Association Capacity of Ribose Bis(Thiosemicarbazonato)Copper(II) with Nitric Oxide

The stability constant for copper(II) complex with ribose bis(thiosemicarbazone) (log K=18.46±0.15) was determined from UV-Vis data using LETAGROP program. Its interaction with nitric oxide was studied by spectroscopic and electrochemical techniques. This interaction was observed in the UV-Vis spectra as a shoulder around 350 nm and an isosbestic point at 420 nm. The corresponding equilibrium constant was calculated and the obtained value (log K=8.68±0.12), indicates the formation of a stable nitrosyl complex. Copper(II) bis(thiosemicarbazonato) complex was immobilized on a gold electrode, as demonstrated by cyclic voltammetric studies and used for NO recognition. The reduction of NO coordinated to the copper centre was observed at a potential around −700 mV.

Keywords:

• bis(thiosemicarbazone)
• copper(II) complexes
• nitric oxide
• self-assembled monolayer

Acknowledgments

T. N. wishes to thank the Zimbabwe–Cuba teacher training program (1999) and the Bindura University of Science Education. The University of Havana under Grant AM 21-2000 supported part of this work.