Niobium isocyanides

Insertions of isocyanide into niobium-carbon bonds follow a path similar to that with vanadium, resulting in the formation of the 7]2-iminoacyl complexes, which can then be involved in further chemistry.175 176 The reaction of acetone with cyclopentadienyl complex 110 under a carbon monoxide atmosphere gives the if -acetone compound 111. Complex 111 subsequently undergoes either stepwise insertion of two isocyanides via 112 or double insertion of the isocyanide to give complex 113 (Scheme 48).177... 

Tantalum and niobium are often studied in parallel, and references from Section 10.09.4.2.1 are relevant as well because of the concomitant nature of these reports.172-174 Within the scope of Gomez s review, organotantalum species including 7]2-kctoncs and isocyanides are well covered.174... 

No homoleptic isocyanide complexes of niobium, tantalum, titanium, zirconium, and halfnium have yet been synthesized. The vanadium cation... 

Niobium and tantalum halides also react with isocyanides to give migration products [equation (12.51)]. Azide complexes react with CNR to afford coordination compounds with tetrazolyl [equation (12.52)]. Codimerization and cooligomerization of... 

Some compounds of transition metals may react with isocyanides to give RN = C = C=NR dimers. Niobium and tantalum compounds of the type M2Cl6(SMe2)3 which possess metal-metal double bonds of the configuration (M = M bond distances ca 265 pm) react with various isocyanides to furnish the follow-... 

Niobium ketene hydrides 11 react with t-butyl isocyanide to give t-butyl isocyanate and L2Nb(H)=C=CPh2. An intermediate 12 in this reaction is most likely formed via a [2-1-1] cycloaddition reaction . 

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