相转移催化无溶剂合成N-(ω-溴烷基)邻苯二甲酰亚胺

本文以N-(3-溴丙基)邻苯二甲酰亚胺合成为模板反应,研究了相转移催化无溶剂合成N-(ω-溴烷基)邻苯二甲酰亚胺的影响因素,实验证实相转移催化剂及其用量、催化剂K2CO3的用量等对反应的影响明显,得到N-(3-溴丙基)邻苯二甲酰亚胺的优化合成条件为:反应物配比为PA∶C3Br2∶K2CO3∶TBAB=1∶2∶4∶0.2,反应温度80℃,反应时间1h,N-(3-溴丙基)邻苯二甲酰亚胺产率为92%。在相同反应条件下,N-(ω-溴烷基)邻苯二甲酰亚胺的产率随α,ω-二溴烷烃的烷基链长度增加而降低。     

气相色谱-质谱法测定压敏胶及其制品中的多溴联苯与多溴二苯醚

建立了气相色谱-质谱法测定压敏胶及其制品中多溴联苯(PBBs)和多溴二苯醚(PBDEs)的分析方法。通过制备的阳性样品,对压敏胶样品的前处理条件进行优化,选择以乙酸乙酯为溶剂溶解样品,甲醇作为沉淀剂除去高聚物,在选择离子监测(SIM)方式下进行GC-MS分析。在优化实验条件下,检测的PBBs和PBDEs在0.1~10 mg/L范围内线性关系良好,相关系数均不小于0.999;对常用的热熔型压敏胶、溶剂型压敏胶和乳液型压敏胶进行3水平空白加标回收实验,PBBs的回收率为86.5%~99.7%,相对标准偏差小于7%;十溴二苯醚的回收率为91.4%~95.8%,相对标准偏差小于5%。该方法简单、灵敏,适用于压敏胶及其制品中多溴联苯和多溴二苯醚的分析确证。     

高效液相色谱法拆分黄酮类化合物对映体

采用直链淀粉Chiralpak AD-H与纤维素Chiralcel OZ-H两种手性柱建立了13种黄酮类化合物对映体的正相高效液相色谱拆分方法。考察了流动相比例、三氟乙酸(TFA)的添加及醇的种类对手性识别的影响。以正己烷-异丙醇(乙醇)-三氟乙酸(75∶25∶0.1)为流动相,于流速为0.5 mL.min-1,柱温为35℃,检测波长为290 nm条件下,在直链淀粉Chiralpak AD-H与纤维素Chiralcel OZ-H两种手性柱上成功拆分了13种黄酮类化合物对映体。研究表明,直链淀粉Chiralpak AD-H与纤维素Chiralcel OZ-H两种手性柱在拆分手性黄酮类化合物及结构相似物上具有极大的潜力。     

德国检测发现一些花果茶含有毒物质

不久前,德国权威机构最新调查发现,德国市场流行的部分花果茶含有超标的有毒物质——吡咯里西啶类生物碱(PA),若长期饮用可能伤身。德国联邦风险评估研究所发布消息称,研究人员选取221种德国市场上常见花果茶样品进行了检测,包括茴香茶、甘菊茶、薄荷茶、荨麻茶等,而红茶、绿茶等因样本数量过小,风险分析时未予考虑。结果发现,部分茶叶中吡咯里西啶类     

Ultrafast Excited State Dynamics of t~rans-4-Aminoazobenzene Studied by Femtosecond Transient Absorption Spectroscopy

The ultrafast excited state dynamics of trans-4-aminoazobenzene （trans-4-AAB） in ethanol was investigated by femtosecond transient absorption spectroscopy. After being excited to the S2 state by 400 nm, trans-4-AAB decays from the S2 state to the hot S1 state by internal conversion with time constant of -70 fs. The photoisomerization through inversion mechanism on the S1 potential energy surface and the internal conversion from the S1 state to the hot So state are observed, respectively. The average timescale of these two decay pathways is -0.7 ps. And the vibrational cooling of the hot So state of cis- and trans-4- AAB occur with time constants of -4 and N13 ps, respectively. Furthermore, the ultrafast intersystem crossing process are also observed. The timescale of intersystem crossing from the S2 state to the T4 state is about 480 ps while from the S1 state to the T2 state is -180 ps.     

