The Protonation and Synthesis of Protonated Ciprofloxacin Compounds with d-Elements Bromides
The third stepwise protonation constant (K3) of ciprofloxacin anion (C17H17FN3O3-, Cf-) has been determined by spectrophotometry. The third proton addition to Cf- in sulphuric acid aqueous solutions takes place beyond [H+] = 4M only, leading to CfH3+ formation. pK3 values obtained by Hammett and Cox-Yates methods make up 4.75±0.05 and 4.74±0.06 respectively. The new compounds CfH3[ZnBr]4, CfH3[CdBr4]. CfH3[HgBr4] and CfH3[CoBr4] have been synthesized, their crystallographic parameters and thermal properties have been studied.