1,3-双(二乙基膦甲基)苯和顺-二氯(三乙基膦)合铂反应的NMR研究

应用３１ＰＮＭＲ技术研究了双膦配体１，３－（Ｅｔ２ＰＣＨ２）２Ｃ６Ｈ４和ｃｉｓ－［ＰＥｔ３）２Ｃｌ２］的反应过程，并对反应产物进行了元素分析和核磁表征。得到的结果表明，该双磷配体容易和ｃｉｓ－［Ｐｔ（ＰＥｔ３）２Ｃｌ２］发生金属环化反应。所选用的初始反应物应有利于和双膦配体形成一个中间体（过渡状态），使苯环上的Ｃ－Ｈ键被活化，这是金属环化反应得以顺利进行的关键，据此提出了可能的反应途径。

Recent Advances in Transition Metal-Based Catalysts for Electrocatalytic Nitrate Reduction Reaction

The accumulation of excessive nitrate in the atmosphere not only jeopardizes human health but also disrupts the balance of the nitrogen cycle in the ecosystem.Among various nitrate removal technologies,electrocatalytic nitrate reduction reaction(eNO_(3)RR)has been widely studied for its advantages of being eco-friendly,easy to operate,and controllable under environmental conditions with renewable energy as the driving force.Transition metal-based catalysts(TMCs)have been widely used in electrocatalysis due to their abundant reserves,low costs,easy-to-regulate electronic structure and considerable electrochemical activity.In addition,TMCs have been extensively studied in terms of the kinetics of the nitrate reduction reaction,the moderate adsorption energy of nitrogen-containing species and the active hydrogen supply capacity.Based on this,this review firstly discusses the mechanism as well as analyzes the two main reduction products(N_(2)and NH_(3))of eNO_(3)RR,and reveals the basic guidelines for the design of efficient nitrate catalysts from the perspective of the reaction mechanism.Secondly,this review mainly focuses on the recent advances in the direction of eNO_(3RR)with four types of TMCs,Fe,Co,Ni and Cu,and unveils the interfacial modulation strategies of Fe,Co,Ni and Cu catalysts for the activity,reaction pathway and stability.Finally,reasonable suggestions and opportunities are proposed for the challenges and future development of eNO_(3)RR.This review provides far-reaching implications for exploring cost-effective TMCs to replace high-cost noble metal catalysts(NMCs)for eNO_(3)RR.

Synthesis and Characterization of Molybdenum（VI） Complexes with 1,10-Phenanthroline

The development of routes and strategies for the design and preparation of complexes of 4d metals in moderate oxidation states is of great importance in magnetochemistry, bioinorganic chemistry, materials chemistry and solid-state chemistry. Bidentate ligands containing N or O donors especially phenanthroline have been widely used to form complexes with interesting structural motif. Reaction of M（CO）6 （M = Cr, Mo, W） with phenanthroline has been done in 1935 and produced an interesting stereo structure, but the reaction of MoOE（acac）2 （acac = acetylacetonato） with phenanthroline has not been studied yet. So, in this research, first of all MoOE（acac） 2 was prepared, and then it reacted with bidentate nitrogen donor to lead to produce the complex of [MoOEL2] （L = Phen） and different aspects of this complex were studied. This complex is very active and highly selective epoxidation catalyst. The structure of the product was characterized by various spectral techniques such as elemental analysis, IH NMR, 13C NMR and IR spectroscopy.

Complexes of Rice Husks Ash for Oxidation of Cyclohexene

The cheap raw rice husks and the products of their thermal degradation WRHA （white rice husk ash） and BRHA （black rice husk ash）, after vigorously grounding and mixing, can successfully be used as a catalyst support to replace the existing expensive ones. The aim of the present research is to prepare new metal-immobilized complexes based on rice husks and to study their catalytic activity in the oxidation of cyclohexene with tert-butylhydroperoxide. The corresponding metal complexes were obtained by interaction of RRH （raw rice husks） or thermally treated WRHA in air atmosphere. The complexes were obtained from aqueous solutions of various salts such as FeCl2.4H2O, COCl2.6H2O, VOSO4.5H2O and Na2MoO4.2H2O at room temperature. The rice husks-supported metal complexes were identified by infrared spectroscopy. The structure of the iron-containing polymeric materials was evaluated by Mossbauer spectroscopy. The catalytic activity of the molybdenum-containing complex catalyst in the principal epoxidation reaction was higher than that of the vanadium-containing one, whereas, the opposite order of activities was found for the side reaction of allylic hydroxylation of cyclohexene. Under selected reaction conditions, the yields of the principal reaction products cyclohexene oxide （1,2-epoxycyclohexane） and 2-cyclohexene-1-ol were 36.4% and 22.7%, respectively.

Gold carbene chemistry from diazo compounds

Diazo compounds are generally used as carbene precursors. Traditionally, dirhodium, copper and iron catalysts were used to decompose diazo compounds to form the key metal carbene intermediates. Recently, the gold catalysts have been developed as a unique type of metal catalyst to decompose diazo compounds. The derived gold carbene showed much different characters comparing with other transition metal carbenes. They could go through a series of cycloaddition, insertion and coupling reactions. Here, the recent progress of the gold carbene chemistry from diazo compounds was reviewed, including the scope of reactions,mechanism and synthetic applications.

Theoretical insight into methanol steam reforming on indium oxide with different coordination environments

Indium oxide(In_2O_3) has demonstrated to be an effective non-noble metal catalyst for methanol steam reforming reaction(MSR).However, the reaction mechanism of MSR and crucial structure-activity relations determining the catalytic performance of In_2O_3 are still not fully understood yet. Using density functional theory(DFT) calculation, we systematically investigate the MSR process over a high-index In_2O_3(211) and a favoured catalytic cycle of MSR is determined. The results show that In_2O_3(211) possesses excellent dehydrogenation and oxidizing ability, on which CH_3 OH can readily adsorb on the In4 c site and be easily activated by the reactive lattice oxygens, resulting in a total oxidation into CO_2 rather than CO, while the H_2 formation through surface H–H coupling limits the overall MSR activity because of the strong H adsorption on the two-coordinated lattice O(O_(2c)). Our analyses show that the relatively inert three-coordinated lattice O(O_(3c)) could play an important catalytic role. To uncover the influence of the local coordination of surface In atoms and lattice O on the catalytic activity, we evaluate the activity trend of several types of In_2O_3 surfaces including(211),(111), and(100) by examining the rate-limiting, which reveals the following activity order:(211)>(111)>(100). These findings provide an in-depth understanding on the MSR reaction mechanism over In_2O_3 catalysts and some basic structure-activity relations at the atomic scale, could facilitate the rational design of In_2O_3-based catalysts for MSR by controlling the local coordination environment of surface active sites.