Alkali-metal complexes. Part V. Crystal structure of a potassium compound with isonitrosoacetophenone, K+[PhC(O)CH:NOHON:CHC(O)Ph]–

Abstract

A three-dimensional crystal structure analysis has been carried out on the complex KHL₂ where HL is isonitrosoacetophenone. Photographs, taken at 98 ± 5 K, about the a axis only, were measured with a densitometer to give 2211 observations. The unit cell is triclinic (space group P) with a= 6·217(9), b= 13·147(6), c= 9·516(4)Å, α= 99·64(2), β= 83·54(2), γ= 78·77(2)°, and Z= 2. The structure was solved by direct methods and has been refined by full-matrix least-squares calculations to a conventional R of 0·104.

The two ligands (L) are joined by a short hydrogen bond (2·47 Å) and have equivalent bond lengths and angles. Both ligands interact with a potassium ion by chelation through the keto-oxygen and oxime-nitrogen atoms to form five-membered rings. Seven co-ordination round the potassium ion is completed by oxygen atoms which are shared with other potassium ions. The oxygens involved are the oxime-oxygen of one ligand and the keto-oxygen of the other ligand. These potassium–oxygen contacts result in a polymeric column parallel to the needle axis (a) of the crystal. The K ⋯ O and K ⋯ N distances lie in the range 2·72 to 2·98 Å.