pH-Controlled syntheses of two hybrids based on octamolybdate and enrofloxacin

Abstract

Two new drug molecules modifying octamolybdate-based hybrid compounds, H₂[Ni(L)₂(H₂O)₂] · (β-Mo₈O₂₆) · H₂O (1) and [Ni₂L₂(H₂O)₄(α-Mo₈O₂₆)] (2) (L = enrofloxacin), have been synthesized at different pH values under hydrothermal conditions. Compound 1 was synthesized at pH ≈ 5, in which the octamolybdate shows β-isomer and the isolated Ni-enrofloxacin coordination subunits array on both sides of β-Mo₈O₂₆. Compound 2 was synthesized at pH ≈ 4, with octamolybdate showing the α-isomer and Ni-enrofloxacin having 1-D chain structure along the a-axis with α-Mo₈ polyoxoanions connecting adjacent Ni1 along the c-axis generating another 1-D inorganic chain. As a result, the two kinds of 1-D chains cross each other forming a 2-D layer structure. The structures of 1 and 2 reveal that pH of the reaction system plays a crucial role in assembly of octamolybdate-based hybrid compounds. Investigation of the antitumor activities on SGC7901 and SMMC7721 cells of 1 and 2 indicates that the two new compounds possess selective antitumor activities, and their antitumor activities can be modulated by transition metal complexes.

Keywords:

• Polyoxometalates
• Octamolybdates
• Enrofloxacin
• Antitumor activity

Acknowledgments

This work is financially supported by the National Natural Science Foundation (Grant No. 20 901 031), the Education Ministry key Teachers Foundation (1155G53), and Scientific and technological project (GC09C317) of Heilongjiang Province.