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The effect of ionization and CH 3 ligand for hydrogen storage in Co‐ and Ni‐based organometallic compounds
Author(s) -
Guo JingHua,
Zhang Hong,
Miyamoto Yoshiyuki,
Cheng XinLu
Publication year - 2011
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.22944
Subject(s) - chemistry , ligand (biochemistry) , ring (chemistry) , hydrogen storage , molecule , transition metal , hydrogen , crystallography , group 2 organometallic chemistry , metal , stereochemistry , catalysis , organic chemistry , biochemistry , receptor
Maximum capacities of the hydrogen storage in organometallic compounds consisting of Co and Ni atoms bound to C m H m ring ( m = 4, 5; capped type) were, respectively, found as 3.48 and 3.49 wt % (Guo et al., Struct Chem, 2009, 20, 1107). Here, we extend this study to structures having a transition metal (TM) inserted in C m H m ring (inserted type), having TM located on either a C 4 H 4 +or a C 5 H 5 +molecule, and the CH 3 ligand bound to the organometallic compounds. We find that for the CoC 4 H 4 and NiC 4 H 4 complexes, the capped types are 1.39 eV and 1.41 eV higher in energy than the inserted types, respectively, while the ground states for CoC 5 H 5 and NiC 5 H 5 complexes are found to be the capped type, which are lower than the inserted types, respectively, by 1.27 eV and 1.31 eV. The maximum capacity of hydrogen storage reached 5.13 wt % for both of CoC 4 H 4 + (H 2 ) 3 complex and the inserted‐type CoC 4 H 4 (H 2 ) 3 complex with a reasonable binding energy (0.3–1.0 eV per H 2 ). The positively charged C 4 H 4 and C 5 H 5 molecules do not only improve the capacity of hydrogen storage but also make all H 2 adsorbing in molecular form and keep the adsorption energy in an ideal range. After adding the CH 3 ligand to the compounds, the average adsorption energy of H 2 decreased to an ideal range 0.61–0.94 eV per H 2 and the stability of the compounds is also improved. Finally, we analyze the HOMO–LUMO gaps and display the kinetic stability when H 2 was added to organometallic compounds. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010