Proton nuclear magnetic resonance study of electronic transmission effects and fluxional behaviour in aryldiazenidotris(dimethyldithiocarbamato)molybdenum

Abstract

The rate of N-methyl exchange in a series of aryldiazenidomolybdenum complexes has been studied by ¹H n.m.r. spectroscopy as a function of temperature and of substitution in the aromatic ring. The results indicate a fluxional rearrangement characterised by a single first-order rate constant. The aromatic-substituent effect shows a better Hammett correlation with σ than with σ⁺ values. The ρ factor is –0.64. Implications for the geometry of the system are discussed.