TY - JOUR
T1 - Density functional study of cucurbituril and its sulfur analogue
AU - Pichierri, Fabio
N1 - Funding Information:
The author is thankful to the Japan Atomic Energy Research Institute (JAERI) for granting access to its ITBL supercomputer. The useful comments of an anonymous referee are gratefully acknowledged. Financial support for this work has been provided by the 21st century Center of Excellence (COE) program `Giant Molecules and Complex Systems' of MEXT hosted at Tohoku University.
PY - 2004/5/21
Y1 - 2004/5/21
N2 - The molecular and electronic structures of cucurbituril (CB) and its sulfur analogue, thia-cucurbituril (TCB), have been investigated by means of density functional theory (DFT) calculations. The HOMO-LUMO (H-L) energy gap of CB is ∼7 eV and it decreases at ∼4 eV upon replacement of its twelve oxygen atoms with sulphur atoms. The vertical ionization potential (IP) of CB and TCB are rather large, being ∼7 and 6 eV, respectively. The vertical electron affinity (EA) of CB calculated in the gas-phase is negative (about -2 eV), thus suggesting that its anion is thermodynamically unstable. On the other hand, formation of the TCB anion might be favoured in electron-donating solvents since its calculated vertical EA is close to zero. An analysis of the Kohn-Sham frontier orbitals of CB and TCB indicates that neither the HOMO nor the LUMO is degenerate.
AB - The molecular and electronic structures of cucurbituril (CB) and its sulfur analogue, thia-cucurbituril (TCB), have been investigated by means of density functional theory (DFT) calculations. The HOMO-LUMO (H-L) energy gap of CB is ∼7 eV and it decreases at ∼4 eV upon replacement of its twelve oxygen atoms with sulphur atoms. The vertical ionization potential (IP) of CB and TCB are rather large, being ∼7 and 6 eV, respectively. The vertical electron affinity (EA) of CB calculated in the gas-phase is negative (about -2 eV), thus suggesting that its anion is thermodynamically unstable. On the other hand, formation of the TCB anion might be favoured in electron-donating solvents since its calculated vertical EA is close to zero. An analysis of the Kohn-Sham frontier orbitals of CB and TCB indicates that neither the HOMO nor the LUMO is degenerate.
UR - http://www.scopus.com/inward/record.url?scp=2342469992&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=2342469992&partnerID=8YFLogxK
U2 - 10.1016/j.cplett.2004.04.006
DO - 10.1016/j.cplett.2004.04.006
M3 - Article
AN - SCOPUS:2342469992
SN - 0009-2614
VL - 390
SP - 214
EP - 219
JO - Chemical Physics Letters
JF - Chemical Physics Letters
IS - 1-3
ER -