Reactions of cyclo-(t-Bu4Sb4) with alkali metals; syntheses and crystal structures of [M(L)n(t-Bu4Sb3)] (M = Na, K; n = 1,2) and [K(L)(t-Bu3Sb2)] (L = (Me2NCH2</s

Article abstract of DOI:10.1016/S0022-328X(02)01852-1

Reduction of cyclo-(t-Bu₄Sb₄) (1) with sodium or potassium in boiling tetrahydrofuran leads to the anions [t-Bu₄Sb₃]^- and [t-Bu₃Sb₂]^-. Crystallization with pentamethyl

Full text of DOI:10.1016/S0022-328X(02)01852-1

Journal of Organometallic Chemistry 660 (2002) 167Á172
/
www.elsevier.com/locate/jorganchem
Reactions of cyclo-(t-Bu4Sb4) with alkali metals; syntheses and crystal
structures of [M(L)n(t-Bu4Sb3)] (MꢀNa, K; nꢀ1, 2) and
[K(L)(t-Bu3Sb2)] (Lꢀ(Me2NCH2CH2)2NMe)
/
/
/
H.J. Breunig *, M.E. Ghesner, E. Lork
Institut fuer Anorganische und Physikalische Chem., Universitat Bremen, Fachbereich 2, Postfach 33 04 40, D-28334 Bremen, Germany
¨
Received 10 May 2002; accepted 8 August 2002
Abstract
Reduction of cyclo-(t-Bu4Sb4) (1) with sodium or potassium in boiling tetrahydrofuran leads to the anions [t-Bu4Sb3]ꢁ and [t-
Bu3Sb2]ꢁ. Crystallization with pentamethyldiethylenetriamine (L) gives [M(L)n(t-Bu4Sb3)] (nꢀ
1, MꢀNa (2), K (3); nꢀ2, Mꢀ
(4)) and [K(L)(t-Bu3Sb2)] (5). Crystal structure analyses reveal coordination of the anionic antimony ligands on the alkali metal ions
K interactions were observed in the structure of 4.
/
/
/
/
K
for 2, 3, and 5. In contrast, no SbÃ
/
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: cyclo-(t-Bu4Sb4); Crystal structures; Alkali metals
1. Introduction
Complex 2 is also remarkable as the first sodium
organoantimonide [2,3] characterized by single crystal
Recently, we reported the formation of an ionic
triantimonide, [K(L)2][t-Bu4Sb3] (4) by reaction of
cyclo-(t-Bu4Sb4) (1) with potassium and excess penta-
methyldiethylenetriamine (L) [1]. The crystal structure
determination showed that the potassium cation is
coordinated by two of the tridentate amine ligands L
and there are no close contacts between the cation and
the [t-Bu4Sb3]ꢁ ion, which is not only an interesting
antimony reagent but also a potential ligand in main
group and transition metal complexes.
X-ray diffraction. Structures of complexes with SbÃ
interactions but without SbÃC bonds have been re-
ported for [{(CyP)4Sb}Na×Me2NH×tmeda] [4] and
[Sb7Na3×3tmeda×3thf] [5] (tmedaꢀtetramethylethylene-
diamine). Alkali metal organoantimonides with re-
ported crystal structures are the potassium
compounds, 4 [1] and [K(thf)1/4(cyclo-(Et4C4Sb)] [6],
/
Na
/
/
/
/
/
/
and the lithium derivatives, [Li(12-crown-4)2][SbPh2]×
3thf [7], [Li(dme){Sb(SiMe3)2}] [8] (dmeꢀ1,2-di-
methoxyethane), and [Li(12-crown-4)2][Sb3Ph4]×thf [7]
(thfꢀtetrahydrofuran). The latter complex, as well as
[Rb(18-crown-6)(Ph4P2N)] [9], and [Li(L)(R4P3)] (Rꢀt-
Bu, i-Pr; Lꢀ2thf, tmeda) [10] are related to the
triantimonides 2Á4. Analogues of the diantimonide 5
/1/
/
/
/
In order to develop the chemistry of this anion, we
have studied the reactions of 1 with Na or K, varying
the reaction time and the concentration of the amine
ligand L. We report here on the syntheses and structures
/
/
/
are [Li(thf)(t-Bu3As2)] [11], [K(L)(t-Bu2HP2)] [12], and
[Li(OEt2)(Ph3PN)] [13].
of [M(L)(t-Bu4Sb3)] (MꢀNa (2), K (3)), two complexes
/
of the triantimonide ligand and on [K(L)(t-Bu3Sb2)] (5),
a potassium complex of a novel diantimonide ligand. In
contrast to 4, all the new complexes exhibit coordination
of the antimonides on the alkali metal centres.
2. Results and discussions
The reactions of 1 with alkali metals and penta-
methyldiethylenetriamine (L) depend on the reaction
time and on the concentration of L. When 1 is reacted in
thf under reflux with excess sodium for 4 h or with
* Corresponding author. Tel.: ꢂ
2184042
E-mail address: breunig@chemie.uni-bremen.de (H.J. Breunig).
/
49-421-2182266; fax: ꢂ49-421-
/
0022-328X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 1 8 5 2 - 1

