TY - JOUR
T1 - β-Octamethoxy-Substituted 22π and 26π Stretched Porphycenes
T2 - Synthesis, Characterization, Photodynamics, and Nonlinear Optical Studies
AU - Rana, Anup
AU - Lee, Sangsu
AU - Kim, Dongho
AU - Panda, Pradeepta K.
N1 - Publisher Copyright:
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - Three meso-expanded tetrapyrrolic aromatic macrocycles, including 22π and 26π acetylene-cumulene bridged stretched octamethoxyporphycenes and octamethoxy[22]porphyrin-(2.2.2.2), are reported, for the first time, by modification of previously reported synthetic methods. This strategy led to an enhancement in the overall yield of their corresponding octaethyl analogues. The methoxy-substituted expanded porphycenes display slightly blueshifted absorption relative to their ethyl analogues, along with very weak fluorescence, probably due to efficient intramolecular charge transfer (ICT). Additionally, the two-photon absorption (TPA) cross sections of these macrocycles were evaluated; these are strongly related to core expansion of the porphyrin aromaticity through increased meso-bridging carbon atoms as well as conformational flexibility and substitution effects at the macrocyclic periphery. In particular, the octamethoxy stretched porphycenes display strong TPA compared with the octaethyl analogues due to the dominant ICT character of methoxy groups with a maximum TPA cross section of 830 GM at 1700 nm observed for 26π-octamethoxyacetylene-cumuleneporphycene.
AB - Three meso-expanded tetrapyrrolic aromatic macrocycles, including 22π and 26π acetylene-cumulene bridged stretched octamethoxyporphycenes and octamethoxy[22]porphyrin-(2.2.2.2), are reported, for the first time, by modification of previously reported synthetic methods. This strategy led to an enhancement in the overall yield of their corresponding octaethyl analogues. The methoxy-substituted expanded porphycenes display slightly blueshifted absorption relative to their ethyl analogues, along with very weak fluorescence, probably due to efficient intramolecular charge transfer (ICT). Additionally, the two-photon absorption (TPA) cross sections of these macrocycles were evaluated; these are strongly related to core expansion of the porphyrin aromaticity through increased meso-bridging carbon atoms as well as conformational flexibility and substitution effects at the macrocyclic periphery. In particular, the octamethoxy stretched porphycenes display strong TPA compared with the octaethyl analogues due to the dominant ICT character of methoxy groups with a maximum TPA cross section of 830 GM at 1700 nm observed for 26π-octamethoxyacetylene-cumuleneporphycene.
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U2 - 10.1002/chem.201501299
DO - 10.1002/chem.201501299
M3 - Article
AN - SCOPUS:84938740454
VL - 21
SP - 12129
EP - 12135
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 34
ER -