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A Co(II)-catalyzed pyridyl C-H bond carbenoid insertion with α-diazoacetates has been realized. This transformation features a highly regioselective C-C bond formation at the C3-position of pyridines, providing an efficient access to diverse α-aryl-α-pyridylacetates.

Lithium carbenoids are important reagents in organic synthesis. Systemic DFT calculations have been carried out to reveal the influence of hetero-aggregation states on the reactivity of lithium carbenoid reagents. The results indicate that the cyclopropanation reaction could be accelerated dramatically by hetero-aggregated lithium carbenoids with a halogen or oxygen as an α-heteroatom. The origin of the enhancement could attribute to the novel structural character of the hetero-aggregated lithium carbenoids. These intriguing finding predicts that it is practical to control a wide range of SN2-type organometallic reactions by using aggregated lithium carbenoids with other economical and convenient compounds.

Catalytic dehydration and dehydrogenation reactions of ethanol have been investigated systematically using the ab initio quantum chemistry methods The catalysts include water, hydrogen peroxide, formic acid, phosphoric acid, hydrogen fluoride, ammonia, and ethanol itself. Moreover, a few clusters of water and ethanol were considered to simulate the catalytic mechanisms in supercritical water and supercritical ethanol. The barriers for both dehydration and dehydrogenation can be reduced significantly in the presence of the catalysts. It is revealed that the selectivity of the catalytic dehydration and dehydrogenation depends on the acidity and basicity of the catalysts and the sizes of the clusters. The acidic catalyst prefers dehydration while the basic catalysts tend to promote dehydrogenation more effectively. The calculated water-dimer catalysis mechanism supports the experimental results of the selective oxidation of ethanol in the supercritical water. It is suggested that the solvent- and catalyst-free self-oxidation of the supercritical ethanol could be an important mechanism for the selective dehydrogenation of ethanol on the theoretical point of view.

The mechanism of the reaction of Methylidyne Radical (CH) with acetaldehyde (CH 3 CHO) has been investigated using CBS-QB3//B3LYP/aug-cc-pVTZ method. The initial CH + CH 3 CHO reaction is a barrierless process, forming a linear intermediate, CH 3 CHOCH, which can be converted into several products. The microscopic mechanism recommended by the present study not only identifies the products observed by previous experimental studies but also explains the isotopic effects (CH/CCD) observed experimentally. In view of the calculated energies, C 2 H 5 + CO is the most exothermic product pair, additionally, the energy barrier of this product channel is the lowest. Concerning the hydrogen elimination channel, acrolein (CH 2 CHCHO) and methylketene (CH 3 CHCO) are preferable co-products. Furthermore, a new product channel, C 2 H 3 + CH 2 O, has been discovered.

The mechanism and kinetics for the O( 3 P) + CH 3 CH CHCN reaction has been investigated firstly. The BHandHLYP and M05-2X methods were employed to obtain the initial geometries. The triplet/singlet potential energy surfaces (PESs) were constructed with high-level BMC-CCSD method. The conventional transition-state theory (CTST) and multichannel RRKM theory were employed to calculate the total and individual rate constants over a wide range of temperatures under high-pressure limit. Our computed rates agree well with the available experimental results. The yield of IM1 is 0.9–0.5 from 200 to 1000 K, and the construction of h-P1(OH + CH 2 CHCHCN) is 0.42 at 2000 K under high-pressure limit. The yields of the predicted decomposition products P1(CH 3 + HCOHCCN), P2(HCCN + CH 3 CHO) and P3(H + CH 3 COHCCN) at 298 K and 1 atom are 0.81, 0.07, and 0.09, respectively.

In this work, using quantum chemistry methods the reactions of Hg and HgO with six organics including methane (CH4), benzene (C6H6), methanol (CH3OH), formaldehyde (HCHO), formic acid (HCOOH) and phenol (C6H5OH) in sludge incineration were investigated. The computational result indicates that Hg reacts with six organics via insertion mechanism to form CH3HgH, CH3OHgH, CH3HgOH, HHgCH2OH, HCOHgH, H2CHgO, HHgCOOH, HOCHHgO, HCOOHgH, HCOHgOH, C6H5HgH, C6H5OHgH, C6H5HgOH, and m-, o-, p-HHgC6H4OH. However, all barriers involved are extremely high and all products are rather unstable, therefore, Hg will be discharged as elements into fuel gas. With extra oxygen supplied Hg could be oxidized to HgO firstly; subsequently, CH3OHgOH, HCOHgOH, HOCOHgOH, C6H5HgOH and o-HOHgC6H4-OH were formed when HgO reacts with above above organics. The corresponding barriers are lower and all products are much more stable, indicating these Hg-contained organic compounds would be generated readily in incineration of sludge. Therefore it is presumed that in presence of oxygen Hg is more active to react with organics in sludge incineration.

This study presents new mechanistic insights into the frustrated Lewis pairs (FLPs) catalyzed C–H activation of heteroarenes. Besides the generally accepted concerted C–H activation, a novel stepwise carbene type pathway is proposed as an alternative mechanism. The reaction mechanisms can be varied by tuning the distance between Lewis acid and Lewis base due to catalyst–substrate match. These results should expand the understanding of the structure and function of FLPs for catalyzed C–H activation.