Tuning of Ratiometric Optical Thermometry in the Family of Magnetic {Nd_1-x ^IIIYb^III _x [Cu₂ ^I(CN)₅]} Frameworks Showing the Large SHG Response

Three-dimensional (3-D) coordination networks providea stableframework preferable to designing materials with tunable propertiesby various chemical modifications, such as solvent exchange, elementdoping, etc. In this work, we explored extensively the 3-D cyanido-bridgedheterometallic assemblies having Nd(III) and Yb(III) centers in combinationwith polycyanidocuprate(I) ions, that is, the family of [Nd1-x Yb-III(III) (x) (2,2 & PRIME;-bpdo)(2)(H2O)][Cu-2 (I)(CN)(5)]& BULL;5H(2)O (x = 0, 0.25, 0.5, 0.75, 1 (1-5);2,2 & PRIME;-bpdo = 2,2 & PRIME;-bipyridine N,N & PRIME;-dioxide) coordination networks. To form a lanthanide-incorporatingmolecule-based matrix, two different types of cuprate(I) moietiesare spontaneously formed during crystallization, resulting in trigonalplanar tricyanido and tetrahedral tetracyanidocopper(I)-based molecularanions. 1-5 exhibit optical thermometrybased on near-infrared (NIR) luminescence. The relative thermal sensitivityof Nd(III)-containing 1 is considerably improved throughthe preparation of the analogous mixed heterometallic compounds byintroducing Yb3+ ions, which also enables tunability overthe operating temperature range. Since all 3-D networks crystallizewithin a non-centrosymmetric Cc space group, theyexhibit a second-harmonic generation (SHG) phenomenon, with the signalhighest among the materials based on cyanido-bridged metal assemblies(the SHG efficiency of & SIM;120% of the reference potassium dihydrogenphosphate). Furthermore, 1-5 showfield-induced single-molecule magnet (SMM) behavior related to lanthanide(3+)ions, with a slow magnetic relaxation occurring via Raman and directrelaxation processes.