通过用低配体取代（η（5）-C5Me5）1-来简便地合成异核铀（μ-η（6）：η（6）-C6H6）2-夹心配合物，并将其转化为异核双（亚胺）化合物。
Synthesis of heteroleptic uranium (mu-eta(6):eta(6)-C6H6)2- sandwich complexes via facile displacement of (eta(5)-C5Me5)1- by ligands of lower hapticity and their conversion to heteroleptic bis(imido) compounds.
机构信息
Department of Chemistry, University of California, Irvine, California 92697-2025, USA.
出版信息
J Am Chem Soc. 2009 Dec 2;131(47):17473-81. doi: 10.1021/ja9075259.
Reactivity studies on the sterically crowded (C(5)Me(5))(2)U(mu-eta(6):eta(6)-C(6)H(6)), 1, have revealed that eta(1)-ligands can displace one of the normally inert (eta(5)-C(5)Me(5))(1-) ligands in each metallocene unit to form a series of heteroleptic bimetallic sandwich complexes of nonplanar (C(6)H(6))(2-), namely, (C(5)Me(5))(X)U(mu-eta(6):eta(6)-C(6)H(6)), where X = N(SiMe(3))(2), OC(6)H(2)(CMe(3))(2)-2,6-Me-4, and CH(SiMe(3))(2). Displacement by an amidinate is also possible, that is, X = (i)PrNC(Me)N(i)Pr. This allows the multielectron reactivity of the (mu-eta(6):eta(6)-C(6)H(6))(2-) sandwich complexes to be studied as a function of ancillary ligands. Specifically, the reaction of 1 with K[N(SiMe(3))(2)], previously found to form {(C(5)Me(5))[(Me(3)Si)(2)N]U}(2)(C(6)H(6)), 2, also occurs with K[OC(6)H(2)(CMe(3))(2)-2,6-Me-4], Li[CH(SiMe(3))(2)], and Li[(i)PrNC(Me)N(i)Pr] to form {(C(5)Me(5))[4-Me-2,6-(Me(3)C)(2)C(6)H(2)O]U}(2)(C(6)H(6)), 3, {(C(5)Me(5))[(Me(3)Si)(2)CH]U}(2)(C(6)H(6)), 4, and {(C(5)Me(5))[(i)PrNC(Me)N(i)Pr]U}(2)(C(6)H(6)), 5, respectively. The reactivity of 2-5 vis-a-vis 1 has been compared with the substrates 1,3,5,7-cyclooctatetraene (C(8)H(8)) and 1-azidoadamantane (AdN(3)). Complex 1 acts as a six electron reductant to convert three equiv of C(8)H(8) to (C(5)Me(5))(C(8)H(8))U(mu-eta(3)-eta(3)-C(8)H(8)), whereas the sterically less crowded 2-5 provide only four electrons to reduce two equiv of C(8)H(8) generating U(4+) products of formula (C(5)Me(5))(X)U(C(8)H(8)). With AdN(3), complexes 1, 2, and 5 react similarly to form bis(imido) U(6+) complexes, (C(5)Me(5))(X)U(=NAd)(2). Complexes 2 and 5 also form the ligand redistribution product, (C(5)Me(5))(2)U(=NAd)(2). The reaction of 4 with AdN(3) generates at least three imido complexes: (C(5)Me(5))(2)U(=NAd)(2) from reduction and ligand redistribution, (C(5)Me(5))[AdN(3)CH(SiMe(3))(2)-kappa(2)N(1,2)]U(=NAd)(2), from reduction and insertion, and (C(5)Me(5))(eta(5):kappaNu-C(5)Me(4)CH(2)NAd)U(=NAd), from reduction, ligand redistribution, metalation, and insertion.
(C(5)Me(5))(2)U(mu-eta(6):eta(6)-C(6)H(6)) 的反应性研究表明，η(1)-配体可以取代每个金属茂单元中通常惰性的(eta(5)-C(5)Me(5))(1-)配体，形成一系列非平面的异双核夹心配合物（C(6)H(6))(2-)，即(C(5)Me(5))(X)U(mu-eta(6):eta(6)-C(6)H(6))，其中 X = N(SiMe(3))(2)、OC(6)H(2)(CMe(3))(2)-2,6-Me-4 和 CH(SiMe(3))(2)。酰胺也可以取代，即 X = (i)PrNC(Me)N(i)Pr。这使得（mu-eta(6):eta(6)-C(6)H(6)）夹心配合物的多电子反应性可以作为取代基的函数进行研究。具体来说，与 K[N(SiMe(3))(2)]反应形成{(C(5)Me(5))[(Me(3)Si)(2)N]U}(2)(C(6)H(6))，2，也与 K[OC(6)H(2)(CMe(3))(2)-2,6-Me-4]、Li[CH(SiMe(3))(2)]和 Li[(i)PrNC(Me)N(i)Pr]反应形成{(C(5)Me(5))[4-Me-2,6-(Me(3)C)(2)C(6)H(2)O]U}(2)(C(6)H(6))，3，{(C(5)Me(5))[(Me(3)Si)(2)CH]U}(2)(C(6)H(6))，4，和{(C(5)Me(5))[(i)PrNC(Me)N(i)Pr]U}(2)(C(6)H(6))，5，分别形成。已将 2-5 相对于 1 的反应性与底物 1,3,5,7-环辛四烯（C(8)H(8))和 1-叠氮金刚烷（AdN(3))）进行了比较。配合物 1 作为六电子还原剂，将三当量的 C(8)H(8)转化为(C(5)Me(5))(C(8)H(8))U(mu-eta(3)-eta(3)-C(8)H(8))，而空间位阻较小的 2-5 只提供四电子还原两当量的 C(8)H(8)，生成式（C(5)Me(5))(X)U(C(8)H(8))的 U(4+)产物。与 AdN(3)反应时，配合物 1、2 和 5 反应相似，形成双亚胺 U(6+)配合物（C(5)Me(5))(X)U(=NAd)(2)。配合物 2 和 5 还形成配体重新分布产物（C(5)Me(5))(2)U(=NAd)(2)。4 与 AdN(3)的反应至少生成三种亚胺配合物：还原和配体重新分布生成（C(5)Me(5))(2)U(=NAd)(2)，还原和插入生成（C(5)Me(5))[AdN(3)CH(SiMe(3))(2)-kappa(2)N(1,2)]U(=NAd)(2)，还原、配体重新分布、金属化和插入生成（C(5)Me(5))(eta(5)：kappaNu-C(5)Me(4)CH(2)NAd)U(=NAd)。
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