Slow magnetic relaxation in a Tb(III)-based coordination polymer

A Tb(III)-based coordination polymer (polyTb) was synthesized by complexation of Tb(NO3)(3)center dot(6H(2)O) and 4',4 ''''-[1,1'-biphenyl]-4,4'-diylbis[6,6 ''-bis(ethoxycarbonyl)2':6',2 ''-terpyridine](L). The polymer structure was determined by Job's plots, DFT calculation, and X-ray absorption fine structure (XAFS) measurement. Job's plots indicated that the mole ratio (Tb ion:L) is 1:1. The optimized model structures suggested a La model: the LaN6 center dot center dot center dot(O=C)(2) model. The bond distances of La-O and La-N are similar to 2.80 angstrom and 2.60 angstrom, respectively. The EXAFS fitting indicated that the bond distances of Tb-O and Tb-N are 2.65 angstrom and 2.95 angstrom, respectively. polyTb shows field-induced magnetic relaxation in the solid and solution state. The luminescence of polyTb, originating from an f-f transition, was observed (phi = 6.9%). polyTb formed a porous structure on a Si substrate, whereas a fibrous complex structure was formed on glass. polyTb chains are orientated on glass, which were determined by XRD.