Solvothermal synthesis of cobalt PCP pincer complexes from [Co2(CO)8]

Heiko Schratzberger; Daniel Himmelbauer; Wolfgang Eder; Michael Weiser; Berthold Stöger; Karl Kirchner

doi:10.1007/s00706-023-03123-x

Solvothermal synthesis of cobalt PCP pincer complexes from [Co₂(CO)₈]

Monatsh Chem. 2023;154(11):1253-1262. doi: 10.1007/s00706-023-03123-x. Epub 2023 Sep 9.

Authors

Heiko Schratzberger¹, Daniel Himmelbauer¹, Wolfgang Eder¹, Michael Weiser¹, Berthold Stöger², Karl Kirchner¹

Affiliations

¹ Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163-AC, 1060 Vienna, Austria.
² X-Ray Center, TU Vienna, Getreidemarkt 9/163-AC, 1060 Wien, Austria.

Abstract

Treatment of [Co₂(CO)₈] with the ipso-substituted P(C-X)P^Y ligands (X = Br, Cl; R = iPr, tBu) bearing Y = NH and CH₂ linkers under solvothermal conditions affords the five-coordinate Co(I) and Co(III) complexes [Co^I(PCP^Y-R)(CO)₂] and [Co^III(PCP^Y-R)X₂]. The later are paramagnetic exhibiting a solution magnetic moment in the range of 3.0-3.3 μ_B which is consistent with a d⁶ intermediate spin system corresponding to two unpaired electrons. In the case of P(C-X)P^Y ligands (X = Br, Cl; R = tBu; Y = NH) the formation of the square planar Co(II) complex [Co(PCP^NH-tBu)X] was favored. This complex gives rise to a magnetic moment of 1.8 μ_B being consistent with a d⁷ low spin system corresponding to one unpaired electron. All complexes are characterized by means of spectroscopic techniques (NMR, IR), HR-MS. Representative complexes were also characterized by X-ray crystallography.

Supplementary information: The online version contains supplementary material available at 10.1007/s00706-023-03123-x.

Keywords: Cobalt; Oxidative addition; Pincer complexes; Transmetalation.