Organotin(IV) complexes of ethylsarcosine hydrochloride: synthesis, characterization and in vitro cytotoxic activity

The synthesis and characterization of new coordination compounds of some organotin(IV) chlorides with ethylsarcosine hydrochloride ( N ‐methylglycine ethyl ester hydrochloride) is reported; the ligand molecules appear to be bound to the tin atoms through the carbonyl oxygen atoms by means of dative bonds. As single crystals were not obtained, a number of experimental techniques were used to accomplish a definitive characterization and determination of their structure. The results obtained by 1 H, 13 C, 119 Sn NMR, FT‐IR and 119m Sn Mössbauer spectroscopy and thermogravimetric analysis suggested pentacoordination for the 1:1 (Sn:ligand (ESH)) derivatives, [R 2 SnCl 2 (ESH)] + Cl − , in a trigonal bipyramidal (TBP) structure, and hexacoordination for the 1:2 complexes, [R 2 SnCl 2 (ESH) 2 ] 2+ 2Cl − , in an octahedral structure (R = Me, n ‐Bu, Ph; ESH = protonated ethylsarcosine, CH 3 CH 2 O(O)CCH 2 N(CH 3 )H 2 + ). The triphenyltin(IV) chloride ethylsarcosine hydrochloride derivative exists only as a 1:1 pentacoordinated adduct in a strongly distorted TBP structure. Finally, the compounds have been tested for in vitro cytotoxic activity against human adenocarcinoma HeLa cells, showing, in some cases, a high potency, even at low concentration. Copyright © 2002 John Wiley & Sons, Ltd.