On the basicity of organic bases in different media Ph 3 N (2,6−Cl 2 −C 6 H 3 ) 3 P 2,3,4,5,6−Cl 5 −Aniline (2,6−F 2 −C 6 H 3 ) 2 (Ph)P (C 6 F 5 )(Ph) 2 P Cl−Phenylfulvene Thymine 2,3,5,6−Cl 4 −Aniline H−Phenylfulvene (2−F−C 6 H 4 ) 3 P 5−Cl−2−NO 2 −Aniline Uracil Me−Phenylfulvene 2−Cl−4−NO 2 −Aniline 4−Cl−2−NO 2 −Aniline BINAPH + BIPHEPH + (2−F−C 6 H 4 ) 2 (Ph)P MeO−Phenylfulvene 2−NO 2 −Aniline 6−NO 2 −Indazole 5−NO 2 −Indazole 2,6−Cl 2 −Aniline (2,6−F 2 −C 6 H 3 )(Ph) 2 P 2−NO 2 −Imidazole Ph 2 P−(CH 2 ) 2 −PPh 2 −H + Ph 2 NH (2−F−C 6 H 4 )(Ph) 2 P 4−NO 2 −Aniline 2,5−Cl 2 −Aniline 4−NO 2 −Imidazole 4−NO 2 −N ,N −Dimethylaniline MePh 2 N (1−Napht) 3 P 2−Cl−Pyridine Benzotriazole TMPH + Ph 2 P−(CH 2 ) 3 −PPh 2 −H + Quinoxaline Caffeine Indazole Ph 3 P 2,6−(MeO) 2 −Pyridine 4−F−3−NO 2 −Aniline 3−NO 2 −Aniline Pyrazine OEPH + BINAP 2−Cl−Aniline 1,2,3−triazole BIPHEP 4−CF 3 −Aniline 9−O−1,5−(COOMe) 2 −N ,N' −Ph 2 −Bispidine 3−NO 2 −N ,N −Dimethylaniline Ph 2 P−(CH 2 ) 4 −PPh 2 −H + 2,4−F 2 −Aniline 4−(4−NO 2 −C 6 H 4 −N=N)−Aniline TCPPH + 4−CF 3 −N ,N −Dimethylaniline Pyrimidine 4−SCN−N ,N −Dimethylaniline TPPH + Pyrazole Quinazoline Ph 2 P−(CH 2 ) 2 −PPh 2 4−Br−Aniline 3−Cl−Pyridine 3−Br−N ,N −Dimethylaniline 1−NaphtNH 2 Ph 2 P−(CH 2 ) 3 −PPh 2 2−MeO−Pyridine MePh 2 P TCPP Pyridazine (4−MeO−C 6 H 4 ) 3 P 4−Br−N ,N −Dimethylaniline TMP Ph 2 P−(CH 2 ) 4 −PPh 2 dma−Phenylfulvene 5−NO 2 −Benzimidazole TPP 2−Me−Aniline Aniline 7,8−Benzoquinoline N −Me−Aniline 9−Cl−Acridine 3−MeO−N ,N −Dimethylaniline 4−NO−N ,N −Dimethylaniline 2,2' −Biquinoline N ,N −Dimethylaniline 8−NH 2 −2−Me−Quinoline Phthalazine 4−MeO−Aniline 5,6−Benzoquinoline Quinoline 4−Me−N ,N −Dimethylaniline Carbendazim 2,2' −Bipyridine OEP Thiabendazole Pyridine Me 2 PhP Acridine Isoquinoline 4−MeO−N ,N −Dimethylaniline 2−Me−Pyridine 9−O−N ,N' −(CHPh 2 ) 2 −Bispidine Benzimidazole 2−NH 2 −Acridine Phenanthroline 9−O−1,5−(COOMe) 2 −N ,N' −Bn 2 −Bispidine 4−CF 3 −7−N=P 1 (Ph) 3 −Coumarin N ,N' −Ph 2 −Bispidine 2,6−Me 2 −Pyridine 2,6−(NO 2 ) 2 −C 6 H 3 P 1 (pyrr) 3 3−NH 2 −Pyridine 4−MeO−Pyridine 2,6−Cl 2 −4−NO 2 −C 6 H 2 P 1 (pyrr) 3 2−NH 2 −Pyridine 2,6−(NH 2 ) 2 −Pyridine 4−(4−NO 2 −C 6 H 4 −N=N)−C 6 H 4 P 1 (Ph) 3 2,4−(NO 2 ) 2 −C 6 H 3 P 1 (pyrr) 3 2,4,6−Me 3 −Pyridine Imidazole 4−CF 3 −7−N=P 1 (Ph) 2 pyrr−Coumarin 2,3−(NH 2 ) 2 −Pyridine Me 3 P 4−(Ph−N=N)−C 6 H 4 P 1 (Ph) 3 Me 2 P−(CH 2 ) 2 −PMe 2 2−NH 2 −Benzimidazole 4−(4−dma−C 6 H 4 −N=N)−C 6 H 4 P 1 (Ph) 3 4−(4−NO 2 −C 6 H 4 −N=N)−C 6 H 4 P 1 (Ph) 2 pyrr 2−NH 2 −1−Me−Benzimidazole 3−NH 2 −Acridine 2−NO 2 −4−CF 3 −C 6 H 3 P 1 (pyrr) 3 4−CF 3 −7−N=P 1 (pyrr) 2 Ph−Coumarin 4−(Ph−N=N)−C 6 H 4 P 1 (Ph) 2 pyrr BnNH 2 9−O−N ,N' −Bn 2 −Bispidine 2−NO 2 −5−Cl−C 6 H 3 P 1 (pyrr) 3 4−(4−dma−C 6 H 4 −N=N)−C 6 H 4 P 1 (Ph) 2 pyrr N ,N' −Me 2 −Piperazine 9−O−1,5−Me 2 −N ,N' −Bn 2 −Bispidine 4−(Ph−N=N)−C 6 H 4 P 1 (dma) 2 Ph 4−NH 2 −Pyridine 2−NO 2 −4−Cl−C 6 H 3 P 1 (pyrr) 3 4−(4−NO 2 −C 6 H 4 −N=N)−C 6 H 4 P 1 (pyrr) 2 Ph N ,N' −(CHPh 2 ) 2 −Bispidine 4−dma−Pyridine N −Me−Piperazine N −Me−Piperidine Me 2 BuN Pr 3 N Me 2 EtN 4−pyrr−Pyridine 9−NH 2 −Acridine Cyclohexylamine 4−(Ph−N=N)−C 6 H 4 P 1 (pyrr) 2 Ph PrNH 2 4−NO 2 −C 6 H 4 P 1 (pyrr) 3 2,5−Cl 2 −C 6 H 3 P 1 (pyrr) 3 [H][Ph]Triazine 2,6−Cl 2 −C 6 H 3 P 1 (pyrr) 3 4−CF 3 −7−N=P 1 (pyrr) 3 −Coumarin ProtonSp−dma N ,N −Me 2 −Cyclohexylamine Me 2 N−(CH 2 ) 2 −NMe 2 Piperazine i −Pr 2 NH Et 3 N N −Me−Cyclohexylamine MePrNH Me 2 NH 4−(4−dma−C 6 H 4 −N=N)−C 6 H 4 P 1 (pyrr) 2 Ph 2−Cl−C 6 H 4 P 1 (dma) 3 Homopiperazine [Me][Ph]Triazine Me 2 N−(CH 2 ) 3 −NMe 2 Piperidine 4−(4−NO 2 −C 6 H 4 −N=N)−C 6 H 4 P 1 (pyrr) 3 Quino[7,8−h ]quinoline Pyrrolidine Me 2 N−(CH 2 ) 3 −NH 2 1−(o −Tolyl)biguanide NH 2 −(CH 2 ) 3 −NH 2 Me 2 N−(CH 2 ) 4 −NMe 2 MeNH−(CH 2 ) 3 −NMe 2 MeNH−(CH 2 ) 3 −NH 2 Me 2 N−(CH 2 ) 2 CHMe−NMe 2 2−Cl−C 6 H 4 P 1 (pyrr) 3 4−CF 3 −C 6 H 4 P 1 (pyrr) 3 4−(Ph−N=N)−C 6 H 4 P 1 (pyrr) 3 MeHN−(CH 2 ) 3 −NHMe 1−NaphtP 1 (pyrr) 3 PhTMG 