Jamila Fattah, J. M. Twyman, S. J. Heyes
Jun 1, 1993
Citations
0
Influential Citations
17
Citations
Journal
Journal of the American Chemical Society
Abstract
The variable-temperature 13 C CP/MAS NMR spectra of the potassium salt of phenoxymethylpenicillin (C 16 H 17 N 2 O 5 SK) (potassium penicillin V) at T<352 K indicate an unusual low-symmetry structure with four molecules in the crystallographic asymmetric unit. This is confirmed by a single-crystal X-ray diffraction study, which employed a novel computational protocol to allow solution of the structure, which indicates that the four distinct molecules differ principally in the orientation of the phenoxy side chain with respect to the penam unit. The packing motif reveals different pseudosymmetry elements relating certain parts of the unit cell, which may explain the occurrence of this uncommon complex structure