Nitrogen-15 nuclear magnetic resonance spectroscopy of hydrazido(2–)-, imido-, and nitrido-complexes of molybdenum and tungsten

Abstract

Nitrogen-15 chemical shifts and coupling constants are reported for the range of hydrazido(2–)-complexes [MX(¹⁵N¹⁵NR¹R²)(dppe)₂]⁺{X = Cl, Br, I, or HSO₄; M = Mo or W; R¹= H, R²= H, Me, or Et [and ¹⁵N₂R¹R₂=¹⁵N¹⁵[graphic omitted]H₂]; dppe = Ph₂PCH₂CH₂PPh₂}, [W(NCPrⁿ)(¹⁵N¹⁵NH₂)(dppe)₂]HSO₄, and [MX₂(¹⁵N¹⁵NH₂)(PMe₂Ph)₃](X = Cl, I, or HSO₄). Nitrogen-15 n.m.r. spectroscopy is used to demonstrate the formation of hydrazido(2–)-complexes by the reaction of trans-[M(¹⁵N₂)₂-(dppe)₂] and [M(¹⁵N₂)₂(dppe)(depe)](depe = Et₂PCH₂CH₂PEt₂) with HBr, and to monitor the reaction of [MoI₂(¹⁵N¹⁵NH₂)(PMe₂Ph)₃] with HI in thf to give ¹⁵NH₃. Chemical shift data are also reported for the imido-complex cations [MoX(¹⁵NR)(dppe)]⁺(X = Cl, Br, or OMe; R = H or Me) and the nitrido-complexes [Mo(¹⁵N)(S₂CNEt₂)₃], [MX(¹⁵N)(dppe)₂], [ReCl₂(¹⁵N)(PPrⁿPh₂)₂], [ReCl₂(¹⁵N)(PMe₂Ph)₃], and [ReCl(¹⁵N)(dppe)₂]Cl.