The complexes mer-[RhCl 3(DMSO-kappa S)(pp)] 1a- 5a may be prepared by reaction of mer,cis-[RhCl 3(DMSO-kappa S) 2(DMSO-kappa O)] with the appropriate polypyridyl ligand (pp = bpy, phen, dpq, dppz, dppn) in CH 3OH/H 2O solution at 75 degrees C. The mer isomers of 1a- 5a are stable in chloroform solution but those of 1a and 2a isomerize rapidly to a mixture of fac and mer isomers in DMSO. The complexes are potent in vitro cytotoxic agents and exhibit IC 50 values that are strongly dependent on the size of the polypyridyl ligand. IC 50 values of, respectively, 4.0 (0.5) and 1.9 (0.5), 0.40 (0.06) and 0.19 (0.05), and 0.079 (0.012) and 0.069 (0.021) microM are observed for 1a- 3a against the human cell lines MCF-7 (breast cancer) and HT-29 (colon cancer). Cellular uptake studies showed a rapid and high accumulation of the polypyridyl compounds. Treatment of HT-29 and MCF-7 cells with 3a leads to significant decreases in cellular oxygen consumption and the rate of extracellular acidification.

A rich variety of chalcogenidoarsenate anions and ligands have been prepared under mild solvothermal conditions in strongly polarizing solvents such as water, methanol and amines in the temperature range 100 -200 • C. This review covers synthetic and structural aspects of such species As x E y z− with particular emphasis being placed on the trends and differences observed for E = S, Se, Te and on developments within the past decade. These include the preparation of quaternary Main Group element chalcogenidoarsenates(III) such as Cs 3 AsGeSe 5 and polymeric selenidoarsenates(II, III) such as Cs 2 As 4 Se 6 . A currently expanding area of interest involves the employment of transition metal-polyamine or -polyimine fragments such as {Mn(tren)} 2+ or {Mn(terpy)} 2+ as structuredirecting agents. The metal atoms of such cations can be connected to the terminal chalcogen atoms of oligomeric or polymeric anions As x E y z− to prevent their further condensation or can be directly incorporated into anionic or neutral networks when at least two free coordination sites are available in the fragment. This strategy has led to the characterization of novel ligands including cyclo-

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Hydrothermal reaction of [MnCl2(terpy)] with elemental As and Se at 150 °C in 1:2:4 and 1:4:8 molar ratios in the presence of Cs2CO3 affords the complexes [{Mn(terpy)}2 (As2Se5)]2 (1) and [{Mn(terpy)}2 (As4Se8)] (2), respectively. 1 contains dipyramidal [As2Se5]4− ligands that bridge three MnII atoms in a tetradentate μ3‐1κ2Se1,Se2:2κSe4:3κSe5 manner. The tetranuclear complex is centrosymmetric and exhibits a central 8‐membered (MnSeAsSe)2 ring. Cyclic [As4Se8]4− ligands are present in the centrosymmetric dinuclear complex 2 and chelate the Mn(II) atoms through adjacent terminal Se atoms. Both 1 and 2 are linked into infinite chains through weak Mn···Se interactions. [{Mn(terpy)}2(As4S8)] (3) and $_{\infty}^{1}\rm [{Mn(terpy)}(As_{2}S_{4})]$ (4) can be obtained by hydrothermal reaction of [MnCl2(terpy)] with As2S3 at respectively 150 °C and 190 °C. Whereas 3 exhibits an identical connectivity pattern to that of 2, the coordination polymer 4 contains vierer $_{\infty}^{1}\rm [AsS_{2}^{-}]$ chains that coordinate {(terpy)Mn}2+ fragments in a bidentate manner through terminal S atoms. The complex $_{\infty}^{1}\rm [{Mn(tren)}\textrm{ } (As_{4}S_{7})]$ (5) contains $_{\infty}^{1}\rm [As_{4}S_{7}^{2-}]$ double chains and results from the analogous hydrothermal reaction of [MnCl2(tren)] with As2S3 at 150 °C.

Solvothermal reaction of [MnCl 2 (cyclam)]Cl with GeSe 2 at a 1:1 molar ratio in CH 3 OH/H 2 O (1/1) at 150°C affords the dimanganese(II) complex [{Mn(cyclam)} 2 (μ-Ge 2 Se 7 )] · CH 3 OH · 1.5H 2 O (1) with a spirotricyclic [Mn(μ-Ge 2 Se 7 )Mn] core. The strained four-membered Mn-Se t -Ge-Se t Ј rings (Se t ϭ terminal Se atom) exhibit long Mn-Se t distances in the range 2.725(2)Ϫ2.745(2) Å and narrow average Se t -Mn-Se t Ј angles of 85.87(4)°. The solvothermal reaction of [MnCl 2 (cyclam)]Cl with SnSe and Se leads to formation of the analogous complex [{Mn(cyclam)} 2 (μ-Sn 2 Se 6.15 )] (2), in which bridging [Sn 2 Se 6 ] 4Ϫ and [Sn 2 Se 7 ] 4Ϫ ligands are disordered at a ratio of 85:15. Employment 1005 of [MnCl 2 (terpy)] under similar conditions generates two complexes of the formula [{Mn(terpy)} 2 (μ-Sn 2 Se 6 )] 3 and 4, of which the former also contains a spirotricyclic core, whereas the Se t atoms of the latter coordinate symmetry-related Mn II atoms in a 1-D polymer. The Mn-Se t bond distances of 2.584(1) and 2.549(1) Å in the resulting chair-shaped eight-membered rings of 4 are much shorter than in 1 and 2.