Syntheses, structures and reactions of a series of β- diketiminatoyttrium compounds

Article abstract of DOI:10.1039/b806451b

This paper describes the synthesis and selected reactions of a series of crystalline mono(β-diiminato)yttrium chlorides 3a, 3b, 4a, 4b, 5a, 5b, 5c and 9. The X-ray structure of each has been determined, as well as of [YCl(L⁴)₂] (6), [Y(L¹)₂OBu ^t] (7) and [Y{CH(SiMe₃)₂}(thf)(μ-Cl) ₂Li(OEt₂)₂(μ-Cl)]₂ (8). The N,N′-κ²-β-diiminato ligands were [{N(R)C(Me)} ₂CH]^- [R = C₆H₄Prⁱ-2 (L¹); R = C₆H₄Bu^t-2 (L²); R = C₆H₃Prⁱ₂-2,6 (L³)], [{N(SiMe₃)C(Ph)}₂CH)]^- (L⁴) and [{N(C₆H₃Prⁱ₂-2,6)C(H)} ₂CPh]^- (L⁵). Equivalent portions of Li[L ^x] and YCl₃ in Et₂O under mild conditions yielded [Y(μ-Cl)(L^x)(μ-Cl)₂Li(OEt₂) ₂]₂ [L^x = L¹ (3a) or L² (3b)] and [Y(μ-Cl)(L³)(μ-Cl)Li(OEt₂) ₂(μ-Cl)]₂ (4a) or its thf (instead of Et₂O) equivalent 4b. Each of the Li(OEt₂)₂Cl₂ moieties is bonded in a terminal (3) or bridging (4) mode with respect to the two Y atoms; the difference is attributed to the greater steric demand of L ³ than L¹ or L². Under slightly more forcing conditions, YCl₃ and Li(L²) (via3b) gave the lithium-free complex [YCl₂(L²)(thf)₂] (5b). Two isoleptic compounds 5a and 5c (having in place of L² in 5b, L³ and L⁵, respectively) were obtained from YCl₃ and an equivalent portion of K[L³] and Na[L⁵], respectively; under the same conditions using Na[L⁴], the unexpected product was [YCl(L⁴)₂] (6) (i.e. incorporating only one half of the YCl₃). A further unusual outcome was in the formation of 8 from 3a and 2 Li[CH(SiMe₃)₂]. Compound [Y(L⁵){N(H) C₆H₃Prⁱ₂-2,6}(thf)(μ₃- Cl)₂K]₂?4Et₂O (9), obtained from 5c and K[N(H)C₆H₃Prⁱ₂-2,6], is noteworthy among group 3 or lanthanide metal (M) compounds for containing MClKCl (M = Y) moieties. The Royal Society of Chemistry 2008.

Full text of DOI:10.1039/b806451b

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PAPER
www.rsc.org/dalton | Dalton Transactions
Syntheses, structures and reactions of a series of b-diketiminatoyttrium
compounds†
Xuehong Wei,a,b Yanxiang Cheng,a,c Peter B. Hitchcocka and Michael F. Lappert*a
Received 16th April 2008, Accepted 2nd July 2008
First published as an Advance Article on the web 26th August 2008
DOI: 10.1039/b806451b
This paper describes the synthesis and selected reactions of a series of crystalline mono(b-
diiminato)yttrium chlorides 3a, 3b, 4a, 4b, 5a, 5b, 5c and 9. The X-ray structure of each has been
determined, as well as of [YCl(L4)2] (6), [Y(L1)2OBut] (7) and [Y{CH(SiMe3)2}(thf)(m-
2
Cl)2Li(OEt2)2(m-Cl)]2 (8). The N,N¢-k -b-diiminato ligands were [{N(R)C(Me)}2CH]- [R = C6H4Pri-2
(L1); R = C6H4But-2 (L2); R = C6H3Pri2-2,6 (L3)], [{N(SiMe3)C(Ph)}2CH)]- (L4) and
[{N(C6H3Pri2-2,6)C(H)}2CPh]- (L5). Equivalent portions of Li[Lx] and YCl3 in Et2O under mild
conditions yielded [Y(m-Cl)(Lx)(m-Cl)2Li(OEt2)2]2 [Lx = L1 (3a) or L2 (3b)] and
[Y(m-Cl)(L3)(m-Cl)Li(OEt2)2(m-Cl)]2 (4a) or its thf (instead of Et2O) equivalent 4b. Each of the
Li(OEt2)2Cl2 moieties is bonded in a terminal (3) or bridging (4) mode with respect to the two Y atoms;
the difference is attributed to the greater steric demand of L3 than L1 or L2. Under slightly more forcing
conditions, YCl3 and Li(L2) (via 3b) gave the lithium-free complex [YCl2(L2)(thf)2] (5b). Two isoleptic
compounds 5a and 5c (having in place of L2 in 5b, L3 and L5, respectively) were obtained from YCl3 and
an equivalent portion of K[L3] and Na[L5], respectively; under the same conditions using Na[L4], the
unexpected product was [YCl(L4)2] (6) (i.e. incorporating only one half of the YCl3). A further unusual
outcome was in the formation of 8 from 3a and 2 Li[CH(SiMe3)2]. Compound [Y(L5){N(H)-
C6H3Pri2-2,6}(thf)(m3-Cl)2K]2·4Et2O (9), obtained from 5c and K[N(H)C6H3Pri2-2,6], is noteworthy
among group 3 or lanthanide metal (M) compounds for containing MClKCl (M = Y) moieties.
L3 derivatives have been described: [YI2(L3)(thf)] (thf
=
Introduction
tetrahydrofuran),2 [YI2(L3)(dme)] (dme = 1,2-dimethoxyethane),2
[{YI(L3)(m-OMe)}2],2 [YCl(L3)(m-Cl)3Y(L3)(thf)]·2PhMe,3 and
b-Diiminates are important spectator ligands in coordination
chemistry. Their use depends on their strong binding to metals,
their widely tunable steric and electronic features by varying
the substituents at the nitrogen and carbon atoms and the
diversity of their bonding modes. In the present context, however,
their general formula is limited to that shown in L1–L5, their
binding to yttrium is invariably N,N¢-chelating and their bonding
mode is monoanionic and p-delocalised. Ligands L1–L4 are b-
diketiminates and L5 is a b-dialdiminate.
3
[Y(h -C3H5)2(L3)].4 Furthermore, various yttrium compounds
have featured as catalysts for ring-opening polymerisation of
methyl methacrylate (MMA) or e-caprolactone, or copoly-
merisation of carbon dioxide and an epoxide. Examples in-
clude [Y(OOCR)3] with ZnEt2 and glycerol for CO2/epoxide
copolymerisation,5a,b [Y{(NPri)2CN(SiMe3)2}2NPri2]6 or [Y{(h -
3
7
C3H3SiMe3)2SiPh2}2(m-K)(thf)0.5(OEt2)1.5]• for poly-MMA or
poly-e-caprolactone formation, and I (R = Me, n = 2; R = But,
5
n = 3) for polylactide synthesis.8 The complex [Y(h -C4PMe2-3,4-
But2-2,5)(CH2C6H4NMe2-2)2] with [Ph3C][B(C6F5)4] was a catalyst
for the syndiospecific polymerisation of styrene.9 The above
considerations have provided the stimulus for the present excursion
into b-diiminatoyttrium chemistry.
b-Diiminates of the majority of the natural elements have
been described. In our 2002 review, however, such yttrium
compounds were notable by their absence.1 Subsequently, various
aDepartment of Chemistry, University of Sussex, Brighton, UK BN1 9QJ.
E-mail: m.f.lappert@sussex.ac.uk; Fax: +44-1273-677193; Tel: +44-1273-
678316
bThe School of Chemistry and Chemical Engineering, Shanxi University,
Taiyuan, 030006, P. R. China
cState Key Laboratory of Polymer Physics and Chemistry, Changchun
Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun,
130022, P. R. China
† CCDC reference numbers 684941–684951. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/b806451b
Results and discussion
The b-diketimines H[{N(C6H4R-2)C(Me)}2CH] [R = Pri (1a)
(∫ HL1);10 R = But (1b) (∫ HL2)] were prepared from acetylacetone
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Scheme 1 Reagents and conditions: i, LiBun, C6H14; ii, YCl3, Et2O, -30 ◦C.
and the relevant amine 2-RC6H4NH2, using the literature proce-
dure outlined for H[{N(C6H3Pri2-2,6)C(Me)}2CH] (∫ HL3).11 The
lithium salts Li[L1] (2a) (which had previously been prepared in situ
as the first step en route to a zinc b-diketiminato derivative)10 and
Li[L2] were obtained from the appropriate b-diketimine and LiBun
(i in Scheme 1); crystalline Li[L3] (2c) and its 1:1-diethyl ether or thf
adducts had already been described.12 The crystalline pentacyclic
dimeric lithio(trichloro)(b-diketiminato)yttrium compounds 3a or
3b were synthesised (ii in Scheme 1) from equimolar portions of
the respective compound 2a or 2b and yttrium(III) chloride.
