Spin manipulation of transition-metal catalysts has great potential in mimicking enzyme electronic structures to improve activity and/or selectivity. However, it remains a great challenge to manipulate room-temperature spin state of catalytic centers. Herein, we report a mechanical exfoliation strategy to in situ induce partial spin crossover from highspin (s = 5/2) to low-spin (s = 1/2) of the ferric center. Due to spin transition of catalytic center, mixed-spin catalyst exhibits a high CO yield of 19.7 mmol g À 1 with selectivity of 91.6 %, much superior to that of high-spin bulk counterpart (50 % selectivity). Density functional theory calculations reveal that low-spin 3d-orbital electronic configuration performs a key function in promoting CO 2 adsorption and reducing activation barrier. Hence, the spin manipulation highlights a new insight into designing highly efficient biomimetic catalysts via optimizing spin state.

Phosphor-converted white light-emitting diodes (pc-wLEDs) are promising candidates for next-generation solid-state lighting and display technologies. However, most of the conventional phosphors in pc-wLED devices suffer from serious thermal quenching (TQ) at high temperatures. Herein, we investigate an unconventional high-efficiency metal−halide cluster-based phosphor with dynamic Cu−Cu interactions that can resist the TQ effect of photoluminescence. The temperature-dependent structure and solid-state and in situ NMR spectroscopy reveal that the weakening of the Cu− Cu interaction in such a phosphor system enables the electronic structural transition from a bonding to a nonbonding state and hence sustains the PL efficiency at high temperatures (up to 100 °C). The pc-wLEDs incorporating the zero-TQ phosphor show a rapid brightness rise even at a high bias current (1000 mA) with a color rendering index as high as 90, comparable to the commercial phosphor-based prototype LEDs (e.g., YAG:Ce 3+ ). This work establishes a novel prototype of a cluster-based phosphor featuring dynamic intermetallic interactions, which paves the way for the exploration of pc-wLEDs against thermal quenching.

Photoluminescence (PL) intensity in organic or metal–organic emitters usually suffers from thermal quenching (TQ), which severely hinders their industrial applications. The development of negative thermal quenching (NTQ) and/or zero thermal quenching (ZTQ) materials depends on a better understanding of the mechanisms underpinning TQ in luminescent solids. In this work, we investigated the temperature dependence of thermally activated delayed fluorescence (TADF) in copper­(I)–organic coordination polymers (CP) ligated with an imidazole or triazole derivative over a broad temperature range. The efficient PL emission of CP1 is heavily quenched as the crystalline samples are cooled to 77 K; the PL intensity shows the NTQ effect in the region of 77–238 K followed by a ZTQ effect in the temperature range of 238–318 K. No NTQ or ZTQ effect is observed for reference coordination polymer CP2, where the 1,2,4-triazole group was used instead of the imidazole one. Our work highlights the important role of the ligand’s electronic structure in optimizing photophysical properties of coordination polymer emitters and may stimulate new efforts to design luminescent materials exhibiting NTQ and ZTQ effect at higher temperature.

The peak photoluminescence (PL) of conventional fluorophores is independent of the excitation wavelength (called Kasha's rule), while the search of metal−organic framework materials with the so-called anti-Kasha's rule emission remains very limited. Herein, we report the observation of anti-Kasha's rule emission in a multicomponent PL three-dimensional nanotubular metal−organic framework (abbr.-3,5-dicarboxylic acid; bix = 1,4bis(imidazole-1-ylmethyl)benzene]. The MOF-NT crystalline sample represents a notable example of strong excitation-dependent fluorescence from the ultraviolet to the visible spectral region. Moreover, by virtue of electronic flexibility and high PL efficiency, MOF-NT shows a discriminative PL response between isomeric nitroaromatic compounds. The work demonstrated the intrinsic anti-Kasha's rule emission in the crystalline-state MOF materials, providing new visions for the development of advanced solid-state emissive materials.

Spin manipulation of transition‐metal catalysts has great potential in mimicking enzyme electronic structures to improve activity and/or selectivity. However, it remains a great challenge to manipulate room‐temperature spin state of catalytic centers. Herein, we report a mechanical exfoliation strategy to in situ induce partial spin crossover from high‐spin (s=5/2) to low‐spin (s=1/2) of the ferric center. Due to spin transition of catalytic center, mixed‐spin catalyst exhibits a high CO yield of 19.7 mmol g−1 with selectivity of 91.6 %, much superior to that of high‐spin bulk counterpart (50 % selectivity). Density functional theory calculations reveal that low‐spin 3d‐orbital electronic configuration performs a key function in promoting CO2 adsorption and reducing activation barrier. Hence, the spin manipulation highlights a new insight into designing highly efficient biomimetic catalysts via optimizing spin state.