Simon E. V. Phillips

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

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)Aα= 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 A 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 A, Cs+–S 3·799 and 3·602 A, and Cs+–N 3·452 A. The O ⋯ S hydrogen-bond distance is 3·219 A.

Crystal structure of a complex of potassium iodide with phenacyl kojate: bis(5-phenacyloxy-2-hydroxymethyl-4H-pyran-4-one)potassium iodide

The structure of the title complex has been determined by three-dimensional X-ray crystal-structure analysis from diffractometer data. Crystals are monoclinic, space group P21/n with dimensions a= 12·095(17), b= 15·885(22), c= 15·037(32)A, β= 98·87(13)°, Z= 4. The structure was solved by Patterson and Fourier methods, and full-matrix least-squares refinement gave R 0·165 for 3080 independent diffractometer observations.The structure consists of layers of planar ligand molecules linked by sandwiched potassium ions and hydrogen-bonded chains of the form –K+–O–H ⋯ I–⋯ H–O–K+–. The potassium ion is eight-co-ordinated by three oxygen atoms from each of two ligands and by hydroxy-groups from two more ligand molecules. The K+–O distances are in the range 2·74–2·92 A and the I–⋯ O hydrogen-bonded distances are 3·39 and 3·43 A.

Crystal structure of phenacylkojate [2-(hydroxymethyl)-5-phenacyl-4H-pyran-4-one] monohydrate and comparison with some of its complexes with alkali-metal salts

The structure of the title compound has been determined by three-dimensional X-ray crystal-structure analysis. Crystals are monoclinic, space group P21/c, with unit-cell dimensions a= 7·883(8), b= 18·781(5), c= 9·649(6)A, β= 112·99(8)°, Z= 4. The structure was solved by direct methods and refined by full-matrix least-squares to R 0·044 for 1063 independent diffractometer observations.The crystal structure is held together by a network of hydrogen bonds involving the water molecules and the carbonyl and hydroxy-groups of the phenacylkojate molecules. The phenacylkojate molecules are approximately planar and the water molecules occupy the same positions relative to the ligands as the cation in the alkali-metal complexes. Comparison with known crystal structures of the complexes shows the conformation of the ligand molecule to be similar throughout apart from the position of the hydroxy-group. The results show no simple trend relating anion and cation size to overall crystal structure but some indication is given of the probable arrangements in the other complexes with alkali-metal halides.

Crystal structure of a hydrated complex of sodium iodide with phenacylkojate [2-(hydroxymethyl)-5-phenacyl-4H-pyran-4-one]

The structure of the title complex has been determined by three-dimensional X-ray crystal-structure analysis. Crystals are orthorhombic, space group P212121, with unit-cell dimensions a= 12·215(7), b= 33·424(11), and c= 7·004 A, Z= 4. The structure was solved by the heavy-atom method and refined by full-matrix least-squares to R 0·067 for 843 independent diffractometer observations. The two independent molecules of phenacylkojate have different environments, one co-ordinating to the sodium ion and the other hydrogen bonding to a water molecule. The environment about the sodium ion is approximately octahedral with Na+–O distances in the range 2·30–2·58 A; three equatorial positions are occupied by oxygen atoms from one molecule, one apex by the hydroxy-group from another, and the two remaining (cis) positions by water molecules. Extensive hydrogen bonding between the hydroxy-groups, water molecules, and the iodide ion as well as the Na+–O co-ordination hold the polymeric structure together. Hydrogen-bond distances are in the range 2·76–2·85 for O ⋯ O and 3·48–3·55 A for O ⋯ I– contacts.