Coordination Structure and Fragmentation Chemistry of the Tripositive Lanthanide-Thio-Diglycolamide Complexes

Tripositive Ln­(TMTDA)₃³⁺ complexes (Ln = La–Lu except Pm, TMTDA = tetramethyl 3-thio-diglycolamide) were observed in the gas phase by electrospray ionization of LnCl₃ and TMTDA mixtures. Collision-induced dissociation (CID) was employed to investigate their fragmentation chemistry, which revealed the influence of metal center as well as ligand on the ligated complexes. Ln­(TMTDA)₂­(TMTDA-45)³⁺ resulting from C_carbonyl–N bond cleavage of TMTDA and hydrogen transfer was the major CID product for all Ln­(TMTDA)₃³⁺ except Eu­(TMTDA)₃³⁺, which predominantly formed charge-reducing product Eu^II(TMTDA)₂²⁺ via electron transfer from TMTDA to Eu³⁺. Density functional theory calculations on the structure of La­(TMTDA)₃³⁺ and Lu­(TMTDA)₃³⁺ revealed that Ln³⁺ was coordinated by six O_carbonyl atoms from three neutral TMTDA ligands, and both complexes possessed <i>C</i>_3<i>h</i> symmetry. The S_ether atom deviating from the ligand plane was not coordinated to the metal center. On the basis of the CID results of Ln­(TMTDA)₃³⁺, Ln­(TMGA)₃³⁺, and Ln­(TMOGA)₃³⁺, the fragmentation chemistry associated with the ligand depends on the coordination mode, while the redox chemistry of these tripositive ions is related to the nature of both metal centers and diamide ligands

Matrix Infrared Spectra of Manganese and Iron Isocyanide Complexes

Mono and diisocyanide complexes of manganese and iron were prepared via the reactions of laser-ablated manganese and iron atoms with (CN)₂ in an argon matrix. Product identifications were performed based on the characteristic infrared absorptions from isotopically labeled (CN)₂ experiments as compared with computed values for both cyanides and isocyanides. Manganese atoms reacted with (CN)₂ to produce Mn­(NC)₂ upon λ > 220 nm irradiation, during which MnNC was formed mainly as a result of the photoinduced decomposition of Mn­(NC)₂. Similar reaction products FeNC and Fe­(NC)₂ were formed during the reactions of Fe and (CN)₂. All the product molecules together with the unobserved cyanide isomers were predicted to have linear geometries at the B3LYP level of theory. The cyanide complexes of manganese and iron were computed to be more stable than the isocyanide isomers with energy differences between 0.4 and 4 kcal/mol at the CCSD­(T) level. Although manganese and iron cyanide molecules are slightly more stable according to the theory, no absorption can be assigned to these isomers in the region above the isocyanides possibly due to their low infrared intensities

A moisture absorbing gel electrolyte enables aqueous and flexible supercapacitors operating at high temperatures

Gel electrolytes are of great importance for supercapacitors (SCs) operating at high temperatures. However, it is a fundamental challenge for SCs using aqueous gel electrolytes at elevated temperatures to ensure good work durability due to the evaporation of water. Here we report a "water-in-salt" gel electrolyte that exhibits superior water-retention and even water-absorption capability. What is noteworthy is that a quasi-solid-state SC utilizing the gel electrolyte is able to work and exhibit long cycling life across a wide temperature range from room temperature up to 120 degrees C in an extremely dry atmosphere, representing the best record among the previously reported aqueous gel-based SCs, as far as we know. This strategy may provide a new way to develop reliable aqueous gel electrolytes for SCs operating at high temperatures

Ghrelin Modulates Lateral Amygdala Neuronal Firing and Blocks Acquisition for Conditioned Taste Aversion

