Tin(II) and Tin(IV) Complexes Incorporating the Oxygen Tripodal Ligands [( η 5 -C 5 R 5 )Co{P(OEt) 2 O} 3 ] − , (R = H, Me; Et = -C 2 H 5 ) as Potent Inflammatory Mediator Inhibitors: Cytotoxic Properties and Biological Activities against the Platelet-Activating Factor (PAF) and Thrombin

Metal complexes displaying antiplatelet properties is a promising research area. In our methodology, Platelet-Activating Factor (PAF), the most potent lipid pro-inflammatory mediator, serves as a biological probe. The antiplatelet activity is exerted by the inhibition of the PAF-induced aggregation in washed rabbit platelets (WRPs) and in rabbit plasma rich in platelets (rPRPs). Herein, the synthesis and biological investigation of a series of organometallic tin(II) and tin(IV) complexes, featuring the oxygen tripodal Kläui ligands [( η 5 -C 5 R 5 )Co{P(OEt) 2 O} 3 ] − , {R = H, (L OEt − ); Me (L* OEt − )}, are reported. Reaction of NaL OEt ( 1a ) and NaL* OEt ( 1b ) with SnCl 2 , yielded the rare four-coordinate L OEt SnCl ( 2a ) and L* OEt SnCl ( 2b ) complexes. Accordingly, L OEt SnPh 3 ( 3a ) and L* OEt SnPh 3 ( 3b ) were prepared, starting from Ph 3 SnCl. Characterization includes spectroscopy and X-ray diffraction studies for 2a , 2b and 3b . The antiplatelet activity of the lead complexes 2b and 3a (IC 50 = 0.5 μΜ) is superior compared to that of 1a and 1b , while both complexes display a pronounced inhibitory activity against thrombin (IC 50 = 1.8 μM and 0.6 μM). The in vitro cytotoxic activities of 3a and 2b on human Jurkat T lymphoblastic tumor cell line is higher than that of cisplatin.