Determination of protonation constants of some fluorinated polyamines by means of 13C NMR data processed by the new computer program HypNMR2000. Protonation sequence in polyamines.
The p K(a) values of 6-fluoro-4,8-diazadodecane-1,12-diamine (6-fluorospermine) (1), 6,6-difluoro-4,8-diazadodecane-1,12-diamine (6,6-difluorospermine) (2), 6-fluoro-4-azaoctane-1,8-diamine (6-fluorospermidine) (3) and 6,6-difluoro-4-azaoctane-1,8-diamine (6,6-difluorospermidine) (4) in D(2)O solution have been determined at 40 degrees C from (13)C NMR chemical shifts data using the new computer program HypNMR2000. The enthalpies of protonation of compounds 1-4 and the parent amines spermine (5) and spermidine (6) have been determined from microcalorimetric titration data. The values of Delta H degrees were used to derive basicity constants relative to 25 degrees C. The NMR data have been analysed by two different methods to obtain information on the protonation sequence in the polyamines 1-5. The protonation sequence for spermine is related to its biological activity.
Frassineti
Chiara
C
Dipartimento di Scienze Biomediche, Università degli Studi di Modena, via Campi 287, 41100 Modena, Italy.
Alderighi
Lucia
L
Gans
Peter
P
Sabatini
Antonio
A
Vacca
Alberto
A
Ghelli
Stefano
S