A diketiminate-bound diiron complex with a bridging carbonate ligand.

Reduction of carbon dioxide by a diiron(I) complex gives mu-carbonato-kappa(3)O:O',O''-bis{[2,2,6,6-tetramethyl-3,5-bis(2,4,6-triisopropylphenyl)heptane-2,5-diiminate(1-)-kappa(2)N,N']iron(II)} toluene disolvate, [Fe(2)(C(41)H(65)N)(2)(CO(3))].2C(7)H(8), a diiron(II) species with a bridging carbonate ligand. The asymmetric unit contains one diiron complex and two cocrystallized toluene solvent molecules that are distributed over three sites, one with atoms in general positions and two in crystallographic 1 sites. Both Fe(II) atoms are eta(2)-coordinated to diketiminate ligands, but eta(1)- and eta(2)-coordinated to the bridging carbonate ligand. Thus, one Fe(II) center is three-coordinate and the other is four-coordinate. The bridging carbonate ligand is nearly perpendicular to the iron-diketiminate plane of the four-coordinate Fe(II) center and parallel to the plane of the three-coordinate Fe(II) center.