Definition of Yukawa-Tsuno equation

1. A multiparameter extension of the Hammett equation to quantify the role of enhanced resonance effects on the reactivity of meta- and para-substituted benzene derivatives, e.g.

   lg k = lg ko + + r (+ - )]

   The parameter r gives the enhanced resonance effect on the scale (+-), or (--), respectively.

   See also -value, -constant. See YUKAWA and TSUNO (1959); SHORTER (1973).

   Z-value

   See below under Z-value.