TY - JOUR
T1 - Three-Dimensional Fully Conjugated Carbaporphyrin Cage
AU - Ke, Xian Sheng
AU - Kim, Taeyeon
AU - He, Qing
AU - Lynch, Vincent M.
AU - Kim, Dongho
AU - Sessler, Jonathan L.
N1 - Publisher Copyright:
© 2018 American Chemical Society.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2018/12/5
Y1 - 2018/12/5
N2 - A fully conjugated three-dimensional (3D) expanded carbaporphyrin (2) was prepared in a one-pot procedure that involves a [2+4] condensation reaction between a dibenzo[g,p]chrysene-bearing tetrapyrrole precursor (1) and pentafluorobenzaldehyde, followed by oxidation. Single crystal X-ray diffraction analysis revealed that 2 possesses a cage-like structure consisting of four dipyrromethenes and two bridging dibenzo[g,p]chrysene units. As prepared, 2 is nonaromatic as inferred from UV-vis-NIR and 1 H NMR spectroscopy and a near-zero (1.75) nucleus-independent chemical shift (NICS) value. In contrast, after protonation with trifluoroacetic acid (TFA), the cage gains global aromatic character as inferred from the large negative NICS value (11.63) and diatropic ring current observed in the anisotropy of the induced current density (ACID) plot, as well as the ca. 8-fold increase in the excited state lifetime. In addition, the size of the cavity increases to ca. 143 Å 3 upon protonation as deduced from a single crystal X-ray diffraction analysis. To our knowledge, this is the largest carbaporphyrin prepared to date and the first with a fully conjugated 3D cage structure whose size and electronic features may be tuned through protonation.
AB - A fully conjugated three-dimensional (3D) expanded carbaporphyrin (2) was prepared in a one-pot procedure that involves a [2+4] condensation reaction between a dibenzo[g,p]chrysene-bearing tetrapyrrole precursor (1) and pentafluorobenzaldehyde, followed by oxidation. Single crystal X-ray diffraction analysis revealed that 2 possesses a cage-like structure consisting of four dipyrromethenes and two bridging dibenzo[g,p]chrysene units. As prepared, 2 is nonaromatic as inferred from UV-vis-NIR and 1 H NMR spectroscopy and a near-zero (1.75) nucleus-independent chemical shift (NICS) value. In contrast, after protonation with trifluoroacetic acid (TFA), the cage gains global aromatic character as inferred from the large negative NICS value (11.63) and diatropic ring current observed in the anisotropy of the induced current density (ACID) plot, as well as the ca. 8-fold increase in the excited state lifetime. In addition, the size of the cavity increases to ca. 143 Å 3 upon protonation as deduced from a single crystal X-ray diffraction analysis. To our knowledge, this is the largest carbaporphyrin prepared to date and the first with a fully conjugated 3D cage structure whose size and electronic features may be tuned through protonation.
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U2 - 10.1021/jacs.8b11158
DO - 10.1021/jacs.8b11158
M3 - Article
C2 - 30452259
AN - SCOPUS:85057818009
VL - 140
SP - 16455
EP - 16459
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 48
ER -