The central [(m-Cl)M(m-Cl)2Li]2 motif of 3a and 3b (M = Y)
resembles that found in the crystalline compounds J (M = Nd,
Sm*, Eu*, Ho, Yb*; those marked with an asterisk were X-ray-
characterised), obtained from Li[N(SiMe3)2] and the correspond-
ing compound MCl3 in thf.13
By using one of the heavier alkali metal salts, K[L3] or Na[L5]
as a b-diiminato ligand-transfer reagent, a similar YCl3/M[L]
reaction in thf afforded (i in Scheme 2) the crystalline alkali
metal-free, mononuclear dichloroyttrium b-diiminate 5a or 5c. A
different outcome, again, resulted from treatment under mild con-
ditions of equivalent portions of Na[L4] and YCl3, which furnished
(ii in Scheme 2) the crystalline chloroyttrium bis(b-diketiminate)
[YCl(L4)2] (6). Related to 5a and 5c, the corresponding compound
[YCl2(L2)(thf)2] (5b) was obtained (iii in Scheme 2) by prolonged
gentle heating of 3b, with elimination of lithium chloride.
In contrast to step ii of Scheme 1, based on Li[L1] or Li[L2],
treatment of YCl3 with an equimolar portion of the more bulky
lithium b-diketiminate 2c12 afforded [eqn (1)] the crystalline
compounds 4a or 4b. Their central [YCl3Li]2 motif differs from
that in 3a or 3b. Whereas in the latter each such moiety occupies a
terminal site with respect to each yttrium atom, in 4a and 4b each
functions as a bridge between its two yttrium atoms. Apart from
the substituents on the nitrogen atoms, compounds 3 and 4 might
be regarded as isomers.
Scheme 2 Reagents and conditions: i, for 5a: K[{N(C6H3Pri2-2,6)C(Me)}2-
CH], Et2O, -30 ◦C, crystd thf–Et2O–C6H14; for 5b: 3b, 60 ◦C, 12 h,
crystd thf–Et2O; for 5c: Na[{N(C6H3Pri2-2,6)C(H)}2Ph], thf, 20 ◦C; ii,
Na[{N(SiMe3)C(Ph)}2CH, thf, 20 ◦C, crystd thf–Et2O; iii, C6H14, 60 ◦C,
crystd C6H14–Et2O–thf.
Regarding the binuclear b-diiminato-Y/Li chlorides 3a, 3b, 4a
and 4b, there are some related 4f metal complexes in the recent
literature. These include K(a),14 K(b),14 K(c)15 and K(d)14 obtained
from Li[L6] and an equivalent portion of LnCl3 in thf; treat-
ment of K(b) with H[{N(C6H3Me2-2,6)C(Me)}2CH] (∫ HL6) in
toluene yielded [SmCl(L6)(m-Cl)3Sm(L6)(m-Cl)Li(L6)(thf)].14 The
compound [YCl(L3)(m-Cl)3Y(L3)(thf)]·2PhMe (mentioned in the
Introduction) was prepared from equivalent portions of [YCl3(thf)]
(1)
◦
and the lithium b-diketiminate in toluene at 90 C.3 Other
tetrachlorobis(b-diketiminatolanthanide) complexes reported re-
cently include [Ln(L6)(thf)(m-Cl)3Ln(Cl)(L6)] (Ln = Sm, Yb), ob-
tained from the appropriate compound K(b) or K(d) in toluene.14
The corresponding Sm2–(L3)2 complex was prepared from SmCl3
and K(L3) in thf.16 As for compounds 5a, 5b and 5c, there
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are recent precedents for mononuclear b-diketiminatometal (M)
dichlorides (M = Sc or Ln): [ScCl2(L3)(thf)],17 [Ln(Lx)Cl2(thf)2]
(Ln(Lx) = Yb(L3),18 Sm(L6),19a Yb(L6),19a,b,c,d and Ln[N(C6H3Pri2-
2,6)C(Me)C(H)C(Me)N(C6H4Cl-4)] (Ln = Sm, Yb)19a,c), and
[YbCl2(L3)(dme)].20
that shown in eqn (3), which, however, was attributed to the steric
hindrance to the formation of [Ce{CH(SiMe3)2}(L4)2];21 and from
5
[{Y(h -C5H4R)2(m-Cl)}2] + 2LiMe in thf the only product isolated
was Li[C5H4R] [R = (+)-neomenthyl].25 Another possible route
to 8 is that the first formed product from 3a and the lithium
alkyl was Y(L1)(m-Cl)2Li{CH(SiMe3)2} (suggested by a referee),
which upon redistribution yields equivalent portions of 8 and
Y(L1)Cl{CH(SiMe3)2} (which may have decomposed) and Li(L1).
Addition of an equivalent portion of potassium 2,6-diisopro-
pylanilide to [Y(L5)Cl2(thf)2] (5c) in diethyl ether at am-
bient temperature yielded [eqn (4)] the crystalline com-
pound [Y(L5){N(H)C6H3Pri2-2,6}(thf)(m3-Cl)2K]2·4Et2O (9). Het-
erobimetallic K–M [M = a group 3 or lanthanide(III) metal]
complexes containing halide bridges between such two met-
als are exceedingly rare. Examples include the X-ray-charac-
The formation of the five-coordinate bis(b-diketiminato)-
yttrium chloride 6 from equivalent portions of YCl3 and Na[L4] (ii
in Scheme 2) is surprising. It is attributed to disproportionation
of the kinetically labile YCl2(L4) [eqn (2)]. An analogous situation
involving an L4-containing Ln compound was previously observed
when the 1 : 1 reaction of [Ce(L4)2Cl] with LiCH(SiMe3)2 gave a
1 : 2 product apparently via the ligand redistribution of the labile
intermediate Ce(L4)Cl{CH(SiMe3)2} [eqn (3)]; it was suggested
that [Ce(L4)2{CH(SiMe3)2}] was too sterically hindered to exist.21
5
terised compounds [Dy(h -C5H2But3-1,2,4)2(m-Cl)2K(18-crown-
5
6)],26 [Ln(h -C5Me5)2(m-Cl)2K(thf)]• (Ln = Ce,27 Sm28a,b) and
6
[Lu{CH(SiMe3)2}3(m-Cl)K(h -PhMe)2].29
2YCL2(L4) → [YCl(L4)2] (6) + YCl3
(2)
2[CeCl(L4)2] + 2LiCH(SiMe3)2 → [Ce{CH(SiMe3)2}2(L4)]
+ [CeCl(L4)2]
(4)
(3)
Treatment of the b-diketimine H[L1] with K[N(SiMe3)2] yielded
(ii in Scheme 3) K[L1]. The latter with half an equivalent each
of successively YCl3 and K[OBut] furnished (iii in Scheme 3) in
modest yield X-ray quality crystals of [Y(L1)2OBut] (7). Several
bis(b-diketiminato)lanthanide(III) compounds (but no alkoxides)
have been reported, including [Ln(L4)2Cl] (Ln = Ce,21,22 Pr,21 Nd,21
Sm,21 Yb21), [Ln(L7)2Br] [L7 = {N(Pr)C(Ph)}2CH; Ln = Sm, Gd],23
and [Tm(L3)2]X [X = BPh4, B(C6F5)4].24
Molecular structures of the crystalline compounds 3a, 3b, 4a, 4b,
5a, 5b, 5c, 6, 7, 8 and 9
X-Ray-quality crystals of 8 (i in Scheme 3) in moderate
yield were obtained from [Y(m-Cl)(L1)(m-Cl)2Li(OEt2)2]2 (3a) and
Li[CH(SiMe3)2]. It is interesting that, under the very mild reaction
conditions used, the alkyl ligand displaced the b-diketiminate,
especially as the alternative leaving groups (the bridging chlorides)
were unaffected. This is a very rare occurrence. Another example is
Each of the compounds, except 8, is a mono- or bis- (6, 7) di-
iminatoyttrium complex, having the N,N¢-centred ligand bonded
2
to the metal in a terminal, chelating (k ) fashion. The endocyclic
geometrical parameters of their six-membered YNCCCN rings
are shown in Table 1. The conformation of each such ring is that
Scheme 3 Reagents and conditions: i, 2Li[CH(SiMe3)2], C6H14, 0 ◦C, crystd thf–Et2O–C6H14; ii, K[N(SiMe3)2], PhMe; iii, YCl3, Et2O, -30 ◦C and KOBut,
C6H14.
