Abstract
Three new lead oxide benzoates have been prepared solvothermally. In two polymorphs, 1 and 2, of Pb2O(C6H5COO)2, distorted Pb4O tetrahedra share edges to form helical ∞1[Pb2O] chains. Unprecedented among Pb4O-based structures, these motifs may be viewed as double helices of lead atoms surrounding the central oxygen atoms. Both right- and left-handed helices are included in each structure. Formation of the polymorphs was controlled through variation in synthetic conditions. Polymorph 1 crystallizes in the achiral, polar space group Fdd2. Polymorph 2, in P21, is a rare example of a kryptoracemate in which crystallographically independent chains of both chiralities occur in the asymmetric unit. This second polymorph is both chiral and polar, and the pseudosymmetric relationship between the helices has been examined. In Pb4O(C6H5COO)6 (3), discrete Pb4O tetrahedra are bridged by benzoate ligands to form a one-dimensional hybrid structure. The compounds have been further characterized via IR spectroscopy, elemental analysis, and thermogravimetric analysis. Measurement of the second-harmonic generating activity of 1 and 2 corroborates the crystallographic findings of noncentrosymmetry.
Repository Citation
Easterday, C.C., L.R. Dedon, M. Zeller, and C.M. Oertel. 2014 "Helical ∞1[Pb2O] Chains in Polymorphs of Pb2O(C6H5COO)2.” Crystal Growth & Design 14(4): 2048-2055.
Publisher
American Chemical Society
Publication Date
3-6-2014
Publication Title
Crystal Growth & Design
Department
Chemistry and Biochemistry
Document Type
Article
DOI
10.1021/cg500177f
Language
English
Format
text
Copyright Statement
Reprinted (Adapted or Reprinted in part) with permission from ACS Publications. Copyright 2014 American Chemical Society.
