The red–orange fluorous rhodium(I) complexes ClRh(P((CH₂)_mR_fn)₃)₃ (m/n = 2/6 (1a), 2/8, 3/6, 3/10; R_fn = (CF₂)_n−1CF₃) are essentially insoluble in organic solvents at 20 °C but have measurable solubilities in dibutyl ether at 55–65 °C. Under these conditions, they are effective catalyst precursors for the hydrosilylation of cyclohexanone by PhMe₂SiH. Upon cooling, the catalyst rest states precipitate, giving colorless solutions of C₆H₁₁OSiPhMe₂. When this sequence is conducted in the presence of poly(tetrafluoroethylene) (PTFE; Teflon) tape, the catalysts precipitate onto the tape but desorb when used in subsequent cycles. The catalyst precursors can also be precoated onto the tape, allowing quantities to be delivered by length instead of mass. Rate measurements (1a) show an induction period in the first cycle, excellent retention of activity in the second and third cycles, and significant activity loss in the fourth. Rhodium leaching is 0.57% and 5.3% for the first two cycles (atomic absorption spectroscopy inductively coupled plasma analysis); (CF₂)₅CF₃ leaching is 11.4% over the first three cycles (¹⁹F NMR). Reactions with added mercury show that metallic rhodium is not responsible for catalysis. Identical protocols are applied to 2-octanone, acetophenone, and benzophenone, albeit with some activity loss in the third cycle. Other forms of PTFE can be similarly employed (e.g., Gore-Tex membrane). However, fluorous/organic liquid/liquid biphase conditions can give better retention of catalyst activity. Nonetheless, the diverse morphologies of PTFE that are commercially available suggest avenues for further optimization.

中文翻译：

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使用聚四氟乙烯的均相氟铑催化剂的回收和运输：“纸带上的催化剂”

橘红色氟铑（I）络合物ClRh（P（（CH ₂）_m R _{f n}）₃）₃（m / n = 2/6（1a），2 / 8，3/6，3 / 10; R _{f n} =（CF ₂）_{n -1} CF ₃）在20°C下基本上不溶于有机溶剂，但在55-65°C下在二丁醚中具有可测量的溶解度。在这些条件下，它们是通过PhMe ₂ SiH进行环己酮氢化硅烷化的有效催化剂前体。冷却后，催化剂的静止状态析出，得到无色C ₆ H溶液₁₁ OSiPhMe ₂。当在聚（四氟乙烯）（PTFE； Teflon）胶带的存在下进行此步骤时，催化剂沉淀到胶带上，但在随后的循环中使用时会脱附。催化剂前体也可以预涂在胶带上，从而可以按长度而不是按质量输送量。速率测量结果（1a）显示了第一个周期的诱导期，第二个和第三个周期的活性保持出色，第四个周期的活性明显下降。前两个周期的铑浸出分别为0.57％和5.3％（原子吸收光谱感应耦合等离子体分析）；（CF ₂）₅前三个循环中CF _3的浸出率为11.4％（¹⁹F NMR）。与添加的汞发生的反应表明，金属铑与催化作用无关。相同的方案适用于2-辛酮，苯乙酮和二苯甲酮，尽管在第三周期中会损失一些活性。可以类似地使用其他形式的PTFE（例如，Gore-Tex膜）。但是，氟/有机液体/液体双相条件可以更好地保留催化剂活性。但是，市售的PTFE形貌多样，为进一步优化提供了途径。