Substitution and Reaction Chemistry of Cobalt Complexes Supported by [N₂P₂] Ligands

The coordination chemistry of mono- and divalent cobalt complexes supported by the monoanionic multidentate ligands, [N2P2] (where [N2P2] = tBuN(−)SiMe2N(CH2CH2PiPr2)2) and [N2P2tolyl] (where [N2P2tolyl] = MeC6H4N(−)SiMe2(CH2CH2PiPr2)2), is presented. The Co(II) halide complex [N2P2]CoI (2) serves as a precursor to the alkyl, hydride, and amide species [N2P2]CoMe (3), [N2P2]CoCH2SiMe3 (4), [N2P2]CoH (5), [N2P2]CoNHPh (10), and [N2P2]CoNHC6H4Me (11). Reduction of 2 results in the formation of a stable, monomeric Co(I) species, [N2P2]Co (6). Compound 6 can be trapped with CO to form either [N2P2]Co(CO) (7) or [tBuN(CO)SiMe2N(CH2CH2PiPr2)2]Co(CO)2 (8) depending on the number of equivalents of CO introduced. Compound 6 also serves as a precursor to transient Co(III) imido species. The Co(II) halide complex [N2P2tolyl]CoI (16) is synthesized through an analogues reaction to that of 2. Reduction of 16 results in the formation of [N2P2tolyl]Co (17), and differences in the coordination and reaction chemistry of 6 and 17 are described.本文阐述了由单阴离子多齿配体[N₂P₂]（其中[N₂P₂] = tBuN(−)SiMe₂N(CH₂CH₂PiPr₂)₂）与[N₂P₂tolyl]（其中[N₂P₂tolyl] = MeC₆H₄N(−)SiMe₂(CH₂CH₂PiPr₂)₂）所支撑的一价及二价钴配合物的配位化学。二价钴卤化物配合物[N₂P₂]CoI (2)可作为烷基、氢化物及酰胺类物种[N₂P₂]CoMe (3)、[N₂P₂]CoCH₂SiMe₃ (4)、[N₂P₂]CoH (5)、[N₂P₂]CoNHPh (10)与[N₂P₂]CoNHC₆H₄Me (11)的前驱体。对配合物2进行还原反应，可得到稳定的单核一价钴物种[N₂P₂]Co (6)。通过CO捕获化合物6，可根据引入的CO当量数，分别生成[N₂P₂]Co(CO) (7)或[tBuN(CO)SiMe₂N(CH₂CH₂PiPr₂)₂]Co(CO)₂ (8)。化合物6同时也是瞬态三价钴亚胺类物种的前驱体。二价钴卤化物配合物[N₂P₂tolyl]CoI (16)可通过与配合物2类似的反应合成。对配合物16进行还原反应，可得到[N₂P₂tolyl]Co (17)，本文同时阐述了6与17在配位化学及反应化学上的差异。