{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,23]],"date-time":"2026-04-23T04:13:47Z","timestamp":1776917627104,"version":"3.51.2"},"reference-count":41,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2019,7,23]],"date-time":"2019-07-23T00:00:00Z","timestamp":1563840000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001808","name":"Kommission f\u00fcr Technologie und Innovation","doi-asserted-by":"publisher","award":["18055.1 PFIW-IW"],"award-info":[{"award-number":["18055.1 PFIW-IW"]}],"id":[{"id":"10.13039\/501100001808","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001711","name":"Schweizerischer Nationalfonds zur F\u00f6rderung der Wissenschaftlichen Forschung","doi-asserted-by":"publisher","award":["150638"],"award-info":[{"award-number":["150638"]}],"id":[{"id":"10.13039\/501100001711","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>In this article, we report the synthesis of 2,4,6-substituted s-triazine-based organophosphorus compounds via a two-step process, which enables their production in high yields, and with a high purity as solids. In the first step, a Michaelis\u2013Arbuzov rearrangement of cyanuric chloride with triethyl phosphite afforded 2,4,6-trisdiethoxyphosphinyl-1,3,5-triazine (HEPT). Subsequently, the nucleophilic substitution reaction on the triazine carbon was achieved, owing to the electron-withdrawing ability of the phosphonate groups. This characteristic of HEPT facilitated its derivatization with bi-functional amines, producing novel P\u2013C containing bridged triazine organophosphorus compounds. The molecular structures of all of the compounds were confirmed by NMR spectroscopy, CHN elemental analysis, and single crystal X-ray analysis. In the thermogravimetric analysis in an N2 environment, &gt;33% char formation was observed for the bridged compounds. The chemical composition analysis of the char obtained under the oxidative thermal decomposition of the bridged compounds confirmed the presence of phosphorus- and nitrogen-enriched species, which indicate their function in the condensed phase. Comparatively, the detection of HPO and H\u2013C\u2261P in the gas phase during the pyrolysis of the bridged compounds can act as a source for PO\u2022, which is known for its gas phase flame inhibition reactions. The synergy of significant char formation and the generation of intermediates leading to PO\u2022 during pyrolysis makes these molecules promising flame-retardant additives.<\/jats:p>","DOI":"10.3390\/molecules24142672","type":"journal-article","created":{"date-parts":[[2019,7,23]],"date-time":"2019-07-23T10:44:51Z","timestamp":1563878691000},"page":"2672","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":20,"title":["Insight into the Synthesis and Characterization of Organophosphorus-Based Bridged Triazine Compounds"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2541-9652","authenticated-orcid":false,"given":"Khalifah A.","family":"Salmeia","sequence":"first","affiliation":[{"name":"Additives and Chemistry, Advanced Fibers, Empa Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5752-2852","authenticated-orcid":false,"given":"Antonia","family":"Neels","sequence":"additional","affiliation":[{"name":"Center for X-ray Analytics, Swiss Federal Laboratories for Materials Science and Technology, Empa, \u00dcberlandstrasse 129, 8600 D\u00fcbendorf, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4120-630X","authenticated-orcid":false,"given":"Dambarudhar","family":"Parida","sequence":"additional","affiliation":[{"name":"Additives and Chemistry, Advanced Fibers, Empa Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sandro","family":"Lehner","sequence":"additional","affiliation":[{"name":"Additives and Chemistry, Advanced Fibers, Empa Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9335-9527","authenticated-orcid":false,"given":"Daniel","family":"Rentsch","sequence":"additional","affiliation":[{"name":"Laboratory for Functional Polymers, Empa Swiss Federal Laboratories for Materials Science and Technology, \u00dcberlandstrasse 129, 8600 D\u00fcbendorf, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sabyasachi","family":"Gaan","sequence":"additional","affiliation":[{"name":"Additives and Chemistry, Advanced Fibers, Empa Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,7,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1016\/B978-0-08-100024-3.00014-3","article-title":"Triazines and tetrazines","volume":"27","author":"Prokhorov","year":"2015","journal-title":"Prog. Heterocycl. Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1599","DOI":"10.1055\/s-0033-1339284","article-title":"Recent developments in the synthesis of bioactive 2,4,6-trisubstituted 1,3,5-triazines","volume":"24","author":"Banerjee","year":"2013","journal-title":"Synlett"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"9507","DOI":"10.1016\/j.tet.2006.07.039","article-title":"Recent applications of 2,4,6-trichloro-1,3,5-triazine and its derivatives in organic synthesis","volume":"62","author":"Blotny","year":"2006","journal-title":"Tetrahedron"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Probst, D.A., Hanson, P.R., and Barda, D.A. (2004). Cyanuric chloride. e-EROS Encyclopedia of Reagents for Organic Synthesis, John Wiley & Sons, Ltd.","DOI":"10.1002\/047084289X.rn00320"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1039\/CT8864900311","article-title":"Contributions to the history of cyanuric chloride and cyanuric acid","volume":"49","author":"Senier","year":"1886","journal-title":"J. Chem. Soc. Trans."