A novel class of polyphosphorus donor ligands based on a calix[n]arene skeleton: structural characterization of a dinuclear iron(O) complex

p-tert-Butylcalix[4] arene has been converted into the corresponding tetra (diphenylphosphinite) derivative which has a cone conformation; reaction with [Fe(CO)3(η2-C8H14)2] led to binding of two Fe(CO)3 units, as confirmed by X-ray analysis, at the surface provided by the four trivalent phosphorus donors.