Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI 48109, USA.
Present address: Drury University, Department of Chemistry and Physics, 900 North Benton Ave., Springfield, MO 65802, USA.
Angew Chem Int Ed Engl. 2023 Mar 20;62(13):e202218907. doi: 10.1002/anie.202218907. Epub 2023 Feb 20.
We present a ligand platform featuring appended ditopic Lewis acids to facilitate capture/activation of diatomic substrates. We show that incorporation of two 9-borabicyclo[3.3.1]nonane (9-BBN) units on a single carbon tethered to a pyridine pyrazole scaffold maintains a set of unquenched nitrogen donors available to coordinate Fe , Zn , and Ni . Using hydride ion affinity and competition experiments, we establish an additive effect for ditopic secondary sphere boranes, compared to the monotopic analogue. These effects are exploited to achieve high selectivity for binding NO in the presence of competitive anions such as F and NO . Finally, we demonstrate hydrazine capture within the second-sphere of metal complexes, followed by unique activation pathways to generate hydrazido and diazene ligands on Zn and Fe, respectively.
我们提出了一个配体平台，其特点是附加的双齿路易斯酸，以促进双原子底物的捕获/活化。我们表明，在一个吡啶吡唑骨架上连接到一个碳上的两个 9-硼杂双环[3.3.1]壬烷（9-BBN）单元的结合保持了一组未猝灭的氮供体，可与 Fe、Zn 和 Ni 配位。通过氢化物离子亲和性和竞争实验，我们确定了双齿次级硼烷的加和效应，与单齿类似物相比。这些效应被利用来实现在存在竞争阴离子如 F 和 NO 的情况下对 NO 的高选择性结合。最后，我们证明了在金属配合物的第二球内捕获肼，然后分别在 Zn 和 Fe 上通过独特的活化途径生成肼基和二氮烯配体。
