Cyano‐Bridged 4f‐3d Assemblies with Achiral Helical Chains: Syntheses, Structures, and Magnetic Properties

Abstract

The self-assembly reaction of [Cr(CN) 6 ] 3-, Ln 3+ , and a chelated phen ligand resulted in the first examples of cyanobridged 3d-4f helical chains [Ln(phen) 3 (H 2 O)][Cr(CN) 6 ]· 3H 2 O [Ln = La (1), Ce (2), Pr (3) and Nd (4)], in which the [a]

Near-Infrared Photoluminescence in Hexacyanido-Bridged Nd–Cr Layered Ferromagnet

“…To form the bimetallic assembly, we decided to explore the complexes of lanthanide­(3+) cations which exhibit a diversity of luminescent effects. − In particular, Nd III is well-known for its near-infrared (NIR) emission which can be widely applied in bioimaging, night vision, optical communications, and computing. − The interaction between Nd III and [Cr III (CN) 6 ] 3– is expected to be fruitful, and it should include the efficient sensitization of NIR lanthanide emission by Cr III , as was proven in various bimetallic Nd–Cr complexes, − and the cyanido-bridged {[Nd III (H 2 O) 2 ­(dmf) 4 ]­[Cr III (CN) 6 ]}­· n H 2 O chains . Except for the canonical {[Nd III (H 2 O) 2 ]­[Cr III (CN) 6 ]}­·2H 2 O network showing magnetic ordering below 6 K, the other reported Nd–Cr hexacyanido-bridged assemblies are very rare and include only binuclear dimers and coordination chains, not revealing the magnetic ordering. − To control the topology of the coordination polymer, and to add the additional possible source of emission, we examined pyridine- and pyrimidine-based derivatives, which are known to play an essential role in the multifunctionality of bimetallic cyanido-bridged coordination frameworks. ,, We thus report the synthesis, crystal structure, and magnetic and optical properties of {[Nd III (pmmo) 2 ­(H 2 O) 3 ]­[Cr III (CN) 6 ]} ( 1 ) (pmmo = pyrimidine N-oxide) layered material that reveal the long-range ferromagnetic ordering coexisting with the near-infrared Nd III -centered fluorescence realized by the energy transfer from both the organic ligand and hexacyanidochromate­(III) anions to 4f metal ion.…”

Structural Conversion and Magnetic Studies of Low-Dimensional LnIII/MoV/IV(CN)8 (Ln = Gd–Lu) Systems: From Helical Chain to Trinuclear Cluster

“…No obvious hydrogen-bonding interactions were observed in our system. To the best of our knowledge, there are limited examples of cyanide-bridged lanthanide complexes with helical structures to date. ,,, …”

“…Particular examples of discrete molecules with large-spin group states include the {M II 9 M′ V 6 (CN) 48 ­(solv) 24 } (M = Mn­(II), Co­(II), Ni­(II), Fe­(II); M′ = Mo, W, Re; solv = MeOH, EtOH, H 2 O) clusters derived from [M′ V (CN) 8 ] 3– precursors, some of which have exhibited fascinating SMMs behaviors, − while SCMs characteristics were also observed in 1D chains. − To fabricate low-dimensional cyanide-based systems, the general synthetic methodology is to employ the aromatic chelated ligands to control the number and spatial arrangement of coordination positions available on the cation for CN-bridging, hence restricting the structural evolution toward higher dimensionalities. This recognition has inspired our group to fabricate low-dimensional hexa- and octacyanometallate-based assemblies. − For instance, the first cyanide-bridged lanthanide helical chains {Ln III M V } (Ln = Pr, Sm, Eu; M = Mo, W) were synthesized by using bidentate 1,10-phenanthroline (phen) or 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen) as chelated and blocking ligands, where antiferromagnetic coupling interactions were observed between Ln­(III) and M­(V) centers …”

New Cyanido-Bridged Heterometallic 3d-4f 1D Coordination Polymers: Synthesis, Crystal Structures and Magnetic Properties

“…The dimensionality of the resulting coordination polymers is dependent on the number of accessible positions at the lanthanide ions. For example, nitrogen donor blocking ligands attached to Ln III ions, such as 1,10-phenanthroline, 2,2 -bipyridine, 2,2 :6 ,2 -terpyridine, 2,4,6-tri(2-pyridyl)-1,3,5-triazine, favor the aggregation of 1D coordination polymers, employing [M(CN) 6 ] 3− as metalloligands [10][11][12][13][14][15][16][17][18]. When the reactions between the lanthanide salts and the hexacyanido building block occur in dimethylformamide (DMF) or dimethyl sulfoxide (DMSO), depending on the experimental conditions, discrete species, 1D, 2D, or even 3D coordination polymers have been obtained [19][20][21][22][23][24].…”