Novel Approach for the Synthesis of Chlorophosphazene Cycles with a Defined Size via Controlled Cyclization of Linear Oligodichlorophosphazenes [Cl(PCl<sub>2</sub>=N)<sub>n</sub>–PCl<sub>3</sub>]<sup>+</sup>[PCl<sub>6</sub>]<sup>−</sup>
Despite a significant number of investigations in the field of phosphazene chemistry, the formation mechanism of this class of cyclic compounds is still poorly studied. At the same time, a thorough understanding of this process is necessary, both for the direct production of phosphazene rings of a g...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-05-01
|
| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/22/11/5958 |
| _version_ | 1797531826309300224 |
|---|---|
| author | Mikhail Gorlov Nikolay Bredov Andrey Esin Igor Sirotin Mikhail Soldatov Volodymyr Oberemok Vyacheslav V. Kireev |
| author_facet | Mikhail Gorlov Nikolay Bredov Andrey Esin Igor Sirotin Mikhail Soldatov Volodymyr Oberemok Vyacheslav V. Kireev |
| author_sort | Mikhail Gorlov |
| collection | DOAJ |
| description | Despite a significant number of investigations in the field of phosphazene chemistry, the formation mechanism of this class of cyclic compounds is still poorly studied. At the same time, a thorough understanding of this process is necessary, both for the direct production of phosphazene rings of a given size and for the controlled cyclization reaction when it is secondary and undesirable. We synthesized a series of short linear phosphazene oligomers with the general formula Cl[PCl2=N]n–PCl<sub>3</sub><sup>+</sup>PCl<sub>6</sub><sup>–</sup> and studied their tendency to form cyclic structures under the influence of elevated temperatures or in the presence of nitrogen-containing agents, such as hexamethyldisilazane (HMDS) or ammonium chloride. It was established that linear oligophosphazenes are inert when heated in the absence of the mentioned cyclization agents, and the formation of cyclic products occurs only when these agents are involved in the process. The ability to obtain the desired size phosphazene cycle from corresponding linear chains is shown for the first time. Known obstacles, such as side interaction with the PCl<sub>6</sub><sup>–</sup> counterion and a tendency of longer chains to undergo crosslinking elongation instead of cyclization are still relevant, and ways to overcome them are being discussed. |
| first_indexed | 2024-03-10T10:50:16Z |
| format | Article |
| id | doaj.art-ecaf237a60c04ba099f0b230fcce4004 |
| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T10:50:16Z |
| publishDate | 2021-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-ecaf237a60c04ba099f0b230fcce40042023-11-21T22:19:32ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-05-012211595810.3390/ijms22115958Novel Approach for the Synthesis of Chlorophosphazene Cycles with a Defined Size via Controlled Cyclization of Linear Oligodichlorophosphazenes [Cl(PCl<sub>2</sub>=N)<sub>n</sub>–PCl<sub>3</sub>]<sup>+</sup>[PCl<sub>6</sub>]<sup>−</sup>Mikhail Gorlov0Nikolay Bredov1Andrey Esin2Igor Sirotin3Mikhail Soldatov4Volodymyr Oberemok5Vyacheslav V. Kireev6Faculty of Petrochemistry and Polymer Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047 Moscow, RussiaFaculty of Petrochemistry and Polymer Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047 Moscow, RussiaFaculty of Petrochemistry and Polymer Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047 Moscow, RussiaFaculty of Petrochemistry and Polymer Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047 Moscow, RussiaFaculty of Petrochemistry and Polymer Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047 Moscow, RussiaTaurida Academy, Department of Biochemistry, V. I. Vernadsky Crimean Federal University, Prospekt Akademika Vernadskogo 4, 295007 Simferopol, RussiaFaculty of Petrochemistry and Polymer Materials, Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047 Moscow, RussiaDespite a significant number of investigations in the field of phosphazene chemistry, the formation mechanism of this class of cyclic compounds is still poorly studied. At the same time, a thorough understanding of this process is necessary, both for the direct production of phosphazene rings of a given size and for the controlled cyclization reaction when it is secondary and undesirable. We synthesized a series of short linear phosphazene oligomers with the general formula Cl[PCl2=N]n–PCl<sub>3</sub><sup>+</sup>PCl<sub>6</sub><sup>–</sup> and studied their