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1. Taming the Chlorine Radical: Enforcing Steric Control over Chlorine-Radical-Mediated C-H Activation

   https://doi.org/10.1021/jacs.1c13333  

   Gonzalez, Miguel; Gygi, David; Qin, Yangzhong; Zhu, Qilei; Johnson, Elizabeth J.; Chen, Yu-Sheng; Nocera, Daniel G. (January 2022, Journal of the American Chemical Society)

   Chlorine radicals readily activate C-H bonds, but the high reactivity of these intermediates precludes their use in regioselective C-H functionalization reactions. We demonstrate that the secondary coordination sphere of a metal complex can confine photoeliminated chlorine radicals and afford steric control over their reactivity. Specifically, a series of iron(III) chloride pyridinediimine complexes exhibit activity for photochemical C(sp(3))-H chlorination and bromination with selectivity for primary and secondary C-H bonds, overriding thermodynamic preference for weaker tertiary C-H bonds. Transient absorption spectroscopy reveals that Cl center dot remains confined through formation of a Cl center dot larene complex with aromatic groups on the pyridinediimine ligand. Furthermore, photocrystallography confirms that this selectivity arises from the generation of Cl center dot within the steric environment defined by the iron secondary coordination sphere. 

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2. CHLORINE-POTASSIUM RELATIONS IN HASTINGSITIC AMPHIBOLES

   https://doi.org/10.1130/abs/2020AM-358490  

   Matteucci, Jared; Jenkins, David M. (January 2020, Geological Society of America Abstracts with Programs)

   null (Ed.)
3. Reformulating the bromine alpha factor and equivalent effective stratospheric chlorine (EESC): evolution of ozone destruction rates of bromine and chlorine in future climate scenarios

   https://doi.org/10.5194/acp-20-9459-2020  

   Klobas, J. Eric; Weisenstein, Debra K.; Salawitch, Ross J.; Wilmouth, David M. (January 2020, Atmospheric Chemistry and Physics)

   null (Ed.)

   Abstract. Future trajectories of the stratospheric trace gas background will alter the rates of bromine- and chlorine-mediated catalytic ozone destruction via changes in the partitioning of inorganic halogen reservoirs and the underlying temperature structure of the stratosphere. The current formulation of the bromine alpha factor, the ozone-destroying power of stratospheric bromine atoms relative to stratospheric chlorine atoms, is invariant with the climate state. Here, we refactor the bromine alpha factor, introducing normalization to a benchmark chemistry–climate state, and formulate Equivalent Effective Stratospheric Benchmark-normalized Chlorine (EESBnC) to reflect changes in the rates of both bromine- and chlorine-mediated ozone loss catalysis with time. We show that the ozone-processing power of the extrapolar stratosphere is significantly perturbed by future climate assumptions. Furthermore, we show that our EESBnC-based estimate of the extrapolar ozone recovery date is in closer agreement with extrapolar ozone recovery dates predicted using more sophisticated 3-D chemistry–climate models than predictions made using equivalent effective stratospheric chlorine (EESC). 

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4. The incorporation of chlorine into calcium amphibole

   https://doi.org/10.2138/am-2019-6768  

   Jenkins, David M. (April 2019, American Mineralogist)
5. Different chlorine and hydroxyl radical environments impact m-xylene oxidation products

   https://doi.org/10.1039/D3EA00024A  

   Bhattacharyya, Nirvan; Modi, Mrinali; Jahn, Leif G.; Hildebrandt Ruiz, Lea (August 2023, Environmental Science: Atmospheres)

   Transportation emissions of aromatic hydrocarbons such as xylenes evolve in the atmosphere due to radical oxidation and can form a variety of products, including secondary organic aerosol (SOA). 

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