Coordination-number dependence of reactivity in an imidoiron(III) complex
Coordination-number dependence of reactivity in an imidoiron(III) complex
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DOI：
10.1002/anie.200601927
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发表时间：
2006-01-01
影响因子：
16.6
通讯作者：
Holland, Patrick L.
中科院分区：
文献类型：
--
作者：
Eckert, Nathan A.;Vaddadi, Sridhar;Holland, Patrick L.
7022 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Angew。化学，2006,118,7022-7025不饱和金属越多反应活性越高的典型情况。我们还报告了电子结构计算，指出了这种有趣现象的可能原因。在低价金属前体中添加有机叠氮化物是将亚胺配体引入晚期过渡金属配合物的一种良好的策略。[4,6]我们最近证明了二氯胺酸负载的二氮配合物[LMeFeNNFeLMe]是铁(I)片段{LMeFe}（LMe= 2,4 -二（2,6 -二异丙基苯基limo）戊-3-基）的来源在[lmefenfelme]和4-叔丁基吡啶（tBuPy， 2等）的蓝色溶液中加入金刚烷酰叠氮（AdN3）会产生气泡，并立即形成橙色溶液生成样品的1H NMR和x波段EPR谱图如图1所示。溶液的1H NMR谱显示了仅含有LMe、金刚烷基和tBuPy的顺磁性配合物的共振（图1a）。核磁共振活性物质的形成率约为70%。x波段EPR谱（图1b）对应于一个孤立的Kramers双重态，geff= 6.12, 1.94, 1.42。EPR谱让人联想到自旋四重奏，可以模拟为S= 3/2种，E/D= 0.33, gx= 1.94, gy= 2.20, gz= 1.94。信号的温度依赖性表明，地克雷默重态与激发态分离良好
7022 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Angew. Chem. 2006, 118, 7022–7025 typical situation in which more unsaturated metals give higher reactivity. We also report electronic structure calculations that indicate possible reasons for this interesting phenomenon. Addition of organic azides to low-valent metal precursors is a well-precedented tactic for introducing the imido ligand into late transition metal complexes.[4, 6] We recently demonstrated that the diketiminate-supported dinitrogen complex [LMeFeNNFeLMe] is a source of the iron (I) fragment {LMeFe}(LMe= 2, 4-bis (2, 6-diisopropylphenylimino) pent-3-yl).[7] Addition of adamantyl azide (AdN3) to a blue solution of [LMeFeNNFeLMe] and 4-tert-butylpyridine (tBuPy, 2 equiv) gave effervescence and immediate formation of an orangered solution.[8] The 1H NMR and X-band EPR spectra of samples generated in this way are shown in Figure 1.The 1H NMR spectra of the solution display resonances for a paramagnetic complex containing only LMe, an adamantyl group, and perhaps tBuPy (Figure 1a). The NMR-active species is formed in about 70% yield. The X-band EPR spectrum (Figure1b) corresponds to an isolated Kramers doublet with geff= 6.12, 1.94, and 1.42. The EPR spectrum is reminiscent of a spin quartet and can be simulated as an S= 3/2 species with E/D= 0.33, gx= 1.94, gy= 2.20, and gz= 1.94. The temperature dependence of the signal shows that the ground Kramers doublet is well separated from the excited