Rerefinement of poly[di-aqua-bis-(μ3-2-methyl-pro-pano-ato-κ4 O: O, O': O')bis-(μ3-2-methyl-propano-ato-κ3 O: O: O)(μ2-2-methyl-propano-ato-κ3 O: O, O')(2-methyl-propano-ato-κ2 O, O')trilead(II)]

Abstract

The crystal structure of the title complex, [Pb₃(C₄H₇O₂)₆(H₂O)₂] _n , was redetermined on basis of modern CCD-based single-crystal X-ray data at 120 K. The current study basically confirms the previous report [Fallon et al. (1997 ▸). Polyhedron, 16, 19-23] at 190 K, but with higher accuracy and precision. In particular, positional disorder of one of the 2-methyl-propano-ate anions over two sets of sites was resolved, showing a refined ratio of the disorder components of 0.535 (9):0.465 (9). The three independent cations in the structure have coordination numbers of [7 + 1], [6 + 1], and [5 + 3], with O atoms belonging either to carboxyl-ate groups or water mol-ecules. This arrangement leads to the formation of sheets parallel to (01), whereby the hydro-phobic 2-methyl-propanyl groups of the anions are oriented above and below the hydro-philic sheets to form a layered structure. Within a sheet, hydrogen bonds of the type O_water-H⋯O are formed, whereas the hydro-phobic groups between adjacent layers inter-act through van der Waals forces.

Keywords: carboxyl­ates; crystal structure; hydrogen bonding; the Cambridge Structural Database.