State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, People's Republic of China.
J Am Chem Soc. 2013 Oct 2;135(39):14784-96. doi: 10.1021/ja406413d. Epub 2013 Sep 18.
The four-coordinate scandium phosphinidene complex, [LSc(μ-PAr)]2 (L = (MeC(NDIPP)CHC(Me)(NCH2CH2N((i)Pr)2)), DIPP = 2,6-((i)Pr)2C6H3; Ar = 2,6-Me2C6H3) (1), has been synthesized in good yield, and its reactivity has been investigated. Although 1 has a bis(μ-phosphinidene)discandium structural unit, this coordinatively unsaturated complex shows high and versatile reactivity toward a variety of substrates. First, two-electron reduction occurs when substrates as 2,2'-bipyridine, elemental selenium, elemental tellurium, Me3P═S, or Ph3P═E (E = S, Se) is used, resulting in the oxidative coupling of two phosphinidene ligands 2PAr into a diphosphene ligand ArP-PAr. Complex 1 easily undergoes nucleophilic addition reactions with unsaturated substrates, such as benzylallene, benzonitrile, tert-butyl isocyanide, and CS2. This complex also shows a peculiar reactivity to CO and Mo(CO)6, that includes C-P bond formation, C-C coupling and C-O bond cleavage of CO, to afford novel phosphorus-containing products. In the last two types of reactivity, reaction profiles have been computed (for the insertion of (t)BuNC and the CO activation by 1) at the DFT level. The unexpected/surprising sequence of steps in the latter case is also revealed.
四配位钪膦烯配合物[LSc(μ-PAr)]2（L = (MeC(NDIPP)CHC(Me)(NCH2CH2N((i)Pr)2))，DIPP = 2,6-((i)Pr)2C6H3；Ar = 2,6-Me2C6H3）（1）以高产率合成，并研究了其反应性。尽管 1 具有双（μ-膦烯）二钪结构单元，但这种配位不饱和的配合物对各种底物表现出高且多功能的反应性。首先，当使用 2,2'-联吡啶、元素硒、元素碲、Me3P═S 或 Ph3P═E（E = S，Se）等底物时，发生两电子还原，导致两个膦烯配体 2PAr氧化偶联成二膦烯配体ArP-PAr。1 容易与不饱和底物（如苄基丙烯、苯甲腈、叔丁基异氰酸酯和 CS2）发生亲核加成反应。该配合物还对 CO 和 Mo(CO)6 表现出特殊的反应性，包括 C-P 键形成、C-C 偶联和 CO 的 C-O 键断裂，从而获得新的含磷产物。在后两种类型的反应性中，在 DFT 水平上计算了（t）BuNC 的插入和 1 对 CO 的活化的反应轮廓。在后一种情况下，还揭示了出乎意料的步骤顺序。
