Experimental study and computer modeling of Ni(II) and Cu(II) complexation with ceftazidime
В. Г. Алексеев, E. M. Sokolova · Russian Journal of Inorganic Chemistry · 2016
The protonation constants of the anion of the cephalosporin antibiotic ceftazidime Ctzd – and formation constants of its complexes with Ni 2+ and Cu 2+ have been determined by pH metric titration at 25°С and ionic strength 0.1 (KNO 3 ): logβ(HCtzd) = 4.82 ± 0.04, logβ(H 2 Ctzd + ) = 7.62 ± 0.06, logβ(H 3 Ctzd 2+ ) = 9.23 ± 0.09, logβ(NiCtzd + ) = 4.04 ± 0.03, logβ(Ni(Ctzd) 2 ) = 6.41 ± 0.06, and logβ(CuCtzd + ) = 5.03 ± 0.06. The potentiometric method has failed to reveal the complexation of Ctzd – with Co 2+ , Zn 2+ , and Cd 2+ . The composition of the [Ni(Ctzd) 2 ] and [CuCtzd] + complexes has been confirmed by spectrophotometry. The computer models of the [NiCtzd] + and [CuCtzd] + complexes have been calculated by the DFT method with the use of the B3LYP hybrid functional and the LACV3P**++ basis set.