Terpenoids from Loxocalyx urticifolius

Two new diterpenoids, loxocalyxin A ( 1 ) and 13‐epiloxocalyxin A ( 2 ), and two new sesquiterpenoids, loxocalyxins B and C ( 3 and 4 , resp.), together with three known compounds, were isolated from the MeOH extract of the whole plant of Loxocalyx urticifolius Hemsl . The structures of the new compounds were established by means of spectroscopic analysis including one‐ and two‐dimensional NMR spectroscopy. All new structures were confirmed by X‐ray crystallographic analysis. Their absolute configurations were established.     

Spectroscopic fingerprints of valence and spin states in manganese oxides and fluorides

We performed a systematic study of soft X-ray absorption spectroscopy in various manganese oxides and fluorides. Both Mn L-edges and ligand (O and F) K-edges are presented and compared with each other. Despite the distinct crystal structure and covalent/ionic nature in different systems, the Mn-L spectra fingerprint the Mn valence and spin states through spectral lineshape and energy position consistently and evidently. The clear O- and F-K pre-edge features in our high resolution spectra enable a quantitative definition of the molecular orbital diagram with different Mn valence. In addition, while the binding energy difference of the O-1s core electrons leads to a small shift of the O-K leading edges between trivalent and quadrivalent manganese oxides, a significant edge shift, with an order of magnitude larger in energy, was found between divalent and trivalent compounds, which is attributed to the spin exchange stabilization of half-filled 3d system. This shift is much enhanced in the ionic fluoride system. This work provides the spectroscopic foundation for further studies of complicated Mn compounds.     

Studies toward the Synthesis of (R)‐(+)‐Harmicine

The study toward the total synthesis of (R)‐(+)‐harmicine is reported in this paper. The enantioselective synthesis of pyrrolidinone, the main backbone of of (R)‐(+)‐harmicine, has been completed by the methodology based on photo‐induced Wolff rearrangement of α‐diazo‐β‐carbonyl compounds.     

Efficient synthesis of pentasubstituted pyrroles via one-pot reactions of arylamines,acetylenedicarboxylates, and 3-phenacylideneoxindoles

An efficient synthetic method for the pentasubstituted pyrroles was successfully developed via the one-pot domino reactions of arylamines, acetylenedicarboxylates, and 3-phenacylideneoxindoles. The reaction mechanism involved the sequential Michael addition and ring closure of the in situ generated β-active enamino ester.     

Covalent Organic Frameworks(COFs) for Sequestration of99TcO4–

Covalent organic frameworks(COFs), as a class of crystalline porous materials with periodic lattices and porous structures, have received extensive attention in the fields of gas storage and separation, energy storage, catalysis and optoelectronics and so on. However, COFs are still in their infancy in the field of nuclear waste treatment, especially for sequestration of long-live problematic radionuclides, such as ⁹⁹Tc. Battle of decontamination of pertechnetate(TcO₄^–), a main existence of ⁹⁹Tc under aerobic environments, is far from finished. In this review, recent progresses of COFs and some relative materials in the sequestration of pertechnetate, and perspective on surmounting the unmet issues are elucidated.     

Cadmium(II)–Triazole Framework as a Luminescent Probe for Ca2+ and Cyano Complexes

A bidentate ligand, 1‐{4‐[4‐(1H‐1,2,4‐triazol‐1‐yl)phenoxy]phenyl}‐1H‐1,2,4‐triazole (TPPT), has been designed and synthesized. By using TPPT as a building block for self‐assembly with Cd(NO₃)₂ ? 4 H₂O and CdCl₂ ? 10.5 H₂O, novel 1D double‐chain {[Cd(TPPT)(NO₃)₂] ? 3 H₂O}_n ( 1 ) and 2D (4,4) layer [Cd(TPPT)Cl₂(H₂O)]_n ( 2 ) have been constructed. When 1 was employed as a precursor and exposed to DMF or N,N′‐dimethylacetamide (DMAC), the crystals of 1 dissolved and reassembled into two types of brown block‐shaped crystals of 1D double chains: {[Cd(TPPT)₂(NO₃)₂] ? DMF}_n ( 1 a ) and {[Cd(TPPT)₂(NO₃)₂] ? DMAC}_n ( 1 b ). The anion‐exchange reactions of complex 2 have also been investigated. After gently stirring crystals of 2 in CHCl₃/C₂H₅OH/H₂O containing NaBr, NaI ? 2 H₂O, or NaOAc ? 3 H₂O, the crystals retained their crystalline appearances. A remarkable single crystal to single crystal transformation was observed and 1D double chains of {[Cd(TPPT)Br₂] ? C₂H₅OH}_n ( 2 a ) and {[Cd(TPPT)₂I₂] ? CHCl₃}_n ( 2 b ), and 1D single chains of [Cd(TPPT)(H₂O)₂(CH₃COO)₂]_n ( 2 c ), can be obtained. Luminescent properties indicate that 1 shows excellent selectivity for Ca²⁺ and cyano complexes. To the best of our knowledge, this is the first example of a luminescent probe for Ca²⁺ based on triazole derivatives.