Near‐Infrared‐III‐Absorbing and ‐Emitting Dyes: Energy‐Gap Engineering of Expanded Porphyrinoids via Metallation. (25th June 2020)

• Record Type: Journal Article
• Authors: Wang, Yue; Ogasahara, Koki; Tomihama, Daisuke; Mysliborski, Radomir; Ishida, Masatoshi; Hong, Yongseok; Notsuka, Yusuke; Yamaoka, Yoshihisa; Murayama, Tomotaka; Muranaka, Atsuya; Uchiyama, Masanobu; Mori, Shigeki; Yasutake, Yuhsuke; Fukatsu, Susumu; Kim, Dongho; Furuta, Hiroyuki
• Is Part Of: Angewandte Chemie. Volume 132:Number 37(2020)
• Page Start: 16295
• Page End: 16300
• Publication Date: 2020-06-25
• Subjects: dyes -- near-infrared region -- orbital interaction -- photoacoustic spectroscopy -- porphyrinoids; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202006026
• Languages: English
• ISSNs: 0044-8249

Abstract

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‐Pd II and bis‐Pt II 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 →S1 absorption beyond 1700 nm was achieved with the bis‐Pt II complex, t ‐Pt2 ‐3 . The emergence of photoacoustic (PA) signals maximized at 1700 nm makes t ‐Pt2 ‐3 potentially useful as a NIR‐III PA contrast agent. The rigid bis‐Pd II complexes, t ‐Pd2 ‐3 and c ‐Pd2 ‐3, are rare examples of NIR emitters beyond 1500 nm. The current study provides new insight into the design of stable, expanded porphyrinic dyes possessing NIR‐III‐emissive and photoacoustic‐response capabilities. Abstract : For your dyes only : Bis‐metallation of expanded porphyrin analogues induced a remarkable dπ –pπ molecular‐orbital mixing that resulted in extremely narrow HOMO–LUMO gaps. The metal‐complex dyes exhibited emissive and photoacoustic properties in the third near‐infrared region (NIR‐III) beyond 1500 nm.