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Iridium(III) bis(thiophosphinite) pincer complexes: synthesis, ligand activation and applications in catalysis
Dalton Transactions ( IF 3.5 ) Pub Date : 2022-06-20 , DOI: 10.1039/d2dt01633h
Alexander Linke 1 , David Decker 1 , Hans-Joachim Drexler 1 , Torsten Beweries 1
Affiliation  

Iridium(III) bis(thiophosphinite) complexes of the type [(RPSCSPR)Ir(H)(Cl)(py)] (RPSCSPR = κ3-(2,6-SPR2)C6H3) (R = tBu, iPr, Ph) can be prepared from the ligand precursors 1,3-(SPR2)C6H4 by C–H activation at Ir using [Ir(COE)2Cl]2 or [Ir(COD)Cl]2. Optimisation of the protocol for complexation showed that direct cyclometallation in the absence or presence of pyridine, as well as C–H activation in the presence of H2 are viable options that, depending on the phosphine substituent furnish the five-coordinate Ir(III) hydride chloride complexes 2-R or the base stabilised species 3-R in good yields. In case of the PhPSCSPPh ligand, P–S activation results in the formation of a thiophosphine stabilised Ir(III) hydride complex [(PhPSCSPPh)Ir(H)(Cl)(PPh2SH)] (4). Reaction of 2-tBu with H2 in the presence of base furnishes an Ir(III) dihydride complex (5) via a labile Ir(III) dihydride–dihydrogen complex (6). All complexes are inactive for transfer dehydrogenation of cyclooctane in the presence of NaOtBu and tert-butylethylene, likely due to decomposition of the Ir complex in the presence of base at higher temperature.

中文翻译:

铱(III)双(硫代亚膦酸盐)钳形配合物:合成、配体活化和催化应用

[( R PSCSP R )Ir(H)(Cl)(py)]型的二(硫代亚膦酸盐)铱 ( III ) 配合物( R PSCSP R = κ 3 -(2,6-SPR 2 )C 6 H 3 ) (R = t Bu , iPr, Ph) 可以通过使用 [Ir(COE) 2 Cl ] 2[ Ir ( COD)Cl] 2 . 络合方案的优化表明,在吡啶不存在或存在下直接环金属化,以及在 H 2存在下 C-H 活化是可行的选择,取决于膦取代基,以良好的收率提供五配位 Ir( III ) 氢化氯化物配合物2-R或碱稳定物质3-R。在Ph PSCSP Ph配体的情况下,P-S 活化导致形成硫代膦稳定的 Ir( III ) 氢化物络合物 [( Ph PSCSP Ph )Ir(H)(Cl)(PPh 2 SH)] ( 4 )。2 - t Bu与 H 2在碱存在下的反应提供 Ir( III ) 二氢化物配合物 ( 5 )通过不稳定的 Ir( III ) 二氢化物-二氢络合物 ( 6 )。在存在 NaO t Bu 和叔丁基乙烯的情况下,所有配合物对于环辛烷的转移脱氢都是无活性的,这可能是由于 Ir 配合物在碱存在下在较高温度下分解所致。
更新日期:2022-06-24
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