The skeleton of 5,7-fused bicyclic imidazole-diazepine for heat-resistant energetic materials

In light of the low yields and complex reaction routes of some well-known 5,5-fused and 5,6-fused bicyclic compounds,a series of 5,7-fused bicyclic imidazole-diazepine compounds were developed with high yields by only two efficient steps.Significantly,the seven-membered heterocyclic ring has a stable energetic skeleton with multiple modifiable sites.However,the 5,7-fused bicyclic energetic compounds were rarely reported in the area of energetic materials.Three neutral compounds 1,2 and 4 were synthesized in this work.To improve the detonation performances of the 5,7-fused neutral compounds,corresponding perchlorate 1a and 2a were further developed.The physicochemical and energetic performances of all newly developed compounds were experimentally determined.All newly prepared energetic compounds exhibit high decomposition temperatures(Td:243.8-336℃)and low mechanical sensitivities(IS:>15 J,FS:>280 N).Among them,the velocities performances of 1a(Dv=7651 m/s)and 4(Dv=7600 m/s)are comparable to that of typical heat-resistant energetic material HNS(Dv=7612 m/s).Meanwhile,the high decomposition temperature and low mechanical sensitivities(Td=336℃;IS=32 J;FS>353 N)of 4 are superior to that of HNS(Td=318℃;IS=5 J;FS=250 N).Hence,the 5,7-fused bicyclic compounds with high thermostability,low sensitivities and adjustable detonation performance have a clear tendency to open up a new space for the development of heat-resistant energetic materials.

Ultrasensitive detection of methamphetamine by antibody-modified transistor assay

Effective detection of methamphetamine(Met)requires a fast,sensitive,and cheap testing assay.However,commercially available methods require expensive instruments and highly trained operators,which are time-consuming and labor-intensive.Herein,an antibody-modified graphene transistor assay is developed for sensitive and minute-level detection of Met in complex environments.The anti-Met probe captured charged targets within 120 s,leading to a p-doping effect near the graphene channel.The limit of detection reaches 50 aM(5.0×10^(-17)M)Met in solution.The graphene transistor would be a valuable tool for Met detection effective prevention of drug abuse.