Introduction

Swain and Lupton developed a method they called DOVE (→ Dual Obligate Vector Evaluation ) which is a forerunner to PCA (→ Principle Component Analysis).
They applied it to derive two-parameter equations with orthogonal parameters for substituent effects and for solvent effects.
The substituent constants are given below.

1. C.G. Swain, S.H. Unger, N.R. Rosenquist, M.S. Swain, J. Am. Chem. Soc. 105 (1983) 492-502

Field and resonance components

Name	Symbol	F (Field)	R (Resonance)
acetamido‐	‐NHCOCH3	0.77	-1.43
acetoxy‐	‐OCOCH3	0.7	-0.04
acetyl‐	‐COCH3	0.5	0.9
acetylthio‐	‐SCOCH3	0.53	0.68
amino‐	‐NH2	0.38	-2.52
bromo‐	‐Br	0.72	-0.18
butoxy‐	‐O(CH2)3CH3	0.72	-2.16
carboxy‐	‐COOH	0.44	0.66
carboxylate‐	‐COO⁻	-0.27	0.4
chloro‐	‐Cl	0.72	-0.24
cyano‐	‐CN	0.9	0.71
diazonium‐	‐N2⁺	2.36	2.81
dimethylamino‐	‐N(CH3)2	0.69	-3.81
dimethylsulfonium‐	‐S⁺(CH3)2	1.62	0.52
ethoxy‐	‐OCH2CH3	0.61	-1.72
ethoxycarbonyl‐	‐COOCH2CH3	0.47	0.67
ethyl‐	‐CH2CH3	-0.02	-0.44
fluoro‐	‐F	0.74	-0.6
hydrogen‐	‐H	0	0
hydroxy‐	‐OH	0.46	-1.89
iodo‐	‐I	0.65	-0.12
iodyl‐	‐IO2	0.99	0.99
isopropoxy‐	‐OCH(CH3)2	0.9	-2.88
mercapto‐	‐SH	0.52	-0.26
methoxy‐	‐OCH3	0.54	-1.68
methyl‐	‐CH3	-0.01	-0.41
methylseleno‐	‐SeCH3	0.28	-0.39
methylsulfanyl‐	‐SCH3	0.68	-1.3
methylsulfinyl‐	‐S(=O)CH3	0.8	0.45
methylsulfonyl‐	‐S(=O)2CH3	0.88	0.85
nitro‐	‐NO2	1	1
pentoxy‐	‐O(CH2)4CH3	0.75	-2.27
phenoxy‐	‐OC6H5	0.76	-1.29
phenyl‐	‐C6H5	0.25	-0.37
phosphonate‐	‐PO3H⁻	0.22	0.58
propoxy‐	‐O(CH2)2CH3	0.63	-1.77
sulfamoyl‐	‐SO2NH2	0.55	1.07
sulfonate‐	‐SO3⁻	-0.05	0.53
tert-butyl‐	‐C(CH3)3	-0.11	-0.29
trifluoromethyl‐	‐CF3	0.64	0.76
trimethylammonium‐	‐N⁺(CH3)3	1.54	0
trimethylsilyl‐	‐Si(CH3)3	-0.1	0.16
trimethylsilylmethyl‐	‐CH2Si(CH3)3	-0.19	-0.32