pKa-Werte von Ethidiumbromid und 7-Amino-9-phenyl-10- äthyl-phenanthridinium-bromid / pKa-Values of Ethidiumbromide and 7-Amino-9-phenyl-10-ethyl-phenanthridinium- bromide
1976 ◽
Vol 31
(11-12)
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pp. 656-660
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Keyword(s):
Abstract Ethidiumbromide (1) has two amino groups in 2-and 7-position which are protonated in acidic water solution. Both pKa-values of 1 are determined at 20 °C by means of the pH-dependence of the electronic spectra using a iterative calculating procedure, pKa1 = 0.713, pKa2 = 2.43. Acetylation of 1 and quantum mechanical calculations lead to the conclusion that the electronic density at the 7-amino group is greater than in 2-position. Therefore with decreasing pH preferably the 7-amino group is protonated (pKa2). followed by the protonation of the 2-amino group (pKa1). The pKa of 7-amino-9-phenyl-10-ethyl-phenanthridinium-bromide in water solution at 20 °C is determined to pKa= 1 .2 5 .
2012 ◽
Vol 97
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pp. 1041-1051
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2003 ◽
Vol 13
(0)
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pp. 95-105
2002 ◽
Vol 67
(4)
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pp. 479-489
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2001 ◽
Vol 567-568
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pp. 375-384
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2005 ◽
Vol 723
(1-3)
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pp. 223-230
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