Utility of arylamido ligands in yttrium and lanthanide chemistry

The reactivity of KNHAr reagents (Ar = C6H5, C(6)H(3)Me(2)-2,6, (C6H3Pr2)-Pr-i-2,6) with lanthanide and yttrium trichlorides has been investigated. With the larger metals Nd and Sm and the smaller 2,6-dimethyl-substituted ligand, the bimetallic dianionic complexes [K(THF)(6)](2)[Ln(mu-NHC(6)H(3)Me(2)-2,6)(NHC(6)H(3)Me(2)-2,6)(3)](2) (Ln: Sm, 1a; Nd, 1b) are isolated as the potassium salts. Under the same reaction conditions YCl3 forms a bimetallic anion which retains chloride: [K(DME)(2)(THF)(3)][Y-2(mu-NHC(6)H(3)Me(2)-2,6)(2)(mu-Cl)(NHC(6)H(3)Me(2)-2,6)(4)(THF)(2)] 2. With the larger 2,6-diisopropyl ligands, neutral complexes are isolated in both solvated monometallic and unsolvated bimetallic forms. With Nd, a distorted octahedral trisolvate, Nd((NHC6H3Pr2)-Pr-i-2,6)(3)(THF)(3), 3, was obtained, whereas with Yb and Y the trigonal bipyramidal disolvates, Ln((NHC6H3Pr2)-Pr-i-2,6)(3)(THF)(2) (Ln: Yb, 4a; Y, 4b), were isolated. THF-free complexes of the (NHC6H3Pr2)-Pr-i-2,6 ligand are available by reacting the amine (NH2C6H3Pr2)-Pr-i-2,6 with Ln[N(SiMe(3))(2)](3) complexes. By this route, the dimers [Ln(mu-(NHC6H3Pr2)-Pr-i-2,6)((NHC6H3Pr2)-Pr-i-2,6)(2)](2) (Ln: Yb, 5a; Y, 5b) were isolated. The reaction of the unsubstituted arylamido salt KNHC6H5 with NdCl3 produced an insoluble material which was characterized as [Nd(NHC6H5)(3)(KCl)(3)], 6. 6 reacted with Al(2)Me(6) in hexanes and produced a heteroleptic mixed-metal complex {[Me(2)Al(mu-Me(2))]Nd-2(mu(3)-NC6H5)(mu-Me)AlMe}(2), 7, and the trimeric aluminum arylamido complex [Me(2)Al(mu-NHC6H5)](3), 8. The solvent of crystallization and relevant crystallographic data for the compounds identified by X-ray analysis follow: 1a, THF, 156 K, P2(1)/n, a = 12.985(2) Angstrom, b = 27.122(5) Angstrom, c = 17.935(3) Angstrom, beta = 100.19(1)degrees, V = 6216(1) Angstrom(3), Z = 2, 6148 reflections (I > 3 sigma(I)), R(F) = 7.1%; 1b, THF, 156 K, P2(1)/n, a = 12.998(2) Angstrom, b = 27.058(3) Angstrom, c = 17.962(2) Angstrom, beta = 99.74(1)degrees, V = 6225(1) Angstrom(3), Z = 2; 2, DME/hexanes, P2(1)/n, a = 23.335(2) Angstrom, b = 12.649(1) Angstrom, c = 27.175(3) Angstrom, beta = 96.36(1)degrees, V = 7971(1) Angstrom(3), Z = 4, 2788 reflections (I > 3 sigma(I)), R(F) = 9.5%; 3, THF, P2(1), a = 12.898(1) Angstrom, b = 16.945(1) Angstrom, c = 13.290(1) Angstrom, beta = 118.64(2)degrees, V = 2549.3(3) Angstrom(3), Z = 2, 3414 reflections (I > 3 sigma(I)), R(F) = 4.3%; 4a, hexanes, P2(1), a = 9.718(2) Angstrom, b = 19.119(3) Angstrom, c = 12.640(2) Angstrom, beta = 112.08(1)degrees, V = 2176.3(6) Angstrom(3), Z = 2, 2933 reflections (I > 3 sigma(I)), R(F) = 4.3%; 4b, hexanes, 158 K, a = 9.729(2) Angstrom, b = 19.095(5) Angstrom, c = 12.744(1) Angstrom, beta = 112.11(1)degrees, V = 2193. 4(6) Angstrom(3); 5b, hot toluene, 158 K, P2(1), a = 19.218(9) Angstrom, b = 9.375(3) Angstrom, c = 19.820(5) Angstrom, beta = 110.25(2)degrees, V = 3350(2) Angstrom(3), Z = 2, 1718 reflections (I > 2 sigma(I)), R1 = 9.7%; 7, hexanes, 156 K, <P(1)over bar>, a = 9.618(3) Angstrom, b = 12.738(4) Angstrom, c = 9.608(3) Angstrom, alpha = 99.32(1)degrees, beta = 108.87(1)degrees, gamma = 94.23(1)degrees, V = 1089.1(6) Angstrom(3), Z = 2, 2976 reflections (I > 3 sigma(I)), R(F) = 3.9%; 8, hexanes, 156 K, Pcab, a = 23.510(5) Angstrom, b = 25.462(5) Angstrom,c = 8.668(2) Angstrom, V = 5188(1) Angstrom(3), Z = 8, 1386 reflections (I > 3 sigma(I)), R(F) = 5.7%.