0000000000237841
AUTHOR
Stuart Robertson
New Insights into the Chemistry of Imidodiphosphinates from Investigations of Tellurium-Centered Systems
Dichalcogenido-imidodiphosphinates, [N(PR2E)2]− (R = alkyl, aryl), are chelating ligands that readily form cyclic complexes with main group metals, transition metals, lanthanides, and actinides. Since their discovery in the early 1960s, researchers have studied the structural chemistry of the resulting metal complexes (where E = O, S, Se) extensively and identified a variety of potential applications, including as NMR shift reagents, luminescent complexes in photonic devices, or single-source precursors for metal sulfides or selenides. In 2002, a suitable synthesis of the tellurium analogs [N(PR2Te)2]− was developed. In this Account, we describe comprehensive investigations of the chemistry…
Experimental and Theoretical Investigations of the Contact Ion Pairs Formed by Reactions of the Anions [(EPR2)2N]− (R = iPr, tBu; E = S, Se) with the Cations [(TePR2)2N]+ (R = iPr, tBu)
Reactions of the sodium salts [(EPR2)2N]Na(TMEDA) (R = iPr, tBu; E = S, Se) with the iodide salts [(TePR2)2N]I (R = iPr, tBu) in toluene produce the mixed-chalcogen systems [(EPR2)2N][(TePR2)2N] (6b, E = Se, R = tBu; 6c, E = S, R = tBu; 7b, E = Se, R = iPr; 7c, E = S, R = iPr). Compounds 6b, 6c, 7b, and 7c have been characterized in solution by variable-temperature multinuclear (31P, 77Se, and 125Te) NMR spectroscopy and in the solid state by single-crystal X-ray crystallography. The structures are comprised of contact ion pairs linked by bonds between Te and S or Se atoms. For the tert-butyl derivatives 6b and 6c, the anionic half of the molecule is coordinated in a bidentate (E,E′) fashio…
Experimental and Theoretical Investigations of the Redox Behavior of the Heterodichalcogenido Ligands [(EPiPr2)(TePiPr2)N]− (E = S, Se): Cyclic Cations and Acyclic Dichalcogenide Dimers
The two-electron oxidation of the lithium salts of the heterodichalcogenidoimidodiphosphinate anions [(EPiPr2)(TePiPr2)N]− (1a, E = S; 1b, E = Se) with iodine yields cyclic cations [(EPiPr2)(TePiPr2)N]+ as their iodide salts [(SPiPr2)(TePiPr2)N]I (2a) and [(SePiPr2)(TePiPr2)N]I (2b). The five-membered rings in 2a and 2b both display an elongated E−Te bond as a consequence of an interaction between tellurium and the iodide anion. One-electron reduction of 2a and 2b with cobaltocene produces the neutral dimers (EPiPr2NPiPr2Te−)2 (3a, E = S; 3b, E = Se), which are connected exclusively through a Te−Te bond. Two-electron reduction of 2a and 2b with 2 equiv of cobaltocene regenerates the corresp…