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

Abstract

coordination networks provide a stable framework preferable to designing materials with tunable properties by various chemical modifications, such as solvent exchange, element doping, etc. In this work, we explored extensively the 3-D cyanido-bridged heterometallic assemblies having Nd(III) and Yb(III) centers in combination with polycyanidocuprate(I) ions, that is, the family ofTo form a lanthanide-incorporating molecule-based matrix, two different types of cuprate(I) moieties are spontaneously formed during crystallization, resulting in trigonal planar tricyanido and tetrahedral tetracyanidocopper(I)-based molecular anions. 1−5 exhibit optical thermometry based on near-infrared (NIR) luminescence. The relative thermal sensitivity of Nd(III)-containing 1 is considerably improved through the preparation of the analogous mixed heterometallic compounds by introducing Yb 3+ ions, which also enables tunability over the operating temperature range. Since all 3-D networks crystallize within a non-centrosymmetric Cc space group, they exhibit a second-harmonic generation (SHG) phenomenon, with the signal highest among the materials based on cyanido-bridged metal assemblies (the SHG efficiency of ∼120% of the reference potassium dihydrogen phosphate). Furthermore, 1−5 show field-induced single-molecule magnet (SMM) behavior related to lanthanide(3+) ions, with a slow magnetic relaxation occurring via Raman and direct relaxation processes.

Optical Phenomena in Molecule-Based Magnetic Materials

“…A much better SHG response was presented for {[Yb III (2,2′-bdpo) 2 (H 2 O)]­[Cu I 2 (CN) 5 ]}·5H 2 O (2,2′-bpdo = 2,2′-bipyridine N , N ′-dioxide) framework and its Nd III -substituted analog, reaching up to ca. 138% of the KDP reference. , For the latter system, both slow relaxation of magnetization effect and sensitized NIR emission were previously presented, as well as zero- dc -field SMM behavior in the case of the Dy III -based analog . Another molecular nanomagnet built with Dy 3+ ions and partially deprotonated N , N ′, N ′′, N ′′′-tetra­(3,5-dimethyl-2-hydroxybenzyl)-1,4,7,10-tetraazacyclo­dodecane combines field-induced SMM behavior with sensitized visible light emission and SH light intensity reaching ca.…”

SHG-active luminescent thermometers based on chiral cyclometalated dicyanidoiridate(iii) complexes

“…50–55 The second strategy relies on using cyanido transition metal complexes which are a great source of stimuli-responsive luminescence, including optical thermometry, usually thanks to the construction of heterometallic coordination frameworks based on inter-metallic cyanido bridges. 56–60 We and others have found that polycyanidometallates of, e.g. , Re( v ) or Ru( ii ), can be strongly emissive and their PL characteristics are sensitive to external stimuli in related molecular hybrids or CPs/MOFs.…”