Lewis donor strength

Lewis bases can arrange accoring to strength using the entalphy of reaction with different Lewis acids. The strength depends of the choice of acid and the ranking of the bases can therefore change somewhat.
The two most popular scales are Gutmann's donor number (DN), which uses SbCl5 as the acid, and the BF3-scale of Maria & Gal. Because SbCl5 is fairly reactive some Donor Numbers have been determined by indirect methods.
There is a fairly strong correlation between the two scales (→ BF3-scale vs DN) as well as between DN (→ SB vs DN) and the BF3-scale (→ SB vs BF3) respectively, and → Catalan's SB solvent polarity parameter.

See → "The donor-acceptor approach to molecular interactions" by V. Gutmann (of mainly historical interest [1978]) and
"Lewis Basicity and Affinity Scales: Data and Measurement" by C. Laurence and J.-F. Gal (for a recent [2009] and comprehensive overview of Lewis basicity).

Note that the DN scale, for historic reasons, is given in kcal/mol whereas the BF3-scale is in kJ/mol.

NameFormulaGal BF3DN
1,2-dimethoxyethaneC4H10O274.720.0
1,3,2-dioxathiolan-2-oxideC2H4O3S50.015.3
1,3-dimethyl-2-imidazolidinoneC5H10N2O98.927.7
1,3-dimethyltetrahydropyrimidin-2(1H)-oneC6H12N2O112.133.0
1,3-dioxolan-2-oneC3H4O366.416.4
1,3-dioxolaneC3H6O268.621.2
1-di(piperidin-1-yl)phosphorylpiperidineC15H30N3OP118.140.9
1-methylazepan-2-oneC7H13NO111.427.1
2,2,4,4-tetramethyl-3-pentanoneC9H18O31.310.3
2,4-dimethyl-3-pentanoneC7H14O68.116.2
2-butanoneC4H8O76.117.4
2-methylpropanenitrileC4H7N60.115.4
2-methyltetrahydrofuranC5H10O92.812.0
2-pentanoneC5H10O76.217.5
2-phenylacetonitrileC8H7N56.615.1
2-propanoneC3H6O76.017.0
3,3-dimethyl-2-butanoneC6H12O72.817.0
3-methyl-2-butanoneC5H10O74.817.1
3-methylpyridineC6H7N130.939.0
3-pentanoneC5H10O72.315.0
4-methyl-2-oxo-1,3-dioxolaneC4H6O364.215.1
4-methyl-2-pentanoneC6H12O75.116.0
4-methylpyridineC6H7N134.234.0
acetonitrileC2H3N60.414.1
acetophenoneC8H8O74.515.0
benzaldehydeC7H6O74.916.0
benzonitrileC7H5N55.411.9
benzophenoneC13H10O62.916.0
butanenitrileC4H7N61.216.6
chloroacetonitrileC2H2ClN44.010.0
cyclohexanoneC6H10O76.418.0
cyclopentanoneC5H8O77.418.0
dibutyl etherC8H18O78.619.0
dibutyl sulfoxideC8H18OS107.631.0
diethyl carbonateC5H10O371.016.0
diethyl etherC4H10O78.819.2
diisopropyl etherC6H14O76.619.0
dimethyl carbonateC3H6O367.617.2
dimethyl sulfoxideC2H6OS105.329.8
dimethylcyanamideC3H6N277.217.0
dioxaneC4H8O274.114.3
dipropyl etherC6H14O79.418.0
ethyl acetateC4H8O275.617.1
ethyl benzoateC9H10O261.215.0
ethyl formateC3H6O271.217.0
hexamethylphosphoramideC6H18N3OP117.538.8
methyl acetateC3H6O272.816.5
methyl benzoateC8H8O259.415.0
N,N,N',N'-tetramethylureaC5H12N2O108.631.0
N,N-diethylacetamideC6H13NO113.632.2
N,N-diethylformamideC5H11NO113.230.9
N,N-dimethylacetamideC4H9NO112.127.8
N,N-dimethylanilineC8H11N109.227.0
N,N-dimethylcarbamoyl chlorideC3H6ClNO72.217.2
N,N-dimethylformamideC3H7NO110.526.6
N,N-dimethylurethaneC5H11NO284.222.4
N-methylpyrrolidoneC5H9NO112.627.3
nitrobenzeneC6H5NO235.84.4
nitromethaneCH3NO237.62.7
oxaneC5H10O85.422.0
oxolan-2-oneC4H6O275.118.0
propanenitrileC3H5N61.016.1
pyridineC5H5N128.133.1
sulfolaneC4H8O2S51.314.8
tetrahydrofuranC4H8O90.420.0
triethylamineC6H15N135.961.0
trimethyl phosphateC3H9O4P84.823.0
tripyrrolidinophosphine oxideC12H24N3OP122.547.2