湿法消解-原子荧光法测定全血中硒

以全血样品为原料,探讨湿法消解-原子荧光法测定全血中的硒含量。血样经硝酸-高氯酸消解后,用硼氢化钠将硒还原成硒化氢,由氩气载入原子化器,产生的原子荧光强度与试液中硒元素含量在一定范围内呈正比,外标法定量。以消解效率为指标,优化样品的消解条件,测定血中硒在0-10μg/L范围内线性情况良好,相关系数为0.9992,最低检出限为0.143μg/L,相对标准偏差为1.51%-1.58%,平均加标回收率为90.86%-104.62%。血中硒的原子荧光测定法灵敏度高,精密度和稳定性好,可应用于血中硒的生物监测。     

An N‐Heterocyclic Carbene with a Saturated Backbone and Spatially‐Defined Steric Impact

The synthesis and coordination chemistry of a saturated analogue of a “bulky‐yet‐flexible” N‐heterocyclic carbene (NHC) ligand are described. “SIPaul” is a 4,5‐dihydroimidazol‐2‐ylidene ligand with unsymmetrical aryl N‐substituents, and is one of the growing class of “bulky‐yet‐flexible” NHCs that are sufficiently bulky to stabilize catalytic intermediates, but sufficiently flexible that they do not inhibit productive chemistry at the central metal atom. Here, the synthesis of SIPaul.HCl and its complexes with copper, silver, iridium, palladium, and nickel, and its selenourea, are reported. The steric impact of the ligand is quantified using percent buried volume (% V_bur), whereas the electronic properties are probed and quantified using the Tolman Electronic Parameter (TEP) and δ_Se of the corresponding selenourea. This work shows that despite the often very different performance of saturated versus unsaturated carbenes in catalysis, the effect of backbone saturation on measurable properties is very small.     

Synthesis and antifungal activity of carvacrol and thymol esters with heteroaromatic carboxylic acids

Aiming to obtain the more effective pathogen inhibitive ingredients and explore the influence of introducing different heterocyclic units to carvacrol and thymol esters, twenty ester derivatives with different heterocyclic units were synthesized. And the in vitro antifungal activity of title compounds against five plant pathogenic fungi was evaluated by mycelium growth rate method. The results showed that some carvacrol and thymol esters showed good to excellent antifungal activity, and compound 9d (4-bromo-5-isopropyl-2-methylphenyl picolinate) exhibited a broad antifungal spectrum. Preliminary study indicated that the introduction of furan, thiophene and pyridine unit could enhance the antifungal activity of carvacrol and thymol esters against Botrytis cinerea and a bromine atom on the para position of benzene moiety could enhance their antifungal activity.     

一种间接从高光谱数据中提取黑土硒含量的新方法

我国东北黑土富含养分，随着土壤数字制图、精确农业和土壤资源调查等研究的深入，引入航空高光谱数据并提供科学的预测结果成为研究热点。硒元素相对于黑土土壤的主要成分属于微量元素，但其对作物的正常生长的作用与大量元素是同等重要的，亦是人体健康所必要的营养元素。针对硒含量反演，建立了一个基于主要成分的间接提取模型，该模型能够显著提升硒含量回归系数，降低实测值与预测值的误差。数据源自CASI-1500航空高光谱成像系统，光谱范围380~1 050 nm，空间分辨率1.5 m。在黑龙江建三江地区采集60个土壤样本，化验获得硒、有机质、全铁、pH和氧化钙含量数据，选择BP神经网络，建立光谱与含量的反演模型。分析不同含量的黑土成分在可见-近红波段范围内光谱变换规律，掌握了硒元素随着含量升高，光谱反射率会逐步升高的规律。但当硒含量较低时，在其他成分的干扰下，这一规律会逐渐减弱，直至不显著。有机质的光谱特征与硒元素相反，总体上随着含量的增高，反射率整体下降，这与有机质的光谱特性紧密相关。全铁光谱呈现出与有机质光谱类似的规律，说明二者具有较高的相关性。不同pH值和氧化钙含量的光谱特征与检测值没有呈现出明显的特征规律，反射规律不明显。对60个采样点不同养分含量进行逐波段求反射率对养分的相关系数。结果表明，pH值各个波段相关系数最高，均值达到0.63；其次是全铁的相关系数，为0.54；有机质和氧化钙的相关系数接近，分别为0.42和0.47；而硒元素含量与逐波段的平均相关系数最低，为0.38。选取相关系数较高的前5个波段，作为建模波段。硒特征波段为447，437，456，466和475 nm；有机质特征波段为447，456，466，437和475 nm；全铁特征波段为752，695，800，762和733 nm；pH特征波段为905，752，800，943和695 nm；氧化钙特征波段为752，695，800，523和762 nm。通过计算样本点硒含量与其他成分的相关系数，硒与有机质呈正相关，相关系数为0.79；与全铁、pH、氧化钙呈负相关，相关系数分别为-0.80，-0.94和-0.69。针对有机质、全铁、pH和氧化钙反演精度较高，而硒元素含量较低，直接反演精度不足的问题，设计了一种先提取4种成分含量，再根据其提取结果建立硒元素函数关系，间接反演硒元素含量的方法。首先将五种成分与特征光谱进行神经网络分析，计算每种成分的回归系数R2和RMSE。显示全铁和pH具有较高的反演精度，有机质和氧化钙归系数虽低于0.8，但也显著高于硒元素的反演精度。建立硒元素与其他4种成分含量的回归模型，得出Se=0.522 9+0.041 8Som-0.016 6Fe₂O₃-0.035 6pH-0.005CaO，进行硒元素间接提取，回归系数从0.516增长到0.724，均方根误差从0.182降低到0.136，显著改进了反演硒含量的精度，为硒元素大范围精确制图提供了一种新技术。     

