Homoleptic complexes tantalum

Besides the phosphoranes, the homoleptic amides of niobium(V) and tantalum(V) are the only pentamides known.1 These compounds, exemplified by M(NMe2)5 (M = Nb, Ta) are volatile, hydrocarbon-soluble solids.37 All physical and spectroscopic data are consistent with a strictly mononuclear existence for these complexes. 

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

Homoleptic platinum carbonyl anions, characteristics, 8, 410 Homoleptic tantalum complexes, preparation and characteristics, 5, 108... 

A recent review gives a chronological survey of the syntheses and characterizations of homoleptic mononuclear metal-carbonyl (see Carbonyl Complexes of the Transition Metals) anions. [M(CO)6] is a key precursor to niobium and tantalum carbonyls. More reliable synthesis of [Ta(CO)6] ... 

Schrock carbenes are typically generated by a-hydrogen elimination from a high-valent, early metal, dialkyl complex concomitant with or followed by elimination of alkane. The first S5mthesis of an alkylidene by Schrock is summarized in Equation 13.13. Addition of neopentyl zinc to tantalum pentachloride generated tris(neopentyl)dichlorotantalum. Subsequent addition of neopentyllithium did not generate the homoleptic neopentyltantalum compound. Instead, this reaction generated the first alkylidene complex, tris(neopentyl) tantalum neopentylidene. ... 

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