Tetrakis(o-benzoylbenzoato-O,O')lead(IV) Dichloromethane Solvate

Abstract

In the title complex, [Pb(CI4H903)4].CH2CI..2, the Pb atom is located at a point of symmetry (4) and is coordinated by eight carboxylate O atoms of four benzoylbenzoate anions at the corners of a somewhat distorted trigonal dodecahedron [Pb---O 2.317 (9) and 2.235 (9)A]. The dichloromethane solvent molecule is disordered in holes in the crystal structure, on the fourfold inversion axis between the Pb atoms.

Lead Coordination and Organometallic Compounds: Classification and Analysis of Crystallographic and Structural Data

“…There are three colourless eight coordinate derivatives Pb(IV) [135][136][137] Eight coordinated polyhedra about Pb(IV) utilize bidentate O-donor ligands, with one example also containing a monodentate phenyl group. The mean Pb-0 bond distance is 234 pm, and the Pb-C(Ph) value is 216 pm.…”

207Pb NMR chemical shifts of lead tetracarboxylates

“…In order to link the orientation of the 207 Pb CSA tensors with the geometric structure of the tetracarboxylate complexes, we refer to the published single-crystal x-ray diffraction structures of this class of compound. Of the only two published single-crystal structures of lead tetracarboxylates, lead tetra(o-benzoylbenzoate), 4 represents an example of an axial 207 Pb NMR tensor whilst lead tetraacetate 3 is an example of the minority case of non-axial 207 Pb NMR tensors (Äυ D C0.66). Examination of the PbO 8 intimate coordination spheres of these structures (see Table 2] that is variable, but axis, whilst the orthogonal plane contains the C 0 2 axes (Fig.…”

“…11,14 We suggest that, in contrast to the situation for lead(II), for lead(IV) compounds the ligating oxygen atoms shield the 207 Pb nucleus by an extent taken to Figure 5. The coordination sphere of lead tetra(o-benzoylbenzoate) from the single-crystal x-ray structure solution, 4 showing the D 2d point symmetry.…”

“…Only two crystal structures of lead(IV) tetracarboxylates have been published to date, those of lead(IV) tetraacetate 3 and lead(IV) tetra(obenzoylbenzoate). 4 In both cases each carboxylate ligand is chelating, leading to 8-coordination of the lead atom. 207 Pb NMR spectroscopy in the solid state could help to elucidate the three-dimensional arrangement of electron density around the lead atom in non-crystalline lead(IV) compounds, which would in turn give some insight into the arrangement of the ligands in these complexes.…”

Novel Lead(iv) Reagents for Carbon-Carbon Bond Formation

“…Because of the known propensity of carboxylates to act as bidentate chelates for lead(IV), 18 spacer arms were chosen to give the diacids sufficient flexibility to facilitate monomeric complex formation. Ligand L 2 H2 was obtained directly from camphoric acid by coupling of the acid chloride with t-butyl m-hydroxybenzoate, followed by trifluoroacetic acid deprotection.…”