Assessment of electrostatic discharge sensitivity of nitrogen-rich heterocyclic energetic compounds and their salts as high energy-density dangerous compounds:A study of structural variables

Nitrogen-rich heterocyclic energetic compounds(NRHECs)and their salts have witnessed widespread synthesis in recent years.The substantial energy-density content within these compounds can lead to potentially dangerous explosive reactions when subjected to external stimuli such as electrical discharge.Therefore,developing a reliable model for predicting their electrostatic discharge sensitivity(ESD)becomes imperative.This study proposes a novel and straightforward model based on the presence of specific groups(-NH_(2) or-NH-,-N=N^(+)-O^(-)and-NNO_(2),-ONO_(2) or-NO_(2))under certain conditions to assess the ESD of NRHECs and their salts,employing interpretable structural parameters.Utilizing a comprehensive dataset comprising 54 ESD measurements of NRHECs and their salts,divided into 49/5 training/test sets,the model achieves promising results.The Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and Maximum Error for the training set are reported as 0.16 J,0.12 J,and 0.5 J,respectively.Notably,the ratios RMSE(training)/RMSE(test),MAE(training)/MAE(test),and Max Error(training)/Max Error(test)are all greater than 1.0,indicating the robust predictive capabilities of the model.The presented model demonstrates its efficacy in providing a reliable assessment of ESD for the targeted NRHECs and their salts,without the need for intricate computer codes or expert involvement.

Syntheses, Crystal Structures and Antibacterial Activities of Two Heterocyclic Schiff Base Compounds

Two heterocyclic Schiff bases were synthesized via the condensation reactions of primary amines with carbonyl compounds. 2-[（4-pyridylmethylene）-amino] phenol （compound 1） was synthesized by the interaction of 4-pyridinecarboxaldehyde with o-aminophenol in ethanol solvent; N,N＇-bis（3-（furan-2-yl）allylidene）benzene-1,4-diamin （compound 2） was synthesized by the interaction of 3-（2-furyl）acrolein with p-phenylenediamine in ethanol medium. The compounds were characterized by elemental analysis, IR, MS and single-crystal X-ray diffraction. Compound 1 （C12H10N2O） crystallizes in the monoclinic system, space group P21/c with α = 7.0771（7）, b = 7.2820（7）, c = 19.849（2）, b = 96.3390（10）°, V = 1016.66（17） ？3, Z = 4, Mr = 198.22, Dc = 1.295 g/cm3, F（000） = 416, GOOF = 1.060, m = 0.085 mm-1, the final R = 0.0371 and wR = 0.0929 for 1497 observed reflections with I 〉 2σ（I）. Compound 2 （C20H16N2O2） crystallizes in the orthorhombic system, space group Fdd2 with α = 26.344（15）, b = 48.50（3）, c = 5.293（3）, V = 6764（7） ？3, Z = 16, Mr = 316.35, Dc = 1.243 g/cm3, F（000） = 2656, GOOF = 1.043, m = 0.081 mm-1, the final R = 0.0526 and wR = 0.1267 for 2059 observed reflections with I 〉 2σ（I）. 1 and 2 molecules are connected through hydrogen bonds to generate a 2D network and a 1D chain structure, respectively. The preliminary antibacterial activity results showed that the title compounds display excellent antibacterial activities to Escherichia coli, Staphylococcus aureus and Bacillus subtilis.

Structural Characterization and Octanol/water Partition Coefficients(LogP) Prediction for Oxygen-containing Organic Compounds

New descriptors were constructed and structures of some oxygen-containing organic compounds were parameterized. The multiple linear regression（MLR） and partial least squares regression（PLS） methods were employed to build two relationship models between the structures and octanol/water partition coefficients（LogP） of the compounds. The modeling correlation coefficients（R） were 0.976 and 0.922, and the ＂leave one out＂ cross validation correlation coefficients（R（CV）） were 0.973 and 0.909, respectively. The results showed that the structural descriptors could well characterize the molecular structures of the compounds; the stability and predictive power of the models were good.

