LAUSR

Abstract This work describes a procedure giving cyclopentadienyl molybdenum(II) compounds bearing carboxylic acid function group. It involves synthesis of carboxylic acid ester functionalized cyclopentadienides, their coordination to molybdenum(II) precursor and saponification of ester function groups. The method is not limited only to compounds with the function group directly attached in the cyclopentadienyl ring but also to those functionalized in the side chain. The attempts to synthesize the indenyl analogues were only partially successful due to low stability in the saponification step. All reported structure types were elucidated from spectroscopic measurements and verified by X-ray crystallography. The second part of the work describes an effect of the outer-coordination sphere on cytotoxicity of the cationic molybdenum(II) compounds bearing N,N-chelating ligands. The cytotoxicity of the modified species bearing phenanthroline ligand toward human leukemia cells MOLT-4 (IC50 = 10.5 ± 0.5 μmol l−1) is higher than reported for cisplatin (IC50 = 15.8 ± 1.9 μmol l−1).