Structural and Luminescence Properties of Anthracene- and Biphenyl-Based Lanthanide Bisphosphonate Ester Coordination Polymers

Coordinative networks containing lanthanide ions attached via phosphonate ester functionalities provide remarkable luminescence properties. On the basis of ditopic phosphonic ester ligands with biphenylene and 9,10-anthracenylene bridges, a series of compounds with formal composition {[M(NO3)3]L}n or {[M(NO3)3]2(L1)3}n (L = C28H40O6P2; L1 = C26H40O6P2) with M = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y have been synthesized, structurally characterized, and the luminescence behavior was explored in the visible and NIR spectral regions, where applicable. In contrast to closely related networks based on biphenyl bisphosphonate esters from previous work, no evidence for ligand-to-metal energy transfer could be observed, despite strong near-infrared emission in some cases. Unique behavior is found for the Eu derivative with the 9,10-anthracenylene bridge, which is nonemissive, showing neither ligand- nor metal-based emission.