Notes

Binding of 3-Aminoacridinium and 7-Aminoquinolinium Monocations to Double-Stranded DNA: Evidence for Nonlinear Binding Isotherm in Intercalative Region

“…The molar absorptivities of 1 and I1 were calculated a t each absorption maximum as well as a t each distinct vibrational band and agreed with published values (31,32). The molar absorptivities of the bound mono-cation& of I and I1 were calculated from the absorbances of solutions of the probes in which pH = pKa -2 and to which a sufficient excess of DNA was added so that further addition of DNA produced no perceptible changes in the absorption.…”

On the Basicity of Conjugated Nitrogen Heterocycles in Different Media

“…The reliability and consistency of the results can be evaluated by using the consistency standard deviation, which is defined by Equation (6). (6) During this work the total number of measurements (n m ) carried out to determine the pK a values was 86 for a total number of compounds (n c ) of 30, hence the consistency parameter s = 0.04, which indicates good consistency of the data.…”

“…The commonly cited, directly measurable experimental value for the aqueous pK a of quinazoline (pK a = 3.51 [6] ) actually corresponds to a more complex equilibrium involving the covalent hydration of quinazoline. [29] A correct experimentally measured aqueous pK a corresponding to the pK a defined in Equation (1) is 1.95.…”

“…different types of heterocycles are available. [4][5][6][7][8][9][10][11][12][13][14][15][16] In non-aqueous media the situation is the opposite. Besides the scarcity of basicity data for N-heterocycles in non-aqueous solvents, the pK a values obtained by different groups are sometimes inconsistent.…”

On the Basicity of Organic Bases in Different Media

“…Pyridine 110-86-1 5.23 [79] 3.4 [60] 12.53 [33] [e] 5.5 [63] 214.7 2,2′-Bipyridine 366-18-7 4.23 [80] 12.27 [36] [e] 223.1 Quinoline 91-22-5 4.93 [79] 11.97 [36] [e] 220.2 2,2′-Biquinoline 119-91-5 3.66 [67] 11.28 [36] [e] 230.0 [36] [g] Isoquinoline 119-65-3 5.46 [79] 12.68 [36] [e] 219.9 Acridine 260-94-6 5.62 [79] 12.66 [36] [e] 224.8 Phenanthroline 66-71-7 5.12 [81] 13.69 [36] [e] 230.9 [36] [g] Imidazole 288-32-4 6.95 [82] 6.26 [83] 15.07 [36] [e] 9.4 ± 1.8 [d] 217.3 Benzimidazole 51-17-2 5.56 [84] 4.36 [83] 13.54 [36] [e] 220.0 1,2,3-Triazole 288-36-8 1.17 [85] 0.0 ± 1.2 [d] 8.0 [36] [e] 2.5 ± 1.8 [d] 202.5 Benzotriazole 95-14-7 0.42 [86] 6.89 [36] [e] 210.2 [36] [g] Pyrazole 288-13-1 2.48 [85] 1.0 ± 1. [87] 7.61 [36] [e] 207.7 Pyridazine 289-80-5 2.33 [79] 1.8 ± 1.2 [d] 10.06 [36] [e] 3.7 ± 1.8 [d] 209.6 Pyrimidine 289-95-2 1.3 [79] 0.55 [88] 8.72 [36] [e] 2.4 ± 1.8 [d] 204.5 Pyrazine 290-37-9 0.6 [79] -0.2 ± 1.2 [d] 7.74…”