Fluorinated phenolates in monomeric and dimeric Co(II) compounds

Five structures of two monometallic cobalt aryloxide compounds and two bimetallic cobalt-thallium compounds with bridging fluorinated aryloxide ligands (OC6F5 = OArF, OC6H3(CF3)2 = OAr′) are presented with magnetic susceptibility and spectroscopic characterization data. The monometallic compounds, [Co(OArF)2(DME)]2, 1, and [Co(OAr′)2(DME)]2, 2, are prepared by metathesis reactions between two equivalents of TlOAr and one of CoI2. The heterobimetallic compounds [Tl2Co(OArF)4]·2 toluene, 3a, and [Tl2Co(OAr′)4]2·2 toluene, 4, were prepared with a 4:1 ratio of the thallium aryloxide to CoI2. An unsolvated form of [Tl2Co(OArF)4], 3b, was also structurally characterized. Magnetic susceptibility studies revealed that 3b is a simple, isolated high-spin CoII with Curie–Weiss behavior. Dimeric compounds 1 and 2 are also high-spin CoII but exhibit antiferromagnetic coupling, via superexchange through two μ2-OArF ligands, as supported by DFT calculations. Compound 4 exhibits ferromagnetic behavior which is ascribed to the presence of μ3-OAr ligands, instead of μ2-OAr groups.

Graphical abstractFive structures of two monometallic cobalt aryloxide compounds and two bimetallic cobalt-thallium compounds with bridging fluorinated aryloxide ligands are presented with magnetic susceptibility and spectroscopic characterization data. The monometallic compounds, [Co(OArF)2(DME)]2, 1, and [Co(OAr′)2(DME)]2, 2, exhibit antiferromagnetic coupling, via superexchange through two μ2-OArF ligands, as supported by DFT calculations. The heterobimetallic compounds [Tl2Co(OArF)4], 3, and [Tl2Co(OAr′)4], 4, exhibit uncoupled and ferromagnetic behavior respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide