Chemical Sciences and Engineering Division , Argonne National Laboratory , 9700 S Cass Avenue , Lemont , Illinois 60439 , United States.
Energy Sciences Division , Argonne National Laboratory , 9700 S Cass Avenue , Lemont , Illinois 60439 , United States.
J Am Chem Soc. 2018 Mar 21;140(11):3940-3951. doi: 10.1021/jacs.7b11981. Epub 2018 Mar 8.
Well-defined organoplatinum(IV) sites were grafted on a Zn(II)-modified SiO support via surface organometallic chemistry in toluene at room temperature. Solid-state spectroscopies including XAS, DRIFTS, DRUV-vis, and solid-state (SS) NMR enhanced by dynamic nuclear polarization (DNP), as well as TPR-H and TEM techniques revealed highly dispersed (methylcyclopentadienyl)methylplatinum(IV) sites on the surface ((MeCp)PtMe/Zn/SiO, 1). In addition, computational modeling suggests that the surface reaction of (MeCp)PtMe with Zn(II)-modified SiO support is thermodynamically favorable (Δ G = -12.4 kcal/mol), likely due to the increased acidity of the hydroxyl group, as indicated by NH-TPD and DNP-enhanced O{H} SSNMR. In situ DRIFTS and XAS hydrogenation experiments reveal the probable formation of a surface Pt(IV)-H upon hydrogenolysis of Pt-Me groups. The heterogenized organoplatinum(IV)-hydride sites catalyze the selective partial hydrogenation of 1,3-butadiene to butenes (up to 95%) and the reduction of nitrobenzene derivatives to anilines (up to 99%) with excellent tolerance of reduction-sensitive functional groups (olefin, carbonyl, nitrile, halogens) under mild reaction conditions.
通过室温下在甲苯中的表面有机金属化学，在 Zn(II)修饰的 SiO 载体上接枝了定义明确的有机铂(IV)位点。固态光谱学，包括 XAS、DRIFTS、DRUV-vis 和通过动态核极化 (DNP) 增强的固态 (SS) NMR，以及 TPR-H 和 TEM 技术，揭示了高度分散的表面（甲基环戊二烯基）甲基铂(IV)位点（(MeCp)PtMe/Zn/SiO，1）。此外，计算模型表明，(MeCp)PtMe 与 Zn(II)修饰的 SiO 载体的表面反应在热力学上是有利的（ΔG = -12.4 kcal/mol），这可能是由于羟基的酸度增加，如 NH-TPD 和 DNP 增强的 O{H} SSNMR 所示。原位 DRIFTS 和 XAS 加氢实验表明，Pt-Me 基团的氢解可能会形成表面 Pt(IV)-H。在温和的反应条件下，异相化的有机铂(IV)-氢化物位点可以催化 1,3-丁二烯的选择性部分加氢生成丁烯（高达 95%），以及硝基苯衍生物还原为苯胺（高达 99%），对还原敏感的官能团（烯烃、羰基、腈、卤素）具有出色的耐受性。
