Propane dehydrogenation is an important field of research due to an increasing world-wide demand of propene while classical production routes through naphtha cracking are in decline. In that context, silica-supported Ga(III) sites, synthesized from surface organometallic chemistry principles, show high selectivity and stability in the propane dehydrogenation reaction. This performance is in significant contrast to the reported fast deactivation and lower selectivity of most Ga₂O₃ and CrO₃ based materials. The Ga-catalyzed propane dehydrogenation reaction is proposed to proceed through the formation of Ga alkyl intermediates for which it would be desirable to have detailed structural and spectroscopic information. Here, we prepare a consistent series of Ga(III) molecular complexes with varying numbers of alkyl and siloxide ligands; they are characterized by single crystal X-Ray diffraction and X-Ray Absorption Near Edge Structure analysis, which is known to be highly sensitive to the Ga coordination environment. We report in particular the structure and the spectroscopic signatures of [Ga(ⁱPr)(OSi(O^tBu)₃)₂(HOSi(O^tBu)₃)], a molecular mimic of the key proposed reaction intermediates in the Ga-catalyzed PDH reaction.

中文翻译：

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二氧化硅负载的 Ga(III) 单中心丙烷脱氢催化剂的 C-H 活化中间体的分子类似物：结构和 XANES 特征

由于世界范围内对丙烯的需求不断增加，而通过石脑油裂解的经典生产路线正在下降，丙烷脱氢是一个重要的研究领域。在这种情况下，由表面有机金属化学原理合成的二氧化硅负载的 Ga(III) 位点在丙烷脱氢反应中显示出高选择性和稳定性。这种性能与报道的大多数 Ga ₂ O ₃和 CrO _{3 的}快速失活和较低的选择性形成鲜明对比基于材料。Ga 催化的丙烷脱氢反应被提议通过 Ga 烷基中间体的形成进行，因此需要具有详细的结构和光谱信息。在这里，我们制备了一系列具有不同数量的烷基和硅氧化物配体的一致的 Ga(III) 分子配合物；它们的特点是单晶 X 射线衍射和 X 射线吸收近边结构分析，已知对 Ga 配位环境高度敏感。我们特别报告了 [Ga( ⁱ Pr)(OSi(O ^t Bu) ₃ ) ₂ (HOSi(O ^t Bu) ₃)]，Ga 催化的 PDH 反应中关键反应中间体的分子模拟。