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of a shallow boat; the central NCCN moiety is planar, with the
Y and the apical carbon being out (Y > C) of that plane. The
overall deviation from the plane is greatest for YL4 (6) and least
for YL5 (5c, 9); and for related compounds: YL1 (3a) > YL2 (3b)
and YL2 (5b) > YL3 (5a). Each Y–N and Y–N¢ bond length is
closely similar for these compounds, the disparity being greatest
for YL2 (3b) and YL5 (9). The average Y–N bond length in the
YL5 dialdiminato complex 9 is by far the longest, unlike in the YL5
complex 5c, and in both the C1–C2–C3 angle is the narrowest.
The structures of the isoleptic crystalline compounds [Y(m-
Cl)(Lx)(m-Cl)2Li(OEt2)2]2 (3a (Lx = L1; Fig. 1) and 3b (Lx = L2;
Fig. 2) are similar, but there are significant differences as evident
both from Table 1 (L1 vs L2) and Table 2 [for endocyclic Y(Lx) data,
see Table 1]. Each of 3a and 3b has a central YClY¢Cl¢ rhombus,
but only 3b is centrosymmetric. For both, the endocyclic angles
are narrower at the Y atoms than at the Cl atoms. The four Y–Cl
bond lengths in 3a are closely similar, whereas the two in 3b differ
substantially; likewise the difference in the angles at Y/Y¢ and
Cl/Cl¢ is greater in 3b (ca. 11◦) than 3a (ca. 3◦). The yttrium atoms
are the spiro centres of YClY¢Cl¢ and YCl¢¢LiCl¢¢¢ rings. Whereas
Fig. 1 Molecular structure of crystalline 3a (20% thermal ellipsoids).
Fig. 2 Molecular structure of crystalline 3b (20% thermal ellipsoids).
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◦
˚
Table 2 Selected bond distances (A) and angles ( ) for the [Li(m-Cl)2Y(m-Cl)]2 moiety of 3a and 3b
3a
3ba
Y1–Cl1
Y1–Cl4
Y1–Cl2
Y1–Cl3
Li2–Cl2
Li2–Cl3
2.705(2)
2.696(20
2.611(2)
2.660(2)
2.391(15)
2.391(15)
Y2–Cl1
Y2–Cl4
Y2–Cl5
Y2–Cl6
Li1–Cl5
Li1–Cl6
2.684(2)
2.707(2)
2.616(2)
2.660(2)
2.391(17)
2.385(16)
Y–Cl1¢
Y–Cl1
Y–Cl3
Y–Cl2
Li–Cl2
Li–Cl3
2.6727(6)
2.7462(6)
2.6169(6)
2.6294(6)
2.443(5)
2.384(4)
Y1–Cl1–Y2
Cl1–Y1–Cl4
Cl1–Y1–Cl2
Cl1–Y1–Cl3
Cl2–Y1–Cl4
Cl3–Y1–Cl4
Cl2–Y1–Cl3
Y1–Cl2–Li2
Y1–Cl3–Li2
Cl2–Li2–Cl3
N1–Y1–Cl1
N1–Y1–Cl4
N1–Y1–Cl3
N1–Y1–Cl2
N2–Y1–Cl1
N2–Y1–Cl4
N2–Y1–Cl3
N2–Y1–Cl2
101.55(6)
Y1–Cl4–Y2
Cl1–Y2–Cl4
Cl4–Y2–Cl5
Cl4–Y2–Cl6
Cl1–Y2–Cl5
Cl1–Y2–Cl6
Cl5–Y2–Cl6
Y2–Cl5–Li1
Y2–Cl6–Li1
Cl5–Li1–Cl6
N3–Y2–Cl4
N3–Y2–Cl1
N3–Y2–Cl6
N3–Y2–Cl5
N4–Y2–Cl4
N4–Y2–Cl1
N4–Y2–Cl6
N4–Y2–Cl5
101.17(6)
Y–Cl–Y¢
104.48(2)
75.52(2)
158.09(2)
83.341(19)
87.37(2)
100.85(2)
83.61(2)
88.44(10)
90.01(11)
92.83(15)
107.07(5)
94.75(5)
161.05(5)
85.92(5)
158.67(5)
83.67(5)
92.06(5)
117.81(5)
78.55(6)
171.26(7)
91.20(7)
94.64(7)
83.17(7)
83.17(7)
92.0(4)
78.73(6)
170.21(7)
88.60(7)
96.30(7)
89.10(7)
82.86(7)
91.9(4)
Cl1–Y–Cl1¢
Cl1¢–Y–Cl3
Cl1–Y–Cl3
Cl1–Y–Cl2
Cl1¢–Y–Cl2
Cl2–Y–Cl3
Y–Cl2–Li
90.8(4)
94.1(5)
91.0(4)
93.9(6)
Y–Cl3–Li
Cl2–Li–Cl3
N1–Y–Cl1
N1–Y–Cl1¢
N1–Y–Cl2
N1–Y–Cl3
N2–Y–Cl1
N2–Y–Cl1¢
N2–Y–Cl2
N2–Y–Cl3
96.22(16)
91.30(17)
172.57(16)
89.34(16)
83.88(17)
159.49(17)
101.77(19)
103.77(17)
96.15(16)
89.88(17)
174.83(16)
92.23(16)
85.61(16)
159.90(17)
103.92(18)
101.05(16)
a Symmetry transformations to generate equivalent atoms: ¢ -x + 1/2, -y + 3/2, -z.
in 3a the Y2Cl5Li1Cl6 ring is planar and the Y1Cl2Li2Cl3 ring is
almost planar, in 3b the YCl2LiCl3 ring is distinctly puckered, Cl3
˚
˚
being 0.72 A out of the YCl2Li plane (cf., for 3a, Cl3 is 0.04 A out
of the Y1Cl2Li2 plane). Each of the yttrium atoms is at the centre
of a distorted octahedron; the angle at the mutually transoid atoms
for 3a decrease in the sequence N1/Cl3 > Cl2/Cl1 ꢀ N2/Cl4 for
Y1 and N3/Cl6 > Cl4/Cl5 ꢀ N4/Cl1 for Y2. In 3b the mutually
transoid pairs (N1/Cl2, N2/Cl1, Cl1¢/Cl3) subtend at the yttrium
atom more closely similar angles (ca. 159.5 1.5◦), whereas in 3a
they range from ca. 159.5 to ca. 172.5◦ for Y1 and ca. 159.5 to ca.
174.8◦ for Y2.
The structures of the isoleptic crystalline complexes [Y(m-
Cl)(L3){(m-Cl)Li(Lg)2(m-Cl)}]2 [Lg = thf (4a), Fig. 3; OEt2 (4b),
Fig. 4a] are closely similar, as shown by the selected [excluding
the Li(Lg)2 fragments] geometrical parameters in Table 3; for
endocyclic Y(L3) data, see Table 1. As for 3a and 3b, the central
core of 4a and 4b is a Y1Cl1Y2Cl2 rhombus; like for 3b, the
two Y–Cl bond lengths of 4a and 4b differ significantly (by ca.
Fig. 3 Molecular structure of crystalline 4a (20% thermal ellipsoids).
˚
0.07 A). Essentially orthogonal to this plane is an eight-membered
macrocycle, Li1Cl3Y1Cl4Li2Cl6Y2Cl5, shown for 4b in Fig. 4b.
As evident from the latter, this ring approximates to a boat
with the atoms Li1 and Li2 out of the only slightly puckered
Cl3Y1Cl4Cl6Y2Cl5 moiety (4a, the Cl1 and Cl2 are transposed
relative to 4b). Each of the Y1 and Y2 atoms is at the centre of
a strongly distorted octahedron, with the atoms N1/Cl2, N2/Cl1
and Cl3/Cl4 being mutually transoid with respect to Y1 (at 166
1.9◦) and N3/Cl1, N4/Cl2 and Cl5/Cl6 with respect to Y2 (at
167 2.5◦) for 4a (cf. 164 1.5◦ for 4b).
endocyclic Y(Lx) data, see Table 1]. The pairs of Y–O and Y–
Cl bonds are closely similar for 5b and 5c, but for 5a the former
are significantly longer and the latter shorter. The yttrium atom
in each is at the centre of a severely distorted octahedron. The
mutually transoid atoms are N1/O1, N2/O2 and Cl1/Cl2 for 5a
and 5b, while for 5c the O1 and O2 atoms are transposed; trans
angles subtended at Y range from ca. 167 8◦ (5a), 171 2◦ (5b)
and 170 6◦ (5c). The geometric parameters of 5a are similar to
those for [Yb(L2)Cl2(dme)].20
The structures of the isoleptic crystalline complexes
[Y(Lx)Cl2(thf)2] [Lx = L3 (5a), L2 (5b), L5 (5c)] are shown in
Fig. 5, 6 and 7, respectively. Selected geometric parameters for
the N1N2YCl1Cl2O1O2 fragments are shown in Table 4 [for
The structures of the crystalline five-coordinate bis(b-
diketiminato)yttrium
compounds
[Y(L4)2Cl]
(6)
and
[Y(L1)2(OBut)] (7) are illustrated in Fig. 8 and 9, respectively;
selected exocyclic geometric parameters for the YXN1N2N3N4
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Fig. 5 Molecular structure of crystalline 5a (20% thermal ellipsoids).
allowing for the larger size of Nd3+ than Y3+. The yttrium atom in
both 6 and 7 is in a distorted trigonal bipyramid having N1 and
N4 as the axial atoms.
