Association constant for the complex between chloroform and trimethylamine in the gas phase and in solution from nuclear magnetic resonance chemical-shift measurements

Abstract

From the dependence of the n.m.r. line position of ¹H of chloroform on the partial pressure of trimethylamine, the formation constant of the 1:1 complex between these two compounds in the gas phase has been determined. Corresponding measurements have been made on the same system in liquid cyclohexane solution. The formation constant in the gas phase (ca. 40 dm³ mol^–1 at 298 K) is of the order 10² greater than for the solution system. By contrast the estimated shift of the ¹H n.m.r. line in chloroform in the complexed state compared with the same resonance in the free chloroform (Δ₀) is ten times less in the gas phase than it is in solution in cyclohexane.