Aliphatic Organoimido Derivatives of Polyoxometalates Containing a Bioactive Ligand.

A series of aliphatic organoimido derivatives of hexamolybdate based on amantadine, namely (nBu4N)2-[Mo6O18(≡NC10H15)] (1), (nBu4N)2 {cis-[Mo6O17(≡NC10H15)2]} (2), (nBu4N)2{trans-[Mo6O17(≡NC10H15)2]} (3), and (nBu4N)2[Mo6O16- (≡NC10H15)3] (4), was synthesized in reasonable yield by dehydration with N,N'-dicyclohexylcarbodiimide (DCC). They were characterized by IR and UV/Vis spectroscopy, elemental analysis, ESI mass spectrometry, and single-crystal X-ray structure analysis. The spectral and structural similarities and differences between monosubstituted, cis-disubstituted, and transdisubstituted organoimido derivatives were elucidated and may provide guidance for related work on organoimido-functionalized Lindqvist-type polyoxometalates. In addition, trans-disubstituted and polysubstituted derivatives containing aliphatic organoimido ligands have not yet been reported, and the crystal structure of the trans isomer may lead us to a deeper understanding of disubstituted derivatives. Furthermore, proliferation and morphology of MCF-7 cells were studied with compound 1. The present results show that the DCC-dehydrating protocol could be an efficient approach to covalently graft bioactive ligands such as amantadine onto POMs and enhance their application in clinical cancer treatment. [ABSTRACT FROM AUTHOR]