The photolysis of Fe(CO)(3){P(OPh)(3)}(2) and reaction of the photoproductwith alkynes: crystal structures of Fe(CO)(2){P(OPh)(3)}(2)(eta(2)-PhCCPh), Fe(CO)(2){P(OPh)(3)}(2){eta(1):eta(1)-C(O)C(Me)C[CH(OEt)(2)]C(O)} and Fe-2(CO)(4){P(OPh)(3)}(2)(PhCCH)(2)

UV-irradiation of Fe(CO)(3){P(OPh)(3)}(2) (1) afforded an orthometallated i ron hydride HFe(CO)(2){P(OPh)(3)}{(PhO)(2)POC6H4} (2) which was reacted in situ with alkynes (RC)-C-1=CR2. Internal alkynes reacted to give either eta (2)-alkyne Fe(CO)(2){P(OPh)(3)}(2)(eta (2)-(RCCR2)-C-1) [3a, R-1 = R-2 = P h; 3b, R-1 = Ph, R-2 = CH(OEt)(2)] or maleoyl Fe(CO)(2){P(OPh)(3)}(2){eta ( 1):eta (1)-C(O)C(R-1)C(R-2)C(O)} [4a R-1 = Ph, R-2 = Me; 4b, R-1 = R-2 - Me ; 4c, R-1 = Me, R-2 = CH(OEt)(2); 4d, R-1 = Me, R-2 = CH2OH; 4e, R-1 = R-2 = CH2OH] complexes. The terminal alkyne HC=CPh reacted with 2 to give the f errole derivative Fe-2(CO)(4){P(OPh)(3)}(2)(PhCCH)(2) (5). The crystal stru ctures of 3a, 4e and 5 were determined. Complex 3a is trigonal bipyramidal about the iron atom with trans apical phosphite ligands and an equatorial a rrangement of the CO groups and alkyne CC moiety. Complex 4e is octahedral with trans phosphite ligands and cis carbonyl groups. The alkyne ligand has undergone double carbonylation to generate a ferracyclopentenedione (maleo yl) ring that occupies the remaining two coordination sites at the metal ce ntre. Complex 5 is formally a derivative of Fe-2(CO)(9) in which an Fe(CO)( 2){(P(OPh)(3)} moiety is pi -bonded to a ferracyclopentadiene ring arising from the tail-to-tail coupling of two HC=CPh ligands. (C) 2000 Elsevier Sci ence B.V. All rights reserved.