Utility of Arylamido Ligands in Yttrium and Lanthanide Chemistry¹

Abstract

The reactivity of KNHAr reagents (Ar = C(6)H(5), C(6)H(3)Me(2)-2,6, C(6)H(3)(i)Pr(2)-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(&mgr;-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 YCl(3) forms a bimetallic anion which retains chloride: [K(DME)(2)(THF)(3)][Y(2)(&mgr;-NHC(6)H(3)Me(2)-2,6)(2)(&mgr;-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(NHC(6)H(3)(i)Pr(2)-2,6)(3)(THF)(3), 3, was obtained, whereas with Yb and Y the trigonal bipyramidal disolvates, Ln(NHC(6)H(3)(i)Pr(2)-2,6)(3)(THF)(2) (Ln: Yb, 4a; Y, 4b), were isolated. THF-free complexes of the NHC(6)H(3)(i)Pr(2)-2,6 ligand are available by reacting the amine NH(2)C(6)H(3)(i)Pr(2)-2,6 with Ln[N(SiMe(3))(2)](3) complexes. By this route, the dimers [Ln(&mgr;-NHC(6)H(3)(i)Pr(2)-2,6)(NHC(6)H(3)(i)Pr(2)-2,6)(2)](2) (Ln: Yb, 5a; Y, 5b) were isolated. The reaction of the unsubstituted arylamido salt KNHC(6)H(5) with NdCl(3) produced an insoluble material which was characterized as [Nd(NHC(6)H(5))(3)(KCl)(3)], 6. 6 reacted with Al(2)Me(6) in hexanes and produced a heteroleptic mixed-metal complex {[Me(2)Al(&mgr;-Me(2))](2)Nd(&mgr;(3)-NC(6)H(5))(&mgr;-Me)AlMe}(2), 7, and the trimeric aluminum arylamido complex [Me(2)Al(&mgr;-NHC(6)H(5))](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) Å, b = 27.122(5) Å, c = 17.935(3) Å, beta = 100.19(1) degrees, V = 6216(1) Å(3), Z = 2, 6148 reflections (I > 3sigma(I)), R(F)() = 7.1%; 1b,THF, 156 K, P2(1)/n, a = 12.998(2) Å, b = 27.058(3) Å, c = 17.962(2) Å, beta = 99.74(1) degrees, V = 6225(1) Å(3), Z = 2; 2,DME/hexanes, P2(1)/n, a = 23.335(2) Å, b = 12.649(1) Å, c = 27.175(3) Å, beta = 96.36(1) degrees, V = 7971(1) Å(3), Z = 4, 2788 reflections (I > 3sigma(I)), R(F)() = 9.5%; 3, THF, P2(1), a = 12.898(1) Å, b = 16.945(1) Å, c = 13.290(1) Å, beta = 118.64(2) degrees, V = 2549.3(3) Å(3), Z = 2, 3414 reflections (I > 3sigma(I)), R(F)() = 4.3%; 4a, hexanes, P2(1), a = 9.718(2) Å, b = 19.119(3) Å, c = 12.640(2) Å, beta = 112.08(1) degrees, V = 2176.3(6) Å(3), Z = 2, 2933 reflections (I > 3sigma(I)), R(F)() = 4.3%; 4b, hexanes, 158 K, a = 9.729(2) Å, b = 19.095(5) Å, c = 12.744(1) Å, beta = 112.11(1) degrees, V = 2193.4(6) Å(3); 5b, hot toluene, 158 K, P2(1), a =19.218(9) Å, b = 9.375(3) Å, c = 19.820(5) Å, beta = 110.25(2) degrees, V = 3350(2)Å(3), Z = 2, 1718 reflections (I > 2sigma (I)), R1 = 9.7%; 7, hexanes, 156 K, P&onemacr;, a = 9.618(3) Å, b = 12.738(4) Å, c = 9.608(3) Å, alpha = 99.32(1) degrees, beta = 108.87(1) degrees, gamma = 94.23(1) degrees, V = 1089.1(6) Å(3), Z = 2, 2976 reflecti...

Distinct Reaction Pathways of Peralkylated LnIIAlIII Heterobimetallic Complexes with Substituted Phenols

“…This Sm1 · · · C16 distance lies in the range of ordinary Sm II -C bond lengths as reported for [Sm{C(SiMe 3 ) 2 (SiMe 2 OMe)} 2 (THF)] (2.787(5) and 2.845(5) Å) 26 and Sm(AlEt 4 ) 2 (THF) 2 (2.774 Å). 27 Similar Ln-heteroatom-C ipso bonding patterns were observed in 29 The Sm-C ipso interactions in 5 imply longer Sm-O2 bond distances (2.5953(12) Å) than those of the asymmetrically homometal-bridging unit (2.4017(12) and 2.4748(13) Å). The latter Sm-O1/O1′ bond lengths, however, are similar to the ones reported for [(C 5 Me 5 )Sm(µ-OC 6 H 2 tBu 3 -2,4,6)] 2 (see Table 2).…”

Mono-cyclopentadienyl complexes of lanthanum: synthesis and characterization of anilido derivatives

“…Pyridine was purchased from Aldrich and distilled over sodium benzophenone prior to use. [g 5 -C 5 H 2 (SiMe 3 ) 3 -1,2,4]K [40,41], LaI 3 (THF) 4 [21], KNHAr [42], (Cp 000 )LaI 2 (py) 3 (1) [19], (Cp 000 )LaI 2 (bipy)(py) (5) [19] and 2-amino-hex-5-ene (7) [43,44] were prepared according to literature procedures. Hexanes, toluene, tetrahydrofuran and diethyl ether were de-oxygenated by passage through a column of supported copper redox catalyst (Cu-0226 S) and dried by passing through a second column of activated alumina [45].…”

A New Type of Lanthanide Complex – Two Divalent Ytterbium Species Assembled from Cation–π Interactions

“…[23] X-ray crystallographic results indicated that complex 3 contains two ytterbium(II) units bridged by a KI molecule, as shown in Figure 2. The L Ph ligands coordinate in a chelating fashion [Yb1-N1 2.322(6) Å, Yb1-N2 2.345(5) Å, Yb2-N3 2.346(6) Å, and Yb2-N4 2.323(6) Å], these Yb-N distances are apparently longer than those observed in related trivalent ytterbium species {e.g., five-coordinate [Yb(NHC 6 H 3 iPr 2 -2,6) 3 (thf) 2 ] 2.17(2)-2.20(2) Å [12] and complex 2}. The Yb-O (Et 2 O or thf) bond lengths are Yb1-O1 2.411(7) Å, Yb1-O2 2.375(7) Å, Yb2-O3 2.373(8) Å, and Yb2-O4 2.450(9) Å.…”

“…[10,11] In contrast to the popular cyclopentadienyl (Cp) ligands, relatively little effort has been devoted to Cp-free ligands. [12] The lanthanide chemistry of complexes with simple amido ligands is limited primarily to an amido ligand, namely diamido ligands are bridged by a KI molecule with cation-π interactions. These two complexes have been fully characterized, particularly by X-ray crystallography.…”