Synthesis, spectroscopic characterization (IR,1H,13C and119Sn NMR, electrospray mass spectrometry) and toxicity of new organotin(IV) complexes withN,N′,O- andN,N′,S-scorpionate ligands

Abstract

New organotin(IV) derivatives containing the anionic ligands bis(3,5-dimethylpyrazol-1-yl)dithioacetate [LCS 2 ] - and bis(3,5-dimethylpyrazol-1-yl)acetate [LCO 2 ] - have been synthesized from reaction between (CH 3 ) 2 SnCl 2 and lithium salts of the ligands. Mononuclear complexes of the type {[LCX 2 ](CH 3 ) 2 SnCl} (X = S or O) have been obtained and fully characterized by elemental analyses and FT-IR in the solid state and by NMR ( 1 H, 13 C and 119 Sn) spectroscopy, conductivity measurements and electrospray ionization mass spectrometry in solution. The acute toxicity of new organotin(IV) derivatives on rat was studied, comparing their effect with those of dimethyltin chloride (CH 3 ) 2 SnCl 2 . The comparison of LD 50 of organotin(IV) complexes and (CH 3 ) 2 SnCl 2 administered intraperitoneally, as a single dose, evaluated in vivo on rats, showed that toxicity decreases as follows: (CH 3 ) 2 SnCl 2 > LCO 2 > LCS 2 . The effect of these organotin(IV) complexes on DNA was evaluated in vitro and in vivo on rats treated with different doses of these compounds (1/20 LD 50 and 1/100 LD 50 ). The lymphocyte DNA status was assessed by the comet assay, a rapid and sensitive single-cell electrophoresis technique, used to detect primary DNA damage in individual cells. After 36 h from the start of treatment the two new organotin(IV) derivatives induced a significant rise in comet assay parameters, indicating an increasing presence of damaged DNA.