Water-Free Rare Earth-Prussian Blue Type Analogues: Synthesis, Structure, Computational Analysis, and Magnetic Data of {Ln^III(DMF)₆Fe^III(CN)₆}_∞ (Ln = Rare Earths Excluding Pm)

Abstract

Water-free rare earth(III) hexacyanoferrate(III) complexes, {Ln(DMF)(6)(mu-CN)(2)Fe(CN)(4)}(infinity) (DMF = N,N-dimethylformamide; Ln = Sm, 1; Eu, 2; Gd, 3; Tb, 4; Dy, 5; Ho, 6; Er, 7; Tm, 8; Yb, 9; Lu, 10; Y, 11; La, 12; Ce, 13; Pr, 14; Nd, 15), were synthesized in dry DMF through the metathesis reactions of [(18-crown-6)K](3)Fe(CN)(6) with LnX(3)(DMF)(n) (X = Cl or NO(3)). Anhydrous DMF solutions of LnX(3)(DMF)(n) were prepared at room temperature from LnCl(3) or LnX(3).nH(2)O under a dynamic vacuum. All compounds were characterized by IR, X-ray powder diffraction (except for 10), and single crystal X-ray diffraction (except for 2, 7, 10). Infrared spectra reveal that a monotonic, linear relationship exists between the ionic radius of the lanthanide and the nu(mu-CN) stretching frequency of 1-10, 12-15 while 11 deviates slightly from the ionic radius relationship. X-ray powder diffraction data are in agreement with powder patterns calculated from single crystal X-ray diffraction results, a useful alternative for bulk sample confirmation when elemental analysis data are difficult to obtain. Eight-coordinate Ln(III) metal centers are observed for all structures. trans-cyanide units of [Fe(CN)(6)](3-) formed isocyanide linkages to Ln(III) resulting in one-dimensional polymeric chains. Structures of compounds 1-9 and 11 are isomorphous, crystallizing in the space group C2/c. Structures of compounds 12-15 are also isomorphous, crystallizing in the space group P2/n. One unique polymeric chain exists in the structures of 1-9 and 11 while two unique polymeric chains exist in structures of 12-15. One of the polymeric chains of 12-15 is similar to that observed for 1-9, 11 while the other is more distorted and has a shorter Ln-Fe distance. Magnetic susceptibility measurements for compounds 3-6, 8, 11 were performed on polycrystalline samples of the compounds.

Cyanide‐Bridged Tetranuclear REIII2FeIII2 (RE = Y, Tb, Dy) Molecular Squares with 2, 2′:6′,2′′‐Terpyridine as a Capping Ligand

“…The magnetization increases continuously and reaches the maximum value (7.92 N μ B ) at 65 kOe without saturation, which is lower than the theoretical one on the basis of the noninteracting ions of the [Dy 2 Fe 2 ] unit. The magnetic behavior for compounds 2 and 3 was also observed in the polymeric chains [Tb(tptz)(H 2 O) 4 Fe(CN) 6 ] · 8H 2 O [tptz = 2, 4,6‐tri(2‐pyridyl)‐1, 3,5‐triazine] and RE (DMF) 6 Fe(CN) 6 ( RE = Tb, Dy),27,28 in which no significant magnetic interactions between the RE III and Fe III ions. Similarly, the magnetic interactions between the RE III and Fe III ions in compounds 2 and 3 are also negligible, due to the significant magnetic anisotropy and/or the population of low‐lying excited states.…”

Further Insights into the Role of Temperature in the Synthesis of the Lanthanide(III)‐Pyrazine‐Octacyanotungstate(V) System: an Example of Discrete Materials

“…The geometrical data of the central Tb III atom are similar to those found in the hexacyanometalate-based compound Tb(DMF) 6 Fe(CN) 6 . [27] Figure 4. ORTEP diagram of compound 3 with thermal ellipsoids at the 30 % probability level.…”

catena-poly[[[(2,2′-bipyridine-2κ2N,N′)-μ-cyanido-1:2κ2N:C-cyanido-2κC-tris(methanol-1κO)(nitrato-1κ2O,O′)iron(II)yttrium(III)]-di-μ-cyanido-1:2′κ2N:C;2:1′κ2C:N] methanol solvate hemihydrate]

“…For background to the design, synthesis and properties of mixed rare earth-transition metal complexes, see: Wilson et al (2009); Zhou et al (2002); Li et al (2008); Karan et al (2002); Sokol et al (2002); Toma et al (2003); Xu et al (2009). For related structures, see: Baca et al (2007); Liu et al (2008); Yuan et al (2004).…”

“…Much attention is currently devoted to the design and synthesis of mixed rare earth-transition metal complexes because rare earth ions have a rich coordination chemistry with high coordination numbers and significant coordination flexibility, which often leads to unanticipated but remarkable structures (Karan et al, 2002;Li et al, 2008;Wilson et al, 2009;Zhou et al, 2002. )…”