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"342","DOI":"10.2174\/157017912801270612","article-title":"Melamine derivatives. A review on synthesis and application","volume":"9","author":"Bretterbauer","year":"2012","journal-title":"Curr. Org. Synth."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2672","DOI":"10.1021\/cr800315j","article-title":"Direct Phosphonylation of Aromatic Azaheterocycles","volume":"109","author":"Stevens","year":"2009","journal-title":"Chem. Rev."},{"key":"ref_8","unstructured":"Huthmacher, K., and Most, D. (2012). Cyanuric acid and cyanuric chloride. Ullmann\u2019s Encyclopedia of Industrial Chemistry, Wiley-VCH Verlag GmbH & Co. KGaA."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"74742","DOI":"10.1039\/C6RA14345H","article-title":"Recent studies on the decomposition and strategies of smoke and toxicity suppression for polyurethane based materials","volume":"6","author":"Liu","year":"2016","journal-title":"RSC Adv."},{"key":"ref_10","unstructured":"Cipolli, R., Masarati, E., Rossi, C., Oriani, R., and Nucida, G. (1993). Self-extinguishing polymeric compositions. (EP551154A1)."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/j.polymdegradstab.2015.07.003","article-title":"Synthesis of a formaldehyde-free phosphorus-nitrogen flame retardant with multiple reactive groups and its application in cotton fabrics","volume":"120","author":"Li","year":"2015","journal-title":"Polym. Degrad. Stab."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1021\/bk-2012-1118.ch009","article-title":"Antiflammable properties of capable phosphorus-nitrogen-containing triazine derivatives on cotton","volume":"1118","author":"Chang","year":"2012","journal-title":"ACS Symp. Ser."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"334","DOI":"10.1007\/s12221-011-0334-7","article-title":"Flame retardant properties of triazine phosphonates derivative with cotton fabric","volume":"12","author":"Chang","year":"2011","journal-title":"Fibers Polym."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"963","DOI":"10.1007\/s12221-012-0963-5","article-title":"Synthesis of a novel flame retardant containing phosphorus-nitrogen and its comparison for cotton fabric","volume":"13","author":"Nguyen","year":"2012","journal-title":"Fibers Polym."},{"key":"ref_15","first-page":"60","article-title":"Cyanuric chloride derivatives for cotton textile treatment-synthesis, analysis, and flammability testing","volume":"11","author":"Easson","year":"2011","journal-title":"AATCC Rev."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1016\/j.polymdegradstab.2018.09.001","article-title":"Novel organophosphorus flame retardants and their synergistic application in novolac epoxy resin","volume":"158","author":"Schmidt","year":"2018","journal-title":"Polym. Degrad. Stab."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"398","DOI":"10.1016\/j.polymdegradstab.2015.10.006","article-title":"Preparation and flame retardancy of a compounded epoxy resin system composed of phosphorus\/nitrogen-containing active compounds","volume":"121","author":"Yang","year":"2015","journal-title":"Polym. Degrad. Stab."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"7309","DOI":"10.1021\/acs.iecr.5b00315","article-title":"Functional Group Effect on Char Formation, Flame Retardancy and Mechanical Properties of Phosphonate\u2013Triazine-based Compound as Flame Retardant in Epoxy Resin","volume":"54","author":"You","year":"2015","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Chen, H., Wang, J., Ni, A., Ding, A., Han, X., and Sun, Z. (2018). The effects of a macromolecular charring agent with gas phase and condense phase synergistic flame retardant capability on the properties of PP\/IFR composites. Materials, 11.","DOI":"10.3390\/ma11010111"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Ma, D., and Li, J. (2019). Synthesis of a bio-based triazine derivative and its effects on flame retardancy of polypropylene composites. J. Appl. Polym. Sci.","DOI":"10.1002\/app.47367"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1016\/j.polymdegradstab.2017.05.023","article-title":"A novel hyperbranched poly(phosphorodiamidate) with high expansion degree and carbonization efficiency used for improving flame retardancy of APP\/PP composites","volume":"142","author":"Ye","year":"2017","journal-title":"Polym. Degrad. Stab."