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Shapley, John R. Szajek, Lawrence Philip 2011-05-07T12:51:59Z 2011-05-07T12:51:59Z 10000-01-01 1991 "The complexes CpIr($\eta\sp2$-C$\sb8$H$\sb{14}$)CO and ($\eta\sp5$-C$\sb9$H$\sb7$)Ir($\eta\sp2$-C$\sb8$H$\sb{14}$)CO were prepared in high yield from (($\eta\sp2$-C$\sb8$H$\sb{14}$)$\sb2$Ir(CO)Cl) $\sb2$ and thallium cyclopentadienide or potassium indenide, respectively. The stereoisomers of CpIr($\eta\sp2$-C$\sb8$H$\sb{14}$)CO, ($\eta\sp5$-C$\sb9$H$\sb7$)Ir($\eta\sp2$-C$\sb8$H$\sb{14}$)CO, and ($\eta\sp5$-C$\sb9$H$\sb7$)Ir($\eta\sp2$-C$\sb8$H$\sb{14}$)$\sb2$, were characterized by two-dimensional NMR techniques. Due to the ""Indenyl Effect,"" ($\eta\sp5$-C$\sb9$H$\sb7$)Ir($\eta\sp2$-C$\sb8$H$\sb{14}$)CO was more reactive than CpIr($\eta\sp2$-C$\sb8$H$\sb{14}$)CO toward Lewis bases. The labile cyclooctene ring of ($\eta\sp5$-C$\sb9$H$\sb7$)Ir($\eta\sp2$-C$\sb8$H$\sb{14}$)CO was readily replaced under mild conditions by other two electron donors such as triphenylphosphine, carbon monoxide, ethylene, or phenylacetylene; CpIr($\eta\sp2$-C$\sb8$H$\sb{14}$)CO was not reactive under identical or more severe conditions. The complex ($\eta\sp5$-C$\sb9$H$\sb7$)Ir($\eta\sp2$-C$\sb8$H$\sb{14}$)CO readily oxidatively added C-Br and Si-H bonds, again under mild conditions, and was found to be an active and robust catalyst for the hydrogenation and hydrosilylation of alkenes and alkynes. The reaction of CO with ($\eta\sp5$-C$\sb9$H$\sb7$)Ir(CO)$\sb2$ resulted in the formation of the $\eta\sp1$-slipped indenyl ring of ($\eta\sp1$-C$\sb9$H$\sb7$)Ir(CO)$\sb3$." "For CpIr($\eta\sp2$-C$\sb2$H$\sb4$)L and ($\eta\sp5$-C$\sb9$H$\sb7$)Ir($\eta\sp2$-C$\sb2$H$\sb4$)L, where L = ethylene or CO, the barrier to ethylene rotation about the iridium-ethylene bond axis was determined by lineshape fitting of variable-temperature $\sp1$H NMR spectra. The free energies of activation were found to be 5-6 kcal/mole less for the indenyl complexes than for the corresponding cyclopentadienyl complexes (14 and 20 kcal/mole, respectively). This lowering of the barrier to ethylene rotation is an attribute of the ""Indenyl Effect.""" Some related projects included the following. Attempted preparation of CpIr($\eta\sp2$-C$\sb8$H$\sb{14}$)$\sb2$ resulted in an unexpected but useful synthesis of the cyclopentadiene complex CpIr($\eta\sp4$-C$\sb5$H$\sb6$). The proton and carbon resonances of the series of complexes CpM($\eta\sp4$-C$\sb5$H$\sb6$), where M = Co, Rh, or Ir, were compared. Protonation studies of CpIr($\eta\sp2$-C$\sb8$H$\sb{12}$) and ($\eta\sp5$-C$\sb9$H$\sb7$)Ir($\eta\sp2$-C$\sb8$H$\sb{12}$) allowed us to examine $\eta\sp5$ to $\eta\sp6$ haptotropic indenyl ring shifts. Synthetic routes to a metal cyclopentaphenanthrene complex Cp*Ru($\eta\sp5$-C$\sb{15}$H$\sb9$), were explored. Made available in DSpace on 2011-05-07T12:51:59Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9211007.pdf: 5694377 bytes, checksum: ac76acfe70837b1cfbeaddae6456a173 (MD5) Previous issue date: 1991 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:46:55Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:21:07-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9211007 (UMI)AAI9211007 http://hdl.handle.net/2142/20881 eng Copyright 1991 Szajek, Lawrence Philip Chemistry, Inorganic The 'Indenyl Effect' in iridium(I) olefin complexes text Chemistry Chemistry University of Illinois at Urbana-Champaign Dissertation Ph.D.