Natural Bound Orbital Analysis Of CL-20 As A Second Order Fock Matrix

Introduction CL-20 is a energetic compound with high density, good oxygen balance (-11%) and high explosive power. However, CL-20 has failed to see widespread implementation due to high mechanical sensitivity, it is relatively easily detonated by physical forces in comparison to other secondary explosives. While cocrystal CL-20/TNT exhibited a mechanical impact sensitivity greatly reduced relative to that of pure CL-20, it was also expected to feature reduced explosive power due to the incorporation of TNT, which is a low-power energetic. Given that interest in CL-20 has been driven by the high explosive power of the compound, a marked reduction in this property, even if it comes with a very attractive reduction in sensitivity,
NBO analysis Natural Bound Orbital (NBO) analysis can provide a convenient basis for investigation of charge transfer or conjugative interactions in molecular system. The second order Fock matrix was carried out to evaluate the donor–acceptor interactions in the NBO analysis. For each donor (i) and acceptor (j), the stabilization energy E(2)which associates with electrondelocalization between i and j is estimated asthe following equation.
E(2) = - qi(F i j 2/εj-εi) ........................................................................ (1.1) where qi is the donor orbital occupancy,εi and εj are diagonal elements and Fi j is the off diagonal NBO Fock matrix
Donor NBO(i) Acceptor NBO(j) E(2) (kcal•mol-1)a
LP(3) O2 BD*(1) O1-N14 44.09
LP(3) O2 BD*(2) O2-N14 66.48
LP(3) O39 BD*(1) O40-N52 111.90
LP(3) O41 BD*(1) O42-N54 101.53
LP(3) O45 BD*(1) O46-N58 188.89
LP(3) O47 BD*(1) O48-N60 190.07
LP(3) O74 BD*(1) O73-N78 150.27
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LP(3) O75 BD*(1) O76-N80 157.09
LP(3) O87 BD*(1) O88-N92 188.68
LP(3) O89 BD*(1) O90-N94 152.01

5 Conclusions A Cl-20/HMX cocrystal was prepared by solvent non-solvent cocrystallization .this cocrystal is mainly formed by CH….N and CH….O hydrogen bonds and π interactions. The cocrystal has an exothermic point at 247.79°c.we can see that the cocrystallization is an effective method to improve energetic materials