Experimental study and computer modeling of Ni(II) and Cu(II) complexation with ceftazidime

• Published in: Russian journal of inorganic chemistry Vol. 61; no. 4; pp. 531 - 534
• Main Authors: Alekseev, V. G., Sokolova, E. M.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-04-2016
• Subjects: Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Physical Chemistry of Solutions; Titration Curve; Thiazole Moiety; Protonation Constant; Thiazole; Ceftazidime
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023616040021

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.