A Novel Eleven-membered Heterocyclic Compound from Algae Sargassum Vachell

A novel eleven-membered heterocyclic compound with high nitrogen has been isolated from the marine alga Sargassum vachell collected from the South China Sea. Its structure has been established by verity of spectroscopic techniques such as IR. EIMS. ID NMR. H-1-(HCOSY)-H-1. HMQC, HMBC.

[(NHC)CrCl(μ-Cl)(THF)]_2 and(NHC)_2CrCl_2(NHC=1,3-Diisopropyl-4,5-dimethylimidazole-2-ylidene):Syntheses,Structures,and Polymerization Activities

The preparation of divalent chromium N-heterocyclic carbene（NHC,1,3-diisopropyl4,5-dimethylimidazole-2-ylidene） compounds is reported.The reaction of 1：1 molar ratio of NHC with CrCl2 led to an isolation of [（NHC）CrCl（μ-Cl）（THF）]2（1）,while that of 2：1 ratio resulted in the formation of（NHC）2CrCl2（2）.1 can be considered as an intermediate in the formation of 2 and further converted into 2 by the addition of another equiv.of NHC.The reaction of 2 with CpNa afforded an ion pair compound [（NHC）2CrCp]＋[Cp]-（3）,indicating a strong coordination ability of NHC supplanting one of the ionic Cr-Cp bonding.In combination of methylalumoxane（MAO） as cocatalyst 1 and 2 both are active for catalyzing ethylene polymerization.

Synthesis and Crystal Structure of 2-Ethoxy-spiro[2H-1, 4,2-benzoxazaphosphorine-3(4H), 1'-Cycloheptane] 2-Oxide

The title compound 2-ethoxy-spiro[2H-1,4,2-benzoxazaphosphorine-3（4H）,1＇-cycloheptane] 2-oxide （C15H22NO3P） was synthesized by the Mannich-type reaction of ο-amino-phenol with ethyl dichlorophosphinite and cycloheptanone, and structurally characterized by single-crystal X-ray diffraction analysis. It crystallizes in orthorhombic, space group P212121 with a = 8.9840（12）, b = 9.2978（12）, c = 37.205（5） A, V= 3107.8（7） ,A^3, Z= 8, Mr = 295.31, Dc = 1.262 g/cm^3, F（000） = 1264, μ = 0.184 mm^-1, S = 1.026, the final R = 0.0502 and wR = 0.1017 for 3849 observed reflections with Ⅰ 〉 2σ（Ⅰ） and 378 variable parameters. The structure exhibits that the six-membered phosphorus heterocycle is in the envelope conformation.

Synthesis, Structure and Antimicrobial Activity of 2-Phenyl-4H-spiro[benzo[e][1,4,2]oxaza- phosphinine-3,3′-indolin]-2′-one 2-oxide

A novel spiro-compound（C20 H15 N2 O3 P） has been synthesized and characterized by means of IR and 1H NMR. Its crystal structure was determined by X-ray diffractometry. The crystal belongs to the monoclinic system, space group P21 /c with a = 9.1628（7）, b = 12.9490（7）, c = 15.7898（11）, β = 103.952（8）o, Mr = 36.08, V = 1818.2（2）3, Z = 4, Dc = 1.382 g/cm3, F（000） = 788, μ = 0.179 mm-1, R = 0.0701 and wR = 0.1513. The preliminary biological test showed that the title compound has activities against Escherichia coli, S.albus, Bacillus subtilis, Staphylocc- ocusaureus and Micrococcus tetragenus with MIC to be 0.038, 0.038, 0.075, 2.48, and 0.15 mg/mL, respectively.

