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

Treatment of [Co-2(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(PCPY-R)(CO)(2)] and [Co-III(PCPY-R)X-2]. The later are paramagnetic exhibiting a solution magnetic moment in the range of 3.0-3.3 mu(B) which is consistent with a d6 intermediate spin system corresponding to two unpaired electrons. In the case of P(C-X)PY ligands (X = Br, Cl; R = tBu; Y = NH) the formation of the square planar Co(II) complex [Co(PCPNH-tBu)X] was favored. This complex gives rise to a magnetic moment of 1.8 mu(B) being consistent with a d(7) 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. [GRAPHICS] .

Automated summary

The treatment of [Co-2(CO)(8)] with ipso-substituted P(C-X)P-Y ligands (X = Br, Cl; R = iPr, tBu) under solvothermal conditions resulted in the synthesis of Co(I) and Co(III) complexes with different coordination numbers and spin states. The complexes were characterized using various spectroscopic techniques and X-ray crystallography.