THE ANOMALOUS ELECTROCHEMICAL-BEHAVIOR OF THE TETRATHIOETHER MACROCYCLIC COMPLEXES [MOX2(ME8[16]ANES4)] (X = CL OR BR) - THE X-RAY STRUCTURES OF [MOBR2(ME8[16]ANES4)]+/0 AND MODULATION OF REDOX POTENTIALS IN CONFORMERS OF THE [MOBR2(ME8[16]ANES4)]+/0 SYSTEM

The anomalous redox properties Of [MoX2(Me8[16]aneS4)], X = Cl or Br, reported previously are rationalised, the authentic reduction of the dibromide occuring at E1/2 = -2.87 V versus ferrocinium-ferrocene to give an unstable 17-electron anion which reacts with carbon monoxide and dinitrogen; low temperature cyclic voltammetry shows the [MoBr2(Me8[16]aneS4)]+/0 system to be fluxional and this is explained by a metal 'in- or out-of-plane' deformation accompanying conformational rearrangement of the macrocyclic ligand, X-ray crystallography showing the neutral dibromide to have the 'all-up' arrangement of the macrocyclic tetrathioether ligand rather than the 'up-up-down-down' conformation of the one-electron oxidised species.