A.R. Petrov et al. / Journal of Organometallic Chemistry 694 (2009) 1212–1218
1217
ful any more – a progressive darkening of the reaction mixture was
observed immediately after the beginning of the reaction, even at
low temperatures. This indicates that for stabilization of dmba-like
complexes of early lanthanides further modification of the dmba li-
DME as solvent. Crystallization from ether yields a pink, microcrys-
talline solid in yield of 69%. Anal. Calc. for C27H36ErN3 (569.87): C,
56.91; H, 6.37; N, 7.37. Found: C, 56.80; H, 6.51; N, 7.24%.
Synthesis of [Yb(dmba)3] [6] (2): The ytterbium complex 2 was
synthesized analogous to the method reported in the literature
using DME as solvent. Crystallization from ether yields a bright yel-
low, microcrystalline solid in yield of 87%. 1H NMR (C6D6,
gand is required. The effects of
a methylation of the dmba ligands
on stability of lanthanide complexes will be the subject of the
forthcoming account [16].
400.1 MHz): d = 97.2 (br s,
m = ca. 1200 Hz, 6H, NMe2), 28.7 (br s,
½
m
= ca. 1900 Hz, 2H, CH2NMe2), ꢀ8.7 (br s,
m = 50 Hz, 1H, HC3Ar),
½
½
2. Experimental
ꢀ17.0 (s, 1H, HC4Ar), ꢀ30.9 (s, 1H, HC5Ar), ꢀ99.1 (br s,
m = 170 Hz,
½
1H, HC6Ar) ppm. 13C{1H} NMR (C6D6, 100.1 MHz): d = ꢀ7.6 (br s,
CH2NMe2), 54.1 (s, C5Ar), 76.6 (CH2NMe2), 82.1 (s, C4Ar), 143 (br
s, C3Ar), 210 (br s, C5Ar), 372 (br s, C2Ar) ppm. Anal. Calc. for
C27H36N3Yb (575.65): C, 56.34; H, 6.30; N, 7.30. Found: C, 56.21;
H, 6.61; N, 7.35%.
2.1. General considerations
Starting lanthanide chlorides [LnCl3 ꢂ 6H2O] were prepared by
dissolving their oxides in conc. hydrochloric acid (p.a.) followed
by continuous evaporation in an evaporating dish at 90 °C. 1,2-
Dimethoxyethane (DME), ether, hexane and toluene were purified
by conventional methods.
Lanthanide content in solvated lanthanide trichlorides was
determined by complexometric titration with EDTA in the pres-
ence of xylenol orange as indicator [17], Chloride content by pre-
cipitation with aqueous AgNO3. Elemental analyses (CHN) were
performed in microanalytical laboratory at chemistry department
of Philipps-Universität Marburg. IR spectra of Ln(dmba)3] (Ln = Lu,
Er, Yb) were measured in analytical laboratory of the Institute of
Chemistry of the Humboldt-University of Berlin and were found
to be identical with the earlier reported [6]. Measurement of IR
spectra of the ate-complexes 5 and 6 because of their instability
against nujol was failed.
Synthesis of [Y(dmba)3] [5] (4): The yttrium complex 4 was syn-
thesized analogous to the method reported in the literature using
THF or DME as solvent. Crystallization from hot hexane yields a
colorless, crystalline solid in yield of 91%. 1H NMR (C7D8,
400.1 MHz): d = 2.12 (s, 6 H, Me2N), 3.37 (s, 2 H, CArCH2), 6.83 (d,
2JHH = 7.3 Hz, HC5Ar), 7.10 (t, JHH = 7.0 Hz, HC4Ar), 7.20 (t,
3
3JHH = 7.0 Hz, HC3Ar), 8.06 (d, JHH = 6.6 Hz, HC2Ar) ppm. 13C{1H}
3
NMR (C6D6, 100.1 MHz): d = 45.9 (Me2N), 69.7 (CArCH2), 124.8
(Ar), 125.2 (Ar), 125.7 (Ar), 138.7 (C2Ar), 146.8 (C6ArCHMe), 186.9
(d, 1JCY = 44 Hz, C1ArY) ppm. Crystallographic data for yttrium com-
plex 4: monoclinic, space group C2/c, a = 24.170(3) Å,
b = 9.362(1) Å, c = 23.880(2) Å, b = 113.47(1)°, V = 4955.9(8) Å3,
Z = 4, Dc = 1.317 g/cm3,
l
= 2.372 mmꢀ1, F(000) = 2064. Anal. Calc.
for C27H36N3Y (491.52): C, 65.98; H, 7.38; N, 8.55%. Found: C,
Following compounds were synthesized as reported in the liter-
ature: Li(dmba) [18], [Er(dmba)3] [6] (1), [Yb(dmba)3] (2) [6],
[LnCl3(dme)2] (Ln = Nd, Sm, Gd) [12]. N,N-Dimethylbenzylamine,
N-benzylpyrrolidine and tert-BuLi (15% solution in pentane) – were
used as supplied (Acros, Aldrich).
64.48; H, 7.55; N, 8.34%.
