SHG-active NIR-emissive molecular nanomagnets generated in layered neodymium(III)-octacyanidometallate(IV) frameworks

Lanthanide(III) single-molecule magnets (Ln-SMMs) offer the fruitful conjunction of magnetic and photoluminescent properties originating from their single-ion anisotropy and emissive f–f electronic transitions. The flexibility of lanthanide(III)-based coordination systems is the most significant prerequisite for the generation of additional physical phenomena, including non-linear optical effects related to the lack of inversion centre. In the quest towards multifunctional molecular nanomagnets, we report heterometallic d–f layered coordination polymers, {[NdIII4(H2O)17(pzdo)5][MIV(CN)8]3}·9H2O (M = Mo (1), W (2); pzdo = pyrazine-N,N′-dioxide). They crystallize in the non-centrosymmetric C2 space group due to the spontaneous resolution process, confirmed by the observation of second harmonic generation (SHG) activity. These materials exhibit UV-to-vis-light-induced near-infrared (NIR) NdIII-centred luminescence sensitized by octacyanidometallates and organic ligand, and slow relaxation of magnetization of NdIII complexes which was investigated by alternate-current (ac) magnetic measurements and the ab initio calculations. The observed magnetic and optical properties are sensitive to the nature of the d-transition metal centre, namely most of their features are improved upon the replacement of MoIV with WIV centres. In this work, we show the generation of SHG-active NIR-emissive SMMs realized by Nd3+ ions inserted into hybrid layers built of inorganic [M(CN)8]4− and organic pzdo linkers.