4−(4−dma−C 6 H 4 −N=N)−C 6 H 4 P 1 (pyrr) 3 PhP 1 (dma) 2 Me 4−Br−C 6 H 4 P 1 (pyrr) 3 PhP 1 (dma) 3 N ,N' −(CHMePh) 2 −Bispidine N ,N' −Bn 2 −Bispidine Bispidine (−)−Sparteine PhP 1 (pyrr) 3 N ,N' −Me 2 −Bispidine [Me][i −Pr]Triazine 4−MeO−C 6 H 4 P 1 (pyrr) 3 [4−MeO−C 6 H 4 ][i −Pr]IYA TMG 4−dma−C 6 H 4 P 1 (pyrr) 3 2−{hpp}C 5 H 4 N 2−Cl−C 6 H 4 P 2 (dma) 5 DBU [H][i −Pr]IYA 4−NO 2 −C 6 H 4 −CH=P(dma) 3 PhP 1 (dma) 2 tmg [OMe][OMe]Guanidine [OMe][H]Guanidine [H][OMe]Guanidine [H][H]Guanidine ProtonSp−tmg 4−CF 3 −C 6 H 4 P 2 (pyrr) 5 Me 2 −IP 2−Cl−C 6 H 4 P 2 (pyrr) 5 MTBD 4−NO 2 −C 6 H 4 −CH=P(pyrr) 3 IP 2,6−{hpp} 2 C 5 H 3 N [dma][H]Guanidine HP 1 (dma) 3 TBD [CH 2 −t −Bu][i −Pr]IYA 4−Br−C 6 H 4 P 2 (pyrr) 5 PhP 2 (dma) 5 [H][dma]Guanidine [(CH 2 ) 3 OMe][(CH 2 ) 3 OMe]TMAIMG t −BuP 1 (pip) 3 t −BuP 1 (dma) 3 HP 1 (pyrr) 3 [i −Pr][i −Pr]TMAIMG [dma][dma]Guanidine [Me][i −Pr]IYA [ch][ch]TMAIMG t −BuP 1 (TACD) MeP 1 (dma) 3 [Et][(CH 2 ) 3 dma]TMAIMG PhP 2 (pyrr) 5 [(CH 2 ) 3 dma][(CH 2 ) 3 dma]TMAIMG [i −Pr][i −Pr]IYA 4−MeO−C 6 H 4 P 2 (pyrr) 5 t −BuP 1 (pyrr) 3 EtP 1 (pyrr) 3 H 2 C{hpp} 2 PhP 1 (tmg) 2 dma 4−CF 3 −C 6 H 4 P 3 (dma) 7 2,5−Cl 2 −C 6 H 3 P 3 (pyrr) 6 NEt 2 HP 1 (pyrr−2−CH 2 −N −pyrr) 3 [CMe 2 −t −Bu][i −Pr]IYA [t −Bu][CH 2 −t −Bu]IYA ProtonSp−N=P(dma) 3 [CMe 2 CH 2 −t −Bu][i −Pr]IYA 2−Cl−C 6 H 4 P 3 (dma) 6 NEt 2 [t −Bu][i −Pr]IYA ProtonSp−N=P(i −Pr) 3 ProtonSp−N=P(Me) 3 4−CF 3 −C 6 H 4 P 3 (pyrr) 7 ProtonSp−N=P(cp) 3 4−NO 2 −C 6 H 4 −CH=P(tmp) 3 ProtonSp−N=P(n −Bu) 3 2−Cl−C 6 H 4 P 3 (pyrr) 6 NEt 2 Ph−CH=P(dma) 3 PhP 1 (tmg) 3 PhP 3 (dma) 7 4−MeO−C 6 H 4 P 3 (dma) 7 ProtonSp−N=P(pyrr) 3 Ph−CH=P(pyrr) 3 PhP 3 (pyrr) 7 t −BuP 2 (dma) 5 Ph−CH=P(−NMe−CH 2 −CH 2 −) 3 N Compound 0.03 1.12 0.78 0.48 0.61 0.51 0.98 0.15 0.08 0.70 0.10 1.28 0.66 0.32 0.14 1.22 1.05 0.50 0.81 0.08 0.64 0.61 0.17 0.64 0.60 0.69 1.21 0.55 0.25 0.95 1.03 1.04 1.70 0.81 1.05 0.61 0.25 1.56 0.28 1.11 1.23 1.77 0.63 1.20 0.03 0.63 1.09 0.10 0.35 0.42 0.44 0.05 0.50 