Metal Complexes with Polydentate Chalcogenophosphinic Amide Ligands

Abstract

Chelating phosphinic amido ([RNP(O)R₂^']^- (R and R^' = alkyl or aryl) ligands have received considerable attention due to their applications in metal-catalyzed organic transformations and selective extraction of f-block elements. Whereas 3d metal oxo and hydroxo complexes with the tripodal phosphinic amido ligand [N{CH₂CH₂NP(O)Ph₂}₃]^3-([poat]^3-) are well documented, the coordination chemistry of its chalcogenide analogues, [N{CH₂CH₂NP(E)R₂}₃]^3- (E = S or Se; R = alkyl or aryl), is relatively unexplored. Herein, we report on the synthesis and structures of metal complexes with [N{CH₂CH₂NP(E)R₂}₃]^3-. Heterobimetallic complexes based on the [N{CH₂CH₂NP(E)R₂}₃]^- ligand frameworks have been synthesized.

Chapter 2 describes the synthesis and structures of rare earth complexes with tripodal chalcogenophosphinic amido ligands. While the reaction of M³⁺ (M = La, Ce) with K₃(poat) afforded dinuclear [M₂(poat)₂], mononuclear [M(N{CH₂CH₂NP(E)ⁱPr₂}₃)] (E = S, Se) [Ce(N{CH₂CH₂NP(E)ⁱPr₂}₃)] with [Ce(L_OEt)₂Cl₂] (L_OEt- = [(n⁵-C₅H₅)Co{P(O)(OEt)₂}₃]^-) afforded the [Ce^IV(N{CH₂CH₂NP(E)iPr₂}₃)][Ce^III(L_OEt)₂Cl₂] that are first cationic Ce(IV) chalcogenolate complexes.

Chapters 3 and 4 describe the synthesis and structures of heterometallic complexes containing the [M(N{CH₂CH₂NP(E)Ph₂}₃)]^- metalloligands. M₂Ni₂(OH)₂ (M = Fe, Ni) and Cu₃Ni(OH)₂ complexes were obtained from the reactions of [Ni(poat)(H₂O)]^- with Fe³⁺, Ni²⁺ [{Fe^III(poat)}₂Ce^III(thf)](CF₃SO₃)₃ (thf = tetrahydrofuran) and the 3d/4d psat complexes [Fe(psat)Ru(n⁶-p-cymene)](CF₃SO₃), [{Fe(psat)}₂Ru](CF₃SO₃)₂, and [Fe(psat)Rh(COD)] (COD = 1,5-cyclooctadiene; [psat]^3- = [N{CH₂CH₂NP(S)Ph₂}₃]^3-) have been synthesized.

[N{CH₂CH₂NP(Se)Ph₂}₃]^3-) afforded [M(pseat)PtCl] that contain M-Pt bonds.

Chapter 5 describes the synthesis and structures of metal complexes with bis(chalcogenophosphinic amido)amine ligands, MeN[CH₂CH₂NHP(E)Ph₂]₂ (E = O, S), H₂L^E.

Finally, the reactions of [Ce(DMAB)₃] (DMAB = o-N,N-dimethylaminobenzyl) with oxidizing agents and dichalcogenides and the migratory insertion of [Ce(L^S)(DMAB)(thf)] are reported in Chapter 6.

Date of Award	2025
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	Wa Hung LEUNG (Supervisor) & Yat Ming SO (Supervisor)