{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:31:06Z","timestamp":1760146266984,"version":"build-2065373602"},"reference-count":21,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2024,10,22]],"date-time":"2024-10-22T00:00:00Z","timestamp":1729555200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000268","name":"Biotechnology and Biological Sciences Research Council","doi-asserted-by":"publisher","award":["BB\/P504373\/1"],"award-info":[{"award-number":["BB\/P504373\/1"]}],"id":[{"id":"10.13039\/501100000268","id-type":"DOI","asserted-by":"publisher"}]},{"name":"GlaxoSmithKline","award":["BB\/P504373\/1"],"award-info":[{"award-number":["BB\/P504373\/1"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Imidazo-fused diazaborines, which serve as intermediary structures somewhat alongside benzene and borazine, had been of particular interest to Dewar and Snyder more than 60 years ago. To this end, Dewar utilised his \u2018\u03c0-complex theory\u2019so as to represent \u2018borazaros\u2019as a \u2018quadrivalent\u2019 species; however, sadly, modern representations have deviated and leapt into \u2018trivalent\u2019 counterparts. Bonding in boron species has never been straightforward, to such an extent that the orthodox \u2018ethane\u2019 like diborane, i.e., H3B\u2013BH3, which conformed to the paradigmatic rules of molecular structure, in particular, hybridisation and electronegativity, was later evolved to a more realistic \u20183-centre 2-electron\u2019 bonding so as to give the lie to the purported diborane structures of X-ray diffractors. Herein 11B NMR together with IR spectroscopy sheds light on the nature of bonding in borazaros, and \u2018caged\u2019 cyclic oxazaborons so as to reinforce, and reinvigorate the old literature, which could be of interest to both the synthetic, and medicinal chemist alike.<\/jats:p>","DOI":"10.3390\/molecules29214998","type":"journal-article","created":{"date-parts":[[2024,10,22]],"date-time":"2024-10-22T11:31:57Z","timestamp":1729596717000},"page":"4998","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["11B NMR Together with Infrared Spectroscopy Provides Insight into Structural Elucidation of Quadrivalent Diazaborines &amp; Cyclic Boronate Esters: Intriguing &amp; Little-Explored"],"prefix":"10.3390","volume":"29","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-5920-2286","authenticated-orcid":false,"given":"Ashley L.","family":"Dey","sequence":"first","affiliation":[{"name":"Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,10,22]]},"reference":[{"key":"ref_1","first-page":"417","article-title":"NMR of Boron Hydrides and Related Compounds","volume":"1","author":"Schaeffer","year":"1964","journal-title":"Prog. Boron Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1016\/0079-6565(79)80001-1","article-title":"NMR Studies of Boranes, Carboranes and Heteroatom Boranes","volume":"13","author":"Todd","year":"1979","journal-title":"Prog. NMR Spectrosc."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1981","DOI":"10.1016\/S0277-5387(00)84535-0","article-title":"Some Electrophilic Substitution Reactions of closo-[1-CB11H12]\u2212 and One-boron Insertion into nido-7-L-7-CB10H12(L\u00a0=\u00a0H\u2212orMe3N) Compounds. Isolation of all Three B-substituted closo-Me3N-1-CB11H11","volume":"6","author":"Jelinek","year":"1987","journal-title":"Polyhedron"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1021\/ja00313a007","article-title":"Two-dimensional 11B\u201311B NMR Spectroscopy as a Probe of Polyhedral Structure: Applicatioin to Boron Hydrides, Carboranes, Metallaboranes, and Metallacarboranes","volume":"106","author":"Venable","year":"1984","journal-title":"J. Am. Chem. Soc."},{"key":"ref_5","unstructured":"Alcock, N.W., Taylor, J.G., and Wallbridge, M.G.H. (1983). An Unexpected Cluster Rearrangement in the Formation of a closo-carbametallaborane from an arachno-carbaborane. The Crystal and Molecular Structure of [1-(PPh3)-2-H-2, 2-(PPh3)2-2, 10-IrCB8H8]. J. Chem. Soc. Chem. Commun., 1168\u20131169."},{"key":"ref_6","unstructured":"Reed, D. (1984). Applications of Two-dimensional NMR for the Boron Chemist. A COSY Study of Some Polyhedral Boranes. J. Chem. Res., 198\u2013199."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"13923","DOI":"10.1039\/D4SC03109A","article-title":"Triborane (B3H7)-mediated Regioselective Substitution Reactions of Pyridine Derivatives","volume":"15","author":"Fan","year":"2024","journal-title":"Chem. