The V comformation of COT has an angle at 135° and is thought to be highly stabilized via bonding with the iron atoms (in free COT, this comformation is disfavored by approximately 36 kcal/mol.
Fascinatingly, in benzene solution, H NMR reveals a single broadened resonance with a chemical shift at -3.15 ppm. This suggests that the cyclooctatetraene ligands are highly fluxional and some degree of paramagnetism.
COT is known to be a highly fluxional ligand in other compounds too, such compounds being deemed “ring-whizzers” (like the related (cyclooctatetraene)iron tricarbony<nowiki/>l).
The conformational fluxionality is supported by computational studies which show very low barriers to COT rotation (on the scale of 1.4 kcal/mol) and rocking (0.1 kcal/mol). The transformation from the C singlet comformation to the triplet C comformation have been calculated to be nearly isoenergetic, driving the possibility of the singlet state existing in equilibrium with the triplet state- an explanation for the observation of paramagnetic NMR resonances at ambient temperatures.