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Here, we report the unexpected finding that pyridinophane Py\n                    <jats:sub>2<\/jats:sub>\n                    N\n                    <jats:sub>2<\/jats:sub>\n                    and PyN\n                    <jats:sub>3<\/jats:sub>\n                    macrocycles act as efficient metal\u2010free radical scavengers toward the stable free radical 2,2\u2010diphenyl\u20101\u2010picrylhydrazyl (DPPH\u2022). Systematic evaluation of substituent effects reveals distinct structure\u2013reactivity relationships. PyN\n                    <jats:sub>3<\/jats:sub>\n                    derivatives exhibit a linear dependence on electronic parameters, consistent with a donor\u2010controlled regime, whereas Py\n                    <jats:sub>2<\/jats:sub>\n                    N\n                    <jats:sub>2<\/jats:sub>\n                    macrocycles show a pronounced parabolic dependence on resonance and inductive effects, indicative of cooperative stabilization.\n                    <jats:sup>1<\/jats:sup>\n                    H NMR spectroscopy supports the formation of a transient ligand\u2013DPPH\u2022 encounter complex, followed by a rapid hydrogen\u2010atom transfer (HAT). Density functional theory identifies the \u03b2\u2010C\u2013H position on the macrocyclic backbone as the thermodynamically preferred hydrogen\u2010donor site. The resulting ligand\u2010centered radical is formed with the Py\n                    <jats:sub>2<\/jats:sub>\n                    N\n                    <jats:sub>2<\/jats:sub>\n                    and stabilized through delocalization across the macrocyclic framework, enabling a captodative\u2010like electronic environment that is inaccessible to the PyN\n                    <jats:sub>3<\/jats:sub>\n                    scaffold. Together, these findings establish a ligand\u2010centered HAT mechanism governed by macrocyclic topology rather than metal coordination and highlight a previously unrecognized design principle for electronically tunable, metal\u2010free macrocyclic radical scavengers.\n                  <\/jats:p>","DOI":"10.1002\/ejoc.70635","type":"journal-article","created":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T18:43:32Z","timestamp":1782758612000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Metal\u2010Free Ligand\u2010Centered Radical Scavenging in Pyridine\u2010Modified Tetraaza Macrocycles"],"prefix":"10.1002","volume":"29","author":[{"given":"Christina","family":"Mantsorov","sequence":"first","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Christian University  Fort Worth Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hannah K.","family":"Pyle","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Christian University  Fort Worth Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tahmina","family":"Afroz","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Christian University  Fort Worth Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Caden\u2010Jack N.","family":"Walls","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Christian University  Fort Worth Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nora Del","family":"Bosque","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Christian University  Fort Worth Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Timothy M.","family":"Schwartz","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Christian University  Fort Worth Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chelsea N.","family":"Miller","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Christian University  Fort Worth Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kristof","family":"Pota","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Christian University  Fort Worth Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Benjamin G.","family":"Janesko","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Christian University  Fort Worth Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8816-7646","authenticated-orcid":false,"given":"Kayla N.","family":"Green","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Biochemistry Texas Christian University  Fort Worth Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,6,29]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1749\u20106632.1999.tb07814.x"},{"key":"e_1_2_10_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/0009\u20102797(94)90033\u20107"},{"key":"e_1_2_10_4_1","doi-asserted-by":"publisher","DOI":"10.5772\/61193"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.cub.2014.03.034"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.4068\/cmj.2025.61.1.32"},{"key":"e_1_2_10_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.freeradbiomed.2009.12.022"},{"key":"e_1_2_10_8_1","doi-asserted-by":"publisher","DOI":"10.1159\/000485089"},{"key":"e_1_2_10_9_1","doi-asserted-by":"publisher","DOI":"10.1113\/expphysiol.1997.sp004024"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.2741\/mates"},{"key":"e_1_2_10_11_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.biopha.2023.114606"},{"key":"e_1_2_10_12_1","doi-asserted-by":"publisher","DOI":"10.3390\/antiox9090859"},{"key":"e_1_2_10_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejmech.2020.112891"},{"key":"e_1_2_10_14_1","doi-asserted-by":"publisher","DOI":"10.1021\/acs.jafc.5b04743"},{"key":"e_1_2_10_15_1","doi-asserted-by":"publisher","DOI":"10.1021\/ja002455u"},{"key":"e_1_2_10_16_1","doi-asserted-by":"crossref","unstructured":"Z. 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