Oxidorhenium(V) complexes with l-histidine and pyranosides

Abstract

The reaction of the oxidorhenium(V) precursor [ReOCl₃(PPh₃)₂] with the proteinogenic amino acid L-histidine (L-hisH) and the glycosides methyl α-D-mannopyranoside (Me-α-D-Manp) and methyl β-D-ribopyranoside (Me-β-D-Ribp) in methanol/triethylamine yielded the crystalline compounds [ReO(L-his)(Me-α-D-Manp2,3H₋₂)]·2MeOH (1) and [ReO(L-his)(Me-β-D-Ribp3,4H₋₂)]·½MeOH (2). The mixed-ligand complexes based on the Re^VO moiety were characterised by single-crystal X-ray diffraction, NMR spectroscopy, elemental analysis and mass spectrometry. Both complexes are hydrolytically stable over prolonged periods of time and are accessible also by a purely aqueous route by replacing the rhenium(V) precursor with a perrhenate/reductant couple.