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dc.contributor.authorJacobs, Brian Patrick
dc.date.accessioned2018-04-26T14:16:47Z
dc.date.available2018-04-26T14:16:47Z
dc.date.issued2017-08-30
dc.identifier.otherJacobs_cornellgrad_0058F_10363
dc.identifier.otherhttp://dissertations.umi.com/cornellgrad:10363
dc.identifier.otherbibid: 10361525
dc.identifier.urihttps://hdl.handle.net/1813/56848
dc.description.abstractA series of transition metal ene-amide complexes {(2,6-iPr2-C6H3)(1-cHexenyl)N}2M (M = Cr, 1-Cr; FePMe3, 2-Fe; Copy2, 3-Co) were prepared, and oxidation studies were conducted to assess intramolecular CC coupling. Addition of CrCl3 to 1-Cr, and FeCl3 to 2-Fe afforded the organic product rac-2,2’-di(2,6-iPr2C6H3N=)2-dicyclohexane (EA2) via an oxidatively triggered CC bond formation. Various lithium ene-amides were coupled, yet attempts to hydrolyze the diimine products produced pyrroles, rather than the target 1,4-diketone species. Some ferrous compounds (e.g., 2-Fe, FeCl2) catalyzed C-arylation of {(2,6-iPr-C6H3)(1-cHexenyl)N}Li upon exposure to phenyl bromide, yet the catalysis was modest (4-9 TO) and featured extended reaction times (3-4 d). A series of octahedral Fe(II) vinyl chelates complexes mer,trans-{3-N,N,C-2-py-CH=NCH2-CH=CH}Fe(PMe3)2CH3 (12), mer,trans-{3-N,N,C-2-py-CH=NCH2-CH=CH}Fe(PMe3)2I (15) and mer,trans-{3-N,N,C-(2-py)CH=NC(Me2)CH=CPh}Fe(PMe3)2CH3 (18) were prepared as potential precursors for the synthesis of Fe(IV) alkylidenes. While protonation of these complexes resulted in degradation, exposure of 15 to KOtBu yielded mer-{3-N,N,C-2-py-CH=NCH2-CH=CH}Fe(PMe3)3 (17). Structural characterization of complexes 15 and 17 revealed the latter to be consistent with an Fe(II) center coordinated by a conjugated vinyl ligand with delocalization in its -system. Electronic structures of the prior Fe(IV) alkylidenes [mer-{3-C,N,C-(2-C6H4)CH=N(1,2-C6H4)C(iPr)=}Fe(PMe3)3] [BArF4] (6) and mer,trans-{3-C,N,C-(2-C6H4)CH(Bn)N(1,2-C6H4)C(iPr)=}Fe(PMe3)2N2 (9) were calculated, and portray the “alkylidene” of 6 as carbenium-like and 9 as a vinyl carbon. A series of Fe chelate complexes [Fe(o-CH2C6H4NMe2)]2(--CH2,N-o-CH2C6H4NMe2)2 (1), [fac-Fe(-C,P-o-CH2C6H4PPh2)3][Li(TMEDA)2] (2), (Me2IPr)Fe(CH2C6H4NMe2)2 (3-C,N), (PMe¬3)2Fe(-C,P-CH2PMe2)2 (5) and trans,cis-(PMe3)2Fe(-C,P-CH2C6H4-o-PMe2)2 (6) were prepared through either salt metathesis or C-H bond activation. The viability of these compounds as Fe alkylidene precursors was probed, and oxidations of each chelate complex yielded organic degradation products. Several low-valent Fe(II) neopentyl (1-Ln) and norbornyl (4-Ln) complexes were prepared bearing ancillary ligands (e.g., TMEDA, PMe3). Efforts to yield Fe alkylidenes via oxidation yielded CC coupled degradation, yet exposure to adamtanyl azide afforded the Fe(IV) imido complexes (Me2IPr)Fe(=N(1-Ad))(CH2C(CH3)3)2 (2-Im) and (Me2IPr)Fe(=N(1-Ad))(1-nor)2 (6-Im). Both Fe imido species exhibit migratory insertion to yield Fe(II) amides. Kinetics indicated the neoPe system was more favorable with G‡ (298 K) = 3.6 kcal mol-1.
dc.language.isoen_US
dc.subjectChemistry
dc.titleOXIDATIVELY TRIGGERED CARBON-CARBON COUPLING IN FIRST ROW TRANSITION METAL ENE-AMIDE COMPLEXES AND PROGRESS TOWARDS DEVELOPMENT OF IRON(IV) ALKYLIDENES
dc.typedissertation or thesis
thesis.degree.disciplineChemistry and Chemical Biology
thesis.degree.grantorCornell University
thesis.degree.levelDoctor of Philosophy
thesis.degree.namePh. D., Chemistry and Chemical Biology
dc.contributor.chairWolczanski, Peter Thomas
dc.contributor.committeeMemberLancaster, Kyle M.
dc.contributor.committeeMemberCoates, Geoffrey
dcterms.licensehttps://hdl.handle.net/1813/59810
dc.identifier.doihttps://doi.org/10.7298/X4JW8C17


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