2D Windmill-like Ln-Containing Organophosphonate-Based Polyoxomolybdates: Synthesis, Characterization, Fluorescence, and Magnetism.

By integration of {Ln(H 2 O) 6 } 3+ into organophosphonate-based polyoxometalates, three Ln-containing organophosphonate-functionalized polyoxomolybdates Na 1.5 H 1.5 [{Ln(H 2 O) 6 } 2 {(Mo 3 O 8 )(O 3 PC(C 3 H 6 NH 3 )OPO 3 )} 4 ]·(CH 3 CO 2 )·43H 2 O (Ln = Eu ( 1 ), Tb ( 2 ), and Dy ( 3 )) are successfully prepared and systematically characterized. The X-ray crystallography analyses display complexes 1 - 3 crystallize in the C 2 /c space group of the monoclinic system and compose several distinctive tetramer windmill-like compounds that further assemble into two-dimensional (2D) frameworks associated with the {Ln(H 2 O) 6 } 3+ core. The fluorescence spectra of 1 - 3 show red, green, and chartreuse emissions, respectively, originating in the typical f-f transitions of Ln 3+ ions. More interestingly, complex 3 shows the field-induced single-molecule magnet (SMM) properties, resulting from the fact that [(Mo 3 O 8 ) 4 {O 3 PC(C 3 H 6 NH 3 )OPO 3 } 4 ] 8- offers excellent magnetic isolation for Dy 3+ ions by the nearest Dy1···Dy2 distance of 11.207 Å. The study demonstrates that the incorporation of {Ln(H 2 O) 6 } 3+ into organophosphonate-based polyoxomolybdates is an effective synthetic strategy in implementing late-model opto-magnetic materials.