Salt-free synthesis of samarium-aluminum mixed-metal alkoxides:: X-ray crystal structures of {[(i-Pr-O)(i-Bu)Al(μ-O-i-Pr)2Sm(O-i-Pr)(HO-i-Pr)](μ-O-i-Pr)}2, [(THF)2Sm(O-t-Bu)2(μ-O-t-Bu)2Al(i-Bu)2], Sm(OAr)3(THF)3 (Ar=2,4,6-Me3C6H2), [Nd(μ-OAr)(OAr)2(py)2]2 (Ar=2,4,6-Me3C6H2), and (ArO)3Sm[(μ-O-t-Bu)2Al2(O-t-Bu)4] (Ar=2,6-i-Pr2C6H3)

Reaction of equimolar quantities of Sm[N(SiMe3)(2)](3) and Al(i-Bu)(3) with 6 equiv of iso-propyl alcohol in toluene leads to the formation of the mixed-metal alkoxide complex {[(i-Pr-O)(i-Bu)Al(mu-O-i-Pr)(2)Sm(O-i-Pr)(HO-i-Pr)](mu-O-i-Pr)}(2) (1). An analogous reaction between 1:1 Sm[N(SiMe3)(2)](3)/Al(i-Bu)(3) and 6 equiv of tert-butyl alcohol, followed by addition of THF, produces the THF adduct [(THF)(2)Sm(O-t-BU)(2)(mu-O-t-BU)(2)Al(i-BU)(2)] (2). Compound I crystallizes in the space group P (1) over bar while 2 crystallizes in space group Cmcm. Cell parameters for 1: a = 11.028(2) Angstrom, b = 12.168(2) Angstrom, c = 12.879(2) Angstrom, alpha = 82.84(1)degrees, beta = 64.88(1)degrees, gamma = 70.80(1)degrees, Z = 1. Cell parameters for 2: a = 11.304(2) Angstrom, b = 22.429(4) Angstrom, c = 15.768(2) Angstrom, z = 4. Attempts to prepare the bulkier derivatives result in the formation of lanthanide aryloxide species only; reaction between equimolar amounts of Ln[N(SiMe3)(2)](3) (Ln = Sm, Nd) and Al(i-Bu)(3) with 6 equiv of HO-2,4,6-Me3C6H2, followed by the addition of THF or pyridine, yields the Lewis base adducts Sm(OAr)(3)(THF)(3) (3) and [Nd(mu-OAr)(OAr)(2)(PY)(2)](2) (4). Compound 3 crystallizes in the space group Pbca while 4 crystallizes in space group P2(1)/c. Cell parameters for 3: a = 16.5822(g) Angstrom, b = 15.5668(g) Angstrom, c 29.902(2) Angstrom, Z 8. Cell parameters for 4: = 13.4496(8) Angstrom, b = 20.034(1) Angstrom, c = 16.206(1) Angstrom, beta = 113.782(1)degrees, Z = 2. Reaction of A(2)(O-t-BU)(6) with [Sm(OAr)(3)](2) (Ar = 2,6-i-Pr2C6H3) yields the adduct (ArO)(3)-Sm[(mu-O-t-Bu)(2)Al-2(0-t-BU)(4)] (5), which crystallizes in the space group P2(1)/n. Cell parameters for 5: a 14.0960(7) Angstrom, b = 27.3037(15) Angstrom, c = 16.7893(g) Angstrom, beta = 92.216(1)degrees, Z = 4.