The structure of the crystalline centrosymmetric complex
[Y(X)(m-Cl)(O)(m-Cl)2Li]2 (8) is shown in Fig. 10. Selected geo-
metric parameters for its core (X = C), together with its isoleptic
analogue J (X = N) are listed in Table 6. The YCl2LiCl3 ring (as
well as the YCl1Y¢Cl1¢ ring) is planar with the endocyclic angles
centred at Y ꢀ Cl2 > Cl3 > Li (ranging from ca. 84◦ at Y and
ca. 94◦ at Li). Each yttrium atom is at the centre of a distorted
octahedron, the trans angles being ca. 163.5 4.5◦; the angles
at mutually transoid atoms decrease in the sequence C/Cl1¢ >
O1/Cl2 > Cl1/Cl3.
Fig. 4 (a) Molecular structure of crystalline 4b (20% thermal ellipsoids)
(top); (b) ORTEP representation of the Li1Cl3Y1Cl4Li2Cl6Y2Cl5 frag-
ment of 4b (bottom).
fragment of each are listed in Table 5 [for endocyclic Y(Lx)2 data,
see Table 1]. The data for 6 are similar to those of [Nd(L4)2Cl],21
The structure of the crystalline centrosymmetric com-
plex [Y(L5){N(H)C6H3Pri2-2,6}(thf)(m3-Cl)2K]2 (9) is shown in
◦
˚
Table 3 Selected bond distances (A) and angles ( ) for the [(N)(N)(m-Cl)Y(m-Cl)Li(m-Cl)]2 fragment of 4a and 4b
4a
4b
Y1–Cl1
Y1–Cl2
Y1–Cl3
Y1–Cl4
Li2–Cl3
Li1–Cl4
2.7543(13)
2.6740(13)
2.6189(15)
2.6180(14)
2.353(13)
2.342(10)
Y2–Cl1
Y2–Cl2
Y2–Cl6
Y2–Cl5
Li1–Cl5
Li2–Cl6
2.7590(13)
2.6811(14)
2.6129(14)
2.6088(14)
2.329(10)
2.330(11)
Y1–Cl1
Y1–Cl2
Y1–Cl3
Y1–Cl4
Li1–Cl3
Li1–Cl5
2.6793(14)
2.7397(14)
2.6326(15)
2.6286(15)
2.339(10)
2.361(10)
Y2–Cl1
Y2–Cl2
Y2–Cl5
Y2–Cl6
Li2–Cl4
Li2–Cl6
2.6766(13)
2.7554(14)
2.6223(15)
2.6223(15)
2.385(12)
2.388(13)
Y1–Cl1–Y2
Y1–Cl2–Y2
Cl1–Y1–Cl2
Cl1–Y1–Cl3
Cl1–Y1–Cl4
Cl2–Y1–Cl3
Cl2–Y1–Cl4
Cl3–Y1–Cl4
Y1–Cl3–Li2
Y1–Cl4–Li1
N1–Y1–Cl1
N1–Y1–Cl2
N1–Y1–Cl3
N1–Y1–Cl4
N2–Y1–Cl1
N2–Y1–Cl2
N2–Y1–Cl3
N2–Y1–Cl4
100.12(4)
104.25(4)
77.91(4)
83.50(5)
84.44(4)
89.09(5)
97.11(4)
164.98(5)
119.1(3)
109.9(2)
113.45(11)
167.47(10)
87.12(10)
89.49(10)
163.72(9)
87.82(10)
104.28(10)
89.66(10)
Cl3–Li2–Cl6
Cl4–Li1–Cl5
Cl1–Y2–Cl2
Cl1–Y2–Cl6
Cl1–Y2–Cl5
Cl2–Y2–Cl6
Cl2–Y2–Cl5
Cl5–Y2–Cl6
Y2–Cl6–Li2
Y2–Cl5–Li1
N3–Y2–Cl2
N3–Y2–Cl1
N3–Y2–Cl6
N3–Y2–Cl5
N4–Y2–Cl2
N4–Y2–Cl1
N4–Y2–Cl6
N4–Y2–Cl5
118.9(5)
122.6(4)
77.71(4)
85.43(4)
82.90(4)
96.28(5)
88.96(5)
165.90(5)
115.0(3)
Y1–Cl1–Y2
Y1–Cl2–Y2
Cl1–Y1–Cl2
Cl1–Y1–Cl3
Cl1–Y1–Cl4
Cl2–Y1–Cl3
Cl2–Y1–Cl4
Cl3–Y1–Cl4
Y1–Cl3–Li1
Y1–Cl4–Li2
N1–Y1–Cl1
N1–Y1–Cl2
N1–Y1–Cl3
N1–Y1–Cl4
N2–Y1–Cl1
N2–Y1–Cl2
N2–Y1–Cl3
N2–Y1–Cl4
102.66(4)
99.10(4)
79.20(4)
99.21(5)
87.41(5)
84.59(5)
84.62(5)
166.06(5)
118.6(2)
121.9(3)
84.26(11)
163.05(11)
89.23(11)
103.51(11)
165.84(11)
113.16(11)
89.18(11)
86.96(11)
Cl3–Li1–Cl5
Cl4–Li2–Cl6
Cl1–Y2–Cl2
Cl2–Y2–Cl5
Cl2–Y2–Cl6
Cl1–Y2–Cl5
Cl1–Y2–Cl6
Cl5–Y2–Cl6
Y2–Cl5–Li1
Y2–Cl6–Li2
N3–Y2–Cl1
N3–Y2–Cl2
N3–Y2–Cl6
N3–Y2–Cl5
N4–Y2–Cl1
N4–Y2–Cl2
N4–Y2–Cl6
N4–Y2–Cl5
113.7(4)
117.1(5)
78.97(4)
83.54(5)
84.04(5)
87.10(5)
95.76(5)
166.48(5)
124.9(2)
114.5(2)
118.4(3)
88.01(10)
164.89(10)
91.32(10)
101.96(10)
169.51(10)
112.02(10)
88.62(10)
88.44(10)
88.09(11)
165.02(11)
89.84(11)
103.49(11)
167.06(12)
112.61(12)
91.37(11)
88.49(11)
5240 | Dalton Trans., 2008, 5235–5246
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Fig. 8 Molecular structure of crystalline 6 (50% thermal ellipsoids).
Fig. 6 Molecular structure of crystalline 5b (50% thermal ellipsoids).
Fig. 7 Molecular structure of crystalline 5c (50% thermal ellipsoids).
Fig. 9 Molecular structure of crystalline 7 (50% thermal ellipsoids).
