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Reactivity of Schiff base-[C,N,S] pincer palladacycles: hydrolysis renders singular trinuclear, tetranuclear, and heteropentanuclear Pd3W2 coordinated complexes.
- Source :
- Dalton Transactions: An International Journal of Inorganic Chemistry; 6/21/2024, Vol. 53 Issue 23, p9680-9691, 12p
- Publication Year :
- 2024
-
Abstract
- Treatment of the Schiff base ligands a–f with Li<subscript>2</subscript>[PdCl<subscript>4</subscript>]/NaAcO in methanol under reflux gave the single nuclear palladacycles 1a–1f, with the metal atom bonded to a terdentate monoanionic [C,N,S] iminic ligand and to a chloride ligand that completes the palladium coordination sphere. Reaction of 1a–1c with silver perchlorate/triphenylphosphine in acetone at room temperature yielded the single nuclear complexes 2a–2c as the perchlorate salts, after substitution of the chloride ligand by a triphenylphosphine. However, reaction of a–c with Na<subscript>2</subscript>[PdCl<subscript>4</subscript>]/NaAcO in methanol at room temperature also gave compounds 1a–1c albeit contaminated with small amounts of the corresponding free aldehyde (mixture A). Reaction of mixture A with silver perchlorate/triphenylphosphine in acetone at room temperature gave analogously 2a–2c with some of the corresponding free aldehyde (mixture B). Attempts to purify mixtures A and B via recrystallization produced single crystals of 5 and 6 respectively: two serendipitously formed complexes, bearing thiomethyl aniline and/or acetate ligands, and void of aldehyde or iminic residue; the structures contain eight- and six-membered rings of alternating palladium and nitrogen atoms, respectively. To clarify this situation the aniline itself was reacted with palladium(II) acetate or with Na<subscript>2</subscript>[PdCl<subscript>4</subscript>]; in the latter case after recrystallization a unique behavior is revealed, giving rise to a tetranuclear complex containing a Pd<subscript>4</subscript>N<subscript>4</subscript> ring with three differing coordination environments on the palladium atoms. Treatment of 1d with Ph<subscript>2</subscript>PCH<subscript>2</subscript>PPh<subscript>2</subscript> (dppm)/AgClO<subscript>4</subscript> or with Ph<subscript>2</subscript>PCH<subscript>2</subscript>(PPh<subscript>2</subscript>)W(CO)<subscript>5</subscript>/AgClO<subscript>4</subscript> gave 3d, with a mono-coordinated dppm ligand, and 4d, respectively; complex 3d could not be converted into 4d by reaction with W(CO)<subscript>5</subscript>(THF). Recrystallization of 4d gave a still further noticeable species, complex 8: a pentanuclear trans-configured heterometallic mixed valent Pd(II)/W(0) linear complex with the palladium atoms supported by two acetate and two thiomethyl aniline bridging ligands. The complexes were fully characterized by microanalysis, IR, <superscript>1</superscript>H, and <superscript>31</superscript>P NMR spectroscopies, as appropriate. The X-ray single-crystal analyses for compounds 1b, 5, 6, 7 and 8 are described. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14779226
- Volume :
- 53
- Issue :
- 23
- Database :
- Complementary Index
- Journal :
- Dalton Transactions: An International Journal of Inorganic Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 177774659
- Full Text :
- https://doi.org/10.1039/d4dt00756e