Synthesis, Structure, and Mössbauer Study of [Fe(H₂O)₂(C₉O₆H₄)]·H₂O:  A Two-Dimensional Iron(II) Trimellitate (MIL-67)

Abstract

The two-dimensional (2D) iron trimellitate [Fe(H(2)O)(2)(C(9)O(6)H(4))].H(2)O, labeled MIL-67, has been obtained under hydrothermal conditions (473 K, 48 h). In the 2D structure of MIL-67, the Fe(2+) ions display two different octahedral environments: [FeO(4)(H(2)O)(2)] and [FeO(2)(H(2)O)(4)]. These octahedra share an apical water molecule to form infinite chains. The chains are linked by partly deprotonated C(9)O(6)H(4)(2-) anions to give hybrid organic-inorganic layers; the remaining acidic-CO(2)H group is dangling in the interlayer space. Below 8(1) K, MIL-67 displays a canted antiferromagnetic behavior, according to analyses via magnetic measurements and Mössbauer spectroscopy. Crystal data for MIL-67 are as follows: triclinic; space group P1 (No. 2), with a = 6.9671(2) A, b = 7.3089(3) A, c = 12.5097(3) A, alpha = 78.758(1) degrees, beta = 89.542(2) degrees, and gamma = 65.197(1) degrees; volume V = 565.21(3) A(3); and Z = 2.

Terephthalate bridged frameworks of Nd and Sm Phthalates

“…2.435 A). The various geometrical parameters observed in both the compounds are comparable to those reported earlier in the literature [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. The bond distances and angles associated with the dicarboxylate anions are also in the ranges expected for this type of bonding.…”

“…The choice of appropriate ligands appears to be one of the important factors for the construction of porous networks, which eventually leads to the observed physical and chemical properties. Most of the metal-organic polymers investigated during the last few years concentrated on transitional metals [5][6][7][8][9][10][11][12]. Recently, metalorganic frameworks of lanthanide compounds have been studied resulting in many new materials with novel structures [13][14][15][16][17][18][19][20][21][22][23].…”

Magnetic behaviour in metal-organic frameworks—Some recent examples

“…39 The field dependence of the magnetization M vs H (0-50 kOe) at 5 K (figure 14f), shows a behaviour that is typical of a canted antiferromagnet with sharp increase of the magnetization at low fields and a linear variation of M at H > 20 kOe. 42 At 50 kOe the magnetizations value reaches 1⋅57 Nβ, a value that is far below the saturation value of 5 Nβ expected for a spin-only Mn 2+ ion. This lack of saturation at high field confirms that the low temperature magnetic ground state is a canted anti-ferromagnetic one, 43 which may be due to the canting of spins caused by the antisymmetric Dzyaloshinsky-Moriya (DM) exchange.…”

Superior Performance of Metal–Organic Frameworks over Zeolites as Solid Acid Catalysts in the Prins Reaction: Green Synthesis of Nopol

“…In CuBTC, the Cu 2 clusters are coordinated through the carboxylate groups of benzene-1,3,5-tricarboxylate to form a paddlewheel unit in a 3D porous cubic network (Figure 1 A). Structurally, FeBTC can be compared with MIL-100, MIL-65, [46] and MIL-67, [47] but the exact crystal structure of FeBTC is still unknown. The flexible framework of MIL-53(Al) is built up by the interconnection of corner-sharing (through OH groups) AlO 4 (OH) 2 octahedra by 1,4-benzenedicarboxylate ligands, which give rise to 1D diamond-shaped channels with pores of a free diameter close to 0.85 nm [48] (Figure 1 B).…”