Bond Activation by a Bimetallic GaI Complex: Avenue to Intermetallic Compounds

The synchronous participation of proximate metal centers in bimetallic complexes in a chemical transformation allows for the realization of otherwise unfeasible reaction pathways. Here, we investigated the potential of the bimetallic GaI complex CyL2Ga2 (1, CyL2 = 1,2-trans-C6H10[NC(Me)C(H)C(Me)N(Dip)]2, Dip = 2,6-i-Pr2C6H3) for the construction of intermetallic compounds by bond activation reactions of organometallic group 13 and 15 compounds. Compound 1 reacts with GaMe3 with insertion into two Ga–C bonds and formation of CyL2(GaMe)2GaMe (3), whereas the reaction with BiEt3 only proceeds with activation of one Bi–C bond and formation of CyL2Ga(Et)Ga(BiEt2) (4). Reactions of 1 with Sb2Et4 and Bi2Ph4 occurred with the insertion of both Ga centers into the E–E bonds and formation of CyL2(GaER2)2 (ER2 = SbEt26, BiPh27) with E–Ga–Ga–E motifs. Compounds 3–7 were characterized by heteronuclear NMR (1H, 13C{1H} (except 4)) and infrared (IR) spectroscopy as well as elemental analysis, and their solid-state structures were determined by single-crystal X-ray diffraction (sc-XRD). The structural features of the complexes hint at differing reaction pathways involving the two proximate GaI centers, which were additionally studied by quantum chemical calculations.

双金属配合物中，邻近金属中心在化学转化过程中的同步参与，可实现原本难以达成的反应路径。本研究针对双金属GaI配合物CyL2Ga2（记为化合物1，其中CyL2 = 1,2-反式-C6H10[NC(Me)C(H)C(Me)N(Dip)]2，Dip = 2,6-二异丙基苯基(2,6-i-Pr2C6H3)），探究了其通过第13族与第15族有机金属化合物的键活化反应构建金属间化合物的潜力。化合物1与三甲基镓（GaMe3）反应时，两条Ga–C键发生插入反应，生成CyL2(GaMe)2GaMe（化合物3）；而其与三乙基铋（BiEt3）的反应仅活化一条Bi–C键，生成CyL2Ga(Et)Ga(BiEt2)（化合物4）。化合物1与四乙基二锑（Sb2Et4）、四苯基二铋（Bi2Ph4）的反应中，两个镓中心均插入E–E键（E代表第15族元素），生成具有E–Ga–Ga–E结构基元的CyL2(GaER2)2（其中ER2 = SbEt2，对应化合物6；ER2 = BiPh2，对应化合物7）。本研究通过异核核磁共振波谱（1H谱、13C{1H}去耦谱，化合物4除外）、红外（IR）光谱及元素分析对化合物3至7进行了表征，并借助单晶X射线衍射（sc-XRD）确定了它们的固态结构。该系列配合物的结构特征表明，两个邻近的GaI中心参与了不同的反应路径，该过程进一步通过量子化学计算得到了探究。