Theoretical Insights into Intermolecular Hydrogen-Bonding Strengthening in Fluorenone-Methanol Complexes Induced by Electronic Excitation and Bulk Solvent Effect

This work presents a theoretical insight into the variation of the site-specific intermolecular hydrogen-bonding （HB）, formed between C=O group of fluorenone （FN） and O-H groups of methanol （MeOL） molecules, induced by both the electronic excitation and the bulk solvent effect. Through the calculation of molecular ground- and excited-state properties, we not only demonstrate the characters of HB strengthening induced by electronic excitation and the bulk solvent effect but also reveal the underlying physical mechanism which leads to the HB variation. The strengthening of the intermolecular HB in electronically excited states and in liquid solution is characterized by the reduced HB bond-lengths and the red-shift IR spectra accompanied by the increasing intensities of IR absorption corresponding to the characteristic vibrational modes of the O-H and C--O stretching. The HB strengthening in the excited electronic states and in solution mainly arises from the charge redistribution of the FN molecule induced by the electronic excitation and bulk solvent instead of the intermolecular charge transfer. The charge redistribution of the solute molecule increases the partial dipole moment of FN molecule and the FN-MeOL intermolecular interaction, which subsequently leads to the HB strengthening. With the bulk solvent effect getting involved, the theoretical IR spectra of HBed FN-MeOL complexes agree much better with the experiments than those of gas-phase FN-MeOL dimer. All the calculations are carried out based on our developed analytical approaches for the first and second energy derivatives of excited electronic state within the time-dependent density functional theory.     

空气稳定的氮杂蒄电子传输材料分子设计及三氮杂蒄衍生物迁移率计算

采用密度泛函理论研究氮功能化对蒄类化合物几何构型、电子结构及载流子传输性质的影响.结果表明,引入杂N原子可以线性降低前线轨道能级,增强电子注入能力与空气稳定性,且邻位掺杂较迫位和均匀掺杂调节效果更为显著.其中,十二氮杂蒄(12ac)具有新颖的"碗状"构型和高的电子亲和势(3.45 eV),是潜在的空气稳定电子传输材料构筑单元.理论预测室温下2,6,10-三对甲氧基苯基-3,4,7,8,11,12-六甲氧基三氮杂蒄(3b)晶体的电子迁移率为0.242 cm2/V s,预计是良好的电子传输材料,值得进一步器件化研究.     

铜基载氧体与可燃固体废弃物化学链燃烧特性研究

采用机械混合法制备了铜基载氧体,利用两段式管式炉反应平台和磁悬浮热重分析仪分别研究了铜基载氧体与石墨、可燃固体废弃物典型组分及可燃固体废弃物热解气模型物CH₄的化学链燃烧特性。结果表明,机械混合法制备的Cu80Si950载氧体强度高,具有良好的转化率和循环稳定性,是实现可燃固体废弃物化学链燃烧的一种比较理想的载氧体。利用扫描电镜(SEM)、X射线衍射仪(XRD)和颗粒强度测定仪对各个反应阶段载氧体进行分析。结果表明,Cu80Si950载氧体参与反应后表面结构发生巨大改变,机械强度骤降。多次循环之后载氧体结构趋于规则均匀化,形成类似球棒形状的大孔隙率结构,强度保持不变,使得载氧体在长时间使用过程中反应性能得以维持。     

β2-AR激动剂BI-167107的合成

BI-167107是一种新的长效β2肾上腺素受体(β2-AR)激动剂,在鉴定G蛋白偶联受体(GPCR)/配体络合物的结构方面具有重要应用.以2-硝基间苯二酚为原料,经过七步反应,合成了目标化合物,其结构经1H NMR,13C NMR和MS确证.此合成路线的优点是避免了使用有毒试剂,可以便捷地用于制备较大量的BI-167107及结构相近的苯并噁嗪类化合物.     

宽离子能量检测范围垂直引入反射式飞行时间质谱仪的研制

本实验室研制了国内首台宽离子能量检测范围飞行时间质谱仪。仪器采用紧凑式电子轰击源设计,配合离子透镜系统有效的调制离子流,飞行时间质量分析器采用了离子垂直引入式,双场加速和双场反射以及大尺寸MCP检测装置设计。仪器单离子信号半峰宽约2 ns,仪器分辨率优于1600FWHM,检测实际样品质量范围为1~127 amu(仪器理论质量检测上限优于800 amu),可检测离子能量范围优于2个数量级(3~140 eV)。若该TOF质量分析器与短瞬高压脉冲放电离子源耦合联用,可广泛应用于高能离子束的快速检测,如真空阴极放电对制备薄膜、离子注入材料的表征,导电材料的离子电荷态分布以及离子扩散速度的测定等。