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Title: Quantum chemical replica-exchange umbrella sampling molecular dynamics simulations reveal the formation mechanism of iron phthalocyanine from iron and phthalonitrile

Phthalocyanine (Pc) and its metal complexes (MPcs) have been used industrially since their discovery in the early 20th century. The phthalonitrile (PN) method is a well-known synthesis method in which Pc or MPc can be afforded by heating a mixture of PN and metal powders over 280 °C with only moderate yield. However, the formation mechanism of the phthalocyanines and the intermediate stages of this seemingly simple reaction have yet to be fully understood. To study this mechanism computationally, we carried out quantum chemical molecular dynamics (MD) simulations based on the density-functional tight-binding (DFTB) method, applying the replica-exchange umbrella sampling (REUS) method, starting from four PN molecules and one iron atom. The DFTB-REUS-MD simulations successfully yielded FePc, and a metastable structure very similar to FePc but with a reactive nitrene unit was also identified that might explain the incomplete conversion of the reactants into FePc. Furthermore, analysis of the MD trajectories reveals a three-step FePc formation mechanism for the PN method.
Authors:
 [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4]
  1. Nagoya Univ., Nagoya (Japan)
  2. Nagoya Univ., Nagoya (Japan); Chinese Academy of Sciences, Changchun (People's Republic of China)
  3. Nagoya Univ., Nagoya (Japan); JST-CREST, Nagoya (Japan)
  4. Nagoya Univ., Nagoya (Japan); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 149; Journal Issue: 7; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; phthalocyanine; phthalonitrile; density-functional tight-binding; replica-exchange umbrella sampling; formation mechanism
OSTI Identifier:
1474873
Alternate Identifier(s):
OSTI ID: 1460501

Ito, Shingo, Wang, Ying, Okamoto, Yuko, and Irle, Stephan. Quantum chemical replica-exchange umbrella sampling molecular dynamics simulations reveal the formation mechanism of iron phthalocyanine from iron and phthalonitrile. United States: N. p., Web. doi:10.1063/1.5026956.
Ito, Shingo, Wang, Ying, Okamoto, Yuko, & Irle, Stephan. Quantum chemical replica-exchange umbrella sampling molecular dynamics simulations reveal the formation mechanism of iron phthalocyanine from iron and phthalonitrile. United States. doi:10.1063/1.5026956.
Ito, Shingo, Wang, Ying, Okamoto, Yuko, and Irle, Stephan. 2018. "Quantum chemical replica-exchange umbrella sampling molecular dynamics simulations reveal the formation mechanism of iron phthalocyanine from iron and phthalonitrile". United States. doi:10.1063/1.5026956.
@article{osti_1474873,
title = {Quantum chemical replica-exchange umbrella sampling molecular dynamics simulations reveal the formation mechanism of iron phthalocyanine from iron and phthalonitrile},
author = {Ito, Shingo and Wang, Ying and Okamoto, Yuko and Irle, Stephan},
abstractNote = {Phthalocyanine (Pc) and its metal complexes (MPcs) have been used industrially since their discovery in the early 20th century. The phthalonitrile (PN) method is a well-known synthesis method in which Pc or MPc can be afforded by heating a mixture of PN and metal powders over 280 °C with only moderate yield. However, the formation mechanism of the phthalocyanines and the intermediate stages of this seemingly simple reaction have yet to be fully understood. To study this mechanism computationally, we carried out quantum chemical molecular dynamics (MD) simulations based on the density-functional tight-binding (DFTB) method, applying the replica-exchange umbrella sampling (REUS) method, starting from four PN molecules and one iron atom. The DFTB-REUS-MD simulations successfully yielded FePc, and a metastable structure very similar to FePc but with a reactive nitrene unit was also identified that might explain the incomplete conversion of the reactants into FePc. Furthermore, analysis of the MD trajectories reveals a three-step FePc formation mechanism for the PN method.},
doi = {10.1063/1.5026956},
journal = {Journal of Chemical Physics},
number = 7,
volume = 149,
place = {United States},
year = {2018},
month = {7}
}