A new polymorph of a carbonyliron complex from tetraphenylhexapentaene: bis(mu(3),eta(2),sigma(2)-diphenylallenylidene)octacarbonyltriiron

The crystal structure of a new polymorphic form of octacarbonyl-1 kappa(3)C ,2 kappa(3)C,3 kappa(2)C-bis[mu(3)-3,3-diphenylallenylidene-1:2 kappa(2)C(1 ):3(1,2-eta(2))]-triangillo-triiron(0)(3 Fe-Fe), [Fe-3(C15H10)(2)(CO)(8)], has been determined, Reaction of tetraphenylhexapentaene with iron dodecaca rbonyl leads to the title complex composed of an Fe-3(CO)(8) central core b ridging two C3Ph2 ligands. The molecule adopts a synclinal conformation of the carbonyl groups in two Fe(CO)(3) groups of the Fe-3 triangle, in contra st to the synperiplanar conformation observed previously.