CO Fragments Research Articles

Study on the effects of the oxidized copper foil on graphene nucleation and growth based on the restricted space

In this study, the oxidized copper foil and the original copper foil were used as substrates to fabricate graphene samples by low pressure chemical vapor deposition (LPCVD) in a restricted growth space. The results demonstrated that in the restricted growth chamber, the oxidized layer on the oxidized copper foil inhabited graphene nucleation in the early nucleation stage, but with the oxidized layer heavily decomposing, decomposed oxygen would accelerate graphene growth. Because the decomposition rate of the oxidized layer would increase with growth temperature increasing, the acceleration effect of oxygen atoms on graphene growth becomes more obvious at higher growth temperature. So millimeter-scale graphene single crystals could be easily fabricated at 1060 °C on the oxidized copper foils in the restricted growth chamber. With the help of density functional theory (DFT) calculations, the influence mechanism of oxygen atoms on graphene nucleation and growth on copper substrate was investigated. The results showed that the oxygen atoms could not only react with CH fragments to form CO fragments to consume the number of carbon monomers, but also accelerate the diffusion and clustering of CH fragments.

Neutral and Cationic Re(I) Complexes with Pnictogen-Based Coligands and Tunable Functionality: From Phosphorescence to Photoinduced CO Release.

In this work, we have explored Re(I) complexes featuring triphenylpnictogen (PnPh3, Pn = P, As, or Sb)-based coligands and bidentate (neutral or monoanionic) luminophores derived from 1,10-phenantroline (phen), as well as from 2-(3-(tert-butyl)-1H-1,2,4-triazol-5-yl)pyridine (H(N-tBu)). The effect of the increasingly heavy elements on the structural parameters, photoexcited-state properties, and electrochemical behavior as well as the hybridization defects and polarization of the Pn atoms was related to the charges of the main luminophores (i.e., phen vs N-tBu) and explored in terms of photoluminescence spectroscopy, X-ray diffractometry, and quantum-chemical methods. Therefore, an in-depth analysis of the bonding, crystal packing, excited-state energies, and lifetimes was assessed in liquid solutions, frozen glassy matrices, and crystalline phases along with a semiquantitative photoactivation study. Notably, by changing the main ligand from phen to N-tBu, an increase in radiative and radiationless deactivation rates (kr and knr, respectively) at 77 K together with a faster photoinduced CO release and fragmentation at room temperature was detected. In addition, a progressively red-shifted phosphorescence was observed with the growing atomic number of the pnictogen atom, along with a boost in kr and knr at 77 K. Down the Vth main group and upon coordination of the Pn atom to the Re(I) center, an increasingly prominent jump of s-orbital participation on the binding sxp3.00-orbitals of the Pn atoms is evidenced. Based on these findings, the ability of these complexes to act as tunable photoluminescent labels able to perform as light-driven CO-releasing molecules is envisioned.

Primary and Secondary Processes in the Ultraviolet Photodissociation of CpCo(CO)2 (Cyclopentadienylcobalt Dicarbonyl).

We investigated the photodissociation dynamics of CpCo(CO)2 (cyclopentadienylcobalt dicarbonyl) in metal-to-ligand charge transfer (MLCT) bands. By employing DFT calculations, the absorption band (210-240 nm) was characterized as a charge transfer from the Co center to the Cp (cyclopentadienyl, C5H5) ligand. Ion imaging was utilized to analyze the CO fragments and coordinatively unsaturated complexes (CpCoCO, CpCo, and CoC3H3) across the entire MLCT band. Measuring the production yields of individual unsaturated complexes as a function of photolysis wavelength by considering wavelength dependence indicated the involvement of several photochemical pathways: the first photodissociation and sequential dissociation of CpCo(CO)2, and the second photodissociation of unsaturated intermediates within the pulse duration of the photolysis laser. The recoil velocity shifts of CpCo and CoC3H3 were attributed to the onset of the sequential dissociation of CpCoCO. Evidence for the second photodissociation of CpCoCO was obtained through the matching of linear momenta between the CO(v = 0, 1) and CpCo fragments. The DFT calculations performed to determine the electronic structures and potential energy curves for photoinduced CO loss in CpCo(CO)2 and CpCoCO supported our interpretation of the experimental results. This study presents a practical approach to selectively detecting specific processes among the mixture of products and intermediates when photolyzing transition-metal carbonyls, as their concurrent generation is unavoidable in laser-based experiments.

