Structural elucidation, EPR and magnetic interpretation of lanthanide (Ln = La, Nd, Sm) compounds with 4,4 '-bipyridine and 2-sulfoterephthalate

摘要

A series of three lanthanide compounds, namely, {[La(stp)(bipy)(H2O)]center dot H2O}n (1), {[Nd(stp)(bipy)(H2O)]center dot 2H(2)O)(n) (2), and {[Sm(stp)(bipy)(H2O)]center dot H2O}(n) (3) has been synthesized through the reaction of 2-sulfoterephthalic acid monosodium salt Na(H(2)stp), trivalent lanthanide nitrate [Ln(NO3)(3).6H(2)O] and N-donor ancillary co-ligand, 4,4'-bipyridine (bipy). As a result of the potential coordination modes of the stp ligand and the bipy co-ligand, the aforementioned compounds are arranged in a 2-D network, as evidenced by single-crystal X-ray diffraction technique. In all the three compounds, the Ln ion presents a distorted tricapped trigonal-prismatic coordination geometry. The EPR measurements evidence a diamagnetic behaviour of compound 1 (La3+) whereas there exhibits a weak antiferromagnetic coupling between paramagnetic Ln(3+) ions (Nd3+ and Sm3+) for compounds 2 and 3. This is also supported by the magnetic data obtained for compounds 1-3. The encapsulation of the lanthanide coordination polymers displays a moderate luminescent property. (C) 2016 Elsevier B.V. All rights reserved.