1.59 0.46 0.58 0.77 1.89 1.44 1.26 0.68 0.01 0.60 1.69 1.69 0.04 0.08 1.07 0.21 0.25 0.70 1.20 0.08 0.98 0.47 1.17 0.40 1.14 1.60 0.21 0.09 0.30 0.37 0.65 1.33 0.27 0.10 0.74 0.44 0.45 0.51 0.22 0.75 0.73 0.52 0.06 0.90 0.98 1.60 1.05 0.63 0.65 0.18 0.18 0.59 0.61 0.77 0.56 0.41 0.25 1.07 0.49 0.04 0.31 0.28 1.01 0.77 0.65 0.88 1.10 0.43 0.57 0.37 0.95 0.56 0.85 0.48 0.19 0.37 0.40 0.13 0.03 0.38 0.33 0.14 0.12 1.77 0.73 0.99 0.85 0.20 0.17 0.35 0.25 0.44 0.17 0.44 0.20 0.05 0.01 0.05 1.43 0.04 0.86 0.86 0.23 0.67 0.85 0.24 0.27 0.24 1.28 0.25 −0.01 1.04 0.91 0.68 0.11 0.25 0.22 1.11 0.97 1.66 0.50 0.56 0.45 1.31 1.01 0.86 0.30 0.57 0.39 0.97 0.27 0.24 0.28 0.61 1.05 1.21 0.68 1.72 0.11 0.80 1.09 0.89 0.38 1.35 0.19 1.01 1.61 0.13 0.93 0.86 1.36 0.86 0.55 1.60 0.84 2.10 1.49 0.34 0.61 0.09 1.57 0.34 0.45 2.22 0.77 0.74 0.72 0.41 0.11 0.08 0.06 0.67 0.62 2.10 0.81 0.80 2.20 0.59 1.10 0.99 1.01 0.59 0.46 0.09 0.91 0.59 0.06 0.02 0.43 0.25 0.17 0.59 0.78 0.65 0.93 1.02 0.19 0.27 1.01 0.77 0.85 1.31 1.96 1.29 0.94 0.93 0.84 0.98 1.13 0.36 0.01 0.22 0.34 0.35 0.05 0.34 0.17 0.52 0.45 0.38 1.02 0.95 0.55 0.79 0.79 0.15 1.72 0.89 0.68 0.36 0.71 0.56 0.69 1.02 1.58 0.59 0.21 0.04 1.16 0.59 1.00 0.85 1.07 0.38 0.06 0.28 0.20 0.14 0.41 0.43 0.16 0.24 0.30 0.11 1.57 0.37 0.74 0.88 1.18 0.83 0.75 0.15 0.42 0.35 0.14 0.17 0.16 0.11 0.07 0.07 1.40 0.05 0.37 0.58 0.77 0.57 0.31 0.31 1.20 0.44 0.25 0.68 1.18 0.48 0.36 1.30 1.16 0.06 1.14 0.26 0.25 0.14 0.96 0.33 0.24 0.47 0.19 0.78 0.36 0.67 0.63 0.64 1.03 1.40 0.91 0.58 0.60 1.52 1.13 0.14 0.80 0.10 0.01 0.02 0.94 0.88 0.13 1.40 1.55 2.54 0.42 0.21 0.23 0.69 0.44 0.07 1.10 0.45 0.05 0.52 0.00 0.75 0.65 0.17 0.49 0.90 0.24 0.46 0.40 0.42 1.07 1.07 1.10 0.83 1.08 1.13 0.36 0.13 0.55 0.90 0.47 0.28 0.41 0.57 0.69 1.03 0.66 0.25 0.68 0.44 0.45 0.12 0.07 0.79 1.28 0.59 0.74 0.22 0.74 0.49 0.24 1.37 1.90 1.06 0.59 0.72 1.11 0.71 0.48 0.35 0.36 1.52 0.30 0.04 0.88 1.95 0.28 0.16 0.28 0.69 0.35 0.29 0.53 1.16 0.13 0.94 0.27 