Palmese Marco, Pérez-Torrente Jesús J, Passarelli Vincenzo
Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, C/Pedro Cerbuna 12, ES-50009 Zaragoza, Spain.
Dalton Trans. 2022 Aug 16;51(32):12334-12351. doi: 10.1039/d2dt02081e.
Monodentate aminophosphanes HNP [NH(4-tolyl)PPh] and SiMeNP [SiMeN(4-tolyl)PPh] react with [Ir(μ-Cl)(cod)] affording tetra- or pentacoordinate complexes of formula [IrCl(L)(cod)] (L = HNP, = 1, 2; L = SiMeNP, = 1). The reaction of [IrCl(SiMeNP)(cod)] with carbon monoxide smoothly renders [Ir(CO)(SiMeNP)][IrCl(CO)]. The reaction of HNP or SiMeNP with [Ir(CHCN)(cod)][PF] yields the cyclometalated iridium(III)-hydride derivatives [IrH{κ,-NR(4-CHCH)PPh}(cod)(CHCN)][PF] (R = H, SiMe) as a result of the intramolecular oxidative addition of the tolyl C-H bond to iridium. The straighforward formation of [IrH{κ,-SiMeN(4-CHCH)PPh}(cod)(CHCN)] was observed when the reaction was monitored by NMR spectroscopy at 233 K, whereas a more complex reaction sequence was observed in the formation of [IrH{κ,-NH(4-CHCH)PPh}(cod)(CHCN)], including the formation of [IrH{κ,-NH(4-CHCH)PPh}(HNP)(cod)] and [Ir(cod)(HNP)]. The "mixed" complex [IrH{κ,-SiMeN(4-CHCH)PPh}(HNP)(cod)] was obtained upon reaction of [IrH{κ,-NH(4-CHCH)PPh}(cod)(CHCN)][PF] with SiMeNP at 233 K. Finally, the reaction of [Ir(CHCN)(coe)][PF] with SiMeNP or HNP resulted in the formation of [Ir(CHCN)(SiMeNP)][PF] and [IrH{κ,-NH(4-CHCH)PPh}(HNP)(CHCN)][PF], respectively. Both the -6-35 and the -6-52 isomers of [IrH{κ,-NH(4-CHCH)PPh}(HNP)(CHCN)] - featuring facial and meridional dispositions of the phosphorus atoms, respectively - were isolated depending on the reaction solvent. Several compounds described herein catalyse the dehydrogenation of formic acid in DMF, [IrCl(HNP)(cod)] being the most active, with TOF of about 2300 h (5 mol% catalyst, 50 mol% sodium formate, DMF, 80 °C).
单齿氨基膦烷HNP [NH(4-甲苯基)PPh] 和SiMeNP [SiMeN(4-甲苯基)PPh] 与 [Ir(μ-Cl)(cod)] 反应，生成式为 [IrCl(L)(cod)] 的四配位或五配位配合物（L = HNP， = 1, 2；L = SiMeNP， = 1）。[IrCl(SiMeNP)(cod)] 与一氧化碳反应顺利生成 [Ir(CO)(SiMeNP)][IrCl(CO)]。HNP 或 SiMeNP 与 [Ir(CHCN)(cod)][PF] 反应，由于甲苯基 C-H 键对铱的分子内氧化加成，生成环金属化铱(III)-氢化物衍生物 [IrH{κ,-NR(4-CHCH)PPh}(cod)(CHCN)][PF]（R = H，SiMe）。当在 233 K 下通过核磁共振光谱监测反应时，观察到 [IrH{κ,-SiMeN(4-CHCH)PPh}(cod)(CHCN)] 的直接形成，而在 [IrH{κ,-NH(4-CHCH)PPh}(cod)(CHCN)] 的形成过程中观察到更复杂的反应序列，包括 [IrH{κ,-NH(4-CHCH)PPh}(HNP)(cod)] 和 [Ir(cod)(HNP)] 的形成。[IrH{κ,-NH(4-CHCH)PPh}(cod)(CHCN)][PF] 与 SiMeNP 在 233 K 下反应得到 “混合” 配合物 [IrH{κ,-SiMeN(4-CHCH)PPh}(HNP)(cod)]。最后，[Ir(CHCN)(coe)][PF] 与 SiMeNP 或 HNP 反应分别生成 [Ir(CHCN)(SiMeNP)][PF] 和 [IrH{κ,-NH(4-CHCH)PPh}(HNP)(CHCN)][PF]。根据反应溶剂的不同，分离得到了 [IrH{κ,-NH(4-CHCH)PPh}(HNP)(CHCN)] 的 -6-35 和 -6-52 异构体，分别具有磷原子的面式和经式排列。本文所述的几种化合物催化 DMF 中甲酸的脱氢反应，[IrCl(HNP)(cod)] 活性最高，TOF 约为 2300 h（5 mol% 催化剂，50 mol% 甲酸钠，DMF，80 °C）。
