Near-Infrared-III-Absorbing and -Emitting Dyes: Energy-Gap Engineering of Expanded Porphyrinoids via Metallation.
Angew Chem Int Ed Engl
; 59(37): 16161-16166, 2020 09 07.
Article
em En
| MEDLINE
| ID: mdl-32469135
ABSTRACT
The synthesis of organometallic complexes of modified 26π-conjugated hexaphyrins with absorption and emission capabilities in the third near-infrared region (NIR-III) is described. Symmetry alteration of the frontier molecular orbitals (MOs) of bis-PdII and bis-PtII complexes of hexaphyrin via N-confusion modification led to substantial metal dπ -pπ interactions. This MO mixing, in turn, resulted in a significantly narrower HOMO-LUMO energy gap. A remarkable long-wavelength shift of the lowest S0 âS1 absorption beyond 1700â
nm was achieved with the bis-PtII complex, t-Pt2 -3. The emergence of photoacoustic (PA) signals maximized at 1700â
nm makes t-Pt2 -3 potentially useful as a NIR-III PA contrast agent. The rigid bis-PdII complexes, t-Pd2 -3 and c-Pd2 -3, are rare examples of NIR emitters beyond 1500â
nm. The current study provides new insight into the design of stable, expanded porphyrinic dyes possessing NIR-III-emissive and photoacoustic-response capabilities.
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MEDLINE
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En
Ano de publicação:
2020
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Article