Two isomers (cis and trans) of (L1O)MoOCl2 have been synthesized and separated using the heteroscorpinate ligand L1OH, which possesses an N2O donor set. These geometric isomers differ in the orientation of the phenolate oxygen with respect to the terminal oxo group. The cis isomer spontaneously converts to the thermodynamically more stable trans isomer. Since the reduction potentials of the two isomers differ by similar to 220 mV and crystal structures of DMSOR and TMAOR exhibit a wide range of O-t-Mo-O-ser angles, we suggest that this angular variation may play a crucial role in gating the electron transfer process in the regeneration step.