Table 3.

Computed and experimental primary kinetic isotope effects (KIE), along with the KIE determined using the Bigeleisen equation with harmonic vibrational frequencies, the anharmonicity correction factor and tunneling contributions, for the protium/deuterium transfer reactions from substituted acetic acid (Y-CH₂CO₂H) to aryl substituted α-Methoxystyrenes (X-1) at 25°C.

X-1	Y-AcOH(D)	${\eta }_{har}^{KIE}$	$h_{anh}^{KIE}$	κtun	KIE(calc)	KIE (expt)
4-MeO-	Cl-	5.547	1.126	1.268	7.92	7.7
H-	Cl-	5.507	1.119	1.162	7.16	7.0
4-NO2-	Cl-	4.775	1.094	1.035	5.53	5.8
3,5-di-NO2-	Cl-	3.951	1.093	1.018	4.40	4.8
H-	di-Cl-	5.532	1.267	1.237	8.67	7.0
H-	NC-	5.605	1.234	1.200	8.30	7.2
H-	Cl-	5.507	1.119	1.162	7.16	7.0
H-	MeO-	5.366	1.111	1.082	6.45	6.8
H-	H-	5.290	1.060	1.045	5.86	5.8
4-NO2-	di-Cl-	5.414	1.291	1.106	7.73	6.7
4-NO2-	NC-	5.260	1.253	1.059	6.98	6.0
4-NO2-	Cl-	4.884	1.094	1.035	5.53	5.8
4-NO2-	MeO-	3.973	1.117	1.014	4.50	5.9
4-NO2-	H-	3.460	1.039	1.007	3.62	5.4