The preparation, structural characterization, and chemical behavior in aqueous solution of a series of new Ru
![single bond single bond](http://www.sciencedirect.com/scidirimg/entities/sbnd)
[9]aneS
3 half-sandwich complexes of the type [Ru([9]aneS
3)Cl(N
![single bond single bond](http://www.sciencedirect.com/scidirimg/entities/sbnd)
N)][CF
3SO
3] and [Ru([9]aneS
3)(dmso-S)(N
![single bond single bond](http://www.sciencedirect.com/scidirimg/entities/sbnd)
N)][CF
3SO
3]
2 (
5–
15, N
![single bond single bond](http://www.sciencedirect.com/scidirimg/entities/sbnd)
N = substituted bpy or 2 × 1-methylimidazole) are described. The X-ray structures of [Ru([9]aneS
3)Cl(3,3′-H
2dcbpy)][CF
3SO
3] (
9) (3,3′-H
2dcbpy = 3,3′-dicarboxy-2,2′-bipyridine), [Ru([9]aneS
3)Cl(4,4′-dmobpy)][CF
3SO
3] (
13) (4,4′-dmobpy = 4,4′-dimethoxy-2,2′-bipyridine), and [Ru([9]aneS
3)Cl(1-MeIm)
2][CF
3SO
3] (
15) (1-MeIm = 1-methylimidazole) were also determined. The new compounds are structurally similar to anticancer-active organometallic half-sandwich complexes of formula [Ru(η
6-arene)Cl(N
![single bond single bond](http://www.sciencedirect.com/scidirimg/entities/sbnd)
N)][PF
6]. Three chloro compounds (
5,
9,
15) were tested
in vitro for cytotoxic activity against two human cancer cell lines in comparison with the previously described [Ru([9]aneS
3)Cl(en)][CF
3SO
3] (
1, en = ethylenediamine), [Ru([9]aneS
3)Cl(bpy)][CF
3SO
3] (
2), and with their common dmso precursor [Ru([9]aneS
3)Cl(dmso-S)
2][CF
3SO
3] (
3). Only the ethylenediamine complex
1 showed some antiproliferative activity, ca. one order of magnitude lower than the reference organometallic half-sandwich compound RM175 that contains biphenyl instead of [9]aneS
3. This compound was further tested against a panel of human cancer cell lines (including one resistant to cisplatin).