Terphenyl Ligand Systems in Lanthanide Chemistry: Use of the 2,6-Di(1-naphthyl)phenyl Ligand for the Synthesis of Kinetically Stabilized Complexes of Trivalent Ytterbium, Thulium, and Yttrium

The molecular structures of terphenyl derivatives of trivalent ytterbium, thulium, and yttrium of general composition DnpLnCl2(THF)2 [Dnp = 2,6-di(1-naphthyl)phenyl] are reported. The complexes (Ln = Yb: 1; Ln = Tm: 2; Ln = Y: 3) are synthesized by reaction of 1 equiv of DnpLi with 1 equiv of LnCl3 (Ln = Yb, Tm, or Y) in tetrahydrofuran at room temperature in 50% yield. Attempts to prepare a Dnp scandium compound gave heterobimetallic [(THF)3Sc2OCl5Li(THF)]2 (4) in low yield. 1 crystallizes in the monoclinic space group C2/c. Crystal data for 1 at 203 K: a = 14.333(3) Å, b = 16.353(3) Å, c = 12.427(2) Å, β = 91.021(4)°, Z = 4, Dcalcd = 1.637 g cm-3, R1 = 4.44%. 2 crystallizes in the monoclinic space group C2/c. Crystal data for 2 at 203 K: a = 14.333(1) Å, b = 16.374(2) Å, c = 12.404(1) Å, β = 90.934(2)°, Z = 4, Dcalcd = 1.628 g cm-3, R1 = 3.00%. 3 crystallizes in the monoclinic space group C2/c. Crystal data for 3 at 203 K: a = 14.348(3) Å, b = 16.476(3) Å, c = 12.356(2) Å, β = 90.987(4)°, Z = 4, Dcalcd = 1.441 g cm-3, R1 = 5.62%. 4 crystallizes in the monoclinic space group P21/n. Crystal data for 4 at 203 K: a = 11.0975(9) Å, b = 11.0976(9) Å, c = 21.3305(18) Å, β = 94.718(2)°, Z = 2, Dcalcd = 1.051 g cm-3, R1 = 3.45%. Complexes 1−3 represent examples of novel chiral (racemic) organometallic complexes of the lanthanide elements ytterbium and thulium and the group 3 element yttrium, respectively. The molecular structures of monomeric 1−3 exhibit distorted trigonal−bipyramidal coordination environments at the metal center, with the two oxygen atoms of the tetrahydrofuran ligands occupying the axial positions of a trigonal−bipyramidal coordination polyeder. The molecular structure of the scandium compound 4 shows a complex polynuclear heterobimetallic arrangement.