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"6869","DOI":"10.1021\/ja01052a067","article-title":"Total Assignment of the Proton NMR Spectrum of 1,2-(CH3)2B5H7 Using Heteronuclear 11B Multiple Resonance Decoupling","volume":"91","author":"Tucker","year":"1969","journal-title":"J. Am. Chem. Soc."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"9472","DOI":"10.1039\/D3CP00253E","article-title":"Accurate Predictions of 11B NMR Chemical Shift of BODIPYs via Machine Learning","volume":"25","author":"Ksenofontov","year":"2023","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"4589","DOI":"10.1039\/C6SC00172F","article-title":"Fast and Selective Labelling of N-Terminal Cysteines at Neutral pH via Thiazolidino Boronate Formation","volume":"7","author":"Bandyopadhyay","year":"2016","journal-title":"Chem. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Li, Q., Yang, Y., Wang, Q., Han, X., Zhu, J., Zhang, N., Wang, Q., Li, K., Gong, P., and Chen, F. (2024). 11B NMR of the Morphological Evolution of Traditional Chinese Medicine Borax. Molecules, 29.","DOI":"10.3390\/molecules29010251"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1020","DOI":"10.1021\/jo01050a081","article-title":"A New Preparation of Some Dimethylamino Derivatives of Boron","volume":"27","author":"Ruff","year":"1962","journal-title":"J. Org. Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"567","DOI":"10.1103\/PhysRev.77.567","article-title":"The Internal Diamagnetic Field Correction in Measurements of the Proton Magnetic Moment","volume":"77","author":"Ramsey","year":"1950","journal-title":"Phys. Rev."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"699","DOI":"10.1103\/PhysRev.78.699","article-title":"Magnetic Shielding of Nuclei in Molecules","volume":"78","author":"Ramsey","year":"1950","journal-title":"Phys. Rev."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"706","DOI":"10.1021\/ja01005a026","article-title":"New Heteroaromatic Compounds. XXVII. 11B Chemical Shifts of Some Heteroaromatic Boron Compounds","volume":"90","author":"Davis","year":"1968","journal-title":"J. Am. Chem. Soc."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"871","DOI":"10.1021\/jacs.6b11115","article-title":"Fast Diazaborine Formation of Semicarbazide Enables Facile Labelling of Bacterial Pathogens","volume":"139","author":"Bandyopadhyay","year":"2017","journal-title":"J. Am. Chem. Soc."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2168","DOI":"10.1021\/jo01031a014","article-title":"Arylboronic Acids. VII. Some Reactions of o-Formylbenzeneboronic Acid","volume":"29","author":"Tschampel","year":"1964","journal-title":"J. Org. Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1555","DOI":"10.1021\/ja01184a078","article-title":"3-Substituted Thiophenes I","volume":"70","author":"Campaigne","year":"1948","journal-title":"J. Am. Chem. Soc."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"464","DOI":"10.1016\/j.molstruc.2015.07.054","article-title":"Alkyl Sulfonic Acid Hydrazides: Synthesis, Characterisation, Computational Studies, and Anticancer, Antibacterial, Anticarbonic Anhydrase II (hCA II) Activities","volume":"1100","author":"Ozdemir","year":"2015","journal-title":"J. Mol. Struct."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"683","DOI":"10.1002\/jlac.198519850404","article-title":"Zum Abbau von 1,2-Dihydro-1-hydroxy-2-organosulfonyl[2,3,1]Benzodiazaborinen und Thieno[3,2-d][1,2,3]-diazaborinen in Alkalischer Wassriger Losung","volume":"4","author":"Grassberger","year":"1985","journal-title":"Liebigs Ann."},{"key":"ref_21","unstructured":"(1978). Sandoz-DE2750878. Chem. Abstr., 89, 109937."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/29\/21\/4998\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:18:03Z","timestamp":1760113083000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/29\/21\/4998"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,10,22]]},"references-count":21,"journal-issue":{"issue":"21","published-online":{"date-parts":[[2024,11]]}},"alternative-id":["molecules29214998"],"URL":"https:\/\/doi.org\/10.3390\/molecules29214998","relation":{},"ISSN":["1420-3049"],"issn-type":[{"type":"electronic","value":"1420-3049"}],"subject":[],"published":{"date-parts":[[2024,10,22]]}}}