tendency to form cyclic structures under the influence of elevated temperatures or in the presence of nitrogen-containing agents, such as hexamethyldisilazane (HMDS) or ammonium chloride. It was established that linear oligophosphazenes are inert when heated in the absence of the mentioned cyclization agents, and the formation of cyclic products occurs only when these agents are involved in the process. The ability to obtain the desired size phosphazene cycle from corresponding linear chains is shown for the first time. Known obstacles, such as side interaction with the PCl<sub>6</sub><sup>–</sup> counterion and a tendency of longer chains to undergo crosslinking elongation instead of cyclization are still relevant, and ways to overcome them are being discussed.https://www.mdpi.com/1422-0067/22/11/5958phosphazenescyclizationcontrolled cycle sizeliving cationic polymerizationhexamethyldisilazane |
| spellingShingle | Mikhail Gorlov Nikolay Bredov Andrey Esin Igor Sirotin Mikhail Soldatov Volodymyr Oberemok Vyacheslav V. Kireev Novel Approach for the Synthesis of Chlorophosphazene Cycles with a Defined Size via Controlled Cyclization of Linear Oligodichlorophosphazenes [Cl(PCl<sub>2</sub>=N)<sub>n</sub>–PCl<sub>3</sub>]<sup>+</sup>[PCl<sub>6</sub>]<sup>−</sup> International Journal of Molecular Sciences phosphazenes cyclization controlled cycle size living cationic polymerization hexamethyldisilazane |
| title | Novel Approach for the Synthesis of Chlorophosphazene Cycles with a Defined Size via Controlled Cyclization of Linear Oligodichlorophosphazenes [Cl(PCl<sub>2</sub>=N)<sub>n</sub>–PCl<sub>3</sub>]<sup>+</sup>[PCl<sub>6</sub>]<sup>−</sup> |
| title_full | Novel Approach for the Synthesis of Chlorophosphazene Cycles with a Defined Size via Controlled Cyclization of Linear Oligodichlorophosphazenes [Cl(PCl<sub>2</sub>=N)<sub>n</sub>–PCl<sub>3</sub>]<sup>+</sup>[PCl<sub>6</sub>]<sup>−</sup> |
| title_fullStr | Novel Approach for the Synthesis of Chlorophosphazene Cycles with a Defined Size via Controlled Cyclization of Linear Oligodichlorophosphazenes [Cl(PCl<sub>2</sub>=N)<sub>n</sub>–PCl<sub>3</sub>]<sup>+</sup>[PCl<sub>6</sub>]<sup>−</sup> |
| title_full_unstemmed | Novel Approach for the Synthesis of Chlorophosphazene Cycles with a Defined Size via Controlled Cyclization of Linear Oligodichlorophosphazenes [Cl(PCl<sub>2</sub>=N)<sub>n</sub>–PCl<sub>3</sub>]<sup>+</sup>[PCl<sub>6</sub>]<sup>−</sup> |
| title_short | Novel Approach for the Synthesis of Chlorophosphazene Cycles with a Defined Size via Controlled Cyclization of Linear Oligodichlorophosphazenes [Cl(PCl<sub>2</sub>=N)<sub>n</sub>–PCl<sub>3</sub>]<sup>+</sup>[PCl<sub>6</sub>]<sup>−</sup> |
| title_sort | novel approach for the synthesis of chlorophosphazene cycles with a defined size via controlled cyclization of linear oligodichlorophosphazenes cl pcl sub 2 sub n sub n sub pcl sub 3 sub sup sup pcl sub 6 sub sup sup |
| topic | phosphazenes cyclization controlled cycle size living cationic polymerization hexamethyldisilazane |
| url | https://www.mdpi.com/1422-0067/22/11/5958 |
| work_keys_str_mv | AT mikhailgorlov novelapproachforthesynthesisofchlorophosphazenecycleswithadefinedsizeviacontrolledcyclizationoflinearoligodichlorophosphazenesclpclsub2subnsubnsubpclsub3subsupsuppclsub6subsupsup AT nikolaybredov novelapproachforthesynthesisofchlorophosphazenecycleswithadefinedsizeviacontrolledcyclizationoflinearoligodichlorophosphazenesclpclsub2subnsubnsubpclsub3subsupsuppclsub6subsupsup AT andreyesin novelapproachforthesynthesisofchlorophosphazenecycleswithadefinedsizeviacontrolledcyclizationoflinearoligodichlorophosphazenesclpclsub2subnsubnsubpclsub3subsupsuppclsub6subsupsup AT igorsirotin novelapproachforthesynthesisofchlorophosphazenecycleswithadefinedsizeviacontrolledcyclizationoflinearoligodichlorophosphazenesclpclsub2subnsubnsubpclsub3subsupsuppclsub6subsupsup AT mikhailsoldatov novelapproachforthesynthesisofchlorophosphazenecycleswithadefinedsizeviacontrolledcyclizationoflinearoligodichlorophosphazenesclpclsub2subnsubnsubpclsub3subsupsuppclsub6subsupsup AT volodymyroberemok novelapproachforthesynthesisofchlorophosphazenecycleswithadefinedsizeviacontrolledcyclizationoflinearoligodichlorophosphazenesclpclsub2subnsubnsubpclsub3subsupsuppclsub6subsupsup AT vyacheslavvkireev novelapproachforthesynthesisofchlorophosphazenecycleswithadefinedsizeviacontrolledcyclizationoflinearoligodichlorophosphazenesclpclsub2subnsubnsubpclsub3subsupsuppclsub6subsupsup |