very large structural rearrangement, which cannot be reasonably modeled by
structural indicators of the parent molecule alone.
We thus have successfully designed two new structural indicators, M and K, for
the identification of the trigger bond and weak bonds. If a compound has multiple
weak bonds of the same type, ρ c can help determine the weakest bond. The utilization of these two new structural indicators will become utterly efficient and
effective especially for very large systems with hundreds of bonds.
4 Conclusions
In conclusion, ordinary bond-strength indicators, including R, MIEN, WBO, ρ c , and
W = WBO/R, are not suitable to be used alone to identify the trigger bond, whereas
M = MIEN/R and the better K = W × M are the indicators of choice for sorting out
weak bonds (with BDE < 350 kJ/mol). When there are several bonds carrying the
same smallest M or K, calculations of their ρ c and BDEs must be subsequently
performed to determine the weakest bond. Especially, these two new indicators,
M and K, will become extremely helpful for analyzing bond breaking processes
within large molecular systems by greatly minimizing computational efforts.
Acknowledgements We are grateful to the grant support from the Natural Sciences and Engineering Research Council (NSERC) of Canada, the National Natural Science Foundation of China
(No. 21403110), and the Natural Science Foundation of Jiangsu Province (No. BK20130755).
This work was mainly carried out at UBC during G.X.W.’s one-year visit to UBC from 16 August
2012 to18 August 2013.
References
1. Xu XJ, Xiao HM, Ju XH, Gong XD, Zhu WH (2006) Computational studies on
polynitrohexaazaadmantanes as potential high energy density materials (HEDMs). J Phys
Chem A 110:5929–5933
2. Qiu L, Xiao HM, Gong XD, Ju XH, Zhu WH (2006) Ab initio and molecular dynamics
studies of crystalline TNAD (trans-1,4,5,8-Tetranitro-1,4,5,8-tetraazadecalin). J Phys Chem A
110:3797–3807
3. Qiu LM, Gong XD, Wang GX, Zheng J, Xiao HM (2009) Looking for high energy density
compounds among 1,3-Bishomopentaprismane derivatives with –CN, –NC, and –ONO 2
groups. J Phys Chem A 113:2607–2614
4. Xu XJ, Xiao HM, Gong XD, Ju XH, Chen ZX (2005) Theoretical studies on the vibrational
spectra, thermodynamic properties, detonation properties and pyrolysis mechanisms for
polynitroadamantanes. J Phys Chem A 109:11268–11274
5. Wang GX, Shi CH, Gong XD, Xiao HM (2009) Theoretical investigation on structures,
density, detonation properties and pyrolysis mechanism of the derivatives of HNS. J Phys
Chem A 113:1318–1326
Effective Bond-Strength Indicators
53
structural indicators of the parent molecule alone.
We thus have successfully designed two new structural indicators, M and K, for
the identification of the trigger bond and weak bonds. If a compound has multiple
weak bonds of the same type, ρ c can help determine the weakest bond. The utilization of these two new structural indicators will become utterly efficient and
effective especially for very large systems with hundreds of bonds.
4 Conclusions
In conclusion, ordinary bond-strength indicators, including R, MIEN, WBO, ρ c , and
W = WBO/R, are not suitable to be used alone to identify the trigger bond, whereas
M = MIEN/R and the better K = W × M are the indicators of choice for sorting out
weak bonds (with BDE < 350 kJ/mol). When there are several bonds carrying the
same smallest M or K, calculations of their ρ c and BDEs must be subsequently
performed to determine the weakest bond. Especially, these two new indicators,
M and K, will become extremely helpful for analyzing bond breaking processes
within large molecular systems by greatly minimizing computational efforts.
Acknowledgements We are grateful to the grant support from the Natural Sciences and Engineering Research Council (NSERC) of Canada, the National Natural Science Foundation of China
(No. 21403110), and the Natural Science Foundation of Jiangsu Province (No. BK20130755).
This work was mainly carried out at UBC during G.X.W.’s one-year visit to UBC from 16 August
2012 to18 August 2013.
References
1. Xu XJ, Xiao HM, Ju XH, Gong XD, Zhu WH (2006) Computational studies on
polynitrohexaazaadmantanes as potential high energy density materials (HEDMs). J Phys
Chem A 110:5929–5933
2. Qiu L, Xiao HM, Gong XD, Ju XH, Zhu WH (2006) Ab initio and molecular dynamics
studies of crystalline TNAD (trans-1,4,5,8-Tetranitro-1,4,5,8-tetraazadecalin). J Phys Chem A
110:3797–3807
3. Qiu LM, Gong XD, Wang GX, Zheng J, Xiao HM (2009) Looking for high energy density
compounds among 1,3-Bishomopentaprismane derivatives with –CN, –NC, and –ONO 2
groups. J Phys Chem A 113:2607–2614
4. Xu XJ, Xiao HM, Gong XD, Ju XH, Chen ZX (2005) Theoretical studies on the vibrational
spectra, thermodynamic properties, detonation properties and pyrolysis mechanisms for
polynitroadamantanes. J Phys Chem A 109:11268–11274
5. Wang GX, Shi CH, Gong XD, Xiao HM (2009) Theoretical investigation on structures,
density, detonation properties and pyrolysis mechanism of the derivatives of HNS. J Phys
Chem A 113:1318–1326
Effective Bond-Strength Indicators
53