0.67 0.24 0.15 0.26 0.19 1.92 0.18 0.14 0.49 0.36 1.01 0.70 0.19 1.52 0.48 1.10 0.23 0.66 1.51 1.40 1.42 0.42 0.43 0.06 1.40 0.60 0.52 0.43 0.96 1.38 0.77 0.06 0.18 0.59 0.31 0.74 2.29 1.50 2.10 1.83 1.05 1.70 1.23 0.46 1.93 0.43 0.18 0.12 0.99 0.10 0.35 0.45 0.46 0.56 1.38 1.20 1.12 0.24 0.12 0.39 0.41 0.68 0.31 1.00 0.19 0.54 0.96 0.85 0.65 0.45 0.60 0.25 0.77 0.58 0.74 0.45 0.40 0.34 0.23 0.04 0.29 0.04 0.68 0.21 0.59 0.80 1.04 0.76 0.10 0.34 0.57 0.85 0.67 1.08 0.19 0.62 0.15 0.47 1.04 0.23 0.08 0.07 0.90 0.40 0.77 0.40 0.83 0.06 1.50 0.03 0.23 0.21 0.34 1.15 0.09 1.04 1.24 0.72 1.24 0.17 1.16 0.09 0.01 1.12 0.28 0.44 0.46 0.88 0.99 0.56 0.31 0.25 0.08 0.04 0.51 0.16 0.62 0.08 0.97 0.45 1.16 0.50 0.94 1.50 0.59 0.60 0.11 0.04 1.43 0.48 0.19 0.04 0.26 0.05 0.19 0.52 0.36 1.67 0.45 0.26 0.73 0.76 0.51 0.64 0.62 0.35 0.83 1.15 0.54 0.60 0.32 0.00 0.54 1.21 0.87 1.40 0.63 0.22 2.20 0.53 0.67 0.45 0.79 1.32 0.21 0.27 0.59 0.67 1.84 1.00 1.10 1.55 0.25 0.56 0.85 0.15 0.50 0.10 0.40 0.26 0.30 0.19 0.18 0.25 0.39 0.53 0.25 0.95 1.60 0.90 1.54 1.48 1.70 0.64 0.33 0.87 0.77 0.39 0.25 0.40 0.27 0.44 1.60 0.98 0.48 0.82 0.19 0.90 0.09 0.17 0.83 0.15 1.28 1.70 2.32 2.50 2.54 2.56 2.68 2.72 2.90 3.01 3.18 3.36 3.50 3.65 3.68 3.8 4.0 4.56 4.56 4.80 4.87 4.91 5.07 5.17 5.55 5.8 5.98 6.11 6.22 6.23 6.34 6.46 6.52 6.55 6.79 6.89 7.0 7.4 7.40 7.51 7.61 7.62 7.65 7.68 7.68 7.74 7.8 7.79 7.86 8.0 7.99 8.03 8.14 8.26 8.3 8.39 8.50 8.5 8.60 8.72 8.78 9.0 9.1 9.20 9.38 9.44 9.56 9.64 9.78 9.84 9.94 9.97 10.01 10.06 10.06 10.13 10.16 10.23 10.30 10.41 10.48 10.49 10.64 10.85 10.97 11.07 11.22 11.27 11.28 11.47 11.56 11.56 11.87 11.96 11.97 12.24 12.25 12.27 12.38 12.41 12.53 12.64 12.66 12.68 12.72 13.28 13.51 13.54 13.67 13.69 13.84 13.92 14.00 14.16 14.17 14.21 14.24 14.45 14.50 14.78 14.90 14.91 15.00 15.07 15.24 15.26 15.48 15.58 15.6 16.10 16.18 16.22 16.32 16.40 16.54 16.86 16.86 16.92 16.94 17.28 17.34 17.38 17.49 17.51 17.63 17.70 17.74 17.79 17.96 18.06 18.24 