CHEMISTRY OF 1,2,4—TRIAZINES XIX THE ANOMALOUS SUBSTITUTED BENZENE SULFONATION AND PROPERTIES OF NUCLEOPHILIC ATTACK ON 6-CARBON OF 3-METHYLTHIO-5-HYDROXY-1,2,4-TRIAZINE

3-Methylthio-5-hydroxy-1,2,4-triazine(1c)reacted with substituted benzenesulfonyl chloride to give 3-methylthio-5-oxy-1,2,4-triazin-6-yl pyridinium betaine(4)in anhydrous pyridine.But when NaOH/H_2O/CH_3COCH_3 or NaOH/CH_3OH were used as reactant and solvent,3-methylthio-4-substituted benzenesulfonyl-5-oxo-6-hydroxy-1,4,5,6-tetrahydro-1,2,4-triazine(6)or 1-tosyl-3-methylthio-5-oxo-6-methyloxy-1,4,5,6-tetrahydro-1,2,4-triazine(7)was obtained respectively.The above reactions show anomalous properties of nucleophilic attack on 6-carbon in 1,2,4-triazine ring.

Structure and property of the hydrogen bonding complex between triazines and water

Density functional theory B3LYP is employed to obtain the optimized geometries of the ground state and interaction energy for triazines and water complexes. The results show that the 1,2,3-triazine-water, 1,2,4-triazine-water and 1,3,5-triazine-water complex on the ground state have Cs, Cs and C1 symmetry, and strong hydrogen bonding interaction with ?17.83, ?17.38 and ?13.55 kJ/mol after basis set superposition error and zero-point vibration energy correction, respectively, and large red-shift for the symmetric H─O stretching vibration frequencies forming N···H─O hydrogen bond in the triazines complex. The first singlet (n, π*) vertical excitation energy of the monomer and the hydrogen bonding complexes between triazines and water is investigated by time-dependent density functional theory.

Chemistry 1,2,4-triazines--Mass spectrometry of 6-azapurines

FOR the purpose of finding novel antitumor and antivirus medicines and understanding themechanism of the metabolic process involved,several 6-azapurine derivatives were synthe-sized from 1,2,4-triazines.Mass spectrometry plays a key role in the structure

CHEMISTRY OF 1,2,4-TRIAZINES Ⅶ——THE PREPARATION AND SUBSTITUTION REACTIONS OF ETHYL N^2- (5- (3- METHYLTHIO-6-ETHOXY-CARBONYL)-1,2,4-TRIAZINYL)-3-METHYLTHIO-5-OXO-2,5-DIHYDRO-1,2,4-TRIAZINE-6-CARBOXYLATE

As a continuation of the studies on the interference of metabolism of nucleic acids by 1,2,4-triazine derivatives, we have studied the preparation and chemical properties of a number of 1,2,4-triazines.

Synthesis and Structure of Azacalix[2]pyrimidine[2]triazines and Their Self-assembly in the Solid State

A number of azacalix[2]pyrimidine[2]triazines were synthesized in moderate to good yields from both a step-wise fragment coupling approach and a one-pot reaction strategy starting from 4,6-diaminopyrimidines and cyanuric chloride.Nucleophilic aromatic substitution reaction of resulting dichloro-substituted azacalix[2]-pyrimidine[2]triazines with NH_(4)Cl led to the formation of NH_(2)-bearing azacalix[2]pyrimidine[2]triazine analogs.Azacalix[2]pyrimidine[2]triazines adopted symmetric 1,3-alternate conformations in solution while twisted 1,3-alternate conformations were observed in the solid state.In the presence of different additives during the growth of single crystals,azacalix[2]pyrimidine[2]triazines containing amino(-NH_(2))groups gave varied self-assembled structures due to the formation of different intermolecular hydrogen bond motifs.

Synthesis of Novel Spiro Thiazolo[3,2-a][1,3,5]triazines via 1,3-Dipolar Cycloaddition of Azomethine Ylide

The 1,3-dipolar cycloaddition of an azomethine ylide generated by a decarboxylative route from sarcosine and acenaphthenequinone to 7-arylmethylidene-3-aryl-3,4-dihydro-2H-thiazolo[3,2-aJ[1,3,5]triazin-6（7H）-ones afforded novel dispiro[acenaphthylene-1,2’-pyrrolidine]-3＇,7″-[1,3]thiazolo[3,2-a][1,3,5]triazines in moderate yields. The structures of the products were determined and characterized thoroughly by NMR, MS, IR, elemental analysis and X-ray crystallographic analysis. The results of experiment indicated that this 1,3-dipolar cycloaddition proceeded with high stereoselectivity and regioselectivity.