Synthesis, Crystal Structure and Biological Activity of 2-Chloro-5-(((5-(1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl)-4-phenyl-4H-1,2,4-triazol-3-yl)thio)methyl)thiazole

The title compound 5-chloro-2-（（（5-（1-methyl-3-（trifluoromethyl）-1H-pyrazol-4-yl）- 4-phenyl-4H-1,2,4-triazol-3-yl）thio）methyl）thiazole （C17H12ClF3N6S2） was synthesized, and its structure was confirmed by 1H NMR, 13C NMR, HRMS and X-ray diffraction. It crystallizes in the triclinic system, space group P with a = 8.214（5）, b = 10.188（6）, c = 12.378（7） , α = 81.679（8）, β = 87.994（8）, γ = 70.351（8）°, Dc = 1.572 g/cm3, Z = 2, V = 965.2（9） ？3, the final R = 0.0591 and wR = 0.1113 for 3005 observed reflections with I 〉 2σ（I）. The preliminary biological test shows that the title compound possesses good herbicidal activities （80%） against rape at 200 μg/mL.

Synthesis, Structure and Antimicrobial Activity of 9,9-Dimethyl-9,10-dihydrospiro[benzo[a]-xanthene-12,3'-indoline]-2',11(8H)-dione

One novel spiro-compound（C_（26）H_（21）NO_3） has been synthesized and characterized by means of NMR spectroscopy,elemental analyses and X-ray diffraction. The single crystal belongs to the monoclinic system,space group P21/c with a = 8.8039（7）,b = 24.123（2）,c = 10.0751（9） ？,β = 108.403（3）°,M3r = 395.44,V = 2030.3（3） ？~3,Z = 4,D_c = 1.294 g/cm,F（000） = 832.0,μ = 0.085 mm^（-1）,R = 0.0801 and wR = 0.2228. The title compound shows good activities against Micrococcus tetragenus,Bacillus cereus,Bacillus subtilis,Staphylococcus aureus,S.albus and Escherichia coli.

Two Amine-tethered Imidazolium NHC Ni(Ⅱ) Complexes: Synthesis, Structure and Catalytic Activity

Nickel（II） complexes Ni（L1）2 （1） and Ni（L2）2·CH3CN·H2O （2） （L1Cl = 2-（3-benzyl- 2,3-dihydroimidazlo-1-yl）-N-（pyridin-2-yl）acetamide, chloride salt, L2Cl = 2-（3-naphthalene-2- ylmethyl）-2,3-dihydro-imidazlo-1-yl）-N-phenylacetamide, chloride salt） with amide-functionalized imidazolium NHC ligand were synthesized and determined by single-crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic system, space group P21/cwith a = 9.2561（19）, b = 15.138（3）, c = 20.750（4） A, β = 90.216（3）°, V = 2907.3（10） A^3 and Z = 4. Complex 2 crystallizes in the orthorhombic system, space group Pbca with a = 15.5469（16）, b = 15.3521（15）, c = 31.177（3） A, V = 7441.2（13） ？3 and Z = 8. They are stable in the air and formed via intermolecular weak interactions, including C-H···π contacts and C–H···O hydrogen bonds. Complex 1 was applied in Suzuki coupling reaction through the investigation of reaction conditions under the optimal choice conditions： 80 ℃, K3PO4, 3% mol catalysts, 6% mol PPh3 and toluene as solvent system could afford 96% yield in 5 h.

Synthesis and Crystal Structure of 1-(o-methylphenyl)-2-(p-methoxyphenyl)-1,3,2-diazaphospholidin-4-thione-2-sulfide

The crystal structure of the title compound C16H17N2OPS2, has beendetermined by single-crystal X-ray diffraction at 299K. The crystal is monoclinic withspace group P21/n, a=9. 549(2), b= 7- 954(5), c=23. 039(8) A, β= 96. 30(2)°,V= 1739(2) A 3, Z=4, Mr= 348. 3, F(000) = 728, μ(MoKa) =0. 386 mm-1, Dc=1. 331 g/cm3- The final R factor is 0. 044 and Rw is 0. 047 for 1002 observed reflections[I≥3δ(I)]. The five-membered heterocycle has a coplanar structure. The P - N (1)bond length(1. 636 A ) indicates the existence of the d-p π bond between P and N(1)atoms of the title compound.

