼酸通向OSH ₃ {κ ² - Ç，Ç - [MeBzim-C ₅（PH）H ₂ N]} （P ⁱ Pr ₃）₂（6），带有阴离子C _py，C _NHC螯合物。另一方面，3-甲基-1-（6-苯基吡啶-2-基）-1ħ -咪唑鎓四氟硼酸盐的产率[OSH ₂ {κ ³ - Ç，Ñ，Ç - （MEIM-PY-C ₆ H ^ ₄）}（P^我镨₃）₂ ] BF ₄（7），含有单阴离子C，N，具有NHC单元的C钳以异常方式进行协调。d ^4-铱五氢化物IrH ₅（P ⁱ Pr ₃）₂（8）也观察到了这些底物的反应模式，该反应生成了IrH ₂ {κ² - Ç，ñ - [C ₅（R）H ₂ N-二吡啶]}（P^我镨₃）₂（R = H，（9）中，Ph（10））和IRH {κ ³ - Ç，Ñ，C- [C ₅ H ₃ N-（Me ₂）py-C ₅ H ₄ ]}（P ⁱ Pr ₃）₂（11）。IV（IV）-碳键比铱（III）-碳键具有更高的共价性。与2相反，的金属化的碳原子9所经受加甲醇的质子的，得到[IRH ₂ {κ ² - Ñ，ñ - （联吡啶）}（P^我镨₃）₂ ] BF ₄（12）。