Deuterated Covalent Organic Frameworks with Significantly Enhanced Luminescence

Abstract

Luminescent covalent organic frameworks (COFs) find promising applications in chemical sensing, photocatalysis, and optoelectronic devices, however, the majority of COFs are non or weakly emissive owing to the aggregation‐caused quenching (ACQ) or the molecular thermal motion‐based energy dissipation. Here, we report a previously unperceived approach to improve luminescence performance of COFs by introducing isotope effect, which is achieved through substitution of hydrogen from high‐frequency oscillators X‐H (X=O, N, C) by heavier isotope deuterium. Combining the “bottom‐up” and in situ deuteration methods generates the first deuterated COF, which exhibits an impressively 19‐fold enhancement in quantum yield over that of the non‐deuterated counterpart. These results are interpreted by theoretical calculations as the consequence of slower C/N‐D and OD⋅⋅⋅O vibrations that impede the nonradiative deactivation process. The proposed strategy is proved applicable to many other types of emissive COFs.

Palladium-Catalyzed Ligand-Free ortho-Deuteration of Aromatic Carboxylic Acids with D2O

“…18 88.6 °C); R f = 0.55 (petroleum ether/EtOAc, 6:1 + 1% CH 3 COOH). 1 H NMR (400 MHz, ):  = 7.85 (d,J = 8.4 Hz,1 H),7.31 (dd,J = 3.3,2.5 Hz,0.81 H,labelled),3.32,3 H), 2.50 (s, 2 H), 1.58 (p, J = 7.4 Hz, 2 H), 1.39-1.18 (m, 2 H), 0.85 (t, J = 6.9 Hz, 3 H). 193.2 (11.6), 194.2 (88.9), 195.2 (16.3).…”

“…H NMR (400 MHz, DMSO-d 6 ):  = 12.73 (s, 1 H), 7.54(d, J = 8.1 Hz, 0.07 H, labelled), 7.35 (s, 0.06 H, labelled), 7.00 (s, 1 H), 6.12 (s, 2 H). MS (EI): m/z (%) = 167.1 (100.00), 168.1 (90.89), 169.1 (12.77).This document was downloaded for personal use only.…”

Quantum-Classical Computational Molecular Design of Deuterated High-Efficiency OLED Emitters

“…Therefore, introduction of heavier deuterium isotopes to replace hydrogen atoms in C-H bonds could effectively lower FC factors (κ nr ) since the vibrational frequencies of C-D stretching modes are on the order of 2200 cm −1 . Many experimental studies show that substitution of hydrogen by its deuterium isotope improve the luminescent performance of organic materials [8][9][10][11] and could potentially be used for optoelectronic applications such as OLED devices [8] and image probes [9].…”

Universal Principle for Large-Scale Production of a High-Quality Two-Dimensional Monolayer via Positive Charge-Driven Exfoliation

“…Unlike their layered bulk structures, the confinement of electrons with two-dimensional (2D) monolayers leads to extraordinary mechanical, electronic, and thermal properties, with implications for fascinating applications in electronics, green energy, functional coatings, etc . In the past nearly two decades, 2D materials have spurred the examination of largely unexplored regions of the materials across a huge range of fields for their potential application. , This inspiring progress suggests 2D materials would revolutionize the industry with their superlative properties. The first yet most challenging obstacle to industrialization of 2D materials is their large-scale, low-cost, and high-quality preparation. , Scientists have identified 5619 compounds with layered structures stabilized by weak van der Waals (vdW) attraction, in which 1825 layered structures can be exfoliated into a monolayer .…”

“…1 In the past nearly two decades, 2D materials have spurred the examination of largely unexplored regions of the materials across a huge range of fields for their potential application. 2,3 This inspiring progress suggests 2D materials would revolutionize the industry with their superlative properties. The first yet most challenging obstacle to industrialization of 2D materials is their large-scale, low-cost, and high-quality preparation.…”