Lutetium‐Methanediide‐Alkyl Complexes: Unique Reactivity toward Carbodiimide and Pyridine

We present the reactivity of four‐coordinate lutetium‐methanediide‐alkyl complexes 1 and 2 ((BODDIR)Lu2(CH2SiMe3)2(µ2‐CHSiMe3)(THF)2, R = iPr (1), R = Et (2)). The reaction of 2 with N,N‐diisopropylcarbodiimide (iPrN=C=NiPr) afforded a nucleophilic adduct 3 through insertion of three molecules of iPrN=C=NiPr into the Lu‐µ2‐CHSiMe3 or Lu‐CH2SiMe3 bonds. In subsequent three component reactions of 1 with N,N‐dicyclohexylcarbodiimide (CyN=C=NCy) and pyridine, different addition patterns led to completely different products. Addition of CyN=C=NCy first and then pyridine into complex 1 resulted in the formation of (BODDIiPr)Lu2(CH2SiMe3)[CyNC(NCy)CHC(NCy)NCy(SiMe3)][CyNC(C6H4N)NCy] (4) with insertion of two molecules of CyN=C=NCy into the Lu‐µ2‐CHSiMe3 bond. Reversing the addition sequence generated (BODDIiPr)Lu2[CyNC(NCy)C6H4N][CyNC(=CHSiMe3)NCy)][CyNC(C6H4N)NCy] (5) with insertion of only one molecule of CyN=C=NCy into the Lu‐µ2‐CHSiMe3 bond. The possible mechanistic pathway to generate 4 was elucidated by DFT calculations. The reactivity of a lutetium‐methanediide‐alkyl complex was exploited to efficiently construct two type of binuclear lutetium complexes. The outcome of these reactions strongly depends on the addition sequence of carbondiimide and pyridine and the reaction temperature.