Syntheses and solid-state structures of two cofacial (bis)dipyrrin dichromium complexes in different charge states

The dichromium Pacman complex (tBudmx)Cr2Cl2 · C4H10O (1) [(tBudmx)H2 is a dimethylxanthene-bridged cofacial (bis)dipyrrin, C49H58N4O] was synthesized by salt metathesis using anhydrous CrCl2 and previously reported (tBudmx)K2. Treatment of 1 with two equivalents of the reductant potassium graphite afforded K2(tBudmx)Cr2Cl2(thf)3 · 0.5C4H10O · 0.5C4H8O (thf is tetrahydrofuran, C4H8O) (2), with both potassium ions intercalated between the pyrrolic subunits. Comparison of the solid-state structures for 1 and 2 reveals minimal changes in the primary coordination sphere of each Cr ion, with notable elongation of the dipyrrin C — C and C — N bonds upon reduction, consistent with computational support for a ligand-based reduction.

Source: Acta Crystallographica Section C - February 26, 2021 Category: Chemistry Authors: Carsch, K. Elder, S.E. Dogutan, D.K. Nocera, D.G. Yang, J. Zheng, S.-L. Daniel, T. Betley, T.A. Tags: dipyrrin Pacman compound crystal structure dichromium xanthene research papers Source Type: research