Assigning Hapticity to Cyclopentadienyl Derivatives of Antimony and Bismuth

Abstract

The chelating diamide [Me 2 Si{NAr} 2 ] 2− (Ar = 2,6-i-Pr 2 C 6 H 3 ) has been used as an ancillary ligand in antimony and bismuth chemistry. In contrast to the monomeric antimony chloride compound Sb(Me 2 Si{NAr} 2 ) Cl (1a), the bismuth derivative (1b) exists as a trimer in the solid state, linked by Bi•••(arene) π-bonding and Bi•••Cl interactions. Compounds 1a,b are used as an entry point into rare antimony and bismuth compounds incorporating Cp and Cp* ligands. Reactions of the chlorides with LiCp and KCp* afford the organometallic species E(Me 2 Si{NAr} 2 )-(C 5 R 5

Bi−P Bond Homolysis as a Route to Reduced Bismuth Compounds and Reversible Activation of P4

“…Bulky N , N ′‐chelating diamido ligands have recently been used to support low‐coordinate organometallic, and cationic bismuth complexes. The disilylamidoether ligand [O(SiMe 2 NAr) 2 ] 2− (abbreviated NON Ar , Ar=2,6‐ i Pr 2 C 6 H 3 ) generates a sufficiently stable environment at bismuth to allow the first monomeric Bi II radical, .…”

Isolation and Characterization of a Bismuth(II) Radical

“…Hirshfield surface (HS) analysis15 indicated that the only intermolecular contacts involving bismuth are weak Bi⋅⋅⋅H (1.3 % of HS) and Bi⋅⋅⋅π(arene)16 (1.2 % of HS) interactions (Supporting Information, Figure S2, Table S1), with the shortest interaction between Bi⋅⋅⋅C19′ at a distance of 3.715(4) Å. This contrasts with the molecular structure of Bi(Me 2 Si{NAr} 2 )Cl,17 in which Bi⋅⋅⋅Cl and Bi⋅⋅⋅π(arene) interactions generate a trimeric aggregate, leading us to conclude that the [NON Ar ] ligand provides effective steric protection of the bismuth center.…”

I. Magnesium Promoted Coupling of Carbodiimides and Terminal Acetylenes, II. Bismuth Compounds Supported by Di(amido) Chelating Ligands

“…The reaction of one equivalent of NEt 3 with 11 did not result in abstraction of HCl and formation of 9, with no reaction observed after 24 hours at 80 The 1 H NMR spectrum of 12a shows a single set of resonances for the SiMe 2 , isopropyl methyl and iso-propyl methine protons (δ H 0.13, 1.21 (br) and 3.49 (br) ppm, respectively). This contrasts with the spectra of 9, where two sets of resonances are observed for these protons, 95 and is consistent with a loss of the C S symmetry imposed by the pyramidal geometry of the bismuth in 9 and formation of a C 2h symmetric centre in 12a. The simplest interpretation of these data is formation of the two coordinate cation, with a mirror plane passing through the metallacycle, although other possible solution-state structures may also correspond to this new symmetry (see Appendix A).…”

“…(THF) 3 as the tris-THF adduct, In contrast to the broad resonances observed for the bismuth mono-chloride 9, these signals are clearly defined at room temperature. 95 The more deshielded iso-propyl methyl protons appear as two separate doublets, consistent with restricted rotation for the aryl substituent adjacent to the bismuth centre.…”