Fig. 11a. Selected geometric data are listed in Table 7 [for
endocyclic YL5 data, see Table 1]. The eight atoms comprising
the central core is shown in Fig. 11b, which contains two planar
rings: the outer KYK¢Y¢ and the inner Cl2Cl1Cl2¢Cl1¢; each Cl
atom bridges one Y and two K atoms. Each six-coordinate yttrium
◦
˚
Table 4 Selected bond distances (A) and angles ( ) for the N1N2YCl1Cl2O1O2 fragment of 5a, 5b and 5c
5a
5b
5c
Y–Cl1
Y–Cl2
Y–O1
Y–O2
2.5487(14)
2.5631(13)
2.426(3)
2.5773(7)
2.5892(7)
2.4015(18)
2.3790(18)
2.5724(6)
2.5823(6)
2.3586(16)
2.381(4)
2.433(5)
N2–Y–Cl1, N2–Y–Cl2
N1–Y–Cl1, N1–Y–Cl2
N1–Y–O1, N1–Y–O2
N2–Y–O1, N2–Y–O2
Cl1–Y–Cl2
Cl1–Y–O1, Cl1–Y–O2
Cl2–Y–O1, Cl2–Y–O2
96.76(8), 98.76(8)
101.64(8), 94.75(7)
175.55(10), 88.33(13)
97.03(10), 168.15(15)
159.14(5)
81.89(8), 87.21(14)
82.44(8), 80.39(13)
93.51(6), 93.42(6)
100.50(5), 88.36(5)
171.02(7), 95.68(7)
101.53(7), 173.78(7)
169.65(2)
88.42(5), 83.99(5)
82.67(5), 89.85(5)
99.87(4), 92.75(4)
92.63(4), 99.69(5)
96.45(6), 176.80(13)
175.88(6), 97.70(13)
163.63(2)
83.29(4), 84.83(10)
84.65(4), 83.18(10)
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◦
Table 5 The Y–X bond distances (A) and angles (◦) for the
Table 6 Selected bond distances (A) and angles ( ) for the [M(X)(m-
Cl)(O)(m-Cl)2Li]2 fragment of 8 (X = C) and J (X = N)13
˚
˚
Y(X)N1N2N3N4 fragment of 6 (X = Cl) and 7 (X = O)
6a
7b
8 (M = Y, X = C)
J (M = Sm, X = N)13
Y–X
2.5566(6)
2.015(2)
M–O1
M–X
M–Cl1, M–Cl1¢
M–Cl2, M–Cl3
Li–Cl2, Li–Cl3
2.340(3)
2.412(5)
2.421(3)
2.284(2)
N1–Y–N3
N1–Y–N4
N1–Y–X
N2–Y–X
N2–Y–N4
N2–Y–N3
N4–Y–X
N3–Y–X
97.31(7)
178.48(7)
89.11(5)
114.29(5)
101.56(7)
125.66(7)
89.81(5)
93.96(7)
166.65(6)
96.72(6)
122.18(6)
95.03(6)
108.96(6)
96.62(6)
128.87(7)
2.6665(13), 2.8107(12) 2.7276(7), 2.8937(7)
2.6169(12), 2.6272(13) 2.6928(8), 2.7276(7)
2.427(11), 2.368(10)
2.347(9), 2.359(7)
M–Cl1–M¢
102.56(4)
77.44(4)
94.03(15)
102.92(2)
77.08(2)
93.22(10)
Cl1–M–Cl1¢
120.04(5)
X–M–O1
X–M–Cl1, X–M–Cl1¢
X–M–Cl2, X–M–Cl3
O1–M–Cl1, O1–M–Cl1¢
O1–M–Cl2, O1–M–Cl3 164.39(9), 84.63(9)
Cl1–M–Cl2, Cl1¢–M–Cl2 104.27(4), 87.39(4)
Cl1–M–Cl3, Cl1¢–M–Cl3 159.77(4), 84.53(4)
M–Cl2–Li, M–Cl3–Li
Cl2–Li–Cl3
91.34(12), 168.17(12) 97.12(6), 171.11(8)
99.17(12), 105.86(12) 102.33(6), 105.42(8)
a X = Cl. b X = O.
83.61(9), 81.13(9)
82.85(5), 79.48(5)
160.73(5), 88.35(5)
99.21(3), 82.67(2)
159.06(3), 82.35(3)
88.73(3), 89.21(3)
98.9(3)
90.7(2), 91.7(3)
93.8(3)
Cl2–M–Cl3
83.77(4)
83.02(3)
Symmetry transformation to generate equivalent atoms for 8: ¢ -x + 1, -y
+ 1, -z + 1.
(3b)], [Y(m-Cl)(L3)(m-Cl)Li(thf)2(m-Cl)]2 (4a) or its (OEt2) ana-
logue (4b), [Y{(CH(SiMe3)2)(thf)(m-Cl)2Li(OEt2)2}2(m-Cl)]2 (8)
and [Y(L5){N(H)C6H3Pri2-2,6}(m3-Cl)2K]2·4Et2O (9). Equivalent
portions of YCl3 and Na[Lx] gave [Y(L3)Cl2(thf)2] (5a) and
[Y(L5)Cl2(thf)2] (5c) but, unexpectedly, [YCl(L4)2] (6). The com-
pound [Y(L1)2(OBut)] (7) is the first bis(b-diketiminato)metal (M)
alkoxide (M = a group 3 or 4f metal). Formation of 8 via 3a
and 2Li[CH(SiMe3)2] is remarkable in that displacement by the
carbanion of L1 rather than Cl- was preferred.
Fig. 10 Molecular structure of crystalline 8 (20% thermal ellipsoids).
Experimental
atom is at the centre of a distorted octahedron; the trans angles
range from ca. 162.5◦ (N2/N3) to ca. 170◦ (N1/Cl1), the third
mutually trans-pair is O1/Cl2 (N1 and N2 belong to the L5 ligand).
In conclusion, the synthesis and characterisation of eleven
new crystalline Y complexes (3a, 3b, 4a, 4b, 5a, 5b, 5c,
6, 7, 8, 9) is presented. Except for 8 and 9, they are
General remarks
All manipulations were performed under argon using stan-
dard Schlenk techniques. Hexane and toluene were dried using
sodium–potassium alloy. Diethyl ether and thf were dried and
distilled from sodium–benzophenone and stored over a sodium
mirror under argon. Deuterated solvents (C6D6, C5D5N and
2
(k -b-diiminato)yttrium chlorides, obtained from YCl3 and
an alkali metal b-diiminate M[Lx], for which Lx = L1–L5:
[{N(R)C(Me)}2CH]- [R = C6H4Pri-2 (L1); R = C6H4But-2
(L2); R = C6H3Pri2-2,6 (L3)], [{N(SiMe3)C(Ph)}2CH)]- (L4)
and [{N(C6H3Pri2-2,6)C(H)}2CPh]- (L5). Several have unusual
structures: [Y(m-Cl)(Lx)(m-Cl)2Li(OEt2)2]2 [Lx = L1 (3a), L2
C4D8O) were freeze–thaw degassed and stored over dried 4 A
˚
molecular sieves under an argon atmosphere. The compounds
Li[CH(SiMe3)2],30 H[{N(C6H4R-2)C(Me)}2CH] [R = Pri (1a),
But (1b)],10 Li[{N(C6H3Pri2-2,6)C(Me)}2CH] (2c),12 Na[L5]31 and
K[N(H)C6H3Pri2-2,6]32 were prepared as described in the literature
◦
i
˚
Table 7 Selected bond distances (A) and angles ( ) for the [NNY{N(H)C6H3Pr 2-2,6}(thf)(m-Cl)2K]2 fragment of 9
Y–N3
2.259(2)
2.6134(7)
2.6093(7)
2.435(2)
1.395(4)
3.332(1)
3.285(1)
3.156(1)
3.173(1)
N3–Y–N1
N3–Y–N2
N3–Y–Cl1
N3–Y–Cl2
N3–Y–O1
N1–Y–O1
N2–Y–O1
N1–Y–Cl1
N2–Y–Cl1
N1–Y–Cl2
N2–Y–Cl2
91.81(8)
162.65(8)
97.47(7)
84.66(7)
106.26(8)
90.61(7)
86.14(7)
169.90(6)
96.05(5)
99.21(6)
85.57(5)
Cl1–Y–O1
Cl2–Y–O1
Cl1–Y–Cl2
N3–K–Cl1
N3–K–Cl2
N3–K–Cl1¢
N3–K–Cl2¢
Cl1–K–Cl2
Cl1¢–K–Cl2¢
Cl1–K–Cl1¢
Cl1–K–Cl2¢
82.99(5)
165.17(5)
85.68(2)
69.29(5)
61.76(5)
128.07(5)
137.03(5)
64.92(2)
68.26(2)
103.79(2)
68.04(2)
Cl1¢–K–Cl2
Cl1¢–K–Cl2¢
Y–Cl1–K
Y–Cl1–K¢
Y–Cl2–K
Y–Cl2–K¢
K–Cl1–K¢
K–Cl2–K¢
Y–N3–C34
68.83(2)
68.26(2)
82.67(2)
98.80(3)
83.66(2)
98.45(3)
76.21(2)
76.64(2)
163.8(2)
Y–Cl1
Y–Cl2
Y–O1
N3–C34
K–Cl1
K–Cl2
K–Cl1¢
K–Cl2¢
Symmetry transformation used to generate equivalent atoms: ¢ -x + 1, -y + 1, -z.
5242 | Dalton Trans., 2008, 5235–5246
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Compound 2b. n-Butyllithium (8.6 cm3 of a 1.6 mol dm-3
solution in C6H14) was added dropwise to a solution of 1b (5.0 g,
13.81 mmol) in n-hexane (40 cm3) at 0 ◦C. The mixture was stirred
at 20 ◦C for 2 h, then cooled to 0 ◦C and filtered. The pale yellow
2b (4.5 g, 89%) (Found: C, 81.1; H, 8.98; N, 7.24%. C25H33LiN2
requires: C, 81.5; H, 9.03; N, 7.60%), mp 113–115 ◦C, was obtained
from the precipitate after washing with cold hexane (3 ¥ 10 cm3)
and drying in vacuo. 1H-NMR: d 1.32 (s, 18 H, CMe3), 1.85 (s, 6 H,
CH3), 4.79 (s, 1 H, CH); 6.66 (d, 2 H), 7.03 (m, 2 H), 7.09 (d, 2 H),
7.40 ppm (d, 2 H, C6H4); 13C-NMR: d 21.13 (CH3), 31.36 (CMe3),
35.48 (CMe3), 94.65 (CH); 122.51, 126.39, 126.92, 141.93, 153.57
(C6H4), 163.22 ppm (CN); 7Li-NMR: d -2.14 ppm.
