Schiff碱作为桥配体的双核钌化合物的合成与性质

合成并表征了3个Schiff碱配体及由其桥联的3个双核钌配合物,并通过核磁共振谱、红外光谱、质谱及元素分析等测试手段对配体及化合物进行了表征.电化学测试结果表明,在3个双核配合物中存在着分子内的金属-金属间相互作用,且连接两个金属的桥配体是影响金属间相互作用强弱的关键因素.     

Damage and fracture prediction of plastic-bonded explosive by digital image correlation processing

By digital correlation processing of Scanning electronic microscopy (SEM) images, the paper presents the deformation and damage analysis of an energetic material—the plastic-bonded explosive (PBX) on mesoscopic scale. The analysis is made by observing the deformation field resulted from the digital image correlation (DIC) processing of the images corresponding to the loading steps and comparing with the surface profiles of the composite material so as to visualize the matter damage near a preset crack. The results show that the local deformation disturbance can reveal the material damage even happened underneath the specimen surface. The strain distribution in the front of the preset crack, can be used to predict the propagating route of the microcrack initiated from the tip of the pre-crack, which is related to the splitting fracture of the granular-based composite under compressive loading.     

Photochemical degradation of environmentally persistent perfluorooctanoic acid （PFOA） in the presence of Fe（Ⅲ）

Environmentally persistent and bioaccumulative perfluorooctanic acid （PFOA） was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe（Ⅲ）, 80% of PFOA with initial concentration of 48μmol/L （20 mg/L） was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction. Shorter chain perfluorocarboxylic acids bearing C3-C7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution. It was proposed that complexes of PFOA with Fe（Ⅲ） initiated degradation of PFOA irradiated with 254 nm UV light.     

Synthesis and biological evaluation of a new series of histone deacetylases inhibitors

Histone deacetylases （HDACs） play an important role in tumorigenesis. Inhibition of HDACs is considered as a potent strategy for cancer therapy. Two lead compounds （ja and jb） were found to have activities against HDACs with IC50 at about 15 μmol/L. Then a new series of hydroximic acid derivatives were designed and synthesized based on them. The HDACs activity assay in vitro found that compounds J04 and ,109 are nearly as potent as the positive control drug Zolinza.     

Trace mild acid-catalysed Z → E isomerization of norbornene-fused stilbene derivatives: intelligent chiral molecular photoswitches with controllable self-recovery

Stilbene derivatives have long been known to undergo “acid-catalyzed” Z → E isomerization, where a strong mineral acid at high concentration is practically necessary. Such severe reaction conditions often cause undesired by-reactions and limit their potential application. Herein, we present a trace mild acid-catalyzed Z → E isomerization found with stilbene derivatives fused with a norbornene moiety. By-reactions, such as the migration of the C C double bond and electrophilic addition reactions, were completely inhibited because of the ring strain caused by the fused norbornene component. Direct photolysis of the E isomers at selected wavelengths led to the E → Z photoisomerization of these stilbene derivatives and thus constituted a unique class of molecular switches orthogonally controllable by light and acid. The catalytic amount of acid could be readily removed, and the Z → E isomerization could be controlled by turning on/off the irradiation of a photoacid, which allowed repeated isomerization in a non-invasive manner. Moreover, the Z isomer produced by photoisomerization could spontaneously self-recover to the E isomer in the presence of a catalytic amount of acid. The kinetics of Z → E isomerization were adjustable by manipulating catalytic factors and, therefore, unprecedented molecular photoswitches with adjustable self-recovery were realized.

Quantitative Z → E isomerization was catalyzed by trace mild acids to offer molecular switches orthogonally controllable by acid and light.     

Edge disjoint cycles in graphs

Ore proved in 1960 that if G is a graph of order n and the sum of the degrees of any pair of nonadjacent vertices is at least n, then G has a hamiltonian cycle. In 1986, Li Hao and Zhu Yongjin showed that if n ? 20 and the minimum degree δ is at least 5, then the graph G above contains at least two edge disjoint hamiltonian cycles. The result of this paper is that if n ? 2δ², then for any 3 ? l₁ ? l₂ ? ? ? l_k ? n, 1 = k = [(δ - 1)/2], such graph has K edge disjoint cycles with lengths l₁, l₂…l_k, respectively. In particular, when l₁ = l₂ = ? = l_k = n and k = [(δ - 1)/2], the graph contains [(δ - 1)/2] edge disjoint hamiltonian cycles.     

Synthesis of aminomethyl and amino analogs of 5-benzylacyclouridine and 5-benzyloxybenzylacyclouridine

Amino analogs of BAU (5-benzylacyclouridine) and BBAU (5-benzyloxybenzylacyclouridine) and their 2′-hydroxymethyl derivatives were synthesized for evaluation as inhibitors of uridine phosphorylase and hence potential cancer chemotherapeutic agents. Both aminomethyl analogs were found to be potent inhibitors of this enzyme and good potentiators of the anti-tumor action of FUdR.     

Nearly monochromatic red electroluminescence from a nonconjugated polymer containing carbazole segments and phenanthroline [Eu(β‐diketonate)3] moieties

A novel nonconjugated copolymer (PVKEu) with carbazole segments and phenanthroline [Eu(β‐diketonate)₃] moieties was synthesized via free radical copolymerization, and characterized by FTIR, ¹H NMR spectroscopy, GPC, ICP, and elemental analysis. The copolymer exhibited good solubility, as well as good thermal stability and high glass transition temperature. The photoluminescence (PL) of this polymer in solution and in solid film has been studied. A multi‐layer device with the configuration of ITO/PEDOT: PSS (40 nm)/PVKEu (70 nm)/BCP (15 nm)/AlQ₃ (30 nm)/LiF/Al exhibited nearly monochromatic red emission at 615 nm and voltage‐independent spectral stability. Our results suggest that enhancing the ligand‐mediated energy transfer between the matrix polymer and europium complex is a potential method to improve the electroluminescence performance of the Eu‐chelated polymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 210–221, 2009     

Crown‐like macrocycle zinc complex derived from β‐diketone ligand for the polymerization of rac‐lactide

Enolic Schiff base zinc (II) complex 1 was synthesized. XRD revealed 1 was a novel crown‐like macrocycle structure consisted of hexanuclear units of (LZnEt)₆ via the coordination chelation between the Zn atom and adjacent amine nitrogen atom. Further reaction of 1 with one equivalent 2‐propanol at RT produced Zn‐alkoxide 2 by in situ alcoholysis. Complex 2 was used as an initiator to polymerize rac‐lactide in a controlled manner to give heterotactic enriched polylactide. Factors that influenced the polymerization such as the polymerization time and the temperature as well as the monomer concentration were discussed in detail in this paper. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 643–649, 2008