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

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 ...