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Series of 1,2,4-triazole Schiff bases (2a-2d, 2f-2h and 3a-3h) have been designed and synthesized. The structure of title compounds was confirmed on the basis of their spectral data and elemental analysis. All the target compounds were screened for their in vitro antifungal activity and antibacterial activity. Two of the tested compounds (2a and 2b) exhibited significant antifungal activity against most fungi, especially compound 2a showed better antifungal activity than triadimefon. Meanwhile, the antibacterial activity assay also indicated compound 2a exhibited excellent antibacterial activities comparable to chloramphenicol. The SAR manifested no substitution at position 5 of the triazole ring caused an increase in activity, and 3-phenoxy phenyl group introduced in 1,2,4-triazole scaffold can enhance the antibacterial activity. The DFT calculation indicated triazole ring, S atom and benzene ring in both of the 2a and 3a make a major contribution to the activity.

In this study, novel solid–solid phase change materials (PCM) composed of polyacrylonitrile, binary of fatty acids ((blending of stearic acid (SA) and lauric acid (LA)) and zeolite molecular sieve (ZMS) were prepared by solution blending process. The structure and properties of the PCM were characterized using flourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), polarized optical microscopy (POM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TG), respectively. DSC analysis indicated that the crystallization latent heat of the PCM was 125.22 J/g and its phase transition temperature was about 17 °C. The temperature curve for step cooling of the PCM showed that it’s holding time achieved 1 480 s, which explains that the PCM had excellent heat-insulating properties. Based on all results it can be concluded that the novel PCM can be considered as potential PCM for thermal energy storage.

A series of novel Mannich base derivatives (E1–E15) of 5-aryl-1,3,4-oxadiazole-2-thione with substituted pyrimidine were synthesized and characterized by elemental analysis, IR, 1H-NMR. The antifungal activities of these compounds were also originally studied. The results showed that most of the title compounds exhibited relatively good fungicidal activities. Especially compounds E8 and E13 showed better antifungal activity than comparison compound hymexazol. The relationship of structure and activity revealed that the presence of the methyl group at four and six positions of pyrimidine ring remarkably enhanced the antifungal activity of title compounds.

5-Propyl-4-amino-1,2,4-triazole Schiff base was characterized by FT-IR, 1H NMR and X-ray single crystal diffraction techniques. The compound crystallizes in the triclinic space group p-1 with z = 2. The molecular geometry was optimized using density functional theory (DFT/B3LYP) and hartree fock (HF) methods with the 6-311G+(d,p) and 6-311G basis set in ground state. From the optimized geometry of the molecule, vibrational frequencies, HOMO–LUMO and natural bond orbital (NBO) were calculated with B3LYP/6-311G+(d,p) level. In addition, gauge independent atomic orbital (GIAO) 1H NMR chemical shift values was calculated at B3LYP/6-311G+(d,p) and HF/6-311G+(d,p) level.

The 4,5-dihydro-1,2,4-triazole Schiff base derivatives were synthesized with 4-amino-4,5-dihydro-3-(phenoxy- methyl)-1H-1,2,4-triazole-5-thione and substituted benzaldehydes. The chemical structures of the compounds have been confirmed by 1H NMR, IR spectra and elemental analysis. Their biological activities were investigated, and the results showed that they exhibited good fungicidal activities.

Eight Schiff bases of 3-amino-1H-1,2,4-triazole have been synthesized by glacial acetic acid catalyzed condensation of 3-amino-1H-1,2,4-triazole with substituted benzaldehyde and structurally confirmed by IR, 1H NMR and elemental analysis. The preliminary bioassay showed that the title compounds exhibited good fungicidal activities.

Eight Schiff bases have been synthesized using 3-alkyl-4-amino-1,2,4-triazole-5-thione and substituted benzaldehyde as starting materials. The structures of the compounds have been confirmed by 1H NMR, IR and elemental analysis and their biological activities to five vegetable pathogens have been tested. The results showed that they exhibited good fungicidal activities.

