Jump to main content
Jump to site search

Issue 11, 2016
Previous Article Next Article

Synthesis of a rhodium(I) germyl complex: a useful tool for C–H and C–F bond activation reactions

Author affiliations

Abstract

The dihydrido germyl complex cis,fac-[Rh(GePh3)(H)2(PEt3)3] (2) was synthesized by an oxidative addition of HGePh3 at [Rh(H)(PEt3)3] (1). Treatment of 2 with neohexene generated the rhodium(I) germyl complex [Rh(GePh3)(PEt3)3] (3). Alternatively, treatment of the methyl complex [Rh(CH3)(PEt3)3] (4) with HGePh3 furnished at room temperature also 3. Low-temperature NMR measurements revealed an initial formation of the oxidative addition product fac-[Rh(GePh3)(H)(CH3)(PEt3)3] (5), which transforms into the intermediate complex [Rh(GePh3)(H)(CH3)(PEt3)2] (6) by dissociation of a triethylphosphine ligand. The reductive elimination of methane and coordination of PEt3 afforded the germyl complex 3. Treatment of 3 with CO gave the biscarbonyl complex [Rh(GePh3)(CO)2(PEt3)2] (7). The molecular structures of the complexes 2, 3 and 7 were determined by X-ray crystallography. The germyl complex 3 reacted with 2,3,5,6-tetrafluoropyridine or pentafluorobenzene to furnish the C–H activation products [Rh(4-C5NF4)(PEt3)3] (8) and [Rh(C6F5)(PEt3)3] (9), respectively. The reaction of 3 with hexafluorobenzene or perfluorotoluene gave selectively the C–F activation products 9 and [Rh(4-C6F4CF3)(PEt3)3] (10). Treatment of 3 with pentafluoropyridine resulted in the formation of the C–F activation products 8 and [Rh(2-C5NF4)(PEt3)3] (11) in a 1 : 10 ratio. The two isomeric activation compounds [Rh{(E)-CF[double bond, length as m-dash]CF(CF3)}(PEt3)3] (12) and [Rh{(Z)-CF[double bond, length as m-dash]CF(CF3)}(PEt3)3] (13) were obtained in a 3 : 1 ratio by reaction of 3 with hexafluoropropene. On exposure to oxygen the highly air sensitive complex 12 reacts to yield the peroxido-bridged dirhodium complex [Rh{(E)-CF[double bond, length as m-dash]CF(CF3)}(μ–κ12-O2)(PEt3)2]2 (14). The molecular structure of 14 was determined by X-ray crystallography.

Graphical abstract: Synthesis of a rhodium(i) germyl complex: a useful tool for C–H and C–F bond activation reactions

Back to tab navigation

Supplementary files

Publication details

The article was received on 11 Dec 2015, accepted on 02 Feb 2016 and first published on 10 Feb 2016


Article type: Paper
DOI: 10.1039/C5DT04845A
Citation: Dalton Trans., 2016,45, 4716-4728
  •   Request permissions

    Synthesis of a rhodium(I) germyl complex: a useful tool for C–H and C–F bond activation reactions

    T. Ahrens, M. Ahrens, T. Braun, B. Braun and R. Herrmann, Dalton Trans., 2016, 45, 4716
    DOI: 10.1039/C5DT04845A

Search articles by author

Spotlight

Advertisements