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1. Efficient Broadband Near‐Infrared Emission in the GaTaO ₄ :Cr ³⁺ Phosphor

   https://doi.org/10.1002/adom.202101800  

   Zhong, Jiyou; Zhuo, Ya; Du, Fu; Zhang, Hongshi; Zhao, Weiren; You, Shihai; Brgoch, Jakoah (November 2021, Advanced Optical Materials)

   Abstract Efficient broadband near‐infrared (NIR) emitting materials with an emission peak centered above 830 nm are crucial for smart NIR spectroscopy‐based technologies. However, the development of these materials remains a significant challenge. Herein, a series of design rules rooted in computational methods and empirical crystal‐chemical analysis is applied to identify a new Cr³⁺‐substituted phosphor. The compound GaTaO₄:Cr³⁺emerged from this study is based on the material's high structural rigidity, suitable electronic environment, and relatively weak electron–phonon coupling. Irradiating this new phosphor with 460 nm blue light generates a broadband NIR emission (λ_em,max = 840 nm) covering the 700–1100 nm region of the electromagnetic spectrum with a full width at half maximum of 140 nm. The phase has a high internal quantum yield of 91% and excellent thermal stability, maintaining 85% of the room temperature emission intensity at 100 °C. Fabricating a phosphor‐converted light‐emitting diode device shows that the new compound generates an intense NIR emission (178 mW at 500 mA) with photoelectric efficiency of 6%. This work not only provides a new material that has the potential for next‐generation high‐power NIR applications but also highlights a set of design rules capable of developing highly efficient long‐wavelength broadband NIR materials. 

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2. Near-infrared emission, energy transfer, and mechanisms of Mn ²⁺ and Cr ³⁺ Co-doped lead-free Cs ₂ AgInCl ₆ double perovskites

   https://doi.org/10.1039/d3tc02410e  

   Chen, Daiwen; Wu, Cu; Li, Huayuan; Zhou, Liya; Chen, Peican; Pang, Qi; Zhang, Xinguo; Zhang, Jin Zhong (September 2023, Journal of Materials Chemistry C)

   Mn²⁺/Cr³⁺codoped Cs₂AgInCl₆double perovskite were synthesizedviaa facile hydrothermal method, which exhibits two photoluminescence bands with a wide emission switch ranging from orange to NIR and the photoluminescence quantum yield of 49.3%. 

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3. [Ga ³⁺ ₈ Sm ³⁺ ₂ , Ga ³⁺ ₈ Tb ³⁺ ₂ ] Metallacrowns are Highly Promising Ratiometric Luminescent Molecular Nanothermometers Operating at Physiologically Relevant Temperatures

   https://doi.org/10.1002/chem.202003239  

   Salerno, Elvin V.; Zeler, Justyna; Eliseeva, Svetlana V.; Hernández‐Rodríguez, Miguel A.; Carneiro Neto, Albano N.; Petoud, Stéphane; Pecoraro, Vincent L.; Carlos, Luís D. (September 2020, Chemistry – A European Journal)

   Abstract Nanothermometry is the study of temperature at the submicron scale with a broad range of potential applications, such as cellular studies or electronics. Molecular luminescent‐based nanothermometers offer a non‐contact means to record these temperatures with high spatial resolution and thermal sensitivity. A luminescent‐based molecular thermometer comprised of visible‐emitting Ga³⁺/Tb³⁺and Ga³⁺/Sm³⁺metallacrowns (MCs) achieved remarkable relative thermal sensitivity associated with very low temperature uncertainty ofS_r=1.9 % K⁻¹andδT<0.045 K, respectively, at 328 K, as an aqueous suspension of polystyrene nanobeads loaded with the corresponding MCs. To date, they are the ratiometric molecular nanothermometers offering the highest level of sensitivity in the physiologically relevant temperature range. 

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4. High‐Resolution Photoelectron Imaging of IrB ₃ ⁻ : Observation of a π‐Aromatic B ₃ ⁺ Ring Coordinated to a Transition Metal

   https://doi.org/10.1002/anie.201902406  

   Czekner, Joseph; Cheung, Ling Fung; Kocheril, G. Stephen; Kulichenko, Maksim; Boldyrev, Alexander I.; Wang, Lai‐Sheng (May 2019, Angewandte Chemie International Edition)

   Abstract In a high‐resolution photoelectron imaging and theoretical study of the IrB₃⁻cluster, two isomers were observed experimentally with electron affinities (EAs) of 1.3147(8) and 1.937(4) eV. Quantum calculations revealed two nearly degenerate isomers competing for the global minimum, both with a B₃ring coordinated with the Ir atom. The isomer with the higher EA consists of a B₃ring with a bridge‐bonded Ir atom (C_s,²A′), and the second isomer features a tetrahedral structure (C_3v,²A₁). The neutral tetrahedral structure was predicted to be considerably more stable than all other isomers. Chemical bonding analysis showed that the neutralC_3visomer involves significant covalent Ir−B bonding and weak ionic bonding with charge transfer from B₃to Ir, and can be viewed as an Ir–(η³‐B₃⁺) complex. This study provides the first example of a boron‐to‐metal charge‐transfer complex and evidence of a π‐aromatic B₃⁺ring coordinated to a transition metal. 

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5. Solvent Effects in Hyperpolarization of ¹⁵ N Nuclei in [ ¹⁵ N ₃ ]Metronidazole and [ ¹⁵ N ₃ ]Nimorazole Antibiotics via SABRE‐SHEATH**

   https://doi.org/10.1002/anse.202400045  

   Yi, Anna P; Salnikov, Oleg G; Burueva, Dudari B; Chukanov, Nikita V; Chekmenev, Eduard Y; Koptyug, Igor V (August 2024, Analysis & Sensing)

   Abstract Metronidazole and nimorazole are antibiotics of a nitroimidazole group which also may be potentially utilized as hypoxia radiosensitizers for the treatment of cancerous tumors. Hyperpolarization of¹⁵N nuclei in these compounds using SABRE‐SHEATH (Signal Amplification By Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei) approach provides dramatic enhancement of detection sensitivity of these analytes using magnetic resonance spectroscopy and imaging. Methanol‐d₄is conventionally employed as a solvent in SABRE hyperpolarization process. Herein, we investigate SABRE‐SHEATH hyperpolarization of isotopically labeled [¹⁵N₃]metronidazole and [¹⁵N₃]nimorazole in nondeuterated methanol and ethanol solvents. Optimization of such hyperpolarization parameters as polarization transfer magnetic field, temperature, parahydrogen flow rate and pressure allowed us to obtain an average¹⁵N polarization of up to 7.2–7.4 % for both substrates. The highest¹⁵N polarizations were observed in methanol‐d₄for [¹⁵N₃]metronidazole and in ethanol for [¹⁵N₃]nimorazole. At a clinically relevant magnetic field of 1.4 T the¹⁵N nuclei of these substrates possess long characteristic hyperpolarization lifetimes (T₁) of ca. 1 to ca. 7 min. This study represents a major step toward SABRE in more biocompatible solvents, such as ethanol, and also paves the way for future utilization of these hyperpolarized nitroimidazoles as molecular contrast agents for MRI visualization of tumors. 

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