杯吡咯和杂杯吡咯的结构、合成与应用

杯吡咯以其特殊的结构和优异性能, 在主客体化学尤其是分子识别等方面的应用前景已备受关注, 合成新型功能化杯吡咯及其衍生物已成为超分子化学领域的研究热点之一. 近年来通过引入新型芳烃基体合成了结构和性能多样的杂杯吡咯. 主要介绍了功能化的杯吡咯和杂杯吡咯的结构、合成及其在分子识别等领域的应用.     

A novel and facile Zn-mediated intramolecular five-membered cyclization of beta-tetraarylporphyrin radicals from beta-bromotetraarylporphyrins

A novel and facile method for the Zn-mediated intramolecular cyclization of beta-porphyrin radicals has been developed for the convenient and effective construction of newly fused five-membered porphyrin systems from readily available beta-bromotetraarylporphyrins.     

食品中残留甲醛次硫酸钠含量的测定

食品中残留甲醛次硫酸钠含量的测定;甲醛次硫酸钠;催化光度法;灿烂甲酚蓝;食品分析     

含稀土铽(Ⅲ)配合物透明树脂的制备及性能研究

含稀土元素的有机高分子 具有稀土离子独特的光、电、磁特性,又具有有机高分子材料优良的性能,是极具潜在应用价值的功能材料,早在1963年,Wolff和Pressley首次研究以高分子为基质的稀土荧光材料,引起了人们的广泛兴趣,80年代以来,高分子链上直接键合稀土配合物的研究也引起了化学家的注意。Okamoto和李文连等在较高稀土浓度下仍可以制成透明柔韧的薄膜。而由于稀土无机物与树脂的相容性差,难以均匀地分散到树脂中,所以获得发光功能高分子体相材料十分困难,本文首次报道将几种稀土铽（Ⅲ）配合物复合于苯乙烯（St）／甲基丙烯酸（HMA）的共聚体系之中,制备了具有发光功能的透明树脂,对其相关性能进行了研究,考察了稀土元素含量、组分配比等因素对聚合物透明性和发光性能的影响,结果表明：高分子网络给稀土配合物提供了稳定的化学环境,有利于展现其优良的发光性能,同时,稀土配合物赋予了光学树脂新的功能性。     

从电纺丝到电喷离子化制备核壳纳米粒子

20世纪80年代,随着纳米科学研究的迅速发展,制备纳米纤维的电纺丝技术引起人们的浓厚兴趣,在电纺丝过程中,人们向聚合物溶液或熔体施加几千至上万伏的高压静电,使电荷在聚合物溶液内大量聚集,当电荷聚集到一定程度,电荷之间的排斥力克服了溶液表面张力后,     

Theoretical Studies on the Intermonomer Interaction of F-·(H2O)n (n = 1,2)

Five optimized geometries of F-·(H2O)n (n = 1, 2) were obtained with ab initio calculation at the B3LYP/6-311++G** level.The accurate intermonomer interaction energy was calculated using the MP2 electron correlation correction as well as the basis set superposition error correction by the Boys-Bernardi "counterpoise" protocol.Natural bond orbital (NBO) theory was applied to quantify the relative strength of these interactions and account for their effects on the stability, structural and vibrational parameters of Fˉ·(H2O)n (n = 1, 2).It is shown that the charge transferring from the lone pair of F-1 to the σ*OH(…F) antibonding orbital is important.The results indicate the occupancy of σ*OH(…F) is increased (denoted Δσ*OH(…F)) and the ΔROH(…F) bond is leng- thened (denoted (ROH(…F)), leading to the red-shift and the red-shift values have linear correlation with both Δσ*OH(…F) and ΔROH(…F).     

Quantum Chemistry Study on Dissociation of Oxalyl Bromide

1 INTRODUCTION In experiment, it is difficult to reveal the pheno- menon that molecules decompose into several frag- ments by UV light mainly due to the insufficient en- ergy of illuminating source. But in oxalyl halides, their bond energies are relatively lower. As a typical system for the study of multi-channel dissociation, oxalyl chloride can be dissociated into four frag- ments: Cl˙, Cl˙, CO and CO, under proper UV light[1, 2], which is the chief way to obtain free radi- cals. …     

分散固相萃取-超高效液相色谱-串联质谱法快速测定苹果中代森锰锌残留

建立了苹果中代森锰锌残留的液质串联确证快速检测方法。苹果样品中的代森锰锌经硫酸二甲脂甲基衍生化后用分散固相萃取(QuEChERS)提取和净化,利用超高效液相色谱-串联质谱(UPLC-MS/MS)在多反应离子监测模式下进行检测。以碎片离子对m/z241/117进行定性分析、m/z241/193进行外标法定量分析。标准曲线线性方程为y=25.496x-228.84,r=0.9968,其线性范围在0.005～1.000mg/kg之间。在0.005～0.5mg/kg范围内设定4个添加水平。代森锰锌在苹果中的平均回收率为88.7%～109.4%;其相对标准偏差为5.9%～8.7%;本方法的检出限(LOD)为0.25μg/kg;定量限为(LOQ)为0.83μg/kg。本方法简便、快速、准确,可用于苹果样品中代森锰锌的农药残留确证检测。     

Recyclable hypervalent iodine(III) reagent iodosodilactone as an efficient coupling reagent for direct esterification, amidation, and peptide coupling

A hypervalent iodine(III) reagent plays a novel role as an efficient coupling reagent to promote the direct condensation between carboxylic acids and alcohols or amines to provide esters, macrocyclic lactones, amides, as well as peptides without racemization. The regeneration of iodosodilactone (1) can also be readily achieved. The intermediate acyloxyphosphonium ion C from the activation of a carboxylic acid is thought to be involved in the present esterification reaction.     

Virosaines A and B, two new birdcage-shaped Securinega alkaloids with an unprecedented skeleton from Flueggea virosa

Two new Securinega alkaloids, virosaines A (1) and B (2), were isolated from the twigs and leaves of Flueggea virosa. The structures and absolute configurations were elucidated by means of NMR, X-ray diffraction, and CD analyses. Compounds 1 and 2 represent the first examples of Securinega alkaloids bearing a 7-oxa-1-azabicyclo[3.2.1]octane ring system, whose plausible biogenetic pathways were also proposed.