Crystal structure of a complex of caesium thiocyanate with phenacylkojate: 5-phenacyl-2-(hydroxymethyl)-4H-pyran-4-one–caesium thiocyanate

Abstract

The structure of the title complex has been determined by three-dimensional X-ray crystal-structure analysis. Crystals are triclinic, space group P, with unit cell dimensions a= 7·809(18), b= 11·270(13), c= 11·152(12)Åα= 92·70(8), β= 101·08(7), γ= 119·21 (10)°, Z= 2. The structure was solved by Patterson and Fourier methods and refined by full matrix least-squares to R 0·071 for 2217 independent diffractometer observations.

The caesium ions lie in pairs (4·157 Å apart) related by centres of symmetry, with four bridging contacts of the type Cs–X–Cs. Each ion is co-ordinated by three oxygen atoms from its associated phenacylkojate (pak) molecule, one shared oxygen atom from the centrosymmetrically related pak, and one oxygen atom from a further pak. The co-ordination number of eight is completed by the nitrogen atom of one NCS and a bridging sulphur atom from each of two further NCS ions. The triply bridging NCS ions hold the overall structure together with hydrogen bonding between the hydroxy-group of the pak molecule and the NCS sulphur atom. Cs⁺–O distances are 3·008–3·322 Å, Cs⁺–S 3·799 and 3·602 Å, and Cs⁺–N 3·452 Å. The O ⋯ S hydrogen-bond distance is 3·219 Å.