Identification and characterization of impurities in an insecticide,bifenthrin technical

The HPLC‐DAD and GC/MS methods were successfully used for the identification and characterization of the impurities in an agrochemical insecticide, bifenthrin technical. Three impurities ranging from 0.175%–0.541% were detected by the HPLC‐DAD method. The LC/MS technique with ESI or APCI source failed to detect the impurities detected by HPLC‐DAD, due to lack of ionization in ESI or APCI. The three impurities were enriched by prep‐HPLC, and then their structures were elucidated based on the GC/EIMS and CIMS data. The EI mass spectra of bifenthrin and its impurities displayed molecular ion and provided structure indicative fragment ions; the CIMS data further confirmed their molecular weight. The identity of the impurity 1 was further confirmed by the synthesis of the authentic sample followed by NMR and GC/MS data.     

ChemInform Abstract: Crystal Structures and Hydrogenation Properties of Palladium‐Rich Compounds with Elements from Groups 12—16.

Crystal structures based on powder XRD and hydrogenation properties of 24 Pd‐rich intermetallics are presented.     

ChemInform Abstract: The ′Sub′ Metallide Oxide Hydrides Sr21Si2O5H12+x and Ba21M2O5H12+x (M: Zn,Cd, Hg,In, Tl Si,Ge, Sn,Pb, As,Sb, Bi).

The title compounds are synthesized from melts of composition A:M:O:H = 21:2:5:24 (A: Sr, Ba; M: Zn, Cd, Hg, In, Tl Si, Ge, Sn, Pb, As, Sb, Bi) using BaH₂/SrH₂ as hydrogen sources.     

A novel two‐dimensional preparative chromatography method designed for the separation of traditional animal Tibetan medicine Osteon Myospalacem Baileyi

Animal medicine is an important part in traditional Tibetan medicine. However, information about the chemical composition of animal medicine is very limited, and there is a lack of comprehensive chromatographic purification methods. In the present work, animal medicine Osteon Myospalacem Baileyi was taken as an example and a novel two‐dimensional preparative chromatographic method was established for the preparation of single compounds with high purity from the extract of Osteon Myospalacem Baileyi. The first‐dimension preparation was carried on a DAISO Silica prep column, and ten fractions were obtained from the 112.3 g crude sample within 12 injections. A diol prep column used in nonaqueous mobile phase was selected for the second‐dimension preparation. The purity of the compounds isolated from the crude extract was >98%, which indicated that the method built in this work was efficient to manufacture single compounds of high purity from the extract of Osteon Myospalacem Baileyi. Additionally, this method showed great potential in the purification of weakly polar chemicals and it could act as a good example in the purification of other traditional animal medicines.     

ChemInform Abstract: Interaction of Metal Ions with Water: Ab initio Molecular Orbital Studies of Structure,Bonding Enthalpies,Vibrational Frequencies and Charge Distributions. Part 1. Monohydrates.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Learning to be prepared

Behavioral economics provides several motivations for the common observation that agents appear somewhat unwilling to deviate from recent choices. More recent choices can be more salient than other choices, or more readily available in the agent’s mind. Alternatively, agents may have formed habits, or use rules of thumb. This paper provides discrete-time adjustment processes for strategic games in which players display such a bias towards recent choices. In addition, players choose best replies to beliefs supported by observed play in the recent past. We characterize the limit behavior of these processes by showing that they eventually settle down in minimal prep sets (Voorneveld in Games Econ Behav 48:403–414, 2004).      

反相液相制备色谱法结合超临界流体制备色谱法分离纯化海风藤中的化合物

建立了基于反相液相制备色谱和超临界流体制备色谱的组合方法,用于分离纯化醇提水沉后石油醚层中的海风藤。首先以甲醇作为改性剂,采用醇提水沉法去除海风藤甲醇提取物中的叶绿素,加入硅藻土后用石油醚回流富集目标成分。选用反相C18制备色谱柱将其分为18个组分,然后将组分在SFC模式下进行制备。选用酰胺色谱柱,以甲醇为改性剂,在柱温30℃、背压15.0 MPa的条件下进行分离。基于反相色谱和超临界流体色谱不同的分离选择性,最后分离得到6个高纯度化合物。该法展示了反相制备色谱和超临界流体制备色谱在海风藤分离纯化方面的优势,特别是超临界流体色谱在天然产物的分析和制备方面的巨大潜力。     

ChemInform Abstract: Isoelectronic Analogues of PN: Remarkably Stable Multiply Charged Cations.

Ab initio calculations performed for PN and its 27 isoelectronic analogues indicate that the dication analogues, namely SO²⁺, NCl²⁺, PF²⁺ CAr²⁺, and SiNe²⁺ are experimentally observable species.