Imidazole linker‐induced covalent triazine framework-ZIF hybrids for confined hollow carbon super‐heterostructures toward a long‐life supercapacitor

Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ordered structure and toxic superacid that dissolves or destabilizes the metal nodes.To solve this problem,herein,we report a straightforward two-step pathway for the covalent hybridization of disordered CTF(d–CTF)–ZIF composites via preincorporation of an imidazole(IM)linker into ordered CTFs,followed by the imidazole-site-specific covalent growth of ZIFs.Direct carbonization of these synthesized d–CTF−IM−ZIF hybrids results in unique hollow carbon super-heterostructures with ultrahigh nitrogen content(>18.6%),high specific surface area(1663m^(2)g^(−1)),and beneficial trace metal(Co/Zn NPs)contents for promoting the redox pseudocapacitance.As proof of concept,the obtained carbon super-heterostructure(Co–Zn–NC_(SNH)–800)is used as a positive electrode in an asymmetric supercapacitor,demonstrating a remarkable energy density of 61Wh kg^(−1)and extraordinary cyclic stability of 97%retention after 30,000 cycles at the cell level.Our presynthetic modifications of CTF and their covalent hybridization with ZIF crystals pave the way toward new design strategies for synthesizing functional porous carbon materials for promising energy applications.

Cyanided Covalent Triazine Frameworks with Enhanced Adsorption Capability Toward Chloranil

Porous polymer(pyrrolopyrrole)was successfully prepared via domino-ring-formation reaction.The chemical-physical properties of cyanided covalent triazine frameworks(CTF-CN)were characteriazed by fourier transform infrared spectra(FT-IR),scanning electron microscopy(SEM),nuclear magnetic resonance(NMR),specific surface area analyzer(BET)and thermogravimetric analysis(TGA),respectively.The experimental results of adsorption of chloranil(TCBQ)in aqueous solution indicated that CTF-CN exhibited distinctive adsorption capacity toward TCBQ owing to its large specific surface area.Specifically,the adsorption equilibrium of as-prepared polymer was executed within 5 h and the calculated adsorption capacity was 499.76 mg/g.Furthermore,the adsorption kinetics could be well defined with the linear pseudo-second-order model,which implies that the chemical interaction are relative important in the course of TCBQ removal.Finally,the current studies verify that CTF-CN has unique rigid and nano-porous framework structure,which can be employed for the treatment of a series of harmful aromatic substances.

Assessment of Triazine Herbicides in Soil by Microwave-assisted Extraction Followed by Gas Chromatography Coupled to Mass Spectrometry Detection

An alternative and fast method for the analysis of a mixture of nine triazines herbicides in soil is presented. The method is based on MAE （microwave-assisted extraction） of herbicides using ethyl acetate as extractant. The economy in the use of solvents coupled with the decrease in extraction time and lower power consumption make MAE a technique that meets the principles of green chemistry. MAE operational parameters, extraction time, mass of the sample and extraction temperature, were optimized by RSM （response surface methodology）. Determination of analytes was completed using gas chromatograph coupled to mass spectrometry detection. The selected triazines could be efficiently extracted by the solvent at 80 ℃ for 10 min, with 80% output of maximum power. When the optimized method was applied to analysis samples, the recoveries of analytes ranged from 81.8 to 106.0% and relative standard deviations were lower than 8.41%. The method is stable and reasonable, which can be used for the determination of ninetriazine herbicides residues in soil.

Determination of Pesticide Residues in Soils of Cotton Farming Areas in Togo

The main cash crop in Togo is cotton, with about 70% of agricultural exports. This crop is very dependent on the use of chemical inputs, in particular pesticides. Pesticides used in cotton farming in Togo include organochlorines, triazines, organophosphates and pyrethroids. We conducted a study on the impact of these pesticide use, in particular organochlorines and triazines, on cotton farming soils. We chose the Plateaux region (southern Togo) as the study area because of its high cotton production. Analysis was carried out on crop soil samples at the 0 - 20 cm horizon. Several pesticide residues were found: simazine (0.051 to 0.103 μg/Kg soil);atrazine (0.149 to 0.197 μg/Kg soil);lindane (0.259 to 0.672 μg/Kg soil);β-endosulfan (1.37 to 5.727 μg/Kg soil);dieldrin (0.063 to 1.16 μg/Kg soil);endrin (0.512 μg/Kg soil), Heptachlor (0.489 to 1.243 μg/Kg soil);Heptachlor epoxide (0.928 to 1.633 μg/Kg soil);[2,4'DDT] (0.257 μg/Kg soil);[4,4'DDE] (0.262 μg/Kg soil). These results show pesticide contamination of cotton farming soils.

