Dimeric rhenium(IV) and monomeric rhenium(I) and (V) complexes of orotic acid

The reaction of orotic acid (H(2)or) with trans-[ReOBr3)PPh3)(2)] in ethanol produced the triply-bridged dimer (mu-Br)(mu-O)(mu-or)[(Re2Br)-Br-IV(OEt)(2)(PPh3)(2)] (1). In 2-propanol as solvent the product (mu-Br)(mu-O) (mu-or)[(Re2Br2)-Br-IV(OPr1)(PPh3)(2)] (2) was isolated. In order to eliminate the oxo group as a bridging ligand, the imido-coordinated [Re-v{=NC6H4(2-NH2)}Br-3(PPh3)(2)] was reacted with H(2)or to give the monomer [Re{NC6H4(NH2)}Br(or)(PPh3)(2)] (3) as product. To remove PPh3 as possible ligand, the reaction of [ReO2(py)(4)]Cl with H(2)or produced [ReO(OEt)(or)(py)(2)] (4). H(2)or was also reacted with [Re(CO)(5)Cl], yielding the product (Ph4P)[Re(CO)(3)(H2O)(or)] (5). The crystal structures of 1-5 were determined by X-ray single crystal diffraction. In addition, infra-red, H-1 NMR, electrochemical and electronic properties are also reported. (C) 2015 Elsevier Ltd. All rights reserved.