Synthesis, crystal structures, cytotoxicity and qualitative structure–activity relationship (QSAR) of cis- bis{5-[( E)-2-(aryl)-1-diazenyl]quinolinolato}di- n-butyltin(IV) complexes, nBu 2Sn(L) 2

Abstract

A series of cis- bis{5-[( E)-2-(aryl)-1-diazenyl]quinolinolato}di- n-butyltin(IV) complexes has been synthesized and characterized by 1H-, 13C-, 119Sn NMR, ESI–MS (electrospray ionization mass spectrometry), IR and 119mSn Mössbauer spectroscopic techniques in combination with elemental analyses. The structures of four di- n-butyltin(IV) complexes, viz., n Bu 2Sn(L 3) 2 ( 3), n Bu 2Sn(L 4) 2 ( 4), n Bu 2Sn(L 5) 2 ( 5) and n Bu 2Sn(L 7) 2 · 0.5C 6H 6 ( 7) (LH = 5-[( E)-2-(aryl)-1-diazenyl)quinolin-8-ol) were determined by single crystal X-ray diffraction. In general, the complexes were found to adopt a distorted cis-octahedral arrangement around the tin atom. These complexes retain their solid-state structure in non-coordinating solvent as evidenced by 119Sn and 13C NMR spectroscopic results. The in vitro cytotoxicity of di- n-butyltin(IV) complexes ( 3– 8) is reported against seven well characterized human tumour cell lines. The basicity of the two quinolinolato donor N and O atoms of the ligands are discussed in relation to the cytotoxicity data.