Synthesis, Characterization, and Chemistry of Pentacarbonylnitrosylvanadium, V(CO)₅NO, a Remarkably Reactive Relative of Hexacarbonylchromium

Thermally unstable, deep red-violet, and remarkably reactive V(CO)₅NO has been prepared in high yields by the reaction of equimolar amounts of [Et₄N] [V(CO)₆] and [NO] [BF₄] in methylene Chloride at -40 °C. Also, V(CO)₅NO has been isolated and characterized for the first time by mass spectra and derivative chemistry. This volatile material undergoes Substitution reactions with a large variety of neutral and anionic bases at -30 to 0°C to provide 42-95% yields of new products. These include [V(CO)₄NO(Ph₂PCH₂)]₂, V(CO)₄(NO)(PMe₃), thermally unstable V(CO)₄(NO)(NMe₃), [Et₄N] [V(CO)₄(NO)I], [Ph₄As] [(CO)₅MnV(CO)₄NO], which contains a Mn-V bond, and [Et₄N] [C₅H₅V(CO)₂NO]. The last substance is the first example of a carbonylnitrosylcyclopentadienylmetalate ion and the final member of the isoelectronic series C₅H₅V(NO)_3-x(CO)_x^1-x (x = 0-3) to be prepared. Attempts to synthesize Ta(CO)₅NO and derivatives thereof are also described.