A cyanide-bridged Fe-Co pearl-chain-like single-chain magnet containing 4-coordinate cobalt(II) ions

3 nm-wide Cyanometallate Fe-Co Tape Exhibiting Single-Chain Magnet Behavior

Treatment of Co(OTf)2·6H2O, Li[(pzTp)FeIII(CN)3], and H3PMo12O40·nH2O in protic solvents afforded two structurally related Fe-Co cyanometallate complexes: [{(pzTp)Fe(CN)3}3Co3(MeOH)10][PMo12O40]·H2O·11MeOH (1, pzTp- = tetra(pyrazolyl)borate) and {[(pzTp)Fe(CN)3]4Co3(MeOH)5(H2O)3}n[HPMo12O40]n·3 nMeOH·6.5nH2O (2). Complex 1 consists of a cyanide-bridged hexanuclear [Fe3Co3] cage, characterized by the fused conjunction of two mutually perpendicular trigonal bipyramids (TBPs, [Fe2Co3] and [Co2Fe3]), while complex 2 showcases an intricate cyanide-bridged Fe-Co tape comprising a central chain backbone of vertex-sharing [Fe2Co3] TBPs alongside peripheral [Fe2Co2] squares. Complex 2 is among the widest one-dimensional coordination assemblies characterized by the single-crystal X-ray diffraction technique. Magnetic studies revealed that complex 2 behaved as a single chain magnet with an effective energy barrier (Ueff/kB) of 46.8 K. Our findings highlight the possibilities in the development of cyanometallate-POM hybrid materials with captivating magnetic properties.

Three-Dimensional Polyoxometalate Organic Frameworks with One-Dimensional Channels Constructed by Multiple Helical Chains Based on 22-Core Ln/Mn/Mo Clusters for Proton Conduction

Two unique 22-core sandwich {[Mn6Mo6O37]Ln3[MnMo6O24]} (Ln = La or Pr) units have been assembled, featuring an undisclosed {Mn6Mo6} cluster. This assembly is subsequently integrated into two three-dimensional polyoxometalate organic frameworks, which exhibit one-dimensional hydrophilic hexagonal channels formed by six intertwined 63 helical chains, leading to effective proton conduction primarily facilitated by an abundance of water molecules within the channels.

Ferromagnetically coupled single-chain magnets exhibiting a magnetic hysteresis of 0.42 Tesla in cyano-bridged FeIII2MII (M = Ni, Fe) coordination polymers

The synthesis, single-crystal structures and magnetic properties of two new double-zigzag-chain cyano-bridged heterobimetallic {[MII(Py-NOH)2][FeIII(Tp*)(CN)3]2}·H2O ([FeIII2MII]) (Py-NOH = 4-pyridinealdoxime, Tp* = tris(3,5-dimethylpyrazol-1-yl)borohydride, M = Ni (1), Fe (2)) compounds are reported. The crystal structures of both compounds were determined by single-crystal X-ray diffraction. Complexes 1 and 2 are isostructural, with the crystal structure comprising neutral double-zigzag (4,2-ribbon-like) bimetallic chains. The FeIII ion is coordinated by three cyanide carbon atoms and three nitrogen atoms of Tp* anions. However, the MII ion is surrounded by four cyanide nitrogen atoms and two nitrogen atoms from two Py-NOH ligands. The crystal structures and magnetic studies demonstrate that both complexes behave as single-chain magnetics (SCMs) with intrachain ferromagnetic coupling. Furthermore, [FeIII2NiII] exhibits an excellent coercive field of 0.42 T at 1.8 K, among cyano-bridged 3d transition-metal-based SCMs reported thus far. Preliminary theoretical calculations provide a deep understanding of the magnetic properties of [FeIII2NiII].

Cyanide-Bridged Rope-like Chains Based on Trigonal-Bipyramidal [Fe2Cu3] Subunits

Extending a selected cyanometalate block into a higher dimensional framework continues to present intriguing challenges in the fields of chemistry and material science. Here, we prepared two rope-like chain compounds of {[(Tp*Me)Fe(CN)3]2Cu2X2(L)}·sol (1, X = Cl, L = (MeCN)0.5(H2O/MeOH)0.5, sol = 2MeCN·1.5H2O; 2, X = Br, L = MeOH, sol = 2MeCN·0.75H2O; Tp*Me = tris(3, 4, 5-trimethylpyrazole)borate) in which the cyanide-bridged trigonal-bipyramidal [Fe2Cu3] subunits were linked with the adjacent ones via two vertex Cu(II) centers, providing a new cyanometallate chain archetype. Direct current magnetic study revealed the presence of ferromagnetic couplings between Fe(III) and Cu(II) ions and uniaxial anisotropy due to a favorable alignment of the anisotropic tricyanoiron(III) units. Moreover, compound 1 exhibits single-chain magnet behavior with an appreciable energy barrier of 72 K, while 2 behaves as a metamagnet, likely caused by the subtle changes in the interchain interactions.

Anthryl-functionalized cyanide-bridged Fe/Co cubes

Two anthryl-functionalized cyanide-bridged [Fe4Co4] cube complexes, [(pzTp)Fe(CN)3Co(TpEtOAn)]4[OTf]4·8MeCN·7Et2O (1) and [NEt4]3[(pzTp)Fe(CN)3Co(TpEtOAn)]4[OTf]7·5MeCN·2Et2O (2) (pzTp- = tetrapyrazolylborate, TpEtOAn = 2,2,2-tris-(pyrazol-1-yl)ethoxy(9-methyl-anthracene)), were synthesized and characterized. The crystallographic study revealed that the [Fe4Co4] cubes are arranged into a linear supramolecular chain through significant anthryl-anthryl π-π stacking interactions in complex 1, whereas a zigzag supramolecular 1D assembly is observed in 2. The magnetic measurements showed that both compounds exhibited incomplete transitions from the paramagnetic {FeIIILS(μ-CN)CoIIHS} state to the diamagnetic {FeIILS(μ-CN)CoIIILS} state at about 200 K. The luminescence measurement of 1 in solution revealed an enhancement of the emission upon dilution or addition of perfluoronaphthalene (PFN) molecules, which could be attributed to the suppression of the aggregation-caused quenching (ACQ) effect, suggesting possible aggregation of the cube units in the solution.