Molecular and Immobilized Tripodal Phosphine Ligands and Their Trinuclear Palladium Complexes
The synthesis and characterization of the tripodal phosphines RSi(CH<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub>)<sub>3</sub> (R = Me, OMe, OEt) (<b>1</b>–<b>3</b>) is described. The <sup>1</sup>H NMR spectra of all pho...
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2025-04-01
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| author | Maxwell R. Kimball Kyle J. Cluff Nattamai Bhuvanesh Janet Blümel |
| author_facet | Maxwell R. Kimball Kyle J. Cluff Nattamai Bhuvanesh Janet Blümel |
| author_sort | Maxwell R. Kimball |
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| description | The synthesis and characterization of the tripodal phosphines RSi(CH<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub>)<sub>3</sub> (R = Me, OMe, OEt) (<b>1</b>–<b>3</b>) is described. The <sup>1</sup>H NMR spectra of all phosphines display virtual coupling patterns. The ligands form the corresponding trinuclear Pd complexes [RSi(CH<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub>)<sub>3</sub>]<sub>2</sub>(PdCl<sub>2</sub>)<sub>3</sub> (<b>4</b>–<b>6</b>) with three PdCl<sub>2</sub> moieties sandwiched between two tripodal ligands. The complexes <b>4</b>, <b>5</b>, and <b>7</b> (R = OH) have been analyzed by single crystal X-ray diffraction. The coordination at the Pd center is square planar with the phosphine groups occupying <i>trans</i> positions. The <sup>31</sup>P{<sup>1</sup>H} MAS NMR spectra of polycrystalline <b>1</b> are in accordance with the packing motif of the molecules in the unit cell. The tripodal ligand <b>3</b> has successfully been immobilized on silica as <b>3i</b>. It coordinates PdCl<sub>2</sub> on the surface, as demonstrated by <sup>31</sup>P{<sup>1</sup>H} MAS NMR. Hereby, the <i>cis</i> coordination is prevalent when <b>3i</b> has maximal surface coverage. At low surface coverage, one tripodal linker can accommodate <i>trans</i> coordination at the metal center. A surface-bound trinuclear Pd complex has been generated, as well as a heterobimetallic Pd/Cu complex. All surface species have been characterized by <sup>31</sup>P{<sup>1</sup>H} MAS NMR. |
| format | Article |
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| language | English |
| publishDate | 2025-04-01 |
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| spelling | doaj-art-d296a776670e4116ae012031f8e86ee72025-08-20T02:09:19ZengMDPI AGMolecules1420-30492025-04-01307161610.3390/molecules30071616Molecular and Immobilized Tripodal Phosphine Ligands and Their Trinuclear Palladium ComplexesMaxwell R. Kimball0Kyle J. Cluff1Nattamai Bhuvanesh2Janet Blümel3Department of Chemistry, Texas A&M University, College Station, TX 77842-3012, USADepartment of Chemistry, Texas A&M University, College Station, TX 77842-3012, USADepartment of Chemistry, Texas A&M University, College Station, TX 77842-3012, USADepartment of Chemistry, Texas A&M University, College Station, TX 77842-3012, USAThe synthesis and characterization of the tripodal phosphines RSi(CH<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub>)<sub>3</sub> (R = Me, OMe, OEt) (<b>1</b>–<b>3</b>) is described. The <sup>1</sup>H NMR spectra of all phosphines display virtual coupling patterns. The ligands form the corresponding trinuclear Pd complexes [RSi(CH<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub>)<sub>3</sub>]<sub>2</sub>(PdCl<sub>2</sub>)<sub>3</sub> (<b>4</b>–<b>6</b>) with three PdCl<sub>2</sub> moieties sandwiched between two tripodal ligands. The complexes <b>4</b>, <b>5</b>, and <b>7</b> (R = OH) have been analyzed by single crystal X-ray diffraction. The coordination at the Pd center is square planar with the phosphine groups occupying <i>trans</i> positions. The <sup>31</sup>P{<sup>1</sup>H} MAS NMR spectra of polycrystalline <b>1</b> are in accordance with the packing motif of the molecules in the unit cell. The tripodal ligand <b>3</b> has successfully been immobilized on silica as <b>3i</b>. It coordinates PdCl<sub>2</sub> on the surface, as demonstrated by <sup>31</sup>P{<sup>1</sup>H} MAS NMR. Hereby, the <i>cis</i> coordination is prevalent when <b>3i</b> has maximal surface coverage. At low surface coverage, one tripodal linker can accommodate <i>trans</i> coordination at the metal center. A surface-bound trinuclear Pd complex has been generated, as well as a heterobimetallic Pd/Cu complex. All surface species have been characterized by <sup>31</sup>P{<sup>1</sup>H} MAS NMR.https://www.mdpi.com/1420-3049/30/7/1616tripodal phosphinesimmobilized phosphinestrinuclear Pd complexesvirtual couplingsimmobilized Pd complexes<i>cis</i>- and <i>trans</i>-coordinated Pd complexes |
| spellingShingle | Maxwell R. Kimball Kyle J. Cluff Nattamai Bhuvanesh Janet Blümel Molecular and Immobilized Tripodal Phosphine Ligands and Their Trinuclear Palladium Complexes Molecules tripodal phosphines immobilized phosphines trinuclear Pd complexes virtual couplings immobilized Pd complexes <i>cis</i>- and <i>trans</i>-coordinated Pd complexes |
| title | Molecular and Immobilized Tripodal Phosphine Ligands and Their Trinuclear Palladium Complexes |
| title_full | Molecular and Immobilized Tripodal Phosphine Ligands and Their Trinuclear Palladium Complexes |
| title_fullStr | Molecular and Immobilized Tripodal Phosphine Ligands and Their Trinuclear Palladium Complexes |
| title_full_unstemmed | Molecular and Immobilized Tripodal Phosphine Ligands and Their Trinuclear Palladium Complexes |
| title_short | Molecular and Immobilized Tripodal Phosphine Ligands and Their Trinuclear Palladium Complexes |
| title_sort | molecular and immobilized tripodal phosphine ligands and their trinuclear palladium complexes |
| topic | tripodal phosphines immobilized phosphines trinuclear Pd complexes virtual couplings immobilized Pd complexes <i>cis</i>- and <i>trans</i>-coordinated Pd complexes |
| url | https://www.mdpi.com/1420-3049/30/7/1616 |
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