Synthesis and crystal structures of the chromium(II) and chromium(III) hexafluoroacetylacetonate complexes trans-Cr(hfac) 2(thf) 2 and Cr(hfac) 3

Abstract

Treatment of a tetrahydrofuran solution of CrCl 2(thf) with Na(hfac), hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate, followed by crystallization from diethyl ether, affords the six-coordinate chromium(II) complex Cr(hfac) 2(thf) 2. The crystal structures of Cr(hfac) 2(thf) 2 and the chromium(III) complex Cr(hfac) 3 have been determined by single-crystal X-ray diffraction. Cr(hfac) 2(thf) 2 adopts a trans octahedral geometry, in which the Cr–O(hfac) and Cr–O(thf) distances are 1.936(3) and 2.019(6) Å, respectively. Cr(hfac) 3 is an octahedral compound with a Cr–O distance of 1.943(5) Å. Structural comparisons with related molecules are given.