Three-Dimensional Extended Frameworks Constructed from Dinuclear Lanthanide(III) 1,4-Naphthalenedicarboxylate Units with Bis(2,2′-biimidazole) Templates: Syntheses, Structures, and Magnetic and Luminescent Properties

Abstract

Eight unprecedented Ln-NDC coordination polymers with BBI as templates {[HBBI][Ln(NDC)2(H2O)]·H2O [Ln = La (1), Pr (2)], [HBBI]2[Sm(NDC)2(H2O)]2·1/2H2O (3), and [HBBI][Ln(NDC)2(H2O)] [Ln = Eu (4), Gd (5), Tb (6), Dy (7), Er (8)] [Ln = lanthanide, H2NDC = 1,4-naphthalenedicarboxylic acid, BBI = bis(2,2′-biimidazole)]} have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction. Complexes 1–8 crystallize in the monoclinic space group P21/c and display similar (8,8)-connected 3-D frameworks with different dinuclear Ln secondary building units due to the effect of Ln contraction and diverse coordination modes of NDC2– ligands. As the ionic radii of Ln ions decrease, the coordination numbers of Ln ions decrease from 10, to 9, to 8. The variable-temperature magnetic properties of 2–8 have been investigated. The strong fluorescent emissions of 4 demonstrate that ligand-to-EuIII energy transfer is efficient. In addition, thermogravimetric analyses and optical diffuse reflectance spectra of these compounds are also described.

Self-assembly of the tetrachlorido(oxalato)rhenate(iv) anion with protonated organic cations: X-ray structures and magnetic properties

“…The average C-C and C-N bond length values agree with those found in previously reported salts containing this monoprotonated organic cation. [64][65][66][67][68] In Figure 6 and Table 3). As seen in 1, short Cl···Cl contacts of 3.507(1) Å [Cl(4)···Cl(4a), (a) = -x+2, -y+1, -z+1] and 3.987(1) Å [Cl(1)···Cl(1b), (b) = -x+2, -y+1, -z+2] between [ReCl4(ox)] 2anions direct anionic chains, which grow along the crystallographic c axis (see Fig.…”

Flexible, Transparent, and Hazy Cellulose Nanopaper with Efficient Near-Infrared Luminescence Fabricated by 2D Lanthanide (Ln = Nd, Yb, or Er) Metal–Organic-Framework-Grafted Oxidized Cellulose Nanofibrils

“…To some degree, the quantum yields of Ln-MOFs and Ln nanopapers depended on the ligand absorption and charge-transfer efficiencies of the ligand metal. Thus, studies of the emission efficiencies of the energy-transfer processes of Ln-MOFs and Ln nanopapers were very meaningful to this subject . In addition, Gd-MOF and Gd nanopaper, as reference materials, allowed the study of chromophore luminescence without energy transfer because Gd 3+ ion cannot receive energy from the chromophore excited state, which results from the energy level of Gd 3+ ion being lower than 32000 cm –1 .…”

Syntheses, Structures, and Photophysical Properties of Two Coordination Polymers Based on 2,3‐Dioxo‐1,2,3,4‐tetrahydroquinoxaline‐6‐carboxylic Acid

“…To explore the conductivity of complexes 1 and 2 , their optical diffuse reflectance spectra were measured using their powdered crystal samples to obtain the optical bandgap ( E g ). The bandgap ( E g ) was determined as the intersection point between the energy axis and the line extrapolated from the linear portion of the absorption edge in a plot of the Kubelka‐Munk function F against energy E . As shown in Figure , the corresponding well‐defined optical absorption associated with bandgap ( E g ) can be assessed at 2.26 eV for 1 and 2.42 eV for 2 .…”