σ- or π-Coordination? Complexes of Univalent Gallium Salts with Aromatic Nitrogen Bases.

Autor: Lichtenthaler, Martin R., Stahl, Florian, Kratzert, Daniel, Benkmil, Boumahdi, Wegner, Hermann A., Krossing, Ingo
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Zdroj: European Journal of Inorganic Chemistry; Sep2014, Vol. 2014 Issue 26, p4335-4341, 7p
Abstrakt: To answer the question as to whether gallium in its oxidation state +1 favors a σ- or a π-coordination of aromatic nitrogen bases, we reacted [Ga(C6H5F)2]+[Al(ORF)4]- {RF = C(CF3)} with pyrazine and 2,6-di- tert-butyl-4-methylpyridine (DTBMP). In doing so, we obtained the first tricoordinate, nonchelated, homoleptic N-donor complex of gallium(I): [Ga(pyrazine)3]+[Al(ORF)4]-, in which each gallium(I) cation is coordinated in a trigonal-pyramidal fashion by three η1-donating pyrazine ligands. Hence, the gallium(I) cations favor σ- over π-coordination. Depending on the reaction conditions, and due to the bifunctionality of pyrazine, 1D coordination polymers of {[Ga(μ-pyrazine)2(η1-pyrazine)]+[Al(ORF)4]-}∞ were also obtained. With the sterically demanding DTBMP, which is conventionally used as a proton scavenger, the mixed complex [Ga(C6H5F)2(DTBMP)]+[Al(ORF)4]- was isolated, thus proving incorrect the perception of DTBMP being 'non-nucleophilic'. The structural findings were confirmed by multinuclear NMR investigations and density functional performed at the RI-BP86/SV(P) level. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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