Giant Multi‐Photon Absorption by Heptazine Organometalation

Abstract

Multi‐photon absorption (MPA) is of increasing interest for applications in technologically important “windows” of the electromagnetic spectrum (near‐infrared III, NIR‐III, 1550–1870 nm; and the new 2080–2340 nm region); however, few molecules exist that display strong MPA at these long wavelengths. We herein report the syntheses of the first 2,5,8‐s‐heptazine‐cored organometallic complexes, together with organic analogues. The complexes exhibit outstanding 3PA cross‐sections in the NIR‐III and exceptional 4PA cross‐sections in the new 2080–2340 nm window. We demonstrate that replacing organic donor groups by organometallic units results in an order of magnitude increase in 3PA, the “switching on” of 4PA, and a dramatic improvement in photo‐stability. Our results highlight the impressive outcomes possible with an “organometalation” approach to NLO materials design.

Self-Adapting Graphitic C6N6-Based Copper Single-Atom Catalyst for Smart Biosensors

“…The aforementioned results further demonstrated that CuSAC6N6 not only had a peroxidase-like Cu-N coordination active center but also owned an unusual donor-πacceptor (D-π-A) unit (Fig. 1h), [62][63][64] where the single Cu atom acted as an electron acceptor, the triazine rings emerged as electron donors (photovoltaic center), and the -N=CH-CH=N-linkers offered π-conjugated charge transfer channels for D-A couples. These π-interconnected D-A couples played a crucial role in addressing the inconsistency of requirements for basic and gain reactions by not only reducing recombination (control sample: Cu 2+ -PCN) and promoting charge separation (control sample: Cu-N-C), but also accelerating intramolecular charge transfer (control sample: Cu-N-C/CNmw).…”