Organometall‐Imide – höhervalente Derivate der d‐Metall‐Säuren, 3. Synthese und Reaktionen von (Pentamethylcyclopentadienyl)(imido)‐Komplexen des Molybdäns und Wolframs und eine effiziente Strategie zur Synthese der Organometallate NBu4[Cp*MO3] (M = Mo, W)

Abstract

AbstractOrganometallic Imido Complexes – Highervalent Derivatives of the d‐Metal Acids, 3[4b]. – Synthesis and Reactions of Pentamethylcyclopentadienyl Imido Complexes of Molybdenum and Tungsten and an Efficient Strategy for the Synthesis of the Organometallates NBu4[Cp*MO3] (M = Mo, W)A convenient and new entry into the chemistry of highvalent pentamethylcyclopentadienyl halfsandwich complexes of molybdenum and tungsten is described. The reaction of Mo‐(NtBu)2Cl2 or W(NtBu)2Cl2(py)2 with Cp*Li (Cp* = η5‐C5Me5) provides a high‐yield route to new complexes Cp*Mo‐(NtBu)2Cl (1a) and Cp*W(NtBu)2Cl (1b) which are converted into a variety of diimido, monoimido, and oxo derivatives. Treatment of 1a,b with MeLi yields the highly volatile methyl derivatives Cp*Mo(NtBu)2Me (2a) and Cp*W(NtBu)2Me (2b), while protolysis of 1a,b with an excess of HCl gas leads to selective cleavage of only one imido function with formation of Cp*Mo(NtBu)Cl3 (3a) and Cp*W(NtBu)Cl3 (3b). In contrast, protolysis of 1a,b with aqueous HCl provides a high‐yield route to the well‐known organometallic oxides [Cp*MoO2]‐(μ‐O) (4a) and [Cp*WO2](μ‐O) (4b). These two key compounds are easily converted into the organomolybdate and organotungstate salts NBu4[Cp*MoO3] (5a) and NBu4[Cp*WO3] (5b) by cleavage of the M–O–M bridge with NBu4[OH]. The X‐ray structure of 3a is reported.