{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,28]],"date-time":"2026-07-28T13:04:48Z","timestamp":1785243888211,"version":"3.55.0"},"reference-count":41,"publisher":"American Chemical Society (ACS)","issue":"29","license":[{"start":{"date-parts":[[2026,7,12]],"date-time":"2026-07-12T00:00:00Z","timestamp":1783814400000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-029"},{"start":{"date-parts":[[2026,7,12]],"date-time":"2026-07-12T00:00:00Z","timestamp":1783814400000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-037"},{"start":{"date-parts":[[2026,7,12]],"date-time":"2026-07-12T00:00:00Z","timestamp":1783814400000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-045"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["22174118"],"award-info":[{"award-number":["22174118"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["22374124"],"award-info":[{"award-number":["22374124"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,7,28]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Azo compounds offer wide-range applications due to their unique structures and properties. The N\u2550N double bond in azo compounds can form a nonrotatable plane, frequently causing spins to experience different magnetic environments, and thus leading to chemical exchange. This may result in line broadening even invisibility in the nuclear magnetic resonance spectra, thus greatly hindering detection and kinetic analysis of azo compounds. Here, a new pulse sequence, termed as FasteR Exchange with chemical-Shift Scaling for Signal enHancement (FRES3H) is developed, which scales down the chemical shift by a factor of \u03bb via manipulating indirect dimension evolution time and converts the spin system to fast-exchange regime, thus boosting chemical exchange signal. The method can recover invisible signals in intermediate-exchange regime, facilitating the analysis of azo compounds. It can detect trace amounts of azo initiators as low as 1 mM in 2D C\u2013H coherence spectra, thus facilitating the quality control of polymer production. And it can confirm the fact of chemical exchange differences of tert-butyl groups in azobenzene cis- and trans-isomers, thus revealing the effect of exchange kinetics on electron transport properties and providing valuable guidance for the synthesis of functional photovoltaic materials.<\/jats:p>","DOI":"10.1021\/acs.analchem.5c03491","type":"journal-article","created":{"date-parts":[[2026,7,12]],"date-time":"2026-07-12T12:56:12Z","timestamp":1783860972000},"page":"21165-21172","source":"Crossref","is-referenced-by-count":0,"title":["Enhancing NMR\nChemical Exchange Signals of Azo Compounds\nvia Chemical-Shift Scaling"],"prefix":"10.1021","volume":"98","author":[{"given":"Xiaoqi","family":"Shi","sequence":"first","affiliation":[{"name":"Xiamen University , , ,","place":["Xiamen, China, 361005"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qing","family":"Zeng","sequence":"additional","affiliation":[{"name":"Johns Hopkins University School of Medicine , , , ,","place":["Baltimore, Maryland, United States, 21205"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-6202-7094","authenticated-orcid":true,"given":"Huiqiang","family":"Lu","sequence":"additional","affiliation":[{"name":"Xiamen University , , ,","place":["Xiamen, China, 361005"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yao","family":"Luo","sequence":"additional","affiliation":[{"name":"Xiamen University , , ,","place":["Xiamen, China, 361005"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9069-5739","authenticated-orcid":true,"given":"Jiale","family":"Huang","sequence":"additional","affiliation":[{"name":"College of Chemistry and Chemical Engineering , , ,","place":["Xiamen, China, 361005"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1473-2224","authenticated-orcid":true,"given":"Zhong","family":"Chen","sequence":"additional","affiliation":[{"name":"Xiamen University , , ,","place":["Xiamen, China, 361005"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0596-0740","authenticated-orcid":true,"given":"Yanqin","family":"Lin","sequence":"additional","affiliation":[{"name":"Xiamen University , , ,","place":["Xiamen, China, 361005"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,7,12]]},"reference":[{"issue":"2","key":"2026072808070933600_cit1","doi-asserted-by":"publisher","first-page":"162","DOI":"10.1039\/C7MH00920H","article-title":"Untapped potential for debonding\non demand: the wonderful world of azo-compounds","volume":"5","author":"Mutlu","year":"2018","journal-title":"Mater. 