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.