Preparation and properties of phase-change materials with enhanced radial thermal conductivities based on anisotropic graphene aerogels.

In this study, anisotropic graphene aerogels are prepared using the heat-flow method. Then, graphene aerogels with nanosilver particles are prepared via a silver mirror reaction. The aerogels are soaked in paraffin wax and the effects on the properties of the wax are investigated. The thermal conductivity of pure paraffin wax is 0.2553 W m-1 K-1. For the prepared PCM, the aerogel content was 0.92 vol%; this increases to 1.2234 W m-1 K-1, which corresponds to a thermal conductivity enhancement efficiency of 582%. The axial thermal conductivity is 1.4953 W m-1 K-1, which corresponds to a thermal conductivity enhancement efficiency of 746%. The graphene aerogels with the nanosilver particles show high phase-change efficiency. Owing to the significant improvements in the axial and thermal conductivities, the radial and axial heat transfer properties show good consistency suitable for practical applications.

Synthesis and Biological Evaluation of Dipeptide-Based Stilbene Derivatives Bearing a Biheterocyclic Moiety as Potential Fungicides.

The escalating demand for crop production, environmental protection, and food safety warrants the development of new fungicides with greater efficiency, environmental friendliness, and innocuous metabolites to fight against destructive phytopathogens. Herein, we report on the synthesis and antifungal activity of dipeptide-based stilbene derivatives bearing a thiophene-substituted 1,3,4-oxadiazole fragment for the first time. In vitro bioassay indicated that the target compounds had remarkable antifungal potency superior to previously reported counterparts without a dipeptidyl group, of which compound 3c exhibited the highest activity against Botrytis cinerea with EC50 values of 106.1 µg/mL. Moreover, the in vivo protective effect of compound 3c (59.1%) against tomato gray mold was more potent than that of carboxin (42.0%). Preliminary investigations on the mode of action showed that compound 3c induced marked hyphal malformations and increased the membrane permeability of B. cinerea as well as inhibiting mycelial respiration. These promising results suggest that this novel type of molecular framework has great potential to be further developed as alternative fungicides.

Synthesis, fluorescence properties and applications of two novel oxadiazole-based stilbene optical brighteners as UV protectants for insect baculovirus.

Two novel symmetrical stilbene optical brighteners based on 1,3,4-oxadiazole bearing sodium sulfonate unit were synthesized. The two target compounds were characterized by NMR and elemental analysis. The photophysical processes of the target compounds were investigated by UV-Vis absorption and fluorescence emission spectra in different solutions. The two optical brighteners were tested as radiation protectants for the Spodoptera litura nuclear polyhedrosis virus (SINPV) against 2nd-instar S. litura larvae. The results indicate that the two compounds exhibit strong blue fluorescence emission, and the fluorescence quantum yield in DMF is 0.86 and 0.75, respectively. The insecticidal effect of SINPV is increased by the addition of the two compounds and especially the compound 3b shows more obvious synergy effect.

Synthesis and optical properties of two novel stilbene derivatives containing 1,3,4-oxadiazole moiety.

Two novel stilbene derivatives containing 1,3,4-oxadiazole moiety were synthesized and characterized by elemental analyses, (1)H NMR, MS. The photophysical processes of the title compounds were investigated by UV-vis absorption and fluorescence emission spectra in different solutions. The fluorescence quantum yield (Phi) of 1a and 1b in THF is 0.65 and 0.69, respectively. The influence of the solution on the fluorescence intensities was also discussed. Under ultraviolet light excitation, the two compounds exhibit strong blue fluorescence emission. They may serve as potential applications in organic electroluminescent materials.

Mesaconitine.

The title compound, (1α,3α,6α,14α,15α,16ß)-3,8,13,14,15-penta-hydr-oxy-1,6,16-trimeth-oxy-4-methoxy-methyl-20-methyl-acon-itan-8,14-diyl 8-acetate 14-benzoate, C(33)H(45)NO(11), a C(19) diterpenoid alkaloid, obtained from the roots of Aconitum kusnezoffii, has been crystallographically characterized in this study. Rings A, B and E have chair conformations, rings C and F display envelope conformations, and ring D adopts a boat conformation. There are inter- and intra-molecular O-H⋯O hydrogen bonds, the latter resulting in the formation of a non-planar seven-membered ring. The inter-molecular inter-actions link the mol-ecules into a two-dimensional network.

1-[2-(3,4-Dichloro-phen-yl)-5-(3,4,5-trimethoxy-phen-yl)-2,3-dihydro-1,3,4-oxadiazol-3-yl]ethanone.

The title compound, C(19)H(18)Cl(2)N(2)O(5), was synthesized by the reaction of N'-(3,4-dichloro-benzyl-idene)-3,4,5-trimethoxy-benzo-hydrazide and acetic anhydride. The oxadiazole ring makes dihedral angles of 82.82 (7) and 9.92 (7)° with the 3,4-dichloro-benzene and the 3,4,5-trimethoxy-benzene ring planes, respectively. The crystal structure is stabilized by inter-molecular C-H⋯ O and C-H⋯ N hydrogen bonds. Intra-molecular C-H⋯O and C-H⋯N hydrogen bonds are also present.

N'-(2-Bromo-benzyl-idene)-3,4,5-tri-methoxy-benzohydrazide methanol solvate.

The title compound, C(17)H(17)BrN(2)O(4)·CH(4)O, was synthesized by the condensation of 3,4,5-trimethoxy-benzohydrazide and 2-bromo-benzaldehyde. The two aromatic rings are approximately planar, the dihedral angle being 3.08 (9)°. The mol-ecules are linked by inter-molecular N-H⋯O and O-H⋯O hydrogen bonds into chains along the a axis.

N'-(4-Fluoro-benzyl-idene)-3,4,5-trimethoxy-benzohydrazide.

The title compound, C(17)H(17)FN(2)O(4), is of inter-est due to its potential pharmaceutical and agrochemical activity. All three meth-oxy groups are twisted with respect to the attached aromatic ring [C-C-O-C torsion angles = 10.43 (18), 97.38 (14), -19.34 (17)°] and the phenyl ring makes a dihedral angle of 40.6 (2)° with the plane through the remaining atoms in the mol-ecule. Inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into chains running along the c axis.

N'-(2-Chloro-benzyl-idene)-3,4,5-tri-methoxy-benzohydrazide methanol solvate.

In the title compound, C(17)H(17)ClN(2)O(4)·CH(4)O, the dihedral angle between the benzene ring planes is 5.29 (6)°. Inter-molecular N-H⋯O and O-H⋯O hydrogen bonds link the mol-ecules into a chain along the a axis.