Huynh Winn, Taylor Jordan W, Harman W Hill, Conley Matthew P
Department of Chemistry, University of California, Riverside, California 92521, USA.
Dalton Trans. 2021 Oct 26;50(41):14855-14863. doi: 10.1039/d1dt02981a.
Transition metal interactions with Lewis acids (M → Z linkages) are fundamentally interesting and practically important. The most common Z-type ligands contain boron, which contains an NMR active B nucleus. We measured solid-state B{H} NMR spectra of copper, silver, and gold complexes containing a phosphine substituted 9,10-diboraanthracene ligand (BP) that contain planar boron centers and weak M → BR linkages ([(BP)M][BAr] (M = Cu (1), Ag (2), Au (3)) characterized by large quadrupolar coupling () values (4.4-4.7 MHz) and large span () values (93-139 ppm). However, the solid-state B{H} NMR spectrum of K[Au(BP)] (4), which contains tetrahedral borons, is narrow and characterized by small and values. DFT analysis of 1-4 shows that and are expected to be large for planar boron environments and small for tetrahedral boron, and that the presence of a M → BR linkage relates to the reduction in and B NMR shielding properties. Thus solid-state B NMR spectroscopy contains valuable information about M → BR linkages in complexes containing the BP ligand.
过渡金属与路易斯酸的相互作用（M→Z键）在基础研究方面很有趣，在实际应用中也很重要。最常见的Z型配体含有硼，硼含有一个核磁共振活性的硼原子核。我们测量了含有膦取代的9,10-二硼蒽配体（BP）的铜、银和金配合物的固态硼氢核磁共振谱，这些配合物含有平面硼中心和较弱的M→BR键（[（BP）M][BAr]（M = Cu（1）、Ag（2）、Au（3）），其特征是具有较大的四极耦合（）值（4.4 - 4.7 MHz）和较大的谱宽（）值（93 - 139 ppm）。然而，含有四面体硼的K[Au（BP）]（4）的固态硼氢核磁共振谱很窄，其特征是和值较小。对1 - 4的密度泛函理论分析表明，对于平面硼环境，和预计较大，而对于四面体硼则较小，并且M→BR键的存在与和硼核磁共振屏蔽性质的降低有关。因此，固态硼核磁共振光谱包含了有关含有BP配体的配合物中M→BR键的有价值信息。
