The Strong-Field Tripodal Phosphine Donor, [PhB(CH[sub 2]P[sup i]Pr[sub 2])[sub 3]][sup -], Provides Access to Electronically and Coordinatively Unsaturated Transition Metal Complexes.
In: Inorganic Chemistry, Jg. 42 (2003-08-25), Heft 17, S. 5074-5084
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Zugriff:
This paper introduces a sterically encumbered, strong-field tris(diisopropylphosphino)borate ligand, [PhBP[sup iPr, sub 3]] ([PhBp[sup iPr, sub 3]] = [PhB(CH[sub 2]P[sup i]Pr[sub 2])[sub 3]][sup -]), to probe aspects of its conformational and electronic characteristics within a host of complexes. To this end, the TI(I) complex, [PhBP[sup iPr, sub 3]]TI (1), was synthesized and characterized in the solid-state by X-ray diffraction analysis. This precursor proves to be an effective transmetallating agent, as evidenced by its reaction with the divalent halides FeCI[sub 2] and CoX[sub 2] (X - CI, I) to produce the monomeric, 4-coordinate, high-spin derivatives [PhBP[sup iPr, sub 3]]FeCI (2) and [PhBP[sup iPr, sub 3]]CoX (X = Cl (3), I (4)) in good yield. Complexes 2-4 were each characterized by X-ray diffraction analysis and shown to be monomeric in the solid-state. For conformational and electronic comparison within a system exhibiting higher than 4-coordination, the 16-electron ruthenium complexes {[PhBP[sup iPr, sub 3]]Ru(μ-CI)}[sub 2] (5) and {[PhBP[sub 3]]Ru(μ-CI)}[sub 2] (6) were prepared and characterized ([PhBP[sub 3]] = [PhB(CH[sub 2]PPh[sub 2])[sub 3]] [sup -]). The chloride complexes 2 and 3 reacted with excess CO to afford the divalent, monocarbonyl adducts [PhBP[sup iPr, sub 3]]FeCI(CO) (7) and [PhBP[sup iPr, sub 3]]CoCI(CO) (8), respectively. Reaction of 4 with excess CO resulted in the monovalent, dicarbonyl product [PhBP[sup iPr, sub 3]]Co[sup I](CO)[sub 2] (9). Complexes 5 and 6 also bound CO readily, providing the octahedral, 18-electron complexes [PhBP[sup iPr, sub 3]]RuCI(CO)[sub 2] (10) and [PhBP[sub 3]]RuCI(CO)[sub 2] (11), respectively. Dimers 5 and 6 were broken up by reaction with trimethylphosphine to produce the mono-PMe[sub 3] adducts [PhBP[sup iPr, sub 3]]RuCI(PMe[sub 3]) (12) and [PhBP[sub 3]]RuCI(PMe[sub 3]) (13). Stoichiometric oxidation of 3 with dioxygen provided the 4-electron oxidation product [PhB(CH[sub 2]P(O)[sup i]Pr[sub 2])[sub 2](CH[sub 2]P[sup i]Pr[sub 2])]CoCI (14), while exposure of 3 to excess oxygen results in the 6-electron oxidation product [PhB(CH[sub 2]P(O)[sup i]Pr[sub 2])[sub 3]]CoCI (15). Complexes 2 and 4 were characterized via cyclic voltammetry to compare their redox behavior to their [PhBP[sub 3]] analogues. Complex 4 was also studied by SQUID magnetization and EPR spectroscopy to confirm its high-spin assignment, providing an interesting contrast to its previously described low-spin relative, [PhBP[sub 3]]Col. The difference in spin states observed for these two systems reflects the conformational rigidity of the [PhB[sub iPr, sub 3]] ligand by comparison to [PhBP[sub 3]], leaving the former less able to accommodate a JTdistorted electronic ground state. [ABSTRACT FROM AUTHOR]
Titel: |
The Strong-Field Tripodal Phosphine Donor, [PhB(CH[sub 2]P[sup i]Pr[sub 2])[sub 3]][sup -], Provides Access to Electronically and Coordinatively Unsaturated Transition Metal Complexes.
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Autor/in / Beteiligte Person: | Betley, Theodore A. ; Peters, Jonas C. |
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Zeitschrift: | Inorganic Chemistry, Jg. 42 (2003-08-25), Heft 17, S. 5074-5084 |
Veröffentlichung: | 2003 |
Medientyp: | academicJournal |
ISSN: | 0020-1669 (print) |
DOI: | 10.1021/ic0343096 |
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