Azoniaallene salts as versatile building blocks in the synthesis of antibacterial and antifungal heterocyclic compounds

Substituted 2-azoniaallene salts 1 are strong bifunctional electrophiles, undergo cyclization reactions furnish many series of heterocyclic compounds, where reacted with p-tolyl urea, phenyl thiourea and thiosemicarbazone derivatives to afford triazinium salts, and converted to corresponding free bases 3, 5, 7 under treatment with Na2CO3. While triazole derivatives 8 and 9 were obtained by the reaction 2-azoniaallene salts 1 with benzohydrazide and phenyl hydrazine, respectively. Benzoxazinium salts 10 and 11 were acquired when asymmetric 2-azoniaallene salt reacted in (1:1) ratio with p-cresol and 3-methyl-1-phenyl-5-pyrazolone, respectively. The reaction of 2-azoniaallene salt with malononitrile furnished the primidinium salt 12 which underwent neutralization with Na2CO3 followed by heterocyclization with hydrazine hydrate afforded the bicyclic compound 3-aminopyrazolo[3,4-d]pyrimidine 14, which is highly reactive for nucleophilic addition to phenyl isothiocyanate to furnish thiourea derivative 15. Moreover, 14 undergo condensation with aldehydes to give imine derivatives 16a,b. All free base compounds were screened for their antimicrobial activities.

Adsorption and correlation with their thermodynamic properties of triazine herbicides on soils

Adsorption of atrazine, prometryne and prometon was determined on six soils with different physical and chemical properties. The adsorption isotherms of three herbicides could well fit Freundlich equation. On all of six soils, adsorption of herbicides increased in the order: atrazine ≈prometon<prometryne. This order is quite the same to the calculation result of by means of excess thermodynamic properties of triazine. The Freundlich adsorption constants, K f, showed to have good correlation with organic matter(OM%) of soils for each of these herbicides, suggesting that OM is the main factor, which dominates in the adsorption process of these triazine herbicides.

A Novel Strategy of In Situ Trimerization of Cyano Groups Between the Ti3C2Tx(MXene) Interlayers for High-Energy and High-Power Sodium-Ion Capacitors

2D MXenes are attractive for energy storage applications because of their high electronic conductivity.However,it is still highly challenging for improving the sluggish sodium(Na)-ion transport kinetics within the MXenes interlayers.Herein,a novel nitrogen-doped Ti3C2Tx MXene was synthesized by introducing the in situ polymeric sodium dicyanamide(Na-dca)to tune the complex terminations and then utilized as intercalation-type pseudocapacitive anode of Na-ion capacitors(NICs).The Na-dca can intercalate into the interlayers of Ti3C2 Tx nanosheets and simultaneously form sodium tricyanomelaminate(Na3TCM)by the catalyst-free trimerization.The as-prepared Ti3C2Tx/Na3TCM exhibits a high N-doping of 5.6 at.%in the form of strong Ti-N bonding and stabilized triazine ring structure.Consequently,coupling Ti3C2Tx/Na3 TCM anode with different mass of activated carbon cathodes,the asymmetric MXene//carbon NICs are assembled.It is able to deliver high energy density(97.6 Wh kg-1),high power output(16.5 kW kg-1),and excellent cycling stability(≈82.6%capacitance retention after 8000 cycles).

A new efficient route for the synthesis of 4,4′,6,6′-tetra-(azido)azo-1,3,5-triazine

A new method for the synthesis of 4,4′,6,6′-tetra(azido)azo-1,3,5-triazine (TAAT) is described. The key intermediate 4,4′,6,6′-tetra(azido)hydrazo-1,3,5-triazine (TAHT) was synthesized by nucleophilic substitution in the case of sodium azide as nucleophile. N-Bromosuccinide (NBS) was used as oxidant to oxidize TAHT by a tractable operation under mild reaction condition. The target compound TAAT was obtained with a facile process and high overall yield of 81%. The structures of TAAT and its intermediates were identified by spectroscopic methods.

Encapsulation of Co single sites in covalent triazine frameworks for photocatalytic production of syngas

The photocatalytic production of syngas using a noble-metal-free catalytic system is a promising approach for renewable energy and environmental sustainability.In this study,we demonstrate an efficient catalytic system formed by integrating Co single sites,which act as the active sites,in covalent triazine frameworks(CTFs),which act as the photoabsorber,for the photocatalytic production of syngas from CO2 in aqueous solution.The enhanced light absorption of the CTFs,which contain intramolecular heterojunctions,in conjunction with 0.8 mmol L^‒1 of the Co complex enables excellent syngas production with a yield of 3303μmol g‒1(CO:H2=1.4:1)in 10 h,which is about three times greater than that achieved using CTF without a heterojunction.In the photocatalytic reaction,the coordinated single Co centers accept the photogenerated electrons from the CTF,and serve as active sites for CO2 conversion through an adsorption-activation-reaction mechanism.Theoretical calculations further reveal that the intramolecular heterojunctions highly promote photogenerated charge separation,thus boosting photocatalytic syngas production.This work reveals the promising potential of CTFs for single-metal-site-based photocatalysis.

