Water-Soluble Rhenium Phosphine Complexes Incorporating The Ph2c(X) Motif (X = O-, Nh-): Structural And Cytotoxicity Studies

Reaction of [ReOCl3(PPh3)(2)] or [ReO2I(PPh3)(2)] with 2,2'-diphenylglycine (dpgH(2)) in refluxing ethanol afforded the air-stable complex [ReO(dpgH)(dpg)(PPh3)] (1). Treatment of [ReO(OEt)I-2(PPh3)(2)] with 1,2,3-triaza-7-phosphaadamantane (PTA) afforded the complex [ReO(OEt)I-2(PTA)(2)] (2). Reaction of [ReOI2(PTA)(3)] with dpgH(2) led to the isolation of the complex [Re(NCPh2)I-2(PTA)(3)]center dot 0.5EtOH (3.0.5EtOH). A similar reaction but using [ReOX2(PTA)(3)] = Cl, Br) resulted in the analogous halide complexes [Re(NCPh2)Cl-2(PTA)(3)]center dot 2EtOH (4.2EtOH) and [Re(NCPh2)(PTA)(3)Br-2]center dot 1.6EtOH (5.1.6EtOH). Using benzilic acid (2,2'-diphenylglycolic acid, benzH) with 2 afforded the complex [ReO(benz)(2)(PTA)][PTAH]center dot EtOH (6 center dot EtOH). The potential for the formation of complexes using radioisotopes with relatively short half-lives suitable for nuclear medicine applications by developing conditions for [Re(NCPh2)(dpg)I(PTA)(3)] (7)[ReO4](-) in a 4 h time scale was investigated. A procedure for the technetium analog of complex [Re(NCPh2)I-2(PTA)(3)] (3) from Tc-99m[TcO4](-) was then investigated. The molecular structures of 1-7 are reported; complexes 3-7 have been studied using in vitro cell assays (HeLa, HCT116, HT-29, and HEK 293) and were found to have IC50 values in the range of 29-1858 mu M.