Constructing porous lanthanide coordination polymers of 4,4'-bipyridine-N,N'-dioxide templated by single- and double-Keggin anions

Three porous coordination polymers, {[Nd(dpdo)2(H2O)5(CH3OH)2](PMo12O40)(CH3OH)-(H2O)5}n (1), {[Tb(dpdo)4(H2O)3](PMo12O40)(H2O)2CH3CN}n (2) and {[Tb(dpdo)4(H2O)3]H(SiMo12O40)(dpdo)0.5(CH3CN)0.5(H2O)4}n (3) (where dpdo is 4,4'-bipyridine-N,N'-dioxide), templated by single- or double-Keggin polyanions were synthesized and characterized by single crystal X-ray diffraction. The compounds exhibit three different 3D non-interwoven frameworks with large cavities occupied by the single- or double-Keggin-type anions. Thermogravimetric analyses suggest different stability for the three metal-organic frameworks. The SHG (second harmonic generation) efficiency of 1 confirms its noncentric framework.