Dendritic macromolecules as nano-scale drug carriers:Phase solubility,in vitro drug release,hemolysis and cytotoxicity study

Potential of nanoscale triazine based dendritic macromolecules G1,G2 and G3 as solubility enhancers of drug was investigated.Effect of pH,concentration and generation of synthesized dendritic macromolecules on solubility of ketoprofen was studied.G3 dendrimer was further exploited as carrier for sustained release.Ketoprofen was encapsulated by inclusion complex method and also characterized by Flourier Transform Infrared spectroscopy.Sustained release study of ketoprofen from ketoprofen loaded dendrimer was carried out and compared with free ketoprofen.Hemolytic potential and Cytotoxicity assay using A-549 lung cancer cell lines revealed that synthesized triazine based dendritic macromolecules having more potential that commercially available PAMAM dendrimer.

Determination of triazine herbicide residues in water samples by on-line sweeping concentration in micellar electrokinetic chromatography

A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters affecting sample enrichment and separation efficiency were systematically studied. Compared with the conventional MEKC method, up to 60-200-fold improvement in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. The compound strychnine was used as the internal standard for the improvement of the experimental reproducibility. The limits of detection （S/ N = 3：1） for atrazine, simazine and prometryn were 9, 10 and 0.5 ng mL-1, respectively. This method has been successfully applied to the analysis of atrazine, simazine and prometryn in lake, steam and ground water.

Facile synthesis of microporous carbonaceous materials derived from a covalent triazine polymer for CO2 capture

Highly porous nitrogen-doped carbon materials were synthesized by the carbonization of a low-cost porous covalent triazine polymer, PCTP-3, which had been synthesized by the AlClcatalyzed FriedelCrafts reaction of readily available monomers. The nature of the bond and structure of the resulting materials were confirmed using various spectroscopic methods, and the effects of KOH activation on the textural properties of the porous carbon materials were also examined. The KOH-activated porous carbon（aPCTP-3c） materials possessed a high surface area of 2271 mgand large micro/total pore volumes of 0.87/0.95 cmg, respectively, with narrower micropore size distributions than the porous carbon prepared without activation（PCTP-3c）. The aPCTP-3c exhibited the best COuptakes of 284.5 and 162.3 mg gand CHuptakes of 39.6 and 25.9 mg gat 273 and 298 K/1 bar, respectively, which are comparable to the performance of some benchmark carbon materials under the same conditions. The prepared materials exhibited high CO/Nselectivity and could be regenerated easily.

2D metal‐free heterostructure of covalent triazine framework/g‐C_(3)N_(4) for enhanced photocatalytic CO_(2) reduction with high selectivity

Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation.In this work,a metal free heterostructure of covalent triazine framework(CTF)and graphite carbon nitride(g‐C_(3)N_(4),abbreviated as CN)is applied in the CO_(2)photoreduction for the first time.Detailed characterization methods such as photoluminescence(PL)and time‐resolved PL(TR‐PL)decay are utilized to reveal the photo‐induced carries separating process on g‐C_(3)N_(4)/CTF(CN/CTF)heterostructure.The introduced CTF demonstrated a great boosting photocatalytic activity for CN,bringing about the transform rates of CO_(2)to CO reaching 151.1μmol/(g·h)with a 30 h stabilization time,while negligible CH_(4)was detected.The optimal CN/CTF heterostructure could more efficiently separate charges with a lower probability of recombination under visible light irradiation,which made the photoreduction efficiency of CO_(2)to CO be 25.5 and 2.5 times higher than that of CTF and CN,respectively.This investigation is expected to offer a new thought for fabricating high‐efficiency photocatalyst without metal in solar‐energy‐driven CO_(2)reduction.

Synthesis and Crystal Structure of 4-Oxo-1,2,4-triazino[4,5-a]benzimidazole

The title compound 4-oxo-1,2,4-triazino[4,5-a]benzimidazole（C9H6N4O,Mr = 186.18） has been synthesized and structurally characterized by IR,NMR and single-crystal X-ray diffraction. The crystal belongs to monoclinic,space group P21/c,with a = 9.1530（18） ,b = 7.2260（14）,c = 12.604（3） ,β = 106.92（3） ,V = 797.5（3）A^3,Z = 4,Dc = 1.551 g/cm^3,λ（MoKa） = 0.71073,F（000） = 384,μ（MoKa） = 0.109 mm^-1,the final R = 0.0632 and wR = 0.1095. A total of 1444 unique reflections were collected,of which 767 with I 〉 2σ（I） were observed. The structure of the title compound is planar. In packing,the molecules are intersected to each other to form chains along three dimensions,together by intermolecular N-H…O and C-H…N hydrogen bonds. The whole structure is further stabilized by π…π interaction between two adjacent tricyclic ring systems,with the centroid-to-centroid distance of 3.369（4） A.