<div><p>Ghrelin is an orexigenic brain-gut hormone promoting feeding and regulating energy metabolism in human and rodents. An increasing number of studies have reported that ghrelin and its identified receptor, the growth hormone secretagogue receptor 1a (GHS-R1a), produces remarkably wide and complex functions and biological effects on specific populations of neurons in central nervous system. In this study, we sought to explore the in vivo effects of acute ghrelin exposure on lateral amygdala (LA) neurons at the physiological and behavioral levels. <i>In vivo</i> extracellular single-unit recordings showed that ghrelin with the concentration of several nanomolars (nM) stimulated spontaneous firing of the LA neurons, an effect that was dose-dependent and could be blocked by co-application of a GHS-R1a antagonist D-Lys3-GHRP-6. We also found that D-Lys3-GHRP-6 inhibited spontaneous firing of the LA neurons in a dose-dependent manner, revealing that tonic GHS-R1a activity contributes to orchestrate the basal activity of the LA neurons. Behaviorally, we found that microinfusion of ghrelin (12 ng) into LA before training interfered with the acquisition of conditioned taste aversion (CTA) as tested at 24 h after conditioning. Pre-treatment with either purified IgG against GHS-R1a or GHS-R1a antagonist blocked ghrelin’s effect on CTA memory acquisition. Ghrelin (12 ng) had no effect on CTA memory consolidation or the expression of acquired CTA memory; neither did it affect the total liquid consumption of tested rats. Altogether, our data indicated that ghrelin locally infused into LA blocks acquisition of CTA and its modulation effects on neuronal firing may be involved in this process.</p></div

Formation and Characterization of Homoleptic Thorium Isocyanide Complexes

Homoleptic thorium isocyanide complexes have been prepared via the reactions of laser-ablated thorium atoms and (CN)₂ in a cryogenic matrix, and the structures of the products were characterized by infrared spectroscopy and theoretical calculations. Thorium atoms reacted with (CN)₂ under UV irradiation to form the oxidative addition product Th­(NC)₂, which was calculated to have closed-shell singlet ground state with a bent geometry. Further reaction of Th­(NC)₂ and (CN)₂ resulted in the formation of Th­(NC)₄, a molecule with a tetrahedral geometry. Minor products such as ThNC and Th­(NC)₃ were produced upon association reactions of CN with Th and Th­(NC)₂. Homoleptic thorium cyanide isomers Th­(CN)_<i>x</i> (<i>x</i> = 1–4) are predicted to be less stable than the corresponding isocyanides. The C–N stretches of thorium cyanides were calculated to be between 2170 and 2230 cm^–1 at the B3LYP level, more than 120 cm^–1 higher than the N–C stretches of isocyanides and with much weaker intensities. No experimental absorptions appeared where Th­(CN)_<i>x</i> should be observed

The Charge Storage Mechanisms of 2D Cation-Intercalated Manganese Oxide in Different Electrolytes

2D ion-intercalated metal oxides are emerging promising new electrodes for supercapacitors because of their unique layered structure as well as distinctive electronic properties. To facilitate their application, fundamental study of the charge storage mechanism is required. Herein, it is demonstrated that the application of in situ Raman spectroscopy and electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D), provides a sufficient basis to elucidate the charge storage mechanism in a typical 2D cation-intercalated manganese oxide (Na0.55Mn2O4 center dot 1.5H(2)O, abbreviated as NMO) in neutral and alkaline aqueous electrolytes. The results reveal that in neutral Na2SO4 electrolytes, NMO mainly displays a surface-controlled pseudocapacitive behavior in the low potential region (0-0.8 V), but when the potential is higher than 0.8 V, an intercalation pseudocapacitive behavior becomes dominant. By contrast, NMO shows a battery-like behavior associated with OH- ions in alkaline NaOH electrolyte. This study verifies that the charge storage mechanism of NMO strongly depends on the type of electrolyte, and even in the same electrolyte, different charging behaviors are revealed in different potential ranges which should be carefully taken into account when optimizing the use of the electrode materials in practical energy-storage devices

3D hierarchical porous amidoxime fibers speed up uranium extraction from seawater

The development of amidoxime-based polymeric (ABP) fibers offers a solution for uranium extraction from seawater (UES) and provides an alternative solution to the uranium resource shortage. However, ABP adsorbents prepared by existing methods cannot meet the requirements of high adsorption capacity, high selectivity, good mechanical strength and long service life. Herein, we fabricated a 3D hierarchical porous, high specific surface area ABP (H-ABP) fiber via self-assembly of axial grafting chains. A high adsorption capacity of 11.50 mg-U per g-adsorbents was achieved in natural seawater, which is a significant breakthrough in UES. Meanwhile, the adsorption capacity of uranium was higher than its major competing element vanadium, which overturned the U/V mass ratio of the ABP fiber. The H-ABP fiber also exhibited good mechanical strength and a long service life of at least 10 adsorptiondesorption cycles. The well-designed structure resulted in groundbreaking properties, which completely meet the requirements for the economic evaluation of UES. This work presents a new technology for the synthesis of highly efficient adsorbents for UES, thus opening a whole new means of nuclear fuel production from the ocean.</p