自然界中的硒及其生物学效应

硒是第4周期第ⅥA族元素，除了具有非金属性外，还有部分金属性。其在地壳中的含量为0.05~0.09 mg/kg，自然界中存在广泛但分布不均。硒是人体和动物必需的微量元素，具有重要的生理生化功能，过量的硒及其化合物有较强毒性，而且硒的适宜剂量范围很窄。本文简单介绍了自然界中硒的存在、硒的生物学效应及其分子基础，以纪念元素周期律发现150周年。     

Ru(II)‐based antineoplastic: A “wingtip” N‐heterocyclic carbene facilitates access to a new class of organometallics that are cytotoxic to common cancer cell lines

The syntheses, structures, and chemotherapeutic activities of Ag(I)‐, Au(I)‐, and Ru(II)‐complexes ligated to a novel N‐heterocyclic carbene ligand, 2‐(4‐nitrophenyl)imidazo[1,5‐a]pyridin‐2‐ylidene ( 1 ), are described. The corresponding complexes, [Ag( 1 )₂][PF₆], [Au( 1 )₂][PF₆] ( 3 ), and [Ru( 1 )(p‐cymene)Cl][PF₆] ( 4 ), were prepared using convenient transmetallation chemistry and characterized using a range of spectroscopic and analytical techniques. X‐ray crystallography revealed that complexes 2 and 3 adopted linear structures whereas 4 exhibited a prototypical “piano‐stool”‐like geometry; the structural assignments were further supported by DFT calculations. A series of in vitro studies revealed that while the aforementioned Ag(I), Au(I) and Ru(II) complexes exhibited significant cytotoxicities against the human colon adenocarcinoma (HCT 116), lung cancer (A549), and breast cancer (MCF7) cell lines, the Ru derivative was most prominent.     

1,10-Phenanthroline: A versatile ligand to promote copper-catalyzed cascade reactions

Ligand-promoted copper-catalyzed cascade reactions have become a robust tool for the synthesis of cyclic compounds. Although numerous ligands have been developed, this review focuses on the introduction of commercially available 1,10-phenanthroline-promoted copper-catalyzed cascade reactions in recent years. Moreover, based on original articles, this review highlights product yields in the presence and absence of the ligand, and the possible mechanistic role of the ‘copper/1,10-phenanthroline’ catalytic system.     

An overview on the copper-promoted synthesis of five-membered heterocyclic systems

The development of novel approaches for the preparation of small-sized heterocyclic products has remained an extremely attractive but challenging proposition. Copper has been known as one of the most applicable and significant transition metals utilized in the synthesis of organic products. A couple of factors such as high earth abundance and versatile catalysis resulted in the growth of copper-promoted synthesis of five-membered heterocyclic products. Utilizations such as making coins and electrical equipment express the importance of copper, as well. Here, a comprehensive overview of the copper-catalyzed synthesis of five-membered heterocyclic products is presented, focusing on the developments over the past 4 years.     

Synthesis of 3-hetarylpyrroles by Suzuki–Miyaura cross-coupling

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新型哌啶-查尔酮类衍生物的设计、合成及抗宫颈癌和逆转顺铂耐药活性

本文采用活性亚结构拼接原理,设计并合成了15个新型含哌啶的查尔酮类衍生物,利用¹H NMR、¹³C NMR和HR-MS对结构进行表征,并初步评价了其抗宫颈癌和抗顺铂耐药宫颈癌活性作用。结果表明,化合物6g具有一定的抗肿瘤活性和逆转顺铂耐药作用;并采用Elisa法、联合顺铂用药、Western Blot和分子对接对化合物6g与VEGFR-2和P-gp靶点进行了初步的研究。本研究为基于VEGFR-2和P-gp双靶点新型分子靶向查尔酮类衍生物的设计提供了一条思路。