On the Wavelength-Dependent Photochemistry of the Atmospheric Molecule CF3COCl.

The wavelength control of photochemistry usually results from ultrafast dynamics following the excitation of different electronic states. Here, we investigate the CF3COCl molecule, exhibiting wavelength-dependent photochemistry both via (i) depositing increasing internal energy into a single state and (ii) populating different electronic states. We reveal the mechanism behind the photon-energy dependence by combining nonadiabatic ab initio molecular dynamics techniques with the velocity map imaging experiment. We describe a consecutive mechanism of photodissociation where an immediate release of Cl taking place in an excited electronic state is followed by a slower ground-state dissociation of the CO fragment. The CO release is subject to an activation barrier and is controlled by excess internal energy via the excitation wavelength. Therefore, a selective release of CO along with Cl can be achieved. The mechanism is fully supported by both the measured kinetic energy distributions and anisotropies of the angular distributions. Interestingly, the kinetic energy of the released Cl atom is sensitively modified by accounting for spin-orbit coupling. Given the atmospheric importance of CF3COCl, we discuss the consequences of our findings for atmospheric photochemistry.

Ultrafine fragments of a 2D Co(II)-imidazole MOF as cocatalysts for highly efficient and selective visible-light-driven reduction of CO2 to CO

We discovered that triethanolamine (TEOA) can break Co–N bonds in a 2D Co(II)-imidazole MOF, {[Co(TIB)2(H2O)4]SO4} (TIB stands for 1,3,5-tris(1-imidazolyl) benzene) (CoTIB) to form the ultrafine fragments of CoTIB with sizes <5.6 nm under stirring, which are highly efficient and selective (>99%) heterogenous cocatalysts for the visible-light-driven photocatalytic CO2 reduction reaction to CO. The efficiency of the ultrafine fragments of CoTIB (2.0–4.2 nm) reaches 42.7 mmol g−1 h−1 or a TOF of 33.7 h−1 based on Co atoms, which are among the best of heterogenous cocatalyst for photocatalytic CO2RR to CO systems. They are also highly stable under stirring with a TON greater than 909 in 54 h. The ultrafine fragments of CoTIB in mixed solvents were obtained by filtration, using a 0.22-μm filter head, of the 9-h stirred mixture of CoTIB/CH3CN/TEOA/trace-H2O or the 9-h reaction mixture using 1.0 mg of CoTIB. The fragments of CoTIB in these filtrates were characterized by high-resolution mass spectrometry (HRMS), size distribution and Zeta-potential measurements, ICP-MS, as well as Linear-Sweep-Voltammetry (LSV) measurements. The formation process of these nanoparticles and the mechanism of the photocatalytic CO2RRs were proposed. In addition, this work provides an easy method for making ultrafine fragments (<10 nm) of a Co(II)-imidazole MOF or other MOFs, which could also be viewed as MOF nanoparticles or quantum dots stabilized by coordination of TEOA molecules.

Intra-catalyst CH4 oxidation pathways on a Pd/Al2O3/CeZrOx-based commercial catalyst and implications on NOx conversion profiles for a natural gas vehicle exhaust under lambda modulation

The performance of a three-way catalyst (TWC) in natural gas-powered vehicles is enhanced by periodic changes in air-to-fuel ratio (λ-modulation). The reaction networks and sequences inside the catalyst that facilitate such enhanced performance have not been extensively investigated. This work applied intra-catalyst measurements (SpaciMS) to analyze the transient spatiotemporal gas concentrations inside a Pd-based TWC to establish relationships between CH4, NOx, CO and H2 conversion pathways. Steam reforming and partial oxidation were revealed to be the main CH4 conversion routes. The cyclic rich-lean conditions combined with the oxygen storage capacity (OSC) of the TWC generate reduced and oxidized zones that are constantly moving within the catalyst, changing the dominant chemical reactions occurring on the surface. In the reduced zones, OSC is depleted while CH4 is converted through steam reforming and NOx is converted through reactions with H2, CO, and other surface-bound reducing fragments formed by CH4 conversion. In the oxidized zones, OSC is replenished, CH4 is converted by partial oxidation, and H2, CO, and NH3 are oxidized. The length of lean-rich phases impacts the catalyst performance significantly; too short or too long of a rich or lean phase can lower the overall conversion of reactive species. An inhibition of CH4 conversion was observed during the rich phase possibly due to CO-poisoning of active sites. The intra-catalyst measurements revealed that the catalyst consists of three distinct reaction zones and their lengths vary with modulation conditions. Various modulation frequencies, amplitudes, λ-centers, and temperatures were investigated which allowed an understanding of how these parameters affect the reaction zones and catalyst utilization. Understandings from this work can enable adaptive λ-control strategies to optimize the overall TWC performance over a range of vehicle operating conditions.