Compound 2a. Compound 2a (86%) (Found: C, 80.6; H, 8.31;
N, 8.02%. C23H29LiN2 requires: C, 81.2; H, 8.59; N, 8.23%) was
obtained from 1a + LiBun in a similar fashion to 2b. 1H-NMR: d
1.11 (d, 12 H, CHMe2), 1.84 (s, 6 H CH3), 3.32 (hept, 2 H, CHMe2),
4.80 (s, 1 H, CH); 6.76 (m, 2 H), 7.04 (m, 4 H), 7.23 ppm (d, 2 H,
C6H4); 13C-NMR: d 20.77 (CH3), 23.38 (CHMe2), 28.01 (CHMe2),
93.96 (CH); 122.92, 124.81, 125.84, 126.06, 141.18, 152.13 (C6H4),
163.49 ppm (CN); 7Li-NMR: d -2.10 ppm.
The potassium b-diketiminate (K[L1]). Potassium bis(trime-
thylsilyl)amide (1.60 g, 8.02 mmol) was added in small portions to
a solution of the b-diketimine 1a (2.68 g, 8.02 mmol) in toluene
(35 cm3) at 0 ◦C. The resulting mixture was stirred for 12 h at
ca. 20 ◦C, then cooled to -25 ◦C and filtered. The precipitate
was washed with hexane (3 ¥ 15 cm3) and dried in vacuo yielding
the off-white powder (K[L1]) (2.57 g, 86%) (Found: C, 74.4; H,
7.68; N, 7.36%. C23H29KN2 requires: C, 74.1; H, 7.85; N, 7.52%).
1H-NMR: d 1.08 (d, 12 H, CHMe2), 1.76 (s, 6 H, CH3), 3.26
(hept, 2 H, CHMe2), 4.68 (s, 1 H, CH); 6.72 (m, 2 H), 6.98 (m,
4 H), 7.08 ppm (d, 2 H, C6H4); 13C-NMR: d 20.07 (CH3), 22.98
(CHMe2), 28.00 (CHMe2), 91.56 (CH); 122.63, 124.36, 125.57,
125.95, 141.02, 152.01 (C6H4), 161.38 ppm (CN).
Fig. 11 (a) Molecular structure of crystalline 9 (50% thermal ellipsoids)
(top); (b) ORTEP representation of the central KYK¢Y¢Cl1Cl1¢Cl2Cl2¢
core of 9 (bottom).
and LiBu, K[N(SiMe3)2], K[OBut] and YCl3 were commercial
samples (Aldrich). The NMR spectra were recorded on a Bruker
DPX 300 (300.1 MHz for 1H, 75.5 MHz for 13C and 116.6 MHz
7
for Li) and referenced externally (7Li, using LiCl) or internally
The compounds [Y(l-Cl){(N(C6H4R-2)C(Me))2CH}(l-Cl)2Li-
(OEt2)2]2 [R = Pri (3a), But (3b)]. Yttrium(III) chloride (0.88 g,
4.53 mmol) was added in small portions to a solution of 2a (1.54 g,
4.53 mmol) in diethyl ether (30 cm3) at -30 ◦C. The resulting
mixture was warmed slowly to ca. 20 ◦C and stirred for 12 h.
The volatiles were removed in vacuo and the residue was extracted
into diethyl ether (40 cm3). The filtered extract was concentrated
in vacuo to ca. 15 cm3 and stored at -25 ◦C to yield colourless
crystals of 3a (2.19 g, 71%) (Found: C, 54.0; H, 7.14; N, 4.08%.
C62H98Cl6Li2N4O4Y2 requires: C, 54.4; H, 7.22; N, 4.10%), mp
77 ◦C (decomp.). 1H-NMR: d 1.04 (t, 12 H, Et2O), 1.14 (d, 12 H,
CHMe2), 1.68 (s, 6 H, CH3), 3.23 (q, 8 H, Et2O), 3.34 (hept, 2 H,
CHMe2), 5.09 (s, 1 H, CH), 6.66 (m, br, 4 H, C6H4), 7.24 ppm (br, 4
H, C6H4); 13C-NMR: d 15.29 (Et2O), 20.73 (CH3), 22.49 (CHMe2),
29.32 (CHMe2), 98.04 (CH); 124.12, 124.49, 125.95, 126.28,
140.63, 143.82 (C6H4), 164.26 ppm (CN); 7Li-NMR: d -2.35 ppm.
to the residual solvent resonances. Unless otherwise stated, all
NMR spectra were measured at 293 K in C6D6 and other than
1H were proton-decoupled. Melting points were taken in sealed
capillaries. Elemental analyses were determined by Medac Ltd.,
Brunel University.
Preparations
The lithium b-diketiminates Li[{N(C6H4R-2)C(Me)}2CH] [R =
Pri (2a), But (2b)]. The precursor b-diketimines 1a (Found: C,
82.3; H, 9.01; N, 8.30%. C23H30N2 requires: C, 82.6; H, 9.04;
N, 8.37%) and 1b (Found: C, 82.4; H, 9.26; N, 7.44%. C25H34N2
requires: C, 82.9; H, 9.45; N, 7.73%) were prepared by literature
procedures.12 For 1a: 1H-NMR: d 1.13 (d, 12 H, CHMe2), 1.76 (s,
6 H, CCH3), 3.35 (hept, 2 H, CHMe2), 4.87 (s, 1 H, CH), 6.84 (m,
2 H, C6H4), 7.01 (m, 4 H, C6H4), 7.18 (m, 2 H, C6H4), 12.87 ppm
(s, 1 H, NH); 13C-NMR: d 20.77 (CH3), 23.34 (CHMe2), 28.47
(CHMe2), 97.19 (CH); 124.15, 124.69, 125.95, 126.23, 141.63,
143.81 (C6H4), 160.08 ppm (CN). For 1b: 1H-NMR: d 1.37 (s, 18 H,
CMe3), 1.74 (s, 6 H, CH3), 4.90 (s, 1 H, CH); 6.80 (d, 1 H), 6.82 (d, 1
H), 6.95 (d, J = 1.46 Hz, 1 H), 6.98 (d, 1 H), 7.02 (d, 1 H), 7.05 (d, 1
H), 7.29 (d, 1 H), 7.32 (d, 1 H) (C6H4), 12.88 ppm (s, 1 H, NH);13C-
NMR: d 21.14 (CH3), 30.61 (CMe3), 35.65 (CMe3), 99.12 (CH);
124.12, 126.26, 128.33, 142.21, 144.22 (C6H4), 167.36 ppm (CN).
Compound 3b. (3.05 g, 63%) (Found: C, 55.2; H, 7.42; N, 4.08%.
C66H106Cl6Li2N4O4Y2 requires: C, 55.7; H, 7.50; N, 3.93%), mp
71 ◦C (decomp.). 1H-NMR: d 1.07 (t, 12 H, Et2O), 1.70 (s, 18 H,
CMe3), 1.75 (s, 6 H, CH3), 3.23 (q, 8 H, Et2O), 5.10 (s, 1 H, CH),
6.64 (m, br, 4 H, C6H4), 7.26 ppm (br, 4 H, C6H4); 13C-NMR:
d 15.52 (Et2O), 25.39 (CH3), 31.66 (CMe3), 33.65 (CMe3), 65.82
(Et2O), 98.35 (CH); 125.28, 125.58, 130.59, 130.93, 137.84, 140.56
(C6H4), 166.62 ppm (CN); 7Li-NMR: d 0.75 ppm.
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i
thf), 5.01 (s, 1 H, CH); 7.02 ( br, 4 H), 7.42 (d, 2 H), 7.52 ppm (br,
2 H, C6H4); 13C-NMR: d 25.29 (CH3), 25.54 (thf), 33.49 (CMe3),
37.20 (CMe3), 71.12 (thf), 98.19 (CH); 125.16, 128.32, 130.45,
144.41, 146.32 (C6H4), 166.84 ppm (CN).
