The mononuclear niobium methylidyne [(PNP)(ArO)Nb≡CH] (1; PNP^– = N[2-PⁱPr₂-4-methylphenyl]₂^–, Ar = 2,6-ⁱPr₂C₆H₃) reacts with the isocyanate O═C═N^tBu to form a mononuclear niobium oxo species with a rare example of an azaallenyl ligand, namely [(PNP)(ArO)Nb═O(CH═C═N^tBu)] (2). When 1 is treated with the phosphaalkyne P≡CAd (Ad = 1-adamantyl), P≡C bond cleavage occurs to form a mononuclear complex where P–P coupling has occurred between the formal phosphaalkyne phosphorus atom and one phosphine arm from the PNP ligand, namely [(PNPP)(ArO)Nb(η²-AdCCH)] (3). Solid-state structural studies and isotopic labeling experiments confirm C–C bond formation of the methylidyne group as well as provide conclusive evidence for the oxo ligand in 2 being terminal and the fate of the phosphorus atom from P≡CAd in complex 3. Computational studies have been applied to understand the pathway involving the P–P bond forming reaction of 1 and P≡CAd.

中文翻译：

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亚甲基与铌的转移反应

单核铌亚甲基[（PNP）（ArO）Nb≡CH]（1 ; PNP ^– = N [2-P ⁱ Pr ₂ -4-甲基苯基] ₂ ^–，Ar = 2,6- ⁱ Pr ₂ C ₆ H ₃）与异氰酸酯发生反应O =^吨卜以形成具有azaallenyl配体，即一种罕见例子的单核铌氧物种[（PNP）（ARO）Nb═O（CH═C═N^吨丁基）]（2）。当1用磷炔烃P≡CAd（Ad = 1-金刚烷基）处理后，P≡C键裂解形成单核络合物，其中正式磷炔烃磷原子与PNP配体的一个膦臂之间发生了P–P偶联，即[（PNPP）（ARO）NB（η ² -AdCCH）]（3）。固态结构研究和同位素标记实验确认次甲基的C-C键的形成，以及提供确凿的证据为氧代配体在2是终端和从P≡CAd在复合物中的磷原子的命运3。已经进行了计算研究，以了解涉及1和P≡CAd的P–P键形成反应的途径。