TY - JOUR
T1 - Bis-Metal Complexes of Doubly N-Confused Dioxohexaphyrins as Potential Near-Infrared-II Photoacoustic Dyes
AU - Shimomura, Keito
AU - Kai, Hiroto
AU - Nakamura, Yuma
AU - Hong, Yongseok
AU - Mori, Shigeki
AU - Miki, Koji
AU - Ohe, Kouichi
AU - Notsuka, Yusuke
AU - Yamaoka, Yoshihisa
AU - Ishida, Masatoshi
AU - Kim, Dongho
AU - Furuta, Hiroyuki
PY - 2020/3/4
Y1 - 2020/3/4
N2 - We investigated the detailed photophysical properties of a series of bis-metal (Zn and Cu) dioxohexaphyrin complexes as potential second near-infrared (NIR-II)-light responsive dyes. A cisoid-configured 28π-electron-conjugated dioxohexaphyrin analogue (c-3a) containing two peculiar "confused pyrrole"moieties in the framework is identified as a reduced isomer derivative of a transoid 26π-dioxohexaphyrin (t-2a). The symmetry-altered structure of c-3a affords a heteroleptic inner environment within the NNNN/NNOO donor core, which imparts its highly flexible electronic features and nonplanar geometry. The macrocycle c-3a can be transformed into the corresponding 26π-electron congener (c-2a) having a coplanar rectangular structure by unique solvent-mediated redox reactivity. Furthermore, upon metal complexation, saddle-distorted bis-metal complexes (c-M2-2a) were formed as the 26π-conjugated structural isomer of the trans-dioxohexaphyrin species (i.e., t-M2-2a). These isoelectronic dioxohexaphyrins demonstrate precise geometry-dependent photophysical properties. Broad tailing NIR-II absorption, weak emissive character, and rapid-decay of the S1 state are observed for c-Zn2-2a. In contrast, the coplanar t-M2-2a exhibits efficient photoacoustic response upon laser excitation with NIR-II light (λ > 1000 nm). To the best of our knowledge, this is the first example of an expanded porphyrin-based photoacoustic contrast agent responsive to NIR-II light.
AB - We investigated the detailed photophysical properties of a series of bis-metal (Zn and Cu) dioxohexaphyrin complexes as potential second near-infrared (NIR-II)-light responsive dyes. A cisoid-configured 28π-electron-conjugated dioxohexaphyrin analogue (c-3a) containing two peculiar "confused pyrrole"moieties in the framework is identified as a reduced isomer derivative of a transoid 26π-dioxohexaphyrin (t-2a). The symmetry-altered structure of c-3a affords a heteroleptic inner environment within the NNNN/NNOO donor core, which imparts its highly flexible electronic features and nonplanar geometry. The macrocycle c-3a can be transformed into the corresponding 26π-electron congener (c-2a) having a coplanar rectangular structure by unique solvent-mediated redox reactivity. Furthermore, upon metal complexation, saddle-distorted bis-metal complexes (c-M2-2a) were formed as the 26π-conjugated structural isomer of the trans-dioxohexaphyrin species (i.e., t-M2-2a). These isoelectronic dioxohexaphyrins demonstrate precise geometry-dependent photophysical properties. Broad tailing NIR-II absorption, weak emissive character, and rapid-decay of the S1 state are observed for c-Zn2-2a. In contrast, the coplanar t-M2-2a exhibits efficient photoacoustic response upon laser excitation with NIR-II light (λ > 1000 nm). To the best of our knowledge, this is the first example of an expanded porphyrin-based photoacoustic contrast agent responsive to NIR-II light.
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U2 - 10.1021/jacs.9b13475
DO - 10.1021/jacs.9b13475
M3 - Article
C2 - 32036651
AN - SCOPUS:85080081087
VL - 142
SP - 4429
EP - 4437
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 9
ER -