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Controlled Release"},{"issue":"47","key":"2026072808070933600_cit29","doi-asserted-by":"publisher","first-page":"19856","DOI":"10.1021\/jacs.1c09090","article-title":"Design of\nazobenzene beyond simple on-off behavior","volume":"143","author":"Mehrparvar","year":"2021","journal-title":"J.\nAm. Chem. Soc."},{"issue":"3","key":"2026072808070933600_cit30","doi-asserted-by":"publisher","first-page":"446","DOI":"10.1038\/s41557-023-01389-6","article-title":"Azobenzene as a photoswitchable mechanophore","volume":"16","author":"Li","year":"2024","journal-title":"Nat. Chem."},{"issue":"18","key":"2026072808070933600_cit31","doi-asserted-by":"publisher","first-page":"3407","DOI":"10.1002\/anie.200705339","article-title":"Light-powered\nelectrical\nswitch based on cargo-lifting azobenzene monolayers","volume":"47","author":"Ferri","year":"2008","journal-title":"Angew. Chem., Int. Ed."},{"issue":"16","key":"2026072808070933600_cit32","doi-asserted-by":"publisher","first-page":"6489","DOI":"10.1073\/pnas.0812402106","article-title":"Using photons\nto manipulate enzyme inhibition by an azobenzene-modified nucleic\nacid probe","volume":"106","author":"Kim","year":"2009","journal-title":"Proc. Natl. Acad. Sci. U.S.A"},{"issue":"28","key":"2026072808070933600_cit33","doi-asserted-by":"publisher","DOI":"10.1002\/anie.202402858","article-title":"tert-Butyl as a functional\ngroup: Non-directed catalytic hydroxylation of sterically congested\nprimary C-H bonds","volume":"63","author":"Chan","year":"2024","journal-title":"Angew. Chem., Int. Ed."},{"issue":"45","key":"2026072808070933600_cit34","doi-asserted-by":"publisher","DOI":"10.1002\/anie.202206825","article-title":"Regulating crystal packing by terminal\ntert-butylation for enhanced solid-state emission and efficacious\ncharge transport in an anthracene-based molecular crystal","volume":"61","author":"Li","year":"2022","journal-title":"Angew. Chem., Int. Ed."},{"issue":"1","key":"2026072808070933600_cit35","doi-asserted-by":"publisher","first-page":"1450","DOI":"10.1038\/s41467-019-09120-1","article-title":"Side-group chemical gating via reversible optical and electric control\nin a single molecule transistor","volume":"10","author":"Meng","year":"2019","journal-title":"Nat. Commun."},{"issue":"10","key":"2026072808070933600_cit36","doi-asserted-by":"publisher","first-page":"6856","DOI":"10.1021\/jacs.3c13752","article-title":"Conductance evolution of photoisomeric single-molecule\njunctions under ultraviolet irradiation and mechanical stretching","volume":"146","author":"Tan","year":"2024","journal-title":"J. Am. Chem. Soc."},{"issue":"2","key":"2026072808070933600_cit37","doi-asserted-by":"publisher","first-page":"2408310","DOI":"10.1002\/advs.202408310","article-title":"Dual-vibration-assisted charge transport through hexabenzocoronene\nin single-molecule junctions","volume":"12","author":"Zhang","year":"2025","journal-title":"Adv. Sci."},{"key":"2026072808070933600_cit38","doi-asserted-by":"publisher","first-page":"101","DOI":"10.1007\/s10858-016-0072-7","article-title":"Sparse multidimensional\niterative lineshape-enhanced (SMILE) reconstruction of both non-uniformly\nsampled and conventional NMR data","volume":"68","author":"Ying","year":"2017","journal-title":"J. Biomol.\nNMR"},{"key":"2026072808070933600_cit39","doi-asserted-by":"publisher","first-page":"1239","DOI":"10.1038\/s41467-019-09054-8","article-title":"Colorless-to-colorful switching electrochromic\npolyimides with very high contrast ratio","volume":"10","author":"Zhang","year":"2019","journal-title":"Nat.\nCommun."},{"issue":"2","key":"2026072808070933600_cit40","doi-asserted-by":"publisher","first-page":"321","DOI":"10.1200\/jco.2016.34.2_suppl.321","article-title":"Identification of a\npredictive factor of metastatic castration-resistant prostate cancer\npatients\u2019 response to alternative antiandrogen therapy with\nflutamide","volume":"34","author":"Yasui","year":"2016","journal-title":"J. Clin. Oncol."},{"issue":"7","key":"2026072808070933600_cit41","doi-asserted-by":"publisher","first-page":"1166","DOI":"10.1021\/ac60263a038","article-title":"Solvent\nand temperature effects in the determination of pyrrolizidine alkaloids\nwith 4-(dimethylamino) benzaldehyde","volume":"40","author":"Bingley","year":"1968","journal-title":"Anal. 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