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H.J. Breunig et al. / Journal of Organometallic Chemistry 660 (2002) 167Á172
/
potassium for 1 h, red solutions containing [t-Bu4Sb3]ꢁ
form. Addition of the triamine in molar ratios, [L]Á
[1]ꢀ1.5 and crystallization leads to the formation of
the complexes [M(L)(t-Bu4Sb3)] (MꢀNa (2), K (3)).
With [L]Á[1]ꢀ3 the salt [K(L)2][t-Bu4Sb3] (4) is ob-
tained [1]. Prolongation of the reaction results in the
decomposition of [t-Bu4Sb3]ꢁ with formation of the
diantimonide [t-Bu3Sb2]ꢁ. Crystallization after addition
of the triamine ligand gives [K(L)(t-Bu3Sb2)] (5). An
overview of the observed reactions is given in Scheme 1.
The progress of the reaction of 1 with potassium in
boiling thf was monitored by 1H-NMR spectra of
samples taken from the reaction mixture after 10 min,
1 h, 1.5 h, and 2 h, which were worked up with addition
of the triamine ligand, removal of the thf, and dissolu-
tion in C6D6. The spectra are shown in Fig. 1. There is
one singlet signal for the [t-Bu4Sb3]ꢁ moiety (Fig. 1b),
Single crystals of 2×
by recrystallization from benzene. Compounds 2Á
red or brownÁred solids which are extremely sensitive
towards traces of moisture or air. In sealed tubes 2, 3,
and 5 are stable up to 70 or 80 8C, whereas 4
/
C6H6, 3×
/
0.5C6H6, or 5 were obtained
/
5 are
/
/
/
/
/
/
decomposes at room temperature. The solubility of 2Á
/
5 in petroleum ether is low; in thf, benzene, toluene or
other organic solvents they are readily soluble (Table 1).
For the characterization of 2×
single crystal X-ray structure analyses were performed.
The structure of 2×C6H6 (Fig. 2) contains the [(t-
Bu)2SbÃSbÃ
Sb(t-Bu)2]ꢁ ion, coordinated through the
/
C6H6, 3×
/
0.5C6H6, and 5
/
/
/
terminal antimony atoms as a bidentate chelating ligand
to the sodium ion, which bears the tridentate amine as
an additional ligand. The coordination geometry around
the sodium centre is distorted trigonal bipyramidal with
Sb(1) and N(2) in axial and Sb(3), N(1), and N(3) in
equatorial positions. The central antimony atom of the
as expected for the symmetric configuration [(t-Bu)2SbÃ
SbÃ
Sb(t-Bu)2]ꢁ, which was confirmed by crystal struc-
ture determinations of 2Á4. The diantimonide gives rise
to two singlets in the 2:1 ratio of intensities (Fig. 2d).
Sb(t-
/
[(t-Bu)2SbÃ
/
SbÃ
/
Sb(t-Bu)2]ꢁ ion is disordered over two
/
positions with an occupancy of 0.78 (Sb(2b)) and 0.22
(Sb(2a)), respectively. The Sb3Na heterocycles are
/
slightly folded; the NaÃ
Sb(3) dihedral angle is 176.18 and the NaÃ
Sb(3)/Sb(1)ÃSb(2a)ÃSb(3) dihedral angle is 171.48. The
SbÃNa bond lengths in 2×C6H6 (330.4(2) and 322.5(2)
/
Sb(1)Ã
/
Sb(3)/Sb(1)Ã
/
Sb(2b)Ã
/
This pattern is characteristic for the [(t-Bu)2SbÃ
/
/
Sb(1)Ã
/
Bu)]ꢁ configuration in a symmetric environment, as
found in the crystal structure. The structures of 2, 3, and
5 were also confirmed by observation of the expected
signals in the 13C-NMR spectra.
/
/
/
/
pm) range between the sums of covalent (294.0 pm) and
van der Waals radii [14] (450.0 pm) of Sb and Na, closer
to the former. They compare well with the correspond-
Other intermediates of the reaction of 1 with alkali
metals were not observed spectroscopically. It is prob-
able however that in the first step of the reduction the
radical anion 1ꢁ should form. Migration of the tert-
butyl groups and elimination of antimony can lead to [t-
Bu4Sb3]ꢁ. Precipitation of Sb was in fact observed
during the reaction. The second step, the transformation
of [t-Bu4Sb3]ꢁ to [t-Bu3Sb2]ꢁ requires the elimination
of a t-BuSb unit, which, after tetramerization, should
give the initial product 1 and react with the alkali
metals. It is remarkable that [t-Bu3Sb2]ꢁ is not formed,
ing values found in [{(CyP)4Sb}Na×
/
Me2NH×
/
tmeda] [4]
(322.9(4) pm) and [Sb7Na3×
/
3tmeda×3thf] [5] (319.6(9)
/
pm), which also contain coordinative bonds between
antimonides and sodium cations. The coordination of
the [(t-Bu)2SbÃ
/
SbÃ
/
Sb(t-Bu)2]ꢁ ion to Naꢂ in 2×
leads to small changes of the geometry of the ligand.
This is shown by comparison with the structure of 4,
/
C6H6
where the [(t-Bu)2SbÃ
cluded in the coordination sphere of the cation. The SbÃ
Sb bond lengths (2×C6H6, 274.97; 4, 276.47 pm), the SbÃ
SbÃSb bond angles (2×C6H6, 90.6; 4, 87.68) are similar,
the SbC2 and Sb2C bond angles range between 97 and
1068 in 2×C6H6 and between 101 and 1058 in 4. The
conformation of [(t-Bu)2SbÃSbÃ
Sb(t-Bu)2]ꢁ is de-
scribed using the dihedral angles FꢀSbÃSbÃSbÃlp,
where lp denotes the assumed direction of the lone pair
of electrons at the terminal antimony atoms. In 2×C6H6
the conformation is close to syn Ásyn (F1ꢀ11.44, F2ꢀ
/
SbÃ
/
Sb(t-Bu)2]ꢁ unit is not in-
/
/
/
when solutions of 2Á4 in C6D6 are exposed to ambient
/
/
/
temperature. Instead decomposition with formation of
t-Bu3Sb and 1 is observed.
The isolation of solid samples of 2, 3, 5 is achieved by
addition of pentamethyldiethylenetriamine to the reac-
tion mixture after the appropriate reaction time fol-
lowed by cooling, filtration, and removal of the solvent.
/
/
/
/
/
/
/
/
/
/
/
17.068) with almost perfect orientation of the lone pairs
of electrons to the Na centres. The conformation of the
‘naked’ anion in 4 is similar (F1ꢀ
is surprising that the [(t-Bu)2SbÃSbÃ
in 2×C6H6 is not coordinated through the central
/
7.23, F2ꢀ
/
24.048). It
/
/
Sb(t-Bu)2]ꢁ ligand
/
antimony atom. Apparently the chelating coordination
through the terminal donor atoms is more effective.
Other examples of this type of coordination are the
complexes [Li(L)(R4P3)] (Rꢀ
/
t-Bu, i-Pr; Lꢀ2thf,
/
Scheme 1.
tmeda) [10].

