Structures of organo-f-element compounds differing in the oxidation state of the central metal: crystal structures of bis([8]annulene) complexes of cerium(IV), ytterbium(III), and uranium(III)

Crystal structures of bis(methyl[8]annulenyl)cerium(IV) (5), [(diethylene glycol dimethyl ether)potassium][bis ([8]annulenyl)ytterbate(III)] (14) and [(diethylene glycol dimethyl ether)potassium][bis(methyl[8]annulenyl)uranate(Ill)] (12) are reported.These include the first structures of an organocerium(IV) compound and of a reduced uranocene.Crystals of S are orthorhombic, P2t2t2J, with a= 11.690(3), b = 14.315(3), c = 8.977(2), Z = 4 and Rr = 2.9%.Crystals of 14 are also orthorhombic, Pbca, with a= 16.611(4), b = 14.219(5), c = 9.257(4), Z = 4 and Rr = 3.6%.Crystals of 12 are monoclinic, P2t/c, with a = 13.833(4),b = 9.989(3), c = 17.581(3), ~ = 95.87(3),Z = 4 and Rr = 3.8%.These structures are compared to the previously reported structures of [(diethylene glycol dimethyl ether)potassium] [bis([8]annulenyl)cerate(III)] ( 13), bis[ (dimethoxyethane )potassium] [bis([8]annulenyl)ynerbium(lnl (14) and uranocene (1).A comparison of the structural parameters of several additional [8]annulenyl metal complexes is also presented.The effect of coordination number on metal ligand distances in ionic complexes is discussed in terms of electrostatic interactions among the ligands.Table 5 Selected Angles ( 0 ) for 5, 14 and 12 5 14 12 Ct1-Ce-Ct2 176.03 Ctl-Yb-Ct2 179.88 Ct1-U-Ct2 176.07 Yb-Ct2-K 177.07 U-Ct2-K 173.83 Ct2-K-01 163.34 Ct2