Abstract. The secure location of node is significant in the WSN (Wireless Sensor Networks) of the troop frontier defence system. The wormhole attack is a big threat in the secure location. The credibility of the beacon node was used to determine the malicious nodes produced by wormhole attack in the WSN. The estimated method of multibeacon nodes was adopted to improve DV-HOP algorithm after excluding the malicious nodes.In this paper,we compared the basic DV-HOP algorithm and the improved DV-HOP algorithm in the coverage percentage and the error of network localization by simulating. The simulation results indicate that the improved DV-HOP algorithm makes the localization coverage percentage can reach 90% on a certain scale of the network,andit makes the error percentage lower when the number of beacons is different.

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The mechanism and origins of site-selectivity of Rh2(S-tfpttl)4-catalyzed C(sp3)–H bond aminations were studied using density functional theory (DFT) calculations. The synergistic combination of the dirhodium complex Rh2(S-tfpttl)4 with tert-butylphenol sulfamate TBPhsNH2 composes a pocket that can access both tertiary and benzylic C–H bonds. The nonactivated tertiary C–H bond was selectively aminated in the presence of an electronically activated benzylic C–H bond. Both singlet and triplet energy surfaces were investigated in this study. The computational results suggest that the triplet stepwise pathway is more favorable than the singlet concerted pathway. In the hydrogen atom abstraction by Rh–nitrene species, which is the rate- and site-selectivity-determining step, there is an attractive π–π stacking interaction between the phenyl group of the substrate and the phthalimido group of the ligand in the tertiary C–H activation transition structure. By contrast, such attractive interaction is absent in the benzylic C–H amination transition structure. Therefore, the DFT computational results clearly demonstrate how the synergistic combination of the dirhodium complex with sulfamate overrides the intrinsic preference for benzylic C–H amination to achieve the amination of the nonactivated tertiary C–H bond.

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