The compounds [Y(l-Cl){(N(C6H3Pr2 -2,6)C(Me))2CH}{(l-
Cl)Li(Lg)2(l-Cl)}]2 [Lg = thf (4a), OEt2 (4b)]. Yttrium(III)
chloride (0.30 g, 1.55 mmol) was added in small portions to a
solution of lithium b-diketiminate Li[L3] (0.66 g, 1.55 mmol) in
diethyl ether (20 cm3) at -30 ◦C. The mixture was allowed to
warm to ca. 20 ◦C and stirred for 18 h, whereafter the volatiles were
removed in vacuo. The residue was extracted into hexane (40 cm3)–
thf (10 cm3). The filtered extract was concentrated to ca. 15 cm3
and stored at-25 ◦C, yielding colourless blocks of 4a (0.61 g, 52%)
(Found: C, 57.4; H, 7.06; N, 3.69%. C74H114Cl6Li2N4O4Y2 requires:
C, 58.2; H, 7.52; N, 3.67%), mp 126 C (decomp.). H-NMR: d
0.87 (t, 8 H, thf), 1.16 (d, 12 H, J = 6.59, CHMe2), 1.28 (d, 12 H,
J = 6.59 Hz, CHMe2), 1.90 (s, 6 H, CH3), 2.67 (m, 8 H, thf),
3.41 (hept, 4 H, CHMe2), 5.00 (s, 1 H, CH), 7.07 ppm (m, br, 6
H, C6H3); 13C-NMR: d 23.14 (CH3), 23.46 (thf), 24.40 (CHMe2),
24.70 (CHMe2), 28.06 (CHMe2), 67.86 (thf), 92.89 (CH); 122.99,
A solution of the sodium b-diketiminate Na[L5] (1.37 g,
2.80 mmol) in thf (20 cm3) was added dropwise to a stirred
suspension of YCl3 (0.55 g, 2.81 mmol) in thf (10 cm3) at ca.
20 ◦C. The mixture was set aside for 24 h, volatiles were removed
in vacuo and the residue was extracted into diethyl ether. The
extract was concentrated to ca. 10 cm3 and maintained at -25 ◦C,
yielding yellow crystals of 5c (1.77 g, 82%) (Found: C, 62.1; H, 6.28;
N, 3.59%. C41H57Cl2N2O2Y requires: C, 64.0; H, 7.46; N, 3.64%;
C37H49Cl2N2OY requires: C, 63.7; H, 7.08; N, 4.02% (i.e. 5c–thf));
MS: m/z, 624 ([M - 2thf]+, 100%), mp 141–148 ◦C (decomp.).
1H-NMR: d 1.15 (d, 12 H, J = 6.7, CHMe2), 1.17 (s, 8 H, thf),
1.58 (d, 12 H, J = 6.7, CHMe2), 3.59 (s, 8 H, thf), 4.23 (heptet, 4
H, J = 6.7, CHMe2), 7.03 (t, 2 H, J = 7.4, p-H of C6H3), 7.05–7.23
(m, CH), 7.48 (d, 2 H, J = 7.8, m-H of C6H3), 7.97 ppm (d, 2
H, J = 2.0 Hz, m-H, of C6H3); 13C-NMR: d 23.2 (CHMe2), 25.2
(CHMe2), 26.3 (thf), 28.5 (CHMe2), 71.2 (thf), 106.9 (CPh); 124.1,
124.9, 143.0, 144.9, 147.9 (Ph and C6H3), 164.4 ppm (NCH).
◦
1
7
123.21, 140.81, 149.48 (C6H3), 163.48 ppm (CN); Li-NMR: d
0.58 ppm.
A solution of the lithium b-diketiminate 2c (1.30 g, 3.06 mmol)
in diethyl ether (20 cm3) was added to a suspension of YCl3 (0.62 g,
3.18 mmol) in Et2O at ca. 20 ◦C. The mixture was stirred for 2 d,
then filtered. The light brown filtrate was concentrated to ca.10 cm3
and stored at -27 ◦C, furnishing colourless crystals of 4b (1.22 g,
51%) (Found: C, 57.9; H, 8.30; N, 3.64%. C74H122Cl6Li2N4O4Y2
requires: C, 58.0; H, 8.41; N, 3.56%), mp 121–122 ◦C (decomp.).
1H-NMR: d 1.16 (d, 24 H, CHMe2), 1.20 (d, 24 H, CHMe2), 1.62 (s,
12 H, CH3), 3.33 (m, 8 H, OEt2), 5.07 (s, 2 H, CH), 7.11–7.24 ppm
(m, 12 H, C6H3); 13C-NMR: d 15.0 (OEt2), 23.46 (CH3), 24.9
(CHMe2), 25.3 (CHMe2), 28.9 (CHMe2), 65.8 (OEt2), 99.1 (CH);
124.4, 126.4, 143.1, 143.9 (C6H3), 167.8 ppm (CN),7Li-NMR: d
-2.34 ppm.
The compound [YCl{(N(SiMe3)C(Ph))2CH}2] (6). A solution
of the sodium b-diketiminate Na[L4] (3.13 g, 8.05 mmol) in thf
(20 cm3) was added to a stirred suspension of YCl3 (1.68 g,
8.60 mmol) in thf (10 cm3) at ca. 20 ◦C. The mixture was set
aside for 48 h, volatiles were removed in vacuo and the residue
was extracted into diethyl ether. The extract was concentrated to
ca. 30 cm3 and maintained at 25 ◦C, furnishing yellow crystals
of 6 (2.17 g, 64% based on Na[L4]). Recrystallisation from Et2O
provided X-ray quality crystals (Found: C, 59.2; H, 7.04; N, 6.50%.
C42H58ClN4Si4Y requires: C, 59.0; H, 6.83; N, 6.55%), mp 152–
153 ◦C. 1H-NMR (C4D8O): d 0.05 [s, 36 H, Si(CH3)3], 5.35 (s, 2 H,
CH), 7.14–7.56 ppm (m, 20 H, C6H5); 13C-NMR (C4D8O): d 1.4
[Si(CH3)3], 1.9 [Si(CH3)3], 3.0 [Si(CH3)3], 3.6 [Si(CH3)3], 97.6 (CH);
126.8, 127.8, 128.5,128.6, 128.9, 129.1, 129.4, 130.5, 130.6 ppm
(C6H5, CN).
The dichloroyttrium b-diketiminates [YCl2{(N(R1)C(R2))2-
CR3}(thf)2] [R2 = Me, R3 = H and R1 = C6H3Pri2-2,6 (5a) or
C6H4But-2 (5b); R1 = C6H3Pri2-2,6, R2 = H, R3 = Ph (5c)].
Yttrium(III) chloride (0.38 g, 1.95 mmol) was added in small
portions to a stirred suspension of the potassium b-diketiminate
K[L3] (0.88 g, 1.93 mmol) in diethyl ether (20 cm3) at -78 ◦C. The
mixture was set aside at ca. 20 ◦C for 18 h, then filtered. Removal of
volatiles in vacuo from the filtrate yielded a yellow powder, which
The compound [Y{(N(C6H4Pri-2)C(Me))2CH}2OBut] (7). Yt-
trium(III) chloride (0.55 g, 2.81 mmol) was added in small portions
to a solution of the potassium b-diketiminate K[L1] (2.07 g,
5.56 mmol) in diethyl ether (50 cm3) at -30 ◦C. The resulting
◦
upon crystallisation from hexane (20 cm3)–thf (5 cm3) at -25 C
afforded colourless crystals of 5a (0.79 g, 57%) (Found: C, 61.3; H,
8.02; N, 3.79%. C37H57Cl2N2O2Y requires: 61.6; H, 7.96; N, 3.88%),
◦
mixture was stirred for 30 min at ca. 20 C, whereafter KOBut
(0.31 g, 2.77 mmol) was slowly added; stirring was continued for
24 h, followed by filtration. Volatiles were removed in vacuo; the
residue was extracted into hexane. ◦The extract was concentrated in
vacuo to ca. 20 cm3 and stored at 0 C, yielding pale yellow crystals
of 7 (0.78 g, 34%) (Found: C, 71.9; H, 8.03; N, 6.◦42%. C50H67N4OY
◦
1
mp 143 C (decomp.). H-NMR: d 1.16 (d, 12 H, J = 6.59 Hz,
CHMe2), 1.26 (d, 12 H, J = 6.59 Hz, CHMe2), 1.38 (t, 8 H, thf),
1.71 (s, 6 H, CH3), 3.62 (hept, 4 H, CHMe2), 3.74 (q, 8 H, thf),
5.15 (s, 1 H, CH), 7.08 ppm (m, br, 6 H, C6H3); 13C-NMR: d 20.51
(CH3), 23.14 (CHMe2), 25.69 (thf), 28.45 (CHMe2), 67.64 (thf),
94.00 (CH); 123.31, 123.42, 141.03, 148.61 (C6H3), 164.78 ppm
(CN).