Six novel Schiff bases have been synthesized by the condensation reaction of 4-amino-5-(4-pyridyl)-2,4-dihy- dro-1,2,4-triazole-3-thione with various benzaldehydes. The structures of the compounds have been confirmed by 1H NMR, IR and elemental analysis. The preliminary bioassay indicated that the title compounds possessed good fungicidal activities to several vegetable pathogens.

Seven pyrimethanil salts were synthesized by organic base containing nitrogen atom reacting with substituted pyridine acids. They are reported for the first time. Their structures have been confirmed by IR, 1H NMR and elemental analysis. The preliminary toxicity tests indicated that most of them exhibited excellent fungicidal activities. The relationship between the structures and the fungicidal activities of the compounds was discussed.

The low-temperature heat capacities of myclobutanil (C15H17CIN4) were precisely measured with an automated adiabatic calorimeter over the temperature range from 78 to 368 K. The sample was observed to melt at (348.800 +/- 0.06) K. The molar enthalpy and entropy of the melting as well as the chemical purity of the substance were determined to be Delta(fus)H(m) = (30931 +/- 11) J.mol(-1), Delta(fus)S(m) = (88.47 +/- 0.02) J.mol(-1).K-1 and 99.41%, respectively. Further research of the melting process for this compound was carried out by means of DSC technique. The result was in agreement with that obtained from the measurements of heat capacities.

Pyrimethanil myristic salt was synthesized and its heat capacities were measured with an automated adiabatic calorimeter over the temperature range from T=(79 to 360) K.The melting point, molar enthalpy, ΔfusHm and entropy, ΔfusSm, of fusion of this compound were determined to be (321.84 ± 0.05) K, (56.53 ± 0.03) kJ · mol−1 and (175.64 ± 0.05) J · mol−1 · K−1, respectively. The purity of the compound was calculated to be 98.99 mol% by using the fractional melting technique. The thermodynamic functions relative to the reference temperature, T=298.15 K, were calculated based on the heat capacity measurements in the temperature ranges from T=(80 to 360) K. The TG-DTG results demonstrate that the mass loss of the sample takes place in one step with the maximum rate at T=500 K, which was caused by evaporation of the sample.

Series of isoxazole derivatives were synthesized by substituted chalcones and 2-chloro-6-fluorobenzene formaldehyde oxime with 1,3-dipolar cycloaddition. The target compounds were determined by melting point, IR, 1H NMR, elemental analyses and HRMS. The crystal structure of compound 3a was detected by X-ray diffraction and it crystallizes in the triclinic space group p2(1)/c with z = 4. The molecular geometry of compound 3a was optimized using density functional theory (DFT/B3LYP) method with the 6-31G+(d,p) basis set in the ground state. From the optimized geometry of the molecule, FT-IR, FT-Raman, HOMO–LUMO and natural bond orbital (NBO) were calculated at B3LYP/6-31G+(d,p) level. Finally, the antifungal activity of the synthetic compounds were evaluated against Pythium solani, Gibberella nicotiancola, Fusarium oxysporium f.sp. niveum and Gibberella saubinetii.

The 4,5-dihydro-1,2,4-triazole Schiff base derivatives were synthesized with 4-amino-4,5-dihydro-3-(phenoxy- methyl)-1H-1,2,4-triazole-5-thione and substituted benzaldehydes. The chemical structures of the compounds have been confirmed by 1H NMR, IR spectra and elemental analysis. Their biological activities were investigated, and the results showed that they exhibited good fungicidal activities.

Eight Schiff bases of 3-amino-1H-1,2,4-triazole have been synthesized by glacial acetic acid catalyzed condensation of 3-amino-1H-1,2,4-triazole with substituted benzaldehyde and structurally confirmed by IR, 1H NMR and elemental analysis. The preliminary bioassay showed that the title compounds exhibited good fungicidal activities.

Eight Schiff bases have been synthesized using 3-alkyl-4-amino-1,2,4-triazole-5-thione and substituted benzaldehyde as starting materials. The structures of the compounds have been confirmed by 1H NMR, IR and elemental analysis and their biological activities to five vegetable pathogens have been tested. The results showed that they exhibited good fungicidal activities.