The study of new complex compounds of Ni (II) and Co (II) with N- hydroxy-succinimide and their potential applications as sensors

Abstract

In this paper, the study of obtaining new coordination compounds of Ni (II) and Co(II) using as ligand, N-hydroxy-succinimide, was presented. Also, the stability constants of these compounds in aqueous medium were determined.The obtaining conditions and the stability of the new compounds were accomplished in aqueous solutions using characteristic methods for coordination compounds: pH-metry, conductometry and UV-VIS absorption spectroscopy. The combination ratios and the stability constants were determined with methods characteristic for studies in solutions. From experimental data resulted that the combination ratio of central metallic atoms with the ligand N-hydroxy-succinimide was: 1:1 and respectively 1:2. In the experiments were used salts of NiCl 2 ·6H 2 O and CoCl 2 ·6H 2 O.The optimal domain of pH stability of the studied compounds is limited between 5.74 -5.86 for Co-N-hydroxy-succinimide (for molar ratio 1:1 and 1:2) and respectively 5.69 -5.87 for Ni-N-hydroxysuccinimide(for molar ratio 1:1 and 1:2, too).It is important to mention that these compounds were used with very good results in determination of wastewaters from textile, metallurgical, chemical and food industry.Complexion reactions with this ligand are very sensitive for the cations in this paper mentioned. Therefore it is used most often with success in analytical chemistry and also it is posibil to use as sensors.The new complex compounds has electronics transitions at λ = 517 nm for both complexes Co-Nhydroxy-succinimide at molar ratio 1:1 and 1:2 and also at the same λ = 397nm for Ni-N-hydroxysuccinimide at molar ratio 1:1 and 1:2.These complexes compounds was separated and recrystallized from aqueous solution. From the spectrophotometric data it was determined the type and the nature of the electronics transitions by Dq parameters.