Concerted stereodynamics of chemical changes: The branching selectivity in the photodissociation of asymmetric‐top molecules, formic acid, and the cold reactivity of the H + H2 exchange reaction

AbstractThis review article presents our recent examples of the branching selectivity in the photodissociation of asymmetric‐top molecules, halothane CF3CHBrCl and isohaloethane CF2BrCHFCl. The former gave the unexpected branching ratio of ([Cl] + [Cl*])/([Br] + [Br*])2 for the Br, Br* and Cl, Cl* atom fragmentations, meaning that the strongly bounded Cl‐C bond gave twice favorable fragmentation, while the later isohaloethane gave almost the same value for all‐atom fragmentations. We interpret this result due to the curve crossing of electronically excited states and the non‐adiabatic interaction on the excited states. The bimodal vibrational distribution of the product CO fragment in the formic acid photodissociation at 193 nm evidenced a roaming signature by using the μs time‐resolved Fourier‐transform infrared emission spectra for the first time. We find the characteristic propensity rule in the time‐dependent interaction potential to judge reactivity in the H + H2 exchange reaction and the roaming‐type of trajectory at temperature 3 K, by use of the impact‐parameter dependent quasi‐classical trajectory simulation, based on the present results, we conclude that reaction dynamics proceeds not only by the prerequisite of energy conservation but also by the timing of the time‐dependent interaction potential which is very sensitive to the steric configuration of reaction intermediate, thus it may be called as the concerted stereodynamics.

Experimental studies on the preparation and properties of starch‐graft‐poly(hexyl acrylate) copolymers

AbstractThe preparation and the properties such as the chemical stability, solution properties, moisture absorption, ability to gelation, glass transition temperatures, thermal stabilities and the decomposition course of starch‐graft‐poly(hexyl acrylate) copolymers have been studied. In general, it can be said that as the grafting percent increases the chemical resistance in alkaline, inert, acidic and buffer environments, and the solubility in non‐polar solvents of the copolymers increases. In turn, the solubility in polar solvents decreases compared to the solubility of starch. The Tg of starch‐g‐poly(hexyl acrylate) copolymers is in the range 102–133°C and is much higher than Tg of poly(hexyl acrylate) homopolymer. The thermal stability of all tested copolymers is higher than 274°C (inert conditions) and 230°C (oxidative conditions). In inert conditions, all tested copolymers decompose in two main stages related to pyrolysis combined with the emissions of the following volatiles: CO, CO2, H2O, aldehydes, alcohols, acids, ester, furanes, aliphatic and alkene fragments. In turn, the copolymers decompose in main three stages in oxidative conditions. The emission of CO, CO2, H2O, aldehydes, alcohols, acids, aliphatic, furanes and alcohols as a result of pyrolysis, oxidation, decarboxylation, dehydration, and combustion processes was confirmed.

Post-Transition-State Direct Dynamics Simulations on the Ozonolysis of Catechol.

On-the-fly dynamics simulations are performed for the reaction of catechol + O3. The post transition state (TS) dynamics is studied at temperatures of 400 and 500 K. The PM7 semiempirical method is employed for calculating the potential energy gradient needed for integrating Hamilton's equations of motion. This semiempirical method provides excellent agreement in terms of energy and geometry of the TSs as well as minimum energy states of the system with respect to B3LYP/6-311+G (2df, 2p) calculated results. In the dynamics, first, a peroxyacid is formed, which further dissociates to different fragments. Four major channels forming CO, CO2, H2O, and small carboxylic acid (SCA) fragments are seen in this reaction. Rates of each of the channels and the overall unimolecular reaction are calculated at both temperatures. Branching ratios of all these product channels are calculated and compared with experiment. The minimum energy profile of CO2, CO, and H2O channels are calculated. A qualitative estimate of activation energies for all the channels are obtained and compared with the explicit TS energies of three product channels, which ultimately correlate with the reaction probabilities.

Bonding situation in isolable silver(I) carbonyl complexes of the Scorpionates.

