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酸性 (II) 双酸化催化:现场光谱和反应研究

Drew M Hood¹, Ryan A Johnson¹, David J Vinyard²

¹Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States.

Journal of the American Chemical Society

|August 29, 2023

概括

这项研究确定了 ((II) 双复合物作为高效的水合甲基化催化剂系统中的活性物种,特别是对于内部. 这项研究阐明了一种涉及气消除的二聚体形成机制.

科学领域:

有机金属化学
催化剂
一致性催化

背景情况:

甲基化是将基转化为基的关键工业过程.
基于的催化剂被广泛使用,但通常与内部的选择性作斗争.
了解活性催化物对催化剂设计和优化至关重要.

研究的目的:

检测[HCo () CO () 双) ] (BF4) 水合催化剂系统中的活性物种.
阐明催化剂激活和失活的机制.
确定阴阳性复合物在化中的作用.

主要方法:

在位红外光谱 (IR)
电子磁共振 (EPR) 光谱
核磁共振 (NMR) 光谱学
密度函数理论 (DFT) 的计算

主要成果:

催化剂系统[HCo ((CO)) ((bisphosphine)))) ((BF4)) 显示出高活性用于水合基,特别是内部分支基.
红外光谱检测显示,在较低的温度下通过H2排放形成了二氧化碳桥接 (CO) 二次体[Co2 (μ-CO) 2 (CO) 2 (bisphosphine) 2+).
在EPR研究中发现了高旋转 (S = 3/2) (II) 复合物.
DFT计算支持具有明显协调几何结构的二极体结构.
反应研究表明,阴阳性二复合物是主要的催化物种,淡化了中性二物种的作用.

结论:

活性化催化剂是一种阴阳性 (II) 双.
提出了一种涉及消除的单体二元平衡,类似于已知的碳酸系统.
这些发现提供了对催化水合形成机制的关键见解,使化物种优于中性物种.

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