A 1D Helical Chain Heterpolyniobate Templated by AsO33.

A novel polyoxoniobate cluster directed by AsO33-, {[Cu(phen)]5[Nb6O19][As2Nb6O22]}2 (1a), has been successfully synthesized by a "two-pot" strategy, namely, the conventional aqueous solution and diffusional methods. It incorporates two {[Cu(phen)]2Nb6O19} and two {[Cu(phen)]3As2Nb6O22} subunits. Surprisingly, by changing the reaction conditions, one of the subunits {[Cu(phen)]2Nb6O19} was isolated as a guanidinium salt. These architectures were structurally characterized by single crystal X-ray diffraction, TGA, IR, elemental analysis and PXRD, etc. Furthermore, the behavior of 1 in aqueous solution was measured by electrospray ionization mass spectrometry, and the magnetic property in the low temperature range indicates the presence of antiferromagnetic interactions.