The molecular structures of a number of 2,6-dimesiyphenyl-based (2,6-dimesitylphenyl = Dmp) complexes of the group 3 elements scandium and yttriurn as well as of the lanthanide element ytterbium are reported. Reaction of I equiv of DmpLi with I equiv of MCl3 (M = Sc, Yb, Y) in tetrahydrofuran at room temperature followed by crystallization from toluene/hexanes at -30 degreesC produces DmpMCl(2)(THF)(2) (M = SC: 1; M = Yb: 2) and DMPMCl2-(THF)(3) (M = Y: 3), respectively. The one-pot reaction of DmpLi with 1 equiv of YbCl3 in tetrahydrofuran at room temperature followed by addition of I equiv of (KOBu)-Bu-t produces the heterobimetallic monoalkoxide complex DmpYb-(THF)((OBu)-Bu-t)(mu-Cl)(2)Li(THF)(2) (4), which was crystallized from toluene/tetrahydrofuran (20:1) at -30 degreesC. Crystal data for 1: monoclinic, P2(1)/n; T = 203 K; a = 10.178(3) Angstrom; b = 15.468(3) Angstrom; c = 20.132(5) Angstrom; beta = 101.85(3)degrees; V = 3102.0(17) Angstrom(3); Z = 4; D-calcd = 1.228 g cm(-3); R-1 = 5.89%. Crystal data for 2: monoclinic, P2(1)/n; T = 173 K; a = 10.2447(7) Angstrom; b = 15,5683(12) Angstrom; c = 20.0979(14) Angstrom; beta = 101.749(4)degrees; V = 3238.3(5) Angstrom(3); Z = 4; D-cald = 1.485 g cm(-3); R-1 = 4.32%. Crystal data for 3: monoclinic, P2(1)/n; T = 203 K; a = 15.950(3) Angstrom; b = 11.865(2) Angstrom; c = 18.254(3) Angstrom; beta = 92.323(3)degrees; V = 3451.9(10) Angstrom(3); Z' = 4; D-calcd 1.327 g cm(-3); R-1 = 4.43%. Crystal data for 4: triclinic, P (1) over bar; T = 193 K; a = 10.2252(2) Angstrom; b = 11.3497(2) Angstrom; c = 18.5814(2) Angstrom; alpha = 98.7353(6)degrees; beta = 102.8964(6)degrees; gamma = 94.8058(5)degrees; V = 2062.09(5) Angstrom(3); Z' = 2; D-calcd = 1.375 g cm(-3); R-1 = 4.56%. The molecular structures of 1-3 feature monomeric complexes with distorted trigonal-bipyramidal (1 and 2) or octahedral (3) coordination geometry about the metal atom, with the two chlorine atoms occupying the axial positions. 4 represents the first example of an alkoxide derivative of a terphenyl lanthanide complex. The molecular structure of the ate complex 4 exhibits a heavily distorted trigonal-bipyramidal coordination polyhedron about the ytterbium atom, with one of the mu-chlorine atoms and the oxygen atom of the tetrahydrofuran ligand representing the axial positions of the trigonal-bipyramidal arrangement. A terminal alkoxide ligand is another main feature of the molecular structure of complex 4.