Synthesis and Thermal Studies of Two Phosphonium Tetrahydroxidohexaoxidopentaborate(1-) Salts: Single-Crystal XRD Characterization of [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O and [MePPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·B(OH)<sub>3</sub>·0.5H<sub>2</sub>O
Two substituted phosphonium tetrahydoxidohexaoxidopentaborate(1-) salts, [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O (<b>1</b>) and [MePPh<sub>3</sub>][B&...
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| Format: | Article |
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MDPI AG
2023-09-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/19/6867 |
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| author | Michael A. Beckett Peter N. Horton Michael B. Hursthouse James L. Timmis |
| author_facet | Michael A. Beckett Peter N. Horton Michael B. Hursthouse James L. Timmis |
| author_sort | Michael A. Beckett |
| collection | DOAJ |
| description | Two substituted phosphonium tetrahydoxidohexaoxidopentaborate(1-) salts, [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O (<b>1</b>) and [MePPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·B(OH)<sub>3</sub>·0.5H<sub>2</sub>O (<b>2</b>), were prepared by templated self-assembly processes with good yields by crystallization from basic methanolic aqueous solutions primed with B(OH)<sub>3</sub> and the appropriate phosphonium cation. Salts <b>1</b> and <b>2</b> were characterized by spectroscopic (NMR and IR) and thermal (TGA/DSC) analysis. Salts <b>1</b> and <b>2</b> were thermally decomposed in air at 800 °C to glassy solids via the anhydrous phosphonium polyborates that are formed at lower temperatures (<300 °C). BET analysis of the anhydrous and pyrolysed materials indicated they were non-porous with surface areas of 0.2–2.75 m<sup>2</sup>/g. Rhe recrystallization of <b>1</b> and <b>2</b> from aqueous solution afforded crystals suitable for single-crystal XRD analyses. The structure of <b>1</b> comprises alternating cationic/anionic layers with the H<sub>2</sub>O/pentaborate(1-) planes held together by H-bonds. The cationic planes have offset face-to-face (<i>off</i>) and vertex-to-face (<i>vf</i>) aromatic ring interactions with the <sup>i</sup>Pr groups oriented towards the pentaborate(1-)/H<sub>2</sub>O layers. The anionic lattice in <b>2</b> is expanded by the inclusion of B(OH)<sub>3</sub> molecules to accommodate the large cations; this results in the formation of a stacked pentaborate(1-)/B(OH)<sub>3</sub> structure with channels occupied by the cations. The cations within the channels have <i>vf</i>, <i>ef</i> (edge-to-face), and <i>off</i> phenyl embraces. Both H-bonding and phenyl embrace interactions are important in stabilizing these two solid-state structures. |
| first_indexed | 2024-03-10T21:39:57Z |
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| institution | Directory Open Access Journal |
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| last_indexed | 2024-03-10T21:39:57Z |
| publishDate | 2023-09-01 |
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| spelling | doaj.art-8d3b0da84f3d48f09a31dc837203242f2023-11-19T14:46:40ZengMDPI AGMolecules1420-30492023-09-012819686710.3390/molecules28196867Synthesis and Thermal Studies of Two Phosphonium Tetrahydroxidohexaoxidopentaborate(1-) Salts: Single-Crystal XRD Characterization of [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O and [MePPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·B(OH)<sub>3</sub>·0.5H<sub>2</sub>OMichael A. Beckett0Peter N. Horton1Michael B. Hursthouse2James L. Timmis3School of Natural Sciences, Bangor University, Bangor LL57 2UW, UKChemistry Department, University of Southampton, Southampton SO17 1BJ, UKChemistry Department, University of Southampton, Southampton SO17 1BJ, UKSchool of Natural Sciences, Bangor University, Bangor LL57 2UW, UKTwo substituted phosphonium tetrahydoxidohexaoxidopentaborate(1-) salts, [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O (<b>1</b>) and [MePPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·B(OH)<sub>3</sub>·0.5H<sub>2</sub>O (<b>2</b>), were prepared by templated self-assembly processes with good yields by crystallization from basic methanolic aqueous solutions primed with