Two-coordinate carbene-M I -amide (cMa, M I = Cu, Ag, Au) complexes have emerged as highly efficient luminescent materials for use in a variety of photonic applications due to their extremely fast radiative rates through thermally activated delayed fluorescence (TADF) from an interligand charge transfer (ICT) process. A series of cMa derivatives was prepared to examine the variables that affect the radiative rate, with the goal of understanding the parameters that control the radiative TADF process in these materials. We find that blue-emissive complexes with high photoluminescence efficiencies (Φ PL > 0.95) and fast radiative rates (k r = 4 × 10 6 s −1 ) can be achieved by selectively extending the π-system of the carbene and amide ligands. Of note is the role played by the increased separation between the hole and electron in the ICT excited state. Analysis of temperature-dependent luminescence data and theoretical calculations indicate that the hole−electron separation exerts a primary effect on the energy gap between the lowest-energy singlet and triplet states (ΔE ST ) while keeping the radiative rate for the singlet state relatively unchanged. This interpretation provides guidelines for the design of new cMa derivatives with even faster radiative rates in addition to those with slower radiative rates and thus extended excited state lifetimes.Article pubs.acs.org/JACS

A series of twelve two coordinate coinage metal, Cu, Ag and Au, complexes with carbene metal amide structures were prepared. They all present thermal assisted delayed fluorescence (TADF) emission from...

Generating sustainable fuel from sunlight plays an important role in meeting the energy demands of the modern age. Herein, we report two-coordinate carbene-metal-amide (cMa, M = Cu­(I) and Au­(I)) complexes that can be used as sensitizers to promote the light-driven reduction of water to hydrogen. The cMa complexes studied here absorb visible photons (εvis > 103 M–1 cm–1), maintain long excited-state lifetimes (τ ∼ 0.2–1 μs), and perform stable photoinduced charge transfer to a target substrate with high photoreducing potential (E +/* up to −2.33 V vs Fc+/0 based on a Rehm–Weller analysis). We pair these coinage metal complexes with a cobalt–glyoxime electrocatalyst to photocatalytically generate hydrogen and compare the performance of the copper- and gold-based cMa complexes. We also find that the two-coordinate complexes herein can perform photodriven hydrogen production from water without the addition of the cobalt–glyoxime electrocatalyst. In this “catalyst-free” system, the cMa sensitizer partially decomposes to give metal nanoparticles that catalyze water reduction. This work identifies two-coordinate coinage metal complexes as promising abundant metal, solar fuel photosensitizers that offer exceptional tunability and photoredox properties.

The thermally unstable, primary perfluoroalcohols, CF OH, C F OH, and nC F OH, were conveniently prepared from the corresponding carbonyl compounds in anhydrous HF solution. Experimental values for the reaction enthalpies and entropies were derived from the temperature dependence of the R COF+HF⇄R CF OH (R =F, CF , CF CF ) equilibria by NMR spectroscopy. Electronic structure calculations of the gas-phase and solution reaction energies, gas-phase acidities and heats of formation were carried out at the G3MP2 level, showing that these compounds are strong acids. Protonation of these alcohols in HF/SbF produced the perfluoroalkyl oxonium salts R CF OH SbF .

The first X-ray crystal structure of an α-fluoroalcohol is reported. Heptafluorocyclobutanol was obtained in quantitative yield from hexafluorocyclobutanone by HF addition in anhydrous hydrogen fluoride. The compound was characterized by its X-ray single crystal structure. Heptafluorocyclobutanol readily undergoes hydrolysis to hexafluorocyclobutane-1,1-diol, which was also structurally characterized by X-ray diffraction.