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  1. Photoacid generators (PAGs) have facilitated a number of technology breakthroughs in the electronic, coating, and additive manufacturing industries. Traditionally, PAGs that contain weakly coordinating anions, such as PF6-, generate Brønsted superacids under UV irradiation for rapid cationic polymerizations. However, PAGs with strongly coordinating anions remain under-utilized as they form weak acids that are inefficient or even incapable of initiating polymerization. To expand the scope of potential counteranions in PAGs, we leveraged a thiophosphoramide hydrogen bond donor (HBD) to catalyze photoinitiated cationic polymerizations from diphenyliodonium PAGs. Through the formation of hydrogen bonds between the HBD and PAG counteranion, acceleration of the polymerization rate was observed for a range of non-coordinating and coordinating anions. The effect of the HBD on the polymerization kinetics was investigated by 1H-NMR titrations and geometry optimizations. Extending HBD catalysis beyond photopolymerizations, addition of HBD also enabled hydrochloric acid to initiate controlled reversible addition-fragmentation chain transfer (RAFT) polymerization under ambient conditions. With the versatility of HBD, there is potential to access initiation systems that were previously believed to be impractical for cationic polymerization. 
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    Free, publicly-accessible full text available March 1, 2025
  2. An analogue of the mitochondrial calcium uniporter (MCU) inhibitor Ru265 containing axial ferrocenecarboxylate ligands is reported. This new complex exhibits enhanced cellular uptake compared to the parent compound Ru265.

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  3. Abstract

    The synthesis and characterization of the15N‐labeled analogue of the mitochondrial calcium uptake inhibitor [Cl(NH3)4Ru(μ‐N)Ru(NH3)4Cl]3+(Ru265) bearing [15N]NH3ligands is reported. Using [1H,15N] HSQC NMR spectroscopy, the rate constants for the axial chlorido ligand aquation of [15N]Ru265 in pH 7.4 buffer at 25 °C were found to bek1=(3.43±0.03)×10−4 s−1andk2=(4.03±0.09)×10−3 s−1. The reactivity of [15N]Ru265 towards biologically relevant small molecules was also assessed via this method, revealing that this complex can form coordination bonds to anionic oxygen and sulfur donors. Time‐based studies on these ligand‐binding reactions reveal this process to be slow relative to the time required for the complex to inhibit mitochondrial calcium uptake, suggesting that hydrogen‐bonding interactions, rather than the formation of coordination bonds, may play a more significant role in mediating the inhibitory properties of this complex.

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