The crystal and molecular structures of the two bis(amine) complexes of rhenium(I), [ReBr(CO) 3(NHR 2) 2] (R = Me or Et), have been studied by X-ray diffraction methods. The complexes crystallize in the monoclinic system, space group P2 1/n, with cell constants (R = Me) a = 9.023(3), b = 11.537(4), c = 12.199(4) Å, β = 97.28(3)°; and (R = Et) a = 7.340(2), b = 9.784(3), c = 22.742(6) Å, β = 95.05(2)°. The molecular structure in both cases consists of facially arranged ligands around six-co-ordinate rhenium(I); the two cis amine ligands do not interact appreciably either by intra- or inter-molecular hydrogen bonding. The ethyl derivative reacts with CO 2 to give the corresponding carbamato-complex [Re(CO) 3(O 2CNEt 2)(NHEt 2)], the latter showing association in solution presumably due to intermolecular hydrogen bonding.