Kinetic buffers.
This paper proposes a new type of molecular device that is able to act as an inverse proton sponge to slowly decrease the pH inside a reaction vessel. This makes the automatic monitoring of the concentration of pH-sensitive systems possible. The device is a composite formed of an alkyl chloride, which kinetically produces acidity, and a buffer that thermodynamically modulates the variation in pH value. Profiles of pH versus time (pH-t plots) have been generated under various experimental conditions by computer simulation, and the device has been tested by carrying out automatic spectrophotometric titrations, without using an autoburette. To underline the wide variety of possible applications, this new system has been used to realize and monitor HCl uptake by a di-copper(II) bistren complex in a single run, in a completely automatic experiment.
Dipartimento di Scienze Chimiche, Università di Messina, Viale F. Stagno d'Alcontres 31, Villaggio S. Agata, 98166 Messina (Italy). galibrandi@unime.it.
Giuseppe
G
Alibrandi
Luigi
L
Fabbrizzi
Maurizio
M
Licchelli
Antonio
A
Puglisi
D002021:Buffers; D002712:Chlorides / Q000737:chemistry*; D003198:Computer Simulation; D056831:Coordination Complexes / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D047028:Macrocyclic Compounds / Q000737:chemistry; D008956:Models, Chemical; D011522:Protons; D013816:Thermodynamics
D002021:Buffers; D002712:Chlorides; D056831:Coordination Complexes; D047028:Macrocyclic Compounds; D011522:Protons; D003300:Copper
kinetic buffers; kinetics; macrocycle complexes; molecular devices; pH-sensitive systems