Controlled crystallization of mixed-ligand complexes of 1,3-bis(4-pyridyl)propane-N,N'-dioxide with metal(II) thiocyanates: isostructurality in coordination networks bearing different mono- and di-nuclear nodes.

The new flexible spacer ligand 1,3-bis(4-pyridyl)propane-N,N'-dioxide forms three classes of isomorphous compounds with metal(iI) thiocyanates at controlled ligand-metal molar ratios, and its mu3-O,O,O' mode leads to a pair of coordination networks having the same (4, 4) topological characteristics but different mono- and di-nuclear nodes.

Stereoselective synthesis of 1,2:4,5-di-O-isopropylidene-3-C-(5-phenyl-1,2,4-oxadiazol-3-yl)-beta-D-psicopyranose and its X-ray crystallographic analysis.

In a novel procedure, when 3-O-benzoyl-3-C-(N-hydroxycarbamimidoyl)-1,2:4,5-di-O-isopropylidene-beta-D-psicopyranose (1) is treated with acetic anhydride, chloroacetyl chloride, propanic anhydride and benzoyl chloride, the 3-O-benzoyl group undergoes an intramolecular replacement reaction with neighbouring group participation and transfer resulting in a more stable conjugated system by the formation of a 1,2,4-oxadiazol ring. A possible mechanism is reported. The structure has been determined by spectroscopic data and X-ray crystallographic analysis.