H.J. Breunig et al. / Journal of Organometallic Chemistry 660 (2002) 167Á
/
172
169
Fig. 1. 1H-NMR (C6D6) spectra of samples taken from the reaction mixture of 1 with K. m, cyclo-(t-BuSb)4; %, [t-Bu4Sb3]ꢁ; *, [t-Bu3Sb2]ꢁ
.
The Sb3K heterocycle is slightly folded with an Sb3Ã
/
Sb2K dihedral angle of 160.88. The central antimony
atom is in a trigonal pyramidal environment (sum of
bond angles at Sb(2)ꢀ
angles and conformation of the ligand in 3×
(SbÃSb 275.94 pm, Sb(1)ÃSb(2)ÃSb(3) 87.59(2)8, F1ꢀ
1.84; F2ꢀ22.228) are similar to the corresponding
values for 2×C6H6 or 4. The coordination number about
each potassium is completed to six by three nitrogen
atoms of a (Me2NCH2CH2)2NMe ligand. The SbÃ
bond lengths in 3×0.5C6H6 (Sb(1)ÃK(1)* 415.7(4),
Sb(3)ÃK(1)* 399.7(6), Sb(2)ÃK(1) 383.3(6) pm) vary in
a large range. The shortest bond results from the
monodentate coordination of the central antimony
atom; the longer bonds represent the asymmetric
bidentate coordination through the terminal atoms.
/
338.598). The bond lengths, bond
/
0.5C6H6
/
/
/
/
/
/
/K
/
/
Fig. 2. ORTEP-like representation of 2×
probability showing the atomic numbering scheme. Bond lenghts (pm)
and angles (8): Sb(1)ÃNa 330.4(2), Sb(3)ÃNa 322.5(2), Sb(1)ÃSb(2a)
272.0(8), Sb(1)ÃSb(2b) 277.6(2), Sb(2a)ÃSb(3) 274.1(8), Sb(2b)ÃSb(3)
276.2(2), SbÃC 221.5(6)Á224.1(6), NaÃN 245.0(5)Á249.5(5), NaÃ
Sb(1)ÃSb(2a) 96.44(18), NaÃSb(1)ÃSb(2b) 97.18(6), Sb(2a)ÃSb(1)Ã
96.9(2)Á107.7(2), Sb(2b)ÃSb(1)Ã 100.5(2)Á103.84(17), Sb(2a)Ã
Sb(3)ÃC 97.3(2)Á106.6(2), Sb(2b)ÃSb(3)ÃC 99.3(2)Á104.2(2), C(1)Ã
Sb(1)ÃC(5) 102.7(3), C(9)ÃSb(3)ÃC(13) 104.2(2), Sb(1)ÃSb(2a)Ã
Sb(3) 91.4(2), Sb(2b)ÃSb(3) 89.80(7), NaÃSb(1)Ã
Sb(1)Ã
120.92(17)Á126.8(2), NaÃSb(3)ÃC 117.0(2)Á128.45(18), Sb(1)ÃNaÃ
Sb(3) 73.54(4), NÃNaÃN 74.97(17)Á75.79(17), C(1)ÃSb(1)ÃSb(2b)Ã
Sb(3) 132.7, C(5)ÃSb(1)ÃSb(2b)ÃSb(3) 121.26, C(9)ÃSb(3)ÃSb(2b)Ã
Sb(1) 134.9, C(13)ÃSb(3)ÃSb(2b)ÃSb(1) 117.84.
/
C6H6 (H atoms omitted) at 30%
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/C
/
/
/
C
/
/
/
/
/
/
/
/
All SbÃ
(368.0 pm) and van der Waals radii (500.0 pm) for Sb
and K. Shorter KÃSb bonds (348.6Á361.8 pm) were
found in [K(thf)1/4(cyclo-Et4C4Sb)] [6].
/
K bonds lie between the sum of the covalent
/
/
/
/
/
/
/
/
/
C
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
The solid-state structure of 5 consists of a centrosym-
metric dimer in which two [(t-Bu)2SbSb(t-Bu)]ꢁ anions
are coordinated through the antimonido atoms as
bridging ligands to two potassium ions (Fig. 4). The
/
/
/
In crystals of 3×
/
0.5C6H6 the coordination of the
triantimonide as a bridging tridentate ligand is realized.
Not only the terminal but also the central antimony
atoms are coordinated to neighbouring potassium
cations and helical chains, [K(L){(t-Bu2Sb)2Sb}]n result.
The C6H6 molecules lie between the chains. A section of
this unique structure is depicted in Fig. 3.
central K2Sb2 unit has a rhombic shape, (K(1)Ã
K(1)* 101.37(3), Sb(2)ÃK(1)ÃSb(2)* 78.63(3)8), with
almost equal Sbà bond lenghts, (K(1)ÃSb(2)
356.55(9), K(1)ÃSb(2)* 359.26(11) pm). The potassium
/
Sb(2)Ã
/
/
/
/
K
/
/
ions are five-coordinate with two antimony ligands and
one triamine. An unexpected aspect of the structure of 5