18.25 18.26 18.33 18.35 18.36 18.36 18.39 18.44 18.50 18.50 18.52 18.56 18.58 18.63 18.67 18.69 18.69 18.82 18.83 18.91 18.93 19.03 19.04 19.10 19.11 19.17 19.28 19.35 19.51 19.60 19.62 19.63 19.72 19.76 19.96 20.07 20.10 20.15 20.19 20.25 20.27 20.45 20.61 20.85 20.88 21.06 21.20 21.26 21.28 21.39 21.56 21.67 22.32 22.73 23.02 23.11 23.24 23.35 23.86 24.2 24.23 24.31 24.44 24.53 24.67 24.73 24.79 24.82 24.90 24.92 25.27 25.30 25.40 25.47 25.49 25.52 25.7 25.83 25.85 26.02 26.25 26.30 26.44 26.63 26.66 26.70 26.98 27.01 27.11 27.15 27.2 27.25 27.38 27.52 27.54 27.56 27.66 27.98 28.23 28.42 28.88 28.98 29.06 29.08 29.15 29.31 29.47 29.89 29.89 29.95 30.14 30.20 30.32 30.32 30.46 30.55 30.68 31.05 31.17 31.24 31.34 31.44 31.95 32.06 32.42 32.74 33.09 33.14 pK aH Directly measured ∆ pK aH Compound family: Phosphorylides Phosphazenes 1,8−Naphtyl−Proton Sponges Amidines Aliphatic amines Heterocycles Porphyrines Aromatic amines Phosphanes Phenylfulvenes dma pyrr pip cp ch tmg bn 1 - Napht tmp Ph - CH=P( - NMe - CH 2 - CH 2 - ) 3 N ProtonSp - R XP 1 (R) 3 XP 2 (R) 5 XP 3 (R) 7 XP 3 (R) 6 NEt 2 t - BuP 1 (TACD) HP 1 (pyrr - 2 - CH 2 - N - pyrr) 3 4 - CF 3 - 7 - N=P 1 (R) 3 - Coumarin 3 TBD MTBD DBU [R1][R2]Guanidine TMG PhTMG [R1][R2]TMAIMG [R1][R2]Triazine 1 - (o - Tolyl )biguanide [R1][R2]IYA IP Me 2 - IP H 2 C{ hpp } 2 2,6 - { hpp } 2 C 5 H 3 N 2 - { hpp }C 5 H 4 N Pyrrolidine Piperidine Bispidine ( - ) - Sparteine Piperazine Homopiperazine 9 1 5 1 2 3 4 5 6 7 8 6 7 8 5 9 1 4 10 2 3 4 7 5 6 1 2 3 4 7 5 6 1 3 2 1 2 3 4 5 4 5 6 3 2 1 Benzotriazole 2,2´-Bipyridine Phenanthroline Isoquinoline 2,2´-Biquinoline Quinoline 5,6-Benzoquinoline 7,8-Benzoquinoline Pyridazine Pyrazole Acridine Pyrimidine Pyrazine Indazole Caffeine Uracil Benzimidazole Pyridine Quinoxaline Phthalazine 1,2,3-Triazole Quino[7,8- h ]quinoline Imidazole Carbendazim Thymine Thiabendazole Quinazoline OEP TPP TMP TCPP BIPHEP BINAP Ph 2 Ph 2 Ph 2 Ph 2 X - Phenylfulvene * Protonation site *