Synthesis and Characterization of 5‐(1,2,4‐Triazol‐3‐yl)tetrazoles with Various Energetic Functionalities

In this contribution the synthesis and full structural as well as spectroscopic characterization of three 5‐(1,2,4‐triazol‐3‐yl)tetrazoles along with selected energetic moieties like nitro, nitrimino, and azido groups are presented. The main goal is a comparative study on the influence of those variable energetic moieties on structural and energetic properties. A complete characterization including IR and Raman as well as multinuclear NMR spectroscopy of all compounds is presented. Additionally, X‐ray crystallographic measurements were performed and reveal insights into structural characteristics as well as inter‐ and intramolecular interactions. The standard enthalpies of formation were calculated for all compounds at the CBS‐4M level of theory and reveal high positive heats of formation for all compounds. The calculated detonation parameters (using the EXPLO5.05 program) are in the range of 8000 m s^?1 (8097 m s^?1 ( 5 ), 8020 m s^?1 ( 6 ), 7874 m s^?1 ( 7 )). As expected, the measured impact and friction sensitivities as well as decomposition temperatures strongly depend on the energetic moiety at the triazole ring. The C? C connection of a triazole ring with its opportunity to introduce a large variety of energetic moieties and a tetrazole ring, implying a large energy content, leads to the selective synthesis of primary and secondary explosives.     

Microwave-Assisted Synthesis of Seven- and Higher-Membered N-Heterocycles

The development of new strategies for synthesis of medium-sized heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in the synthesis of nitrogen-containing seven- and higher membered heterocyclic compounds is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of N-heterocycles. The literature data are summarized based on the size of cycles.     

藻类蛋白质模型化合物苯丙氨酸的水热反应

利用石英毛细管反应器,研究了藻类蛋白质的模型化合物苯丙氨酸在水热条件下的反应特性;考察了低温段（130~220 ℃）苯丙氨酸的转化规律,并解析了苯丙氨酸在温度为220~340 ℃、反应时间为5~240 min的主要分解途径及其氮元素的转化途径和分布规律。结果表明,苯丙氨酸在130~190 ℃下转化率很低,可作为藻类水热液化过程中提取蛋白质的参考温度;在220~280 ℃下,苯乙胺是主要产物,随着反应温度升高和反应时间加长,苯乙烯产率增加。苯丙氨酸先脱羧生成苯乙胺,随着反应的加剧,苯乙胺经脱氨生成苯乙烯,苯乙烯进一步加成生成少量苯乙醇;大部分氮元素先经脱羧反应转移到苯乙胺中,进一步由脱氨反应转移到水溶性较强的NH₄⁺中。     

Excitation and quenching of ultraviolet nitrogen bands in the mixture of N2 and O2 molecules

Total quenching rate coefficients of three singlet and three triplet states of molecular nitrogen in the collisions with O₂ molecules are calculated on the basis of quantum-chemical approximations. The calculated rate coefficients of electronic quenching of N₂^? molecules are compared with the available experimental data. An influence of collisional processes on vibrational populations of electronically excited N₂(a¹Π_g) and N₂(A³Σ_u⁺) molecules is studied for conditions of laboratory discharge in N₂ and O₂ at admixtures of molecular oxygen 0%-20% for the pressures 1-1000 Pa. It is indicated that molecular collisions cause changes in relative populations of vibrational levels of these states and intensity relations of ultraviolet bands of N₂ with rise in the pressure and the O₂ admixture.     

Mn／ZSM-5催化剂及其SCR催化性能研究

采用液态离子交换法制备了不同含量的Mn／ZSM-5型分子筛催化剂,并考察了上述催化剂的物理化学特性及其在NH3-SCR反应中的催化性能。理化分析结果表明：所制备催化剂在Mn含量≤9．2％时具有高度的分散性,分子筛表面团聚的氧化锰颗粒粒径小于4nm;锰元素主要富集于分子筛的浅层及表面。催化性能研究结果表明：Mn含量达到1...     

Carbene‐Catalyzed Enantioselective Aromatic N‐Nucleophilic Addition of Heteroarenes to Ketones

The aromatic nitrogen atoms of heteroarylaldehydes are activated by carbene catalysts to react with ketone electrophiles. Multi‐functionalized cyclic N,O‐acetal products are afforded in good to excellent yields and optical purities. Our reaction involves the formation of an unprecedented aza‐fulvene‐type acylazolium intermediate. A broad range of N‐heteroaromatic aldehydes and electron‐deficient ketone substrates works effectively in this transformation. Several of the chiral N,O‐acetal products afforded through this protocol exhibit excellent antibacterial activities against Ralstonia solanacearum (Rs) and are valuable in the development of novel agrichemicals for plant protection.     

Molecular Evidence for Metallic Cobalt Boosting CO2 Electroreduction on Pyridinic Nitrogen

Nitrogen‐doped carbon materials (N‐C_mat) are emerging as low‐cost metal‐free electrocatalysts for the electrochemical CO₂ reduction reaction (CO₂RR), although the activities are still unsatisfactory and the genuine active site is still under debate. We demonstrate that the CO₂RR to CO preferentially takes place on pyridinic N rather than pyrrolic N using phthalocyanine (Pc) and porphyrin with well‐defined N‐C_mat configurations as molecular model catalysts. Systematic experiments and theoretic calculations further reveal that the CO₂RR performance on pyridinic N can be significantly boosted by electronic modulation from in‐situ‐generated metallic Co nanoparticles. By introducing Co nanoparticles, Co@Pc/C can achieve a Faradaic efficiency of 84 % and CO current density of 28 mA cm^?2 at ?0.9 V, which are 18 and 47 times higher than Pc/C without Co, respectively. These findings provide new insights into the CO₂RR on N‐C_mat, which may guide the exploration of cost‐effective electrocatalysts for efficient CO₂ reduction.     

Synthesis of a “Masked” Terminal Zinc Sulfide and Its Reactivity with Brønsted and Lewis Acids

The “masked” terminal Zn sulfide, [K(2.2.2‐cryptand)][^MeLZn(S)] ( 2 ) (^MeL={(2,6‐ⁱPr₂C₆H₃)NC(Me)}₂CH), was isolated via reaction of [^MeLZnSCPh₃] ( 1 ) with 2.3 equivalents of KC₈ in THF, in the presence of 2.2.2‐cryptand, at ?78 °C. Complex 2 reacts readily with PhCCH and N₂O to form [K(2.2.2‐cryptand)][^MeLZn(SH)(CCPh)] ( 4 ) and [K(2.2.2‐cryptand)][^MeLZn(SNNO)] ( 5 ), respectively, displaying both Brønsted and Lewis basicity. In addition, the electronic structure of 2 was examined computationally and compared with the previously reported Ni congener, [K(2.2.2‐cryptand)][^tBuLNi(S)] (^tBuL={(2,6‐ⁱPr₂C₆H₃)NC(^tBu)}₂CH).