Two Ln26 @CO3 (Ln=Dy and Tb) cluster-based lanthanide-transition-metal-organic frameworks (Ln MOFs) formulated as [Dy26 Cu3 (Nic)24 (CH3 COO)8 (CO3 )11 (OH)26 (H2 O)14 ]Cl ⋅3 H2 O (1; HNic=nicotinic acid) and [Tb26 NaAg3 (Nic)27 (CH3 COO)6 (CO3 )11 (OH)26 Cl(H2 O)15 ]⋅7.5 H2 O (2) have been successfully synthesized by hydrothermal methods and characterized by IR, thermogravimetric analysis (TGA), elemental analysis, and single X-ray diffraction. Compound 1 crystallizes in the monoclinic space group Cc with a=35.775(12) Å, b=33.346(11) Å, c=24.424(8) Å, β=93.993(5)°, V=29065(16) Å(3) , whereas 2 crystallizes in the triclinic space group P$\bar 1$ with a=20.4929(19) Å, b=24.671(2) Å, c=29.727(3) Å, α=81.9990(10)°, β=88.0830(10)°, γ=89.9940(10)°, V=14875(2) Å(3) . Structural analysis indicates the framework of 1 is a 3D perovskite-like structure constructed out of CO3 @Dy26 building units and Cu(+) centers by means of nicotinic acid ligand bridging. In 2, however, nanosized CO3 @Tb26 units and [Ag3 Cl](2+) centers are connected by Nic(-) bridges to give rise to a 2D structure. It is worth mentioning that this kind of 4d-4f cluster-based MOF is quite rare as most of the reported analogous compounds are 3d-4f ones. Additionally, the solid-state emission spectra of pure compound 2 at room temperature suggest an efficient energy transfer from the ligand Nic(-) to Tb(3+) ions, which we called the "antenna effect". Compound 2 shows a good two-photon absorption (TPA) with a TPA coefficient of 0.06947 cm GM(-1) (1 GM=10(-50) cm(4) s photon(-1) ), which indicates that compound 2 might be a good choice for third-order nonlinear optical materials.
In this work, a low-viscosity ionic liquid 1-buthyl-3-methylimidazole thiocyanate ([BMIM]SCN) was utilized as extractant for the extractive desulfurization of thiophene in model oil. Several conditions were investigated respectively, including extraction time, temperature, and volume ratio of ionic liquid to model oil. Also the kinetics of extraction of thiophene were proposed. Under the optimal extractive conditions, the removal of thiophene in model oil was 55.6%. Other sulfur compounds and real oil were also investigated. Furthermore, the total desulfurization efficiency could reach 98.3%. In addition, the ionic liquid could be recycled seven times with negligible decrease in activity.
Invited for the cover of this issue is the group of Hua Mei and Yan Xu at Nanjing Tech University, China. The image depicts star-like {Tb26 } clusters, which are simplified as blue balls, and Ag atoms, which are distributed in the MOF structure uniformly to give a lanthanide-MOF structure with good optical properties. Read the full text of the article at 10.1002/chem.201405178.
Once a new high‐nuclearity cluster is obtained the accompanying question is how to make it into extended multi‐dimensional metal–organic frameworks (MOFs), in order to explore their optical properties. In their Full Paper on , H. Mei, Y. Xu et al. report two Ln26‐HNic cluster‐based multidimensional MOFs with Ag+ or Cu+ ions as linkers, of which the rare 4d–4f one shows characteristic luminescence of Tb3+ and good two‐photon absorption with an absorption coefficient β of 0.06947 cm GM−1.
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