The bonding situation of Ag(I)CO complexes having a Scorpionate ligand directly attached to the transition metal has been analyzed in detail by means of relativistic density functional theory calculations. To this end, different experimentally characterized complexes together with other representative species have been considered to rationalize the observed shift of the corresponding ν(CO) stretching frequencies and the influence of the substituents in the Scorpionate ligand. With the help of the energy decomposition analysis method combined with the natural orbital for chemical valence it is found that the main contribution to the bonding comes from the electrostatic attractions between the LAg(I) and CO fragments. Despite that, the LAg→CO π-backdonation is also significant in these species as well as in related LCu(I)CO complexes.

A Molecular-Wide and Electron Density-Based Approach in Exploring Chemical Reactivity and Explicit Dimethyl Sulfoxide (DMSO) Solvent Molecule Effects in the Proline Catalyzed Aldol Reaction.

Modelling of the proline (1) catalyzed aldol reaction (with acetone 2) in the presence of an explicit molecule of dimethyl sulfoxide (DMSO) (3) has showed that 3 is a major player in the aldol reaction as it plays a double role. Through strong interactions with 1 and acetone 2, it leads to a significant increase of energy barriers at transition states (TS) for the lowest energy conformer 1a of proline. Just the opposite holds for the higher energy conformer 1b. Both the ‘inhibitor’ and ‘catalyst’ mode of activity of DMSO eliminates 1a as a catalyst at the very beginning of the process and promotes the chemical reactivity, hence catalytic ability of 1b. Modelling using a Molecular-Wide and Electron Density-based concept of Chemical Bonding (MOWED-CB) and the Reaction Energy Profile–Fragment Attributed Molecular System Energy Change (REP-FAMSEC) protocol has shown that, due to strong intermolecular interactions, the HN-C-COOH (of 1), CO (of 2), and SO (of 3) fragments drive a chemical change throughout the catalytic reaction. We strongly advocate exploring the pre-organization of molecules from initially formed complexes, through local minima to the best structures suited for a catalytic process. In this regard, a unique combination of MOWED-CB with REP-FAMSEC provides an invaluable insight on the potential success of a catalytic process, or reaction mechanism in general. The protocol reported herein is suitable for explaining classical reaction energy profiles computed for many synthetic processes.

Generation of Highly Vibrationally Excited CO in Sequential Photodissociation of Iron Carbonyl Complexes

Ultraviolet photochemistry of iron pentacarbonyl, Fe(CO)5, was investigated with resonantly enhanced multiphoton ionization (REMPI) spectroscopy and ion imaging. The REMPI spectrum of CO photofragments, generated by ultraviolet irradiation of Fe(CO)5, showed the generation in the highly vibrationally excited states with v = 11-15. Analysis of the band intensities observed in the 213-235 nm region indicated that the high-v CO generation was maximized at around 220 nm. Generation yields of the coordinatively unsaturated intermediates, Fe(CO)n=1-4, were measured as a function of the photolysis wavelength using a nonresonant detection scheme. The yield spectrum of FeCO was correlated with that of the high-v CO fragments, suggesting high-v CO generation in the photodissociation of FeCO. The density functional theory calculations of the excited states of FeCO showed an intense photoabsorption to the metal-centered state near 220 nm. The theoretical results were consistent with the interpretation of FeCO + hν → Fe + high-v CO, which was experimentally indicated. The momentum distribution obtained from the velocity distributions of Fe, Fe(CO)4, and CO fragments further supported that Fe is the counter-product of the high-v CO fragment. The present results provided selective observation of the photochemistry of the unsaturated iron carbonyl complexes, which has not been well elucidated in laser-based experiments because of the uncontrollable sequential photodissociation producing mixed Fe(CO)n intermediates.

Direct Access to Palladium(II) Complexes Based on Anionic C,C,C-Phosphonium Ylide Core Pincer Ligand.

The reaction of readily available imidazolium-phosphonium salt [MesIm(CH2)3PPh3](OTf)2 with PdCl2 in the presence of an excess of Cs2CO3 afforded selectively in one step the cationic Pd(II) complex [(C,C,C)Pd(NCMe)](OTf) exhibiting an LX2-type NHC-ylide-aryl C,C,C-pincer ligand via formal triple C-H bond activation. The replacement of labile MeCN in the latter by CNtBu and CO fragments allowed to estimate the overall electronic properties of this phosphonium ylide core pincer scaffold incorporating three different carbon-based donor ends by IR spectroscopy, cyclic voltammetry, and molecular orbital analysis, revealing its significantly higher electron-rich character compared to the structurally close NHC core pincer system with two phosphonium ylide extremities. The pincer complex [(C,C,C)Pd(CO)](OTf) represents a rare example of Pd(II) carbonyl species stable at room temperature and characterized by X-ray diffraction analysis. The treatment of isostructural cationic complexes [(C,C,C)Pd(NCMe)](OTf) and [(C,C,C)Pd(CO)](OTf) with (allyl)MgBr and nBuLi led to the formation of zwitterionic phosphonium organopalladates [(C,C,C)PdBr] and [(C,C,C)Pd(COnBu)], respectively.