Synthesis of Li[Gd(dmba)4] (5): To a stirred suspension of Li(dm-
ba) (568 mg, 4.0 mmol) in 40 mL ether, solid [GdCl3(dme)2]
(442 mg, 1.0 mmol) was added at ambient temperature. The color
of the reaction mixture turned slowly yellowish depositing a col-
orless heavy microcrystalline solid. It was filtered off and dried in
vacuum. This solid was triturated with toluene (20 mL) where-
upon LiCl precipitates. The solution was filtered through a Cel-
iteÒ-pad and the filtrate was concentrated to 20% of the original
volume. Addition of ether (20 mL) at 0 °C causes formation of col-
orless crystalline solid. It was filtered off and dried in vacuum.
Yield: 56% (450 mg, 0.56 mmol). Anal. Calc. for C36H48GdLiN4
(701.00): C, 61.68; H, 6.90; N, 7.99. Found: C, 63.89; H, 6.83; N,
7.02%.
2.1.1. Synthesis of starting materials
N-Synthesis of o-(pyrrolidylmethyl)-phenyllithium (Li(pyba)): To
N-benzylpyrrolidine (10.0 g, 62.1 mmol) in ca. 120 mL ether, solu-
tion of tert-BuLi (50 mL, 1.5 m in hexane, 75 mmol, 1.2 equiv.) was
added at ambient temperature and stirred for 48 h. The precipi-
tated solid was filtered off from deep yellow mother liquor and
thoroughly washed with hexane (3 ꢂ 50 mL). The product was ob-
tained as colorless, crystalline solid in 94% yield (9.8 g).
1H NMR (C6D6, 300.1 MHz): d = ppm. 0.70 (s br, 1H), 1.09 (s br,
1H), 1.24 (s br, 2H), 1.57 (dd, 1H, J = 8.4 Hz, J = 17.2 Hz), 1.81 (dd,
1H, J = 8.5 Hz, J = 17.4 Hz), 2.27 (m. br, 1H), 2.71 (m br, 1H), 3.19
(d, J = 13.1 Hz, 1H), 4.48 (d, J = 13.0 Hz, 1H), 7.20 (m, Ar, 4H), 8.38
(d, J = 5.3 Hz, 1H, o-Ar) ppm.
Synthesis of [LiNd(pyba)4] (6): To a suspension of Li(pyba)
(668 mg, 4.00 mmol) in 20 mL of ether [NdCl3(dme)] (340 mg,
1.00 mmol) was added. The obtained green suspension was stirred
for 10 min at ambient temperature and the solution over precipi-
tate of LiCl was decantated into a flask pre-cooled to 0 °C. Stirring
for ½ h resulted in formation of blue green crystalline precipitate
that was filtered off and dried in vacuum. A sky blue, microcrystal-
line solid was obtained in 13% yield (96 mg). The complex is stable
at ambient temperature for couple of days and therefore was
stored at ꢀ30 °C. 1H NMR (C6D6, 300.1 MHz): d = ꢀ0.4 (br s,
13C{1H} NMR (C6D6, 75.5 MHz): d = 22.6, 23.5 (NCH2CH2), 54.1,
55.1 (NCH2CH2), 67.7 (ArCH2N), 125.3 (Ar), 126.1 (Ar), 126.7 (Ar),
139.3 (C2Ar), 152.8 (C6ArCH2), 174.7 (br s, C1Ar) ppm. Anal. Calc.
for C11H14LiN (167.18): C, 79.03; H, 8.44; N, 8.38. Found: C,
77.94; H, 8.92; N, 8.24%.
Synthesis of [YCl3(dme)2]: To a suspension of [YCl3 ꢂ 6H2O]
(12.0 g, 40 mmol) in ca. 120 mL DME thionyl chloride (25 mL,
360 mmol, 9.0 equiv.) was added during 0.5 h. The reaction mix-
ture was heated 2 h at 70 °C till no gas evolution observed. The so-
lid formed was filtered off, washed thoroughly with ether
(5 ꢂ 20 mL) and dried in vacuum. A colorless, compact microcrys-
talline solid was obtained in 97% yield (14.5 g). Anal. Calc. for
C8H20Cl3O4Y (375.50): Cl, 28.32; Y, 23.68. Found: Cl, 28.38; Y,
23.52%.
m
½
= 780 Hz), 11.4 (br s, m = 1000 Hz), 29.5 (br s, m = 1300 Hz)
½ ½
ppm. Anal. Calc. for C44H56LiN4Nd (792.14): C, 66.72; H, 7.13; N,
7.07. Found: C, 64.32; H, 6.81; N, 6.82%.
2.1.3. X-ray crystallographic studies
The structures of 1, 2, 4–6, were solved by direct methods and
expanded by difference-Fourier syntheses using SHELX-97 software
package. G.M. Sheldrick, Program for solution of crystal structures,
SHELXS-97, Universität Göttingen, 1997; G.M. Sheldrick, Program for
the refinement of crystal structures, SHELXL-97, Universität Göttin-
gen, 1997. Crystallographic data for all compounds are summa-
rized in Table 3.
2.1.2. Synthesis of aryl-complexes
Synthesis of [Er(dmba)3] [6] (1): The erbium complex 1 was syn-
thesized analogous to the method reported in the literature using