Lead halide compounds, including lead halide perovskite nanocrystals (NCs), have attracted the interest of researchers in optoelectronics and photonics because of their high photoluminescence quantum yields (PLQYs) coupled with relatively short PL lifetimes (on the order of a few nanoseconds). However, lead-free metal halides of high PLQY, including double perovskites and their doped NCs, typically possess long PL lifetimes (up to microseconds) that limit their application space. Here, we introduce CsMnBr3 NCs, which are lead-free and red-emitting, that combine a high PLQY with an exceptionally short radiative lifetime (on the order of picoseconds). We find that the octahedral coordination of Mn2+ in CsMnBr3 induces a red emission centered at ∼643 nm with a PLQY of ∼54% and a fast radiative decay rate. Femtosecond transient absorption and transient PL spectroscopies reveal the existence of a low-lying excited state of Mn2+ that relaxes to the ground state within around 605 ps by emitting light at around 643 nm. At greater excitation energies, higher excited states of Mn2+ relax in the sub-nanosecond time scale to this low-lying excited state. A similarly positioned PL peak with a short picosecond scale PL lifetime and a PLQY of ∼6.7% was also detected in bulk CsMnBr3 single crystals reported in this studya relatively high quantum yield for a bulk material. Our experimental results and density functional theory modelling show that the crystal structure and the strong coupling among Mn2+ ions govern those luminescence properties of CsMnBr3 NCs and single crystals. These findings pave the way for new lead-free materials that combine high PLQY and ultrafast luminescence.

The first heptacoordinate cobalt catalyst for light‐driven hydrogen production in water has been synthesized and characterized. Photochemical experiments using [Ru(bpy)3]2+ as photosensitizer gave a turnover number (TON) of 16300 mol H2 (mol cat.)−1 achieved in 2 hours of irradiation with visible (475 nm) light. This promising result provides a path forward in the development of new structures to improve the efficiency of the catalysis.

Luminescent coordination polymers (CPs) of Zn 2+ or Cd 2+ and bis-9,10-(pyridine-4-yl)-anthracene (BA) show different 1D and 2D topologies depending on the anion used in the precursor. Compounds {[Zn(μ 2-BA)(MeOH) 2 (p-Tos) 2 ]} n (1) and {[Zn(μ 2-BA)(MeOH) 2 (CF 3 CO 2) 2 ]} n (2) f o r m l i n e a r s t r u c t u r es a n d { B A @ [ Z n (μ 2-B A)-(MeOH) 2 (H 2 O) 2 ](CF 3 SO 3) 2 } n (3) featuring intercalation of uncoordinated BA molecules into linear ribbons. Cd-based CPs {[Cd(μ 2-BA) 2 (ClO 4) 2 ]•n(DCM)} n (4) and {[Cd(μ 2-BA)(MeOH) 2 (Dioxane)(η 2-SiF 6)]•mDioxane} n (5) form porous structures with 2D lattices. All complexes exhibit strong blue emission in the solid state with average lifetimes between 8 and 13 ns. The emission of compound 4 is sensitive to the presence of nitro aromatics, simazine, and trichloroanisole (TCA) and demonstrates nonlinear Stern−Volmer quenching kinetics. Limits of detection (LOD) of 15 and 16 ppb for picric acid and TCA were achieved, respectively.

Double helicenes are appealing chiral frameworks. Their π-extension is desirable to achieve (chir)optical response in the visible and near-infrared (NIR) region, but access to higher double [n]helicenes (n � 8) has remained challenging. Herein, we report an unprecedented π-extended double [9]helicene (D9H), unambiguously revealing its structure by single-crystal X-ray diffraction. D9H shows remarkable NIR emission from 750 to 1100 nm with a high photoluminescence quantum yield of 18 %. In addition, optically pure D9H exhibits panchromatic circular dichroism with a notable dissymmetry factor (g CD ) of 0.019 at 590 nm, which is among the highest in the visible region for reported helicenes.

The design of materials and their manufacture into membranes that can handle industrial conditions and separate complex nonaqueous mixtures are challenging. We report a versatile strategy to fabricate polytriazole membranes with 10-nanometer-thin selective layers containing subnanometer channels for the separation of hydrocarbons. The process involves the use of the classical nonsolvent-induced phase separation method and thermal cross-linking. The membrane selectivity can be tuned to the lower end of the typical nanofiltration range (200 to 1000 gram mole −1 ). The polytriazole membrane can enrich up to 80 to 95% of the hydrocarbon content with less than 10 carbon atoms (140 gram mole −1 ). These membranes preferentially separate paraffin over aromatic components, making them suitable for integration in hybrid distillation systems for crude oil fractionation.