1
requires: C, 72.4; H, 8.15; N, 6.76%), mp 171 C (decomp.). H-
NMR: d 0.46 (s, 9 H, OCMe3), 1.14 (d, 12 H, CHMe2), 1.39 (d, 12
H, CHMe2), 1.72 (s, 12 H, CH3), 3.34 (heptet, 4 H, CHMe2), 4.90
(s, 2 H, CH); 6.13 (br, 4 H), 6.89 (t, 4 H), 6.93 (t, 4 H), 7.25 ppm
(d, 4 H, C6H4); 13C-NMR: d 23.91 (CH3), 24.33 (CHMe2), 24.90
(CHMe2), 27.75 (CHMe2), 32.97 (OCMe3), 71.90 (OCMe3), 95.68
(CH); 125.04, 126.11, 126.19, 141.67, 148.61 (C6H4), 165.74 ppm
(CN).
A suspension of 3b (1.52 g, 1.07 mmol) in n-hexane (40 cm3)
was heated to 60 C with stirring for 12 h. The hot mixture was
◦
filtered. Volatiles were removed from the filtrate in vacuo and the
residue was extracted into hexane (30 cm3)–diethyl ether (10 cm3)–
thf (5 cm3). The extract was concentrated in vacuo to ca. 15 cm3 and
stored at -25 ◦C to afford colourless crystals of 5b (1.12 g, 79%)
(Found: C, 55.6; H, 7.26; N, 4.20%. C33H49Cl2N2O2Y requires: C,
59.55; H, 7.42; N, 4.21%), mp 158 ◦C (decomp.). 1H-NMR: d 1.18
(br, 8 H, thf), 1.65 (s, 18 H, CMe3), 1.72 (s, 6 H, CH3), 3.62 (br, 8 H,
The compound [Y{CH(SiMe3)2}(thf){(l-Cl)2Li(OEt2)2}(l-Cl)]2
(8). Li[CH(SiMe3)2] (0.36 g, 2.17 mmol) was added in small
portions to a solution of compound 3a (1.48 g, 1.08 mmol) in
5244 | Dalton Trans., 2008, 5235–5246
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hexane (50 cm3) at 0 ◦C. The resulting mixture was stirred for
48 h at ca. 20 ◦C. Volatiles were removal in vacuo. The residue
was extracted into hexane (40 cm3)–diethyl ether (20 cm3)–thf
(10 cm3). The extract was concentrated to ca.15 cm3 and stored at
-25 ◦C. After 12 h, this yielded colourless crystals of 8 (0.51 g, 41%)
(Found: C, 38.5; H, 7.98%; C38H94Cl6Li2O6Si4Y2 requires: C, 3 9.2;
H, 8.14%), mp 94 ◦C (decomp.). 1H-NMR (C6D6–C5D5N): d -0.40
(s, 1 H, CH), -0.09 [s, 18 H, Si(CH3)3], 1.06 (t, 12 H, OEt2), 1.41
(t, 4 H, thf), 3.23 (q, 8 H, OEt2), 3.54 ppm (t, 4 H, thf); 13C-NMR
(C6D6–C5D5N): d -0.05 (CH), 1.36 [Si(CH3)3], 15.52 (OEt2), 25.73
(thf), 65.82 (OEt2), 67.77 ppm (thf); 7Li-NMR (C6D6–C5D5N): d
-1.84 ppm.
i
i
The
compound
[Y{N(H)C6H3Pr2 -2,6}{(N(C6H3Pr2 -2,6)-
C(H))2CPh}(thf){l-Cl}2K}]2·4Et2O (9). The potassium amide
i
K[N(H)C6H3Pr2 -2,6] (0.45 g, 2.09 mmol) was added in small
portions to a solution of the dichloroyttrium b-diketiminate 5c
(1.51 g, 1.96 mmol) in diethyl ether (30 cm3) at ca. 20 ◦C. The
mixture was stirred for 24 h, then filtered. The filtrate,
when concentrated and cooled at -27 ◦C, yielded the yellow
crystalline 9 (1.20 g, 67%) (Found: C, 64.6; H, 7.55; N, 4.63%.
C98H134Cl4K2N6O2Y2 (ether-free) requires: C, 64.6; H, 7.41; N,
4.61%), mp 95–96 ◦C (decomp.). X-Ray quality crystals of 9 were
obtained by crystallisation from Et2O. 1H-NMR (C4D8O): d 0.85
(d, 24 H, J = 6.6, CHMe2), 0.99 (d, 12 H, J = 6.6, CHMe2),
1.04 [t, 24 H, O(CH2CH3)2], 1.13 (d, 12 H, J = 6.6, CHMe2),
1.25 (d, 24 H, J = 6.6, CHMe2), 1.69 (t, 8 H, thf), 2.89 (m, 4 H,
CHMe2), 3.30 (q, 16 H, O(CH2CH3)2), 3.54 (t, 8 H, thf), 3.63
(m, 8 H, CHMe2), 3.94 (br, 2 H, NH), 6.13 (t, 2 H, J = 7.4,
C6H3), 6.58 (d, 4 H, J = 7.4 Hz, C6H3), 6.80–7.18 (m, 22 H,
C6H5), 7.56 ppm (s, 4 H, CH); 13C-NMR (C4D8O): d 14.9, 22.1,
22.6, 23.2, 23.6, 25.5, 26.3, 27.5, 28.4 [CHMe2, O(CH2CH3)2, thf],
65.5, 67.4 [O(CH2CH3)2, thf], 105.2, 112.7 (CPh); 121.3, 122.2,
123.1, 123.6, 125.1, 125.2, 128.3, 135.0, 143.2, 144.2, 151.2 (C6H3,
C6H5), 162.6 ppm (NCH).
Crystal data and refinement details for 3a, 3b, 4a, 4b, 5a, 5b, 5c, 6,
7, 8 and 9
Diffraction data were collected on a Nonius Kappa CCD diffrac-
˚
tometer using monochromated Mo-Ka radiation, l 0.71073 A at
173(2) K. Crystals were coated in oil and then directly mounted
on the diffractometer under a stream of cold nitrogen gas.
In 3a diffraction was weak but with no apparent disorder in
the structure. In 4a all the thf ligands were included with 1,2
distance restraints and for the O2 thf disordered components
were included with isotropic C atoms. In 4b the Et2O ligands
were poorly defined and with disordered components for one
thf. They were included with isotropic C atoms and 1,2 distance
restraints and with an isotropic O atom for the disordered ligand.
In 5a and in 5c the disordered components of the O2 thf ligand
were included with isotropic displacement parameters and 1,2
distance restraints. In 8 the Et2O ligands were poorly defined,
discrete alternative positions defined only for C18; they were
included with isotropic C atoms and 1,2 distance restraints. In
all figures only the larger occupancy orientation is shown for
disordered ligands. Absorption corrections using MULTISCAN
were applied. Drawings are ORTEP-3 for Windows, with 20%
ellipsoids for 3a, 3b, 4a, 4b, 5a, and 8 and 50% ellipsoids for 5b,
5c, 6, 7, and 9. The structures were refined on all F2 atoms with H
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atoms in riding mode using SHELXL-97.33 Further details are in
Table 8.
CCDC reference numbers 684941–684951.
For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b806451b
14 Z.-Q. Zhang, Y.-M. Yao, Y. Zhang, Q. Shen and W.-T. Wong, Inorg.
Chim. Acta, 2004, 357, 3173.
15 Z.-Q. Zhang, Q. Shen, Y. Zhang, Y.-M. Yao and J. Lin, Inorg. Chem.
Commun., 2004, 7, 305.
16 C. Cui, A. Shafir, J. A. R. Schmidt, A. G. Oliver and J. Arnold, Dalton
Trans., 2005, 1387.
17 (a) L. W. M. Lee, W. E. Piers, M. R. J. Elsegood, W. Clegg and M.
Parvez, Organometallics, 1999, 18, 2947; (b) L. K. Knight, W. E. Piers
and R. McDonald, Chem.–Eur. J., 2000, 6, 4322; (c) P. G. Hayes, W. E.
Piers, L. W. M. Lee, L. K. Knight, M. Parvez, M. R. J. Elsegood and
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18 Q. Shen and Y.-M. Yao, J. Organomet. Chem., 2002, 647, 180.
19 (a) Y.-M. Yao, Y.-J. Luo, R. Jiao, Q. Shen, K.-B. Yu and L.-H. Wong,
Polyhedron, 2003, 22, 441; (b) Y.-M. Yao, M. Xue, Y.-J. Luo, Z. Zhang,
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Chem., 2003, 678, 108; (c) Y.-J. Luo, Y.-M. Yao, Y. Zhang, Q. Shen and
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Acknowledgements
For postdoctoral fellowships we thank BASF (Ludwigshafen)
and Drs H. Go¨rtz and G. Luinstra for the award to X. W., the
Royal Society for a Sino–British Fellowship to Y. C., and Dr
A. V. Protchenko for valuable comments.
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