A Series of Lanthanide(III)-bpdo-Octacyanotungstate(V) Compounds (bpdo = 4,4'-Bipyridine-N,N'-dioxide) Involving the Structural Transformation from Ion Pair to Three-Dimensional Pillared Layer via a Two-Dimensional Layer.

The slow diffusion reaction of octacyanometalate [W(CN)8]3-, lanthanide ions, and 4,4'-bipyridyl-N,N'-dioxide (bpdo) has generated a series of isostructural three-dimensional pillared-layer networks with general formula [Ln(bpdo)1.5(H2O)W(CN)8]·0.5CH3OH·6H2O (Ln = Dy-Yb, Gd), in which Ln(III) atoms adopted an unusual seven-coordinated geometry in the cyanometalate-based lanthanide system. This building approach on the basis of the simultaneous employment of cyanide and bpdo bridges offers potential possibilities for designing and constructing 5d-4f coordination networks with high dimensionalities. Interestingly, the LnIII-bpdo-WV(CN)8 system has undergone an unique two-step phase transition upon prolonging the diffusion reaction time, together with the structural changing from initial ion pair through two-dimensional layer to final three-dimensional pillared-layer network. Magnetic studies of all compounds revealed typical and dominant single-ion magnetic behaviors over the weak coupling interactions between spin centers. [ABSTRACT FROM AUTHOR]