Electronic and Spin-State Effects on Dinitrogen Splitting to Nitrides in a Rhenium Pincer System
Electronic and Spin-State Effects on Dinitrogen Splitting to Nitrides in a Rhenium Pincer System
复制标题
铼钳系统中二氮分裂成氮化物的电子和自旋态效应
DOI：
10.1021/acs.inorgchem.0c03778
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发表时间：
2021
影响因子：
4.6
通讯作者：
Holland, Patrick L.
中科院分区：
文献类型：
--
作者：
Weber, Jeremy E.;Hasanayn, Faraj;Fataftah, Majed;Mercado, Brandon Q.;Crabtree, Robert H.;Holland, Patrick L.
双金属氮（N2）裂解形成金属氮化物是一种有吸引力的固定N2的方法。虽然越来越多的钳支持系统可以结合和分裂N2，配体的性能和N2的结合/分裂之间的精确关系仍然难以捉摸。在这里，我们报告了N2-桥连的N2（III）配合物的第一个例子，[（trans-P2 tBuPyrr）ReCl 2]2（μ-η1：η1-N2）（P2 tBuPyrr = [2，5-（CH 2 PtBu 2）2C 4 H2 N]−）。在这种情况下，N2结合发生在一个更高的氧化水平比其他报告钳类似物。通过计算研究的电子结构分析表明，弱π-供体钳形配体稳定了开壳层电子构型，导致N2在桥连络合物中的结合增强。利用SQUID磁强计，我们证明了一个单重基态的Re-N-N-Re配合物，我们提供了两个localS= 1网站的反铁磁耦合的初步解释。还原和随后加热的双（III）-二氮络合物导致氯离子损失和N-N键断裂，分离出末端双（V）氮化物络合物（P2 tBuPyrr）ReNCl。
Bimetallic nitrogen (N2) splitting to form metal nitrides is an attractive method for N2fixation. Although a growing number of pincer-supported systems can bind and split N2, the precise relationship between the ligand properties and N2binding/splitting remains elusive. Here we report the first example of an N2-bridged rhenium(III) complex, [(trans-P2tBuPyrr)ReCl2]2(μ-η1:η1-N2) (P2tBuPyrr = [2,5-(CH2PtBu2)2C4H2N]−). In this case, N2binding occurs at a higher oxidation level than that in other reported pincer analogues. Analysis of the electronic structure through computational studies shows that the weakly π-donor pincer ligand stabilizes an open-shell electronic configuration that leads to enhanced binding of N2in the bridged complex. Utilizing SQUID magnetometry, we demonstrate a singlet ground state for this Re–N–N–Re complex, and we offer tentative explanations for antiferromagnetic coupling of the two localS= 1 sites. Reduction and subsequent heating of the rhenium(III)–dinitrogen complex leads to chloride loss and cleavage of the N–N bond with isolation of the terminal rhenium(V) nitride complex (P2tBuPyrr)ReNCl.