B(OH)<sub>3</sub> and the appropriate phosphonium cation. Salts <b>1</b> and <b>2</b> were characterized by spectroscopic (NMR and IR) and thermal (TGA/DSC) analysis. Salts <b>1</b> and <b>2</b> were thermally decomposed in air at 800 °C to glassy solids via the anhydrous phosphonium polyborates that are formed at lower temperatures (<300 °C). BET analysis of the anhydrous and pyrolysed materials indicated they were non-porous with surface areas of 0.2–2.75 m<sup>2</sup>/g. Rhe recrystallization of <b>1</b> and <b>2</b> from aqueous solution afforded crystals suitable for single-crystal XRD analyses. The structure of <b>1</b> comprises alternating cationic/anionic layers with the H<sub>2</sub>O/pentaborate(1-) planes held together by H-bonds. The cationic planes have offset face-to-face (<i>off</i>) and vertex-to-face (<i>vf</i>) aromatic ring interactions with the <sup>i</sup>Pr groups oriented towards the pentaborate(1-)/H<sub>2</sub>O layers. The anionic lattice in <b>2</b> is expanded by the inclusion of B(OH)<sub>3</sub> molecules to accommodate the large cations; this results in the formation of a stacked pentaborate(1-)/B(OH)<sub>3</sub> structure with channels occupied by the cations. The cations within the channels have <i>vf</i>, <i>ef</i> (edge-to-face), and <i>off</i> phenyl embraces. Both H-bonding and phenyl embrace interactions are important in stabilizing these two solid-state structures.https://www.mdpi.com/1420-3049/28/19/6867organotriphenylphosphonium saltsπ-interactionspentaborate(1-)phenyl embracesphosphonium saltstetrahydroxidohexaoxidopentaborate(1-) |
| spellingShingle | Michael A. Beckett Peter N. Horton Michael B. Hursthouse James L. Timmis Synthesis and Thermal Studies of Two Phosphonium Tetrahydroxidohexaoxidopentaborate(1-) Salts: Single-Crystal XRD Characterization of [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O and [MePPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·B(OH)<sub>3</sub>·0.5H<sub>2</sub>O Molecules organotriphenylphosphonium salts π-interactions pentaborate(1-) phenyl embraces phosphonium salts tetrahydroxidohexaoxidopentaborate(1-) |
| title | Synthesis and Thermal Studies of Two Phosphonium Tetrahydroxidohexaoxidopentaborate(1-) Salts: Single-Crystal XRD Characterization of [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O and [MePPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·B(OH)<sub>3</sub>·0.5H<sub>2</sub>O |
| title_full | Synthesis and Thermal Studies of Two Phosphonium Tetrahydroxidohexaoxidopentaborate(1-) Salts: Single-Crystal XRD Characterization of [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O and [MePPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·B(OH)<sub>3</sub>·0.5H<sub>2</sub>O |
| title_fullStr | Synthesis and Thermal Studies of Two Phosphonium Tetrahydroxidohexaoxidopentaborate(1-) Salts: Single-Crystal XRD Characterization of [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O and [MePPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·B(OH)<sub>3</sub>·0.5H<sub>2</sub>O |
| title_full_unstemmed | Synthesis and Thermal Studies of Two Phosphonium Tetrahydroxidohexaoxidopentaborate(1-) Salts: Single-Crystal XRD Characterization of [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O and [MePPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·B(OH)<sub>3</sub>·0.5H<sub>2</sub>O |
| title_short | Synthesis and Thermal Studies of Two Phosphonium Tetrahydroxidohexaoxidopentaborate(1-) Salts: Single-Crystal XRD Characterization of [<sup>i</sup>PrPPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·3.5H<sub>2</sub>O and [MePPh<sub>3</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>]·B(OH)<sub>3</sub>·0.5H<sub>2</sub>O |
| title_sort | synthesis and thermal studies of two phosphonium tetrahydroxidohexaoxidopentaborate 1 salts single crystal xrd characterization of sup i sup prpph sub 3 sub b sub 5 sub o sub 6 sub oh sub 4 sub ·3 5h sub 2 sub o and mepph sub 3 sub b sub 5 sub o sub 6 sub oh sub 4 sub ·b oh sub 3 sub ·0 5h sub 2 sub o |
| topic | organotriphenylphosphonium salts π-interactions pentaborate(1-) phenyl embraces phosphonium salts tetrahydroxidohexaoxidopentaborate(1-) |
| url | https://www.mdpi.com/1420-3049/28/19/6867 |
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