Advances in Transition‐Metal Catalyzed Carbonylative Suzuki‐Miyaura Coupling Reaction: An Update

AbstractTransition metals have been an indispensable component of modern catalysis and among these palladium is the top‐ranked choice of chemists as a catalyst. After the several important developments of palladium catalysed C−C cross‐coupling reactions, carbonylative transformations have been realised as an attractive post modification of these reactions. Carbonylative Suzuki‐Miyaura coupling reaction is among such transformations for direct incorporation of CO fragment for the preparation of biaryl or aryl/alkyl ketones via transition‐metal catalysis. Ketone functionality is basically a valuable building block having huge pharmaceutical and agrochemical applications. Moreover, carbonylative Suzuki‐Miyaura coupling is also used in the synthesis of various natural bioactive molecules through the direct joining of molecular fragments via CO bridge. In this review, the past decade developments in the carbonylative Suzuki‐Miyaura coupling reactions are documented in detail with modern approaches in transition‐metal catalysis.magnified image

Exploring the next step in micro-solvation of CO in water: Infrared spectra and structural calculations of (H2O)4-CO and (D2O)4-CO.

We extend studies of micro-solvation of carbon monoxide by a combination of high-resolution IR spectroscopy and ab initio calculations. Spectra of the (H2O)4-CO and (D2O)4-CO pentamers are observed in the C-O stretch fundamental region (≈2150 cm-1). The H2O containing spectrum is broadened by predissociation, but that of D2O is sharp, enabling detailed analysis that gives a precise band origin and rotational parameters. Ab initio calculations are employed to confirm the assignment to (water)4-CO and to determine the structure in which the geometry of the (water)4 fragment is a cyclic ring very similar to the isolated water tetramer. The CO fragment is located "above" the ring plane, with a partial hydrogen bond between the C atom and one of the "free" protons (deuterons) of the water tetramer. Together with the previous results on D2O-CO, (D2O)2-CO, and (D2O)3-CO, this represents a probe of the four initial steps in the solvation of carbon monoxide at a high resolution.

Light-activated cytotoxicity of dicarbonyl Ru(II) complexes with a benzimidazole coligand towards breast cancer.

Reaction between [RuCl2(CO)2]n and 1H-benzimidazol-2-ylmethyl-(N-phenyl)amine ligands (LR) functionalized with various electron-donating and electron-withdrawing substituents on the phenyl ring (R = H, 4-CH3, 4-Cl, 4-COOCH3, and 3-COOCH3) afforded the dark-stable photoactivatable carbon monoxide prodrugs of the general formula [RuCl2(CO)2LR]. Release of the CO molecules from the Ru(II) compounds was examined by monitoring the electronic and IR spectra upon illumination at 365 nm. A noticeable decrease in the intensities of the two characteristic ν(CO) modes for Ru(CO)II2 species, and the growth of two new bands for the mono-carbonyl species and free CO, were the main features of the photolysis profiles. The cytotoxicity of the complexes towards breast cancer (MCF-7) cells was assessed with and without illumination at 365 nm. All the complexes except that with a 4-COOCH3 group (IC50 = 45.08 ± 3.5 μM) are nontoxic under dark conditions. Upon illumination, all the compounds acquired cytotoxicity in the following order: H > 4-COOCH3 > 4-CH3 > 4-Cl > 3-COOCH3. Investigation of the cytotoxicity of the CO-depleted fragments showed that the light-induced cytotoxicity can be attributed to the liberated CO and CO-depleted metal fragments, including the liberated benzimidazole ligands.

Primary and Secondary Loss of CO and NO Ligands in the Ultraviolet Photodissociation of the Heteroleptic Co(CO)3NO Complex.