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"7593","DOI":"10.3390\/molecules15117593","article-title":"Synthesis and application in polypropylene of a novel of phosphorus-containing intumescent flame retardant","volume":"15","author":"Zuo","year":"2010","journal-title":"Molecules"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Morgan, A.B., and Wilkie, C.A. (2014). Nitrogen-based flame retardants. Non-Halogenated Flame Retardant Handbook, Scrivener Publishing LLC.","DOI":"10.1002\/9781118939239"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"504","DOI":"10.3390\/polym7030504","article-title":"An Overview of Mode of Action and Analytical Methods for Evaluation of Gas Phase Activities of Flame Retardants","volume":"7","author":"Salmeia","year":"2015","journal-title":"Polymers"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1016\/j.polymdegradstab.2014.12.014","article-title":"An overview of some recent advances in DOPO-derivatives: Chemistry and flame retardant applications","volume":"113","author":"Salmeia","year":"2015","journal-title":"Polym. Degrad. Stability"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1556","DOI":"10.1002\/app.20792","article-title":"Synthesis and characterization of a novel nitrogen-containing flame retardant","volume":"94","author":"Hu","year":"2004","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1880","DOI":"10.4028\/www.scientific.net\/AMR.332-334.1880","article-title":"Development of environmental friendly flame retardants for wood plastic composites (WPC)","volume":"332\u2013334","author":"Liu","year":"2011","journal-title":"Adv. Mater. Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"583","DOI":"10.1002\/pola.1988.080260221","article-title":"Synthesis, physical, and thermal properties of linear poly(dialkoxyphosphinyl-s-triazines)","volume":"26","author":"Mikroyannidis","year":"1988","journal-title":"J. Polym. Sci. Part A Polym. Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"11236","DOI":"10.3390\/molecules200611236","article-title":"Understanding the mechanism of action of triazine-phosphonate derivatives as flame retardants for cotton fabric","volume":"20","author":"Nguyen","year":"2015","journal-title":"Molecules"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"444","DOI":"10.1021\/jo01355a603","article-title":"sym-Triazinetriphosphonic acid esters","volume":"22","author":"Morrison","year":"1957","journal-title":"J. Org. Chem."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Hewertson, W., Shaw, R.A., and Smith, B.C. (1963). 313. 1,3,5-Triazines. Part III. Arbuzov reactions of chlorotriazines. J. Chem. Soc., 1670\u20131675.","DOI":"10.1039\/jr9630001670"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Hewertson, W., Shaw, R.A., and Smith, B.C. (1964). 197. 1,3,5-Triazines. Part IV. Phosphino-1,3,5-triazines. J. Chem. Soc., 1020\u20131026.","DOI":"10.1039\/jr9640001020"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1080\/10426509808033727","article-title":"Dynamic NMR studies of phosphorylated diamine-coupled bis-1,3,5-triazines","volume":"141","author":"Kreher","year":"1998","journal-title":"Phosphorus Sulfur Silicon Relat. Elem."},{"key":"ref_34","unstructured":"Salmeia, K., Gaan, S., and Bruehwiler, M. (2018). Flame retardants. (WO2018069249A1)."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1021\/je60047a009","article-title":"New method for preparing alkyl (amino-s-triazinyl) phosphonates","volume":"15","author":"Moreau","year":"1970","journal-title":"J. Chem. Eng. Data"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"112","DOI":"10.1107\/S0108767307043930","article-title":"A short history of SHELX","volume":"64","author":"Sheldrick","year":"2008","journal-title":"Acta. Crystallogr. A"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1107\/S0021889802022112","article-title":"Single-crystal structure validation with the program PLATON","volume":"36","author":"Spek","year":"2003","journal-title":"J. Appl. Crystallogr."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1799","DOI":"10.1016\/j.polymdegradstab.2008.07.012","article-title":"Flame retardation and char formation mechanism of intumescent flame retarded polypropylene composites containing melamine phosphate and pentaerythritol phosphate","volume":"93","author":"Zhou","year":"2008","journal-title":"Polym. Degrad. Stability"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1016\/j.polymdegradstab.2014.03.041","article-title":"Synergistic effect between a novel triazine charring agent and ammonium polyphosphate on flame retardancy and thermal behavior of polypropylene","volume":"105","author":"Su","year":"2014","journal-title":"Polym. Degrad. Stability"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"947","DOI":"10.1016\/j.polymdegradstab.2007.03.012","article-title":"s-Triazine containing flame retardant hyperbranched polyamines: Synthesis, characterization and properties evaluation","volume":"92","author":"Mahapatra","year":"2007","journal-title":"Polym. Degrad. Stability"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1073","DOI":"10.1002\/chem.201404271","article-title":"Elucidating the Thermal Decomposition of Dimethyl Methylphosphonate by Vacuum Ultraviolet (VUV) Photoionization: Pathways to the PO Radical, a Key Species in Flame-Retardant Mechanisms","volume":"21","author":"Liang","year":"2015","journal-title":"Chem. Eur. J."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/24\/14\/2672\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:08:45Z","timestamp":1760188125000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/24\/14\/2672"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,7,23]]},"references-count":41,"journal-issue":{"issue":"14","published-online":{"date-parts":[[2019,7]]}},"alternative-id":["molecules24142672"],"URL":"https:\/\/doi.org\/10.3390\/molecules24142672","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,7,23]]}}}