Synthesis,Crystal Structure and Cytotoxicity Evaluation of 2-Phenoxy-4H-spiro{naphtho[2,3-e][1,4,2] oxazaphosphinane-5,10-dione,1'-cyclohexane} 2-Oxide

2-Phenoxy-4H-spiro { naphtho[2,3-e] [ 1,4,2]oxazaphosphinane-5,10-dione, 1′-cyclo- hexane}2-oxide （C22H20NO5P） was synthesized by the Mannich-type reaction of 2-amino-3- hydroxy-l,4-naphthoquinone with phenyl phosphorodichloridite and cyclohexanone, and structurally characterized by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P2 1/n with a = 7.9133（11）, b = 13.0269（18）, c = 19.091（3） ,A,β = 101.906（2）°, V= 1925.6（5） ,A^3, Z= 4, Mr = 409.36, Dr = 1.412 g/cm^3, F（000） = 856,μ = 0.178 mm^-1, S = 1.015, the final R = 0.0381 and wR = 0.0906 for 2718 observed reflections with 1 〉 2σ（I） and 262 variable parameters. This compound may be used as DNA-intercalator. Its cytotoxic activities were also tested in vitro on four human tumor cell lines.

Crystal Structure of 3-[(α-Phenyl) triphenyl germylethyl]-4-phenyl -Δ￣2-1, 2, 4-triazoline-5-thione

The crystal structure of the title compound, C_34H_29GeN_3S, has been determined by single-crystal X-ray diffraction at 299 (±1)K. The crystal is trichlnic with space group P1, a=9. 772(3), b= 11. 643(3), c= 13. 960(3) A . α=66. 55(2),β=83. 49(2),γ=88. 49(2)°, Z=2, V= 1440. 0(8) A￣3, M_r=584. 28, F(000) =604, μ(MoKα) = 11. 44 cm￣-1. D_c= l. 349 g/cm￣-3. The final R factor is 0. 058, and R_w is 0. 068. The result of X-ray analysis indicates that the heterocycle of the title compound appears as a triazoline instead of a triazole.

Crystal Structure of 1,3-Dibenzyl-2-benzylaminothiocarbonyl-1,3,4- diazaphospholidin-5-thione-4-sulfide

The title compound, C31H30N3OPS3, crystallizes in monoclinic system, space group P21/n,with a = 11.839(7), b = 8.975(5), c = 29.15(2)? b = 100.07(1), V = 3049(3)?, Z = 4, Dc = 1.280g/cm3, Mr = 587.73, F(000) = 1232, m = 0.324mm-1, the final R = 0.0434 and wR = 0.1140 for 4787 observed reflections with I >2s(I). The title compound is a five-membered heterocycle containing a phosphorus, two nitrogen and two carbon atoms.The analysis result shows that the five-membered ring is nearly coplanar. The P(1)N(1) bond length(1.685? indicates the existence of pd?bond between N(1) and P(1) atoms of the title compound.

Synthesis and Crystal Structure of Bis(N’-(Pyridine-3-Carboxaldehyde) Isonicotinoylhydrazone) Zinc(II)

Zinc complexes of Schiff base ligands exhibit interesting properties which could be exploited for potential applications as catalysts and models for biochemical systems. In this study, we report of the synthesis of a new zinc Schiff base complex, bis(N’-(pyridine-3-carboxaldehyde) isonicotinoylhydrazone) zinc(II), which has been characterized by physico-chemical methods. The X-ray single crystal structure of the complex has also been determined. The Schiff base ligand is bonded to the metal in a monodentate manner, coordinating through the pyridine N-atom, as shown from spectral studies. The crystal structure shows the zinc atom bonded to two Schiff bases and four aqua ligands, with each Schiff base ligand coordinating through its pyridine N-atom forming a distorted octahedral ZnN2O4 complex. Two water molecules and two nitrate ions found in the crystal structure link the different monomers through hydrogen bonding to form a layered supramolecular structure.

