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1. Benchmarking the dynamic luminescence properties and UV stability of B ₁₈ H ₂₂ -based materials

   https://doi.org/10.1039/d2dt01225a  

   Anderson, Kierstyn P.; Hua, Ash Sueh; Plumley, John B.; Ready, Austin D.; Rheingold, Arnold L.; Peng, Thomas L.; Djurovich, Peter I.; Kerestes, Christopher; Snyder, Neil A.; Andrews, Andrew; et al (June 2022, Dalton Transactions)

   The dynamic photoluminescence properties, and potential quenching mechanisms, ofanti-B₁₈H₂₂, 4,4′-Br₂-anti-B₁₈H₂₀, and 4,4′-I₂-anti-B₁₈H₂₀are investigated in solution and polymer films. 

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2. Crystal structure of a (carboxymethyl)triethylazanium bromide–2-(triethylazaniumyl)acetate (1/1) hydrogen-bonded dimer

   https://doi.org/10.1107/S2056989023006850  

   Carlson, Faith M; Staples, Richard J; Biros, Shannon M (September 2023, Acta Crystallographica Section E Crystallographic Communications)

   The title compound, C₈H₁₈NO₂⁺·Br⁻·C₈H₁₇NO₂, crystallizes as the bromide salt of a 50:50 mixture of (triethylazaniumyl)carboxylic acid and the zwitterionic (triethylazaniumyl)carboxylate. The two organic entities are linked by a half-occupied bridging carboxylic acid hydrogen atom that is hydrogen-bonded to the carboxylate group of the second molecule. The tetralkylammonium group adopts a nearly perfect tetrahedral shape around the nitrogen atom with bond lengths that agree with known values. The carboxylic acid/carboxylate group is orientedantito one of the ethyl groups on the ammonium group, and the carbonyl oxygen atom is engaged in intramolecular C—H...O hydrogen bonds. 

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3. Long-lived photoluminescence from an eight-coordinate zirconium( iv ) complex with four 2-(2′-pyridyl)pyrrolide ligands

   https://doi.org/10.1039/D2CC04912K  

   Leary, Dylan C.; Martinez, Jordan C.; Akhmedov, Novruz G.; Petersen, Jeffrey L.; Milsmann, Carsten (October 2022, Chemical Communications)

   The photoluminescent eight-coordinate zirconium complex Zr( H PMP H ) 4 supported by four monoanionic 2-(2′-pyridine)pyrrolide ligands was synthesized. This molecule shows dual emission via fluorescence and phosphorescence with an overall quantum efficiency of 4% at room temperature in solution. The phosphorescence lifetime is dependent on concentration, indicating excimer formation at higher concentrations, and reaches almost 800 μs at high dilution. 

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4. Interplay between Perovskite Magic-Sized Clusters and Amino Lead Halide Molecular Clusters

   https://doi.org/10.34133/2021/6047971  

   Vickers, Evan T.; Chen, Ziyi; Cherrette, Vivien; Smart, Tyler; Zhang, Peng; Ping, Yuan; Zhang, Jin Z. (January 2021, Research)

   Recent progress has been made on the synthesis and characterization of metal halide perovskite magic-sized clusters (PMSCs) with ABX 3 composition ( A = C H 3 N H 3 + or Cs + , B = P b 2 + , and X = C l − , Br - , or I - ). However, their mechanism of growth and structure is still not well understood. In our effort to understand their structure and growth, we discovered that a new species can be formed without the CH 3 NH 3 + component, which we name as molecular clusters (MCs). Specifically, CH 3 NH 3 PbBr 3 PMSCs, with a characteristic absorption peak at 424 nm, are synthesized using PbBr 2 and CH 3 NH 3 Br as precursors and butylamine (BTYA) and valeric acid (VA) as ligands, while MCs, with an absorption peak at 402 nm, are synthesized using solely PbBr 2 and BTYA, without CH 3 NH 3 Br. Interestingly, PMSCs are converted spontaneously overtime into MCs. An isosbestic point in their electronic absorption spectra indicates a direct interplay between the PMSCs and MCs. Therefore, we suggest that the MCs are precursors to the PMSCs. From spectroscopic and extended X-ray absorption fine structure (EXAFS) results, we propose some tentative structural models for the MCs. The discovery of the MCs is critical to understanding the growth of PMSCs as well as larger perovskite quantum dots (PQDs) or nanocrystals (PNCs). 

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5. Solid-state ¹¹ B NMR studies of coinage metal complexes containing a phosphine substituted diboraanthracene ligand

   https://doi.org/10.1039/d1dt02981a  

   Huynh, Winn; Taylor, Jordan W.; Harman, W. Hill; Conley, Matthew P. (October 2021, Dalton Transactions)

   Transition metal interactions with Lewis acids (M → Z linkages) are fundamentally interesting and practically important. The most common Z-type ligands contain boron, which contains an NMR active 11 B nucleus. We measured solid-state 11 B{ 1 H} NMR spectra of copper, silver, and gold complexes containing a phosphine substituted 9,10-diboraanthracene ligand (B 2 P 2 ) that contain planar boron centers and weak M → BR 3 linkages ([(B 2 P 2 )M][BAr F 4 ] (M = Cu (1), Ag (2), Au (3)) characterized by large quadrupolar coupling ( C Q ) values (4.4–4.7 MHz) and large span ( Ω ) values (93–139 ppm). However, the solid-state 11 B{ 1 H} NMR spectrum of K[Au(B 2 P 2 )] − (4), which contains tetrahedral borons, is narrow and characterized by small C Q and Ω values. DFT analysis of 1–4 shows that C Q and Ω are expected to be large for planar boron environments and small for tetrahedral boron, and that the presence of a M → BR 3 linkage relates to the reduction in C Q and 11 B NMR shielding properties. Thus solid-state 11 B NMR spectroscopy contains valuable information about M → BR 3 linkages in complexes containing the B 2 P 2 ligand. 

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