Dinuclear Rh(II) complexes with one polypyridyl ligand, structure, properties and antitumor activity

Rhodium(II) complexes [Rh2(μ-OAc)3(N–N)(H2O)3]PF6 and [Rh2(μ-OAc)3(OAc)(N–N)] (N–N=polypyridyl) have been characterized using NMR, IR and UV–Vis spectroscopic methods. X-ray structure of complex [Rh2(μ-OAc)3(OAc)(Ph2phen)]has been determined and its electronic structure has been elucidated using DFT methods. Optimized geometry of complex agrees well with crystallographic data. The HOMO is δ∗dyz and LUMO π∗phen orbital. Calculated UV–Vis spectra of compound 4 indicate that absorption in 15000–20000cm−1 results from CT transition, mainly from δ∗(Rh2), π∗(Rh2) and σ(Rh2) orbitals to the π∗phen and σ∗(Rh2) orbitals. The compounds are promising cytostatic agents against Caco-2 tumor cells.