TY - JOUR
T1 - Extraction of One-Handed Helical Frontier Orbital in even [ n]Cumulenes by Breaking Mirror Images of Right- and Left-Handed Helical Orbitals
T2 - Theoretical Study
AU - Orimoto, Yuuichi
AU - Aoki, Yuriko
AU - Imamura, Akira
N1 - Funding Information:
The authors thank Ikuko Okawa for her technical support to this study including computations and data reduction. The authors acknowledge financial support for this work by JSPS/ MEXT (KAKENHI: 23245005, 16KT0059, 25810103, 15KT0146, and 16K08321), and JST-CREST. All the computations were carried out using Linux OS systems in our group and computing facilities in the Research Institute for Information Technology, Kyushu University.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/5/2
Y1 - 2019/5/2
N2 - Even [n]cumulenes with an even number n of double bonds are known to have degenerate helical frontier orbitals even in linear-chain structures. Theoretical analysis was conducted to separate one-handed helical orbitals from the others in cumulenes to determine their enantioselective chemical/physical properties. Donor ((NH2)3C-) and acceptor ((NO2)3C-) substituents separate the degenerate energy levels of right- and left-handed helical frontier orbitals in even [n]cumulenes. Lone pairs (LPs) in the donor group can interact with helical orbitals on the cumulene backbone, leading to "LP-helical orbital" interactions. A difference in the manner of interaction between left- and right-handed orbitals, depending on the LP direction, breaks the mirror symmetry between them. Consequent energy splitting between left- and right-handed orbitals results in extraction of a one-handed helical frontier orbital only. This is the first example of extracting a one-handed helical frontier orbital while maintaining sufficiently large energy splitting in even [n]cumulene in the framework of C1 molecular symmetry by donor-acceptor substitutions.
AB - Even [n]cumulenes with an even number n of double bonds are known to have degenerate helical frontier orbitals even in linear-chain structures. Theoretical analysis was conducted to separate one-handed helical orbitals from the others in cumulenes to determine their enantioselective chemical/physical properties. Donor ((NH2)3C-) and acceptor ((NO2)3C-) substituents separate the degenerate energy levels of right- and left-handed helical frontier orbitals in even [n]cumulenes. Lone pairs (LPs) in the donor group can interact with helical orbitals on the cumulene backbone, leading to "LP-helical orbital" interactions. A difference in the manner of interaction between left- and right-handed orbitals, depending on the LP direction, breaks the mirror symmetry between them. Consequent energy splitting between left- and right-handed orbitals results in extraction of a one-handed helical frontier orbital only. This is the first example of extracting a one-handed helical frontier orbital while maintaining sufficiently large energy splitting in even [n]cumulene in the framework of C1 molecular symmetry by donor-acceptor substitutions.
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U2 - 10.1021/acs.jpcc.9b01829
DO - 10.1021/acs.jpcc.9b01829
M3 - Article
AN - SCOPUS:85065306441
SN - 1932-7447
VL - 123
SP - 11134
EP - 11139
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 17
ER -