Photolysts of cis-(Me2SiSiMe2)[η5-t-BuC5H3)Fe(CO)]2(u-CO)2(2c) in the presence of P(Oph)3 ligands afforded only cis-[η5:η5-t-BuC5H3Me2SiSiMe2C5H3-t-Bu)Fe2(CO)P(Oph)3(μ-CO2](3c), whereas similar traeatment of 2t yielded only the trans isomer 3t. When 3c and 3t were heated, in xylene, the cis compound (3c) rearranged to the trans product [{Me2Si(η5-t-BuC5H3)Fe}2(CO)3P(OPh)3](4t), while the trans compound (3t) afforded the cis product [{Me2-Si(η5-t-BuC5H3)Fe}2(CO)3P(OPh)3] (4c); thus, the rearrangement is stereospecific.

Treatment of (Me2SiSiMe2)[η5-C5H3R1)Fe(CO)]2(u-CO)2(R1=H(1), R1=t-Bu(5)) with R2NC(R2=C6H11, t=Bu) in benzene afforded isocyanide-substituted complexes [(η5:η5-C5H3R1-Me2SiMe2C5H3R1)Fe2(CO)(CNR2)(u-CO)2] (R1=H, R2=t-Bu(4); R1=R2=t-Bu(6)). Turther investigations indicated that the cis substrate 5c afforded only the cis product (6c), while the trans substrate 5t afforded only the trans product (6t). When 3 and 4 were heated respectively in xylene, three different rearranged products (6t). When 3 and 4 were heated respectively in xylene, three different rearranged products [{(Me2Si)(η5-C5H4)-Fe(CO)L1}{(Me2Si)(η5-C5H4)-Fe(CO)L2}](L1=L2=CO(2); L1=C6H11NC, L2=CO(7), L2=C6H11NC(9); L1=t-BuNC, L2=CO(8), L2=t-BuNC(10)) were obtained. Similarly, thermal treatment of 6t afforded three different cls rearranged products, 11c, 12c, and 13c, while treatment of 6c afforded three different cis rearranged products, 11t, 12t, and 13t, This indicated that the rearrangement still follows the reaction mechanism proposed previously on the basis of the intramolecular nature of this reaction mechanism proposed previously on the basis of the intramolecular nature of this reaction if we only take into accunt the configuration of two tert-buty1 groups on the Cp rings. To explain the formation of three different products, an alternative mechanism involving free ligand exchange to from three different iron-centerde radical intermediater is proposed as a supplement to the previous mechanism. The complex stereochemistry in the moecules of 12 and 13 is discussed. Molecular structures of 8,9t, 12t, and 13c have benn determined by single-crystal X-ray diffraction.

The indenyl iron compound (η5-C9H7)Fe(η5-C5H5) (1) was found to react with benzyne, generated from o-trimethylsilylphenyl triflate by fluoride-induced 1, 2-elimination, to afford the Diels-Alder adduct 1,2-(1,4-dihydro-naphthalen-1,4-diyl)ferrocene (2). When the bis-(indenyl) iron complexes (η5-R-C9H6)2Fe [R=H(3); 2-Me(6); 1-SiMe3(9)] reacted with benzyne, the bisadducts [R=H(5); 2-Me(8); 1-SiMe3(11)] were obtained along with the corresponding monoadducts [R=H(4); 2-Me(7); 1-SiMe3(10)]. The reaction of teramethyl-dislyene-bridged bis(indenyl) iron (Me2SiSiMe2)(η5-C9H6)2Fe(12) with benzyne gave only the monoadduct (13). Complex 2 was also tested for ring-opening metathesis polymerization (ROMP) in the presence of Grubbs' catalyst [(PCy3)2RuCl2=CHPh] but was found to be inactive under normal conditions. The molecular structures of 2, 5, 8, and 13 have been determinde by X-ray diffraction.