The photodissociation dynamics of the heteroleptic Co(CO)3NO complex were investigated in the metal-to-carbonyl (CO) ligand charge-transfer band to compare the reactivity of the CO and nitrosyl (NO) ligands. The final state distributions of both the CO and NO fragments were measured using resonance-enhanced multiphoton ionization (REMPI) spectroscopy and velocity-map ion-imaging. The primary CO photofragment was differentiated from the secondary fragments of the subsequent unimolecular decomposition of coordinatively unsaturated intermediates by comparing the momentum distributions. The internal energy of the Co(CO)2NO intermediate was sufficiently high (≥348 kJ/mol) to be generated in the electronic excited state, indicating the occurrence of the primary CO elimination on an excited state. The NO fragments exhibited two velocity components. The analysis of the final state distributions suggested that the higher- and lower-kinetic-energy components originated from the direct primary elimination and sequential elimination, respectively. The direct photoelimination through a transiently bent ligand conformation was illustrated on the basis of a two-dimensional REMPI approach and time-dependent density functional theory calculations. The present results of both ligands demonstrate the correlation between elimination mechanisms and possible ligand conformations in the electronic excited state.

N-Tosylcarboxamide in C–H Functionalization: More than a Simple Directing Group

C–H activation with transition metal catalysis has become an important tool in organic synthesis for the functionalization of low reactive bonds and the preparation of complex molecules. The choice of the directing group (DG) proves to be crucial for the selectivity in this type of reaction, and several different functional groups have been used efficiently. This review describes recent advances in C–H functionalization of aromatic rings directed by a N-tosylcarboxamide group. Results regarding alkenylation, alkoxylation, halogenation, and arylation of C–H in the ortho position to the tosylcarboxamide are presented. Moreover, the advantage of this particular directing group is that it can undergo further transformation and act as CO or CON fragment reservoir to produce, in sequential fashion or one-pot sequence, various interesting (hetero)cycles such as phenanthridinones, dihydroisoquinolinones, fluorenones, or isoindolinones.

Decomposition course of anticancer active imidazolidine-based hybrids with diethyl butanedioate studied by TG/FTIR/QMS-coupled method

The course of pyrolysis and combustion processes of four diethyl (2E)-2-{(2E)-[1-(R-phenyl)imidazolidin-2-ylidene]hydrazinylidene}butanedioates which act as anticancer agents was studied using simultaneous thermal analysis method (TG/DSC) coupled online with Fourier transform infrared spectroscopy (FTIR) and Quadrupole mass spectrometry (QMS) analyzers in helium and synthestic air atmospheres. It was found that the decomposition processes of the tested compounds in inert and oxidative conditions were complex and included some of the simultaneous reactions. The following decomposition reactions were observed: (i) pyrolysis of CO, CC and CN bonds, partial decarboxylation and dehydration (ii) further partial fragmentation and pyrolysis of CO, CC and CN bonds connected with decarboxylation and dehydration of intermediate products; (iii) simultaneous cracking of CN and partial pyrolysis of formed aromatic-rich residue and additional oxidation processes in air conditions; (iv) fragmentation and pyrolysis processes (in inert conditions) and additional combustion processes (in oxidative conditions) of fused aromatic rings in connection with some chemical reactions between the decomposition fragments.

Germplasm differences among three species of genus Erythroculter based on morphological characters and gene sequences of mitochondrial CO I and Cyt b

Fish of genus Erythroculter (Cypriniformes, Cyprinidae, Abramidinae) are important commercial freshwater species in China. In this work, morphological characters and gene sequences of mitochondrial CO I and Cyt b were analysed to investigate the germplasm differences among E. mongolicus, E. dabryi and E. ilishaeformis. Results demonstrated that about countable trait, there were six traits (scale in/ above/ below lateral line, gill‐raker in first left gill‐arch and branched fin‐ray in anal/ pectoral fin) showed significant differences. Gene fragments of CO I and Cyt b was 905 bps and 1,142 bps respectively. In CO I, there were 54.3% base content of A + T, 14 haplotypes and 84 nucleotide variable sites. As to Cyt b, there were 56.3% base content of A + T, 20 haplotypes and 142 nucleotide variable sites. In both CO I and Cyt b, the highest and lowest nucleotide diversity was detected in E. ilishaeformis and E. mongolicus respectively. According to morphological distance, genetic distance, genetic differentiation coefficient (Fst) and gene flow, E. dabryi was grouped together with E. ilishaeformis firstly, and then clustered with E. mongolicus. These results might be useful in the conservation and management of fishery resources of these three species.