Bismuth(III) coordination compounds. Synthesis, characterization, and X-ray structures of [Bi(Cl)(μ-Cl) 2(THF) 2] ∞, Bi(O 2CMe) 3(Solv) x (Solv = py, x = 2 or MeIm, x = 4) [1], and [Bi(μ-OCH 2CMe 3)(OCH 2CMe 3) 2(Solv)] 2 (Solv = HOCH 2CMe 3 or py)

Abstract

We have isolated and structurally characterized several novel bismuth coordination compounds. Dissolution of Bi(NO 3) 3 · 5H 2O in concentrated HCl, followed by crystallization from THF lead to the isolation of [Bi(Cl)(μ-Cl) 2(THF 2] ∞ 1. Each bismuth metal center of 1 adopts a 7-coordinated pentagonal bipyramidal geometry. One THF solvent molecule and one terminal chloride ligand are located in each of the axial positions. A terminal THF solvent molecule and four bridging chlorides reside in the equatorial positions. Dissolution of Bi(O 2CMe) 3 in pyridine (py) or N-methylimidazole (MeIm) results in the isolation of the appropriate amine adduct, either Bi(O 2CMe) 3(py) 2, 2 or Bi(O 2CMe) 3(MeIm) 3 · (MeIm), 3. Compound 2 uses two py molecules to adopt an unusual (for bismuth acetate species) 8-coordinated triangular dodecahedral geometry. In contrast, 3 incorporates three MeIm molecules to adopt the 9-coordinated tricapped trigonal prismatic geometry typically observed for bismuth acetate compounds (a “free” MeIm molecule is located in the lattice). The reaction of Bi[N(SiMe 3) 2] 3 with HOCH 2CMe 3 (HONp) yields [Bi(μ-ONp)(ONp) 2(HONp)] 2, 4. An alternative synthetic route to 4 is the metathical exchange between BiCl 3 and 3 equivalents of NaONp in the presence of HONp. The bismuth atoms of 4 are 5-coordinated and adopt an apical-shared, square base pyramidal (SP) arrangement. Recrystallization of 4 from py yields the dinuclear complex [Bi(μ-ONp)(ONp) 2(py)] 2, 5. The Bi atoms of 5 also adopt a 5-coordinated SP geometry; however, the two metal centers are linked through a basal-shared arrangement. The apical ONp ligands are in an up-down relationship to each other.