TRANSITION-METAL SUBSTITUTED ACYLPHOSPHANES AND PHOSPHAALKENES .25. UNPRECEDENTED CONDENSATION OF THE PENTAMETHYLCYCLOPENTADIENYL LIGAND WITH A METHYLENE PHOSPHANE MOIETY IN (ETA(5)-C(5)ME(5))(CO)(2)FEP=C(NME(2))(2) INDUCED BY AZODICARBOXYLATES - STRUCTURE OF (4)CH=C(NME(2))P[N(CO(2)TBU)NH(CO(2)TBU)]FE(CO)(2)

The metallophosphaalkene (eta(5)-C(5)Me(5))(CO)(2)FeP=C(NMe(2))(2) (1) undergoes reaction with dialkyl azodicarboxylates RO(2)CN=NCO(2)R (R = tBu, Et, CH(2)Ph) to afford complexes 5-Me(4)CH=C(NMe(2))P[N(CO(2)R) NH(CO(2)R)]Fe(CO)(2) [R = tBu (6a), Et (6b), CH(2)Ph (6c)] with the no vel chelating (tetramethylcyclopentadienyl)-1-phospha-2-propenyl ligan d. This ligand system results from a yet unprecedented azocarboxylate- induced condensation of a ring methyl substituent with the methylene p hosphane fragment of educt 1. The molecular structure of (4)CH=C(NMe(2 ))P[N(CO(2)tBu)NH(CO(2)tBu)]Fe(CO)(2) (6a) (P2(1)/c, a = 10.522-(3) An gstrom, b = 22.124(9) Angstrom, c = 12.806(4) Angstrom, beta = 101.58( 3)degrees) was determined by single-crystal X-ray analysis.