title: Homo- and heteroleptic alkoxycarbene f-element complexes and their reactivity towards acidic N-H and C-H bonds.
abstract: The reactivity of a series of organometallic rare earth and actinide complexes with hemilabile NHC-ligands towards substrates with acidic C-H and N-H bonds is described. The synthesis, characterisation and X-ray structures of the new heteroleptic mono- and bis(NHC) cyclopentadienyl complexes LnCp2(L) 1 (Ln = Sc, Y, Ce; L = alkoxy-tethered carbene [OCMe2CH2(1-C{NCHCHN(i)Pr})]), LnCp(L)2 (Ln = Y) , and the homoleptic tetrakis(NHC) complex Th(L)4 4 are described. The reactivity of these complexes, and of the homoleptic complexes Ln(L)3 (Ln = Sc 3, Ce), with E-H substrates is described, where EH = pyrrole C4H4NH, indole C8H6NH, diphenylacetone Ph2CC(O)Me, terminal alkynes RC≡CH (R = Me3Si, Ph), and cyclopentadiene C5H6. Complex 1-Y heterolytically cleaves and adds pyrrole and indole N-H across the metal carbene bond, whereas 1-Ce does not, although 3 and 4 form H-bonded adducts. Complexes 1-Y and 1-Sc form adducts with CpH without cleaving the acidic C-H bond, 1-Ce cleaves the Cp-H bond, but 2 reacts to form the very rare H(+)-[C5H5](-)-H(+) motif. Complex 1-Ce cleaves alkyne C-H bonds but the products rearrange upon formation, while complex 1-Y cleaves the C-H bond in diphenylacetone forming a product which rearranges to the Y-O bonded enolate product.
authors.affiliation: EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, EH9 3JJ, UK. jason.love@ed.ac.uk polly.arnold@ed.ac.uk.
authors.forename: Polly L
authors.initials: PL
authors.lastname: Arnold
authors.forename: Thomas
authors.initials: T
authors.lastname: Cadenbach
authors.forename: Isobel H
authors.initials: IH
authors.lastname: Marr
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Fyfe
authors.forename: Nicola L
authors.initials: NL
authors.lastname: Bell
authors.forename: Ronan
authors.initials: R
authors.lastname: Bellabarba
authors.forename: Robert P
authors.initials: RP
authors.lastname: Tooze
authors.forename: Jason B
authors.initials: JB
authors.lastname: Love