3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine.Structure and energy abilities as a component of solid composite propellants

The work addresses to the study of the molecular and crystal structure and properties of a new energyintensive compound 3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine(NBTAT),first obtained by the authors in 2020.NBTAT compound crystallizes in the monoclinic system,space group P2(1)/n,density at room temperature 1.939 g/cm^(3).The energies of crystal packing and pairwise intermolecular interactions in NBTAT and its unnitrated analogue BTAT were calculated,and their comparative analysis was carried out.The enthalpy of formation of NBTAT molecules was calculated by quantum-chemical methods using Gaussian 09,and the enthalpy of formation of NBTAT in the solid phase(618 kJ/mol)was estimated.The energy capabilities of NBTAT as an oxidizer of solid composite propellants are estimated.It is shown that in metal-free compositions NBTAT is significantly superior to ammonium perchlorate(AP),dinitramide ammonium salt(ADN),HMX,BTAT at all stages of rocket systems,and is comparable to the superdense CL-20 yielding to the latter at the lower stages and slightly winning at the upper stages.

Synthesis, Characterization and Crystal Structure of Cobalt(II) Complex of a Schiff Base Derived from Isoniazid and Pyridine-4-Carboxaldehyde

A new hydrogen bonded Cobalt(II) Schiff base complex,?N’-(pyridine-4-carboxaldehyde) isonicotinoylhydrazone Cobalt(II), has been synthesized from isoniazid and pyridine-4-carboxaldehyde and characterized by IR spectroscopy, 1H-NMR, elemental analysis, TGA and single crystal X-ray structure determination. X-ray crystal structure analysis shows an octahedral complex with a metal centre coordinated to two ligand molecules through the pyridine nitrogen atoms and four water molecules and containing two nitrate groups as counter ions. The complex crystallizes in the monoclinic crystal system and P2(1)/n space group. The unit cell dimensions are: a = 7.2108(4) Å, b = 16.6020(9) Å, c = 13.0389(6) Å,α = 90°, β = 103.972(4)°, γ = 90°. The molecule is symmetrical about the cobalt centre as observed from the 1H-NMR and 13C-NMR and confirmed by the single crystal X-ray structure of the complex. Thermogravimetric analysis shows two steps decomposition of the complex to leave a metal oxide residue. The title compound is expected to be biologically active as one of the precursors (isoniazid) is a therapeutic agent with well-established clinical applications.

Synthesis and crystal structure of bis (1,3-diisopropyl-4,5-dimethylimidazolium) hexatungstate

The title compound bis（1,3-diisopropyl-4,5-dimethylimidazolium） hexatungstate,[C11H21N2]2[W6O19],was synthesized and characterized by single-crystal X-ray diffraction,IR and elemental analysis.It crystallizes in the monoclinic system,space group P21/n with a=1.112 84（14）,b=1.283 84（17）,c=1.293 28（17）nm,β=96.410（2）°,V=1.836 2（4）nm^3,C22H42N4O19W6,Mr=1 769.70,Dc=3.201 g/cm3,F（000）=1 596,Z=2,μ（Mo Kα）=18.797 mm-1,the final R=0.031 3,wR=0.059 8for observed reflections（I〉2σ（I））.

Crystal and Molecular Structure of 3，4－diphenyl－5－methyl－5－propyl－1，3，4－diazaphospholidin－2－thione－4－sulfide

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Crystal and Molecular Structure of 3，4－diphenyl－5－ethyl－5－methyl－1，3，4－diazaphospholidin－2－thione－4－oxide

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