Cerium(III) and Cerium(IV) Bis(η⁸-pentalene) Sandwich Complexes:  Synthetic, Structural, Spectroscopic, and Theoretical Studies

Abstract

The Ce(III) anionic bis(pentalene) sandwich complex K[Ce{C8H4(Si i Pr3-1,4)2}2] (1) has been prepared by treatment of CeCl3 with K2[C8H4(Si i Pr3-1,4)2] and crystallographically characterized as its 18-crown-6 complex. Oxidation of 1 with Ag[BPh4] affords the neutral, formally Ce(IV) sandwich complex [Ce{C8H4(Si i Pr3-1,4)2}2] (2), whose molecular structure has also been determined. The electronic structure of 2 has been investigated in detail by a combination of magnetic studies, K-edge XANES measurements, gas-phase photoelectron spectroscopy, and density functional calculations.

A base-free synthetic route to anti-bimetallic lanthanide pentalene complexes

“…(5) In an attempt to prepare an authentic sample of (η 8 -atoms in 5 as the 'ate' complex shown Figure S3 of the ESI, however the low quality of the data precluded accurate refinement of metric parameters. There is precedent for such Ln(III) anionic bis(pentalene) sandwich complexes with Ln = Ce, 71,72 emphasising the steric and electronic stabilisation achieved for the f-elements with the pentalene ligand in η 8 -mode.…”

Covalency in CeIV and UIV Halide and N‐Heterocyclic Carbene Bonds

“…[19] Examples of organometallic Ce IV complexes are also rare. The synthesis of [CeA C H T U N G T R E N N U N G (cot) 2 ] [28] (cot = cyclooctatetraenyl) and related complexes, [29][30][31] combining a highly oxidising metal cation with a reducing anionic ligand, has led to intensive study and debate into assignment of the metal oxidation state. [32][33][34][35][36][37] The first Ce IV cyclopentadienyl complex [38] was the tris(cyclopentadienyl)-supported Ce IV isopropoxide (D) reported by Marks et al, [39] closely followed by the crystallographically characterised tert-butoxide analogue reported by Evans et al [40] We have demonstrated the synthesis of [CeL 4 ] (L= OCMe 2 CH 2 (CNCHCHNiPr); E).…”

Intermediate-Valence Tautomerism in Decamethylytterbocene Complexes of Methyl-Substituted Bipyridines

“…Recent experimental and theoretical studies of certain Ce-and Yb-based organometallic complexes [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] have highlighted the importance of multiconfigurational interactions in understanding their electronic, structural, and magnetic properties. The canonical examples include Ce(cot) 2 , also known as "cerocene," where cot = cyclooctatetraene = C 8 H 8 , and Cp * 2 Yb(bipy), where Cp * = pentamethylcyclopentadienyl, and bipy = 2,2 ′ -bipyridine.…”