170
H.J. Breunig et al. / Journal of Organometallic Chemistry 660 (2002) 167Á172
/
Table 1
Crystal data, data collection, and structure refinement parameters for 2×C6H6, 3×0.5C6H6, and 5
2×C6H6
3×0.5C6H6
5
Empirical formula
Formula weight
C
25H59N3NaSb3×C6H6
C25H59KN3Sb3×0.5C6H6
845.16
173(2)
C21H50KN3Sb2
627.24
173(2)
868.10
173(2)
0.71073
Monoclinic
C2/c
Temperature (K)
˚
MoÁ/Ka (A)
0.71073
0.71073
Crystal system
Space group
Monoclinic
P21/c
Orange
Monoclinic
P21/c
Orange
Color
Unit cell dimensions
Red
a (pm)
b (pm)
1248.8(10)
1876.5(3)
3486.4(3)
90
1234.4(4)
2065.2(5)
1602(2)
90
1047.7(2)
1666.6(3)
1790.5(4)
90
c (pm)
a (8)
b (8)
91.660(10)
90
111.47(5)
90
106.24(3)
90
g (8)
V (nm3)
8.1665(16)
8
2.002
3.80(1)
4
2.245
3.0016(10)
4
1.948
Z
Absorptions coefficient
(mmꢁ1
)
Absorptions correction
Diffractometer
F(000)
DIFABS
DIFABS
DIFABS
Siemens P4
3488
Siemens P4
1692
Stoe IPDS
1272
Crystal size (mm3)
Total majority to u
Index ranges
0.5ꢃ0.4ꢃ0.2
99.6%
0.8ꢃ0.8ꢃ0.2
98.3%
0.4ꢃ0.3ꢃ0.3
97.8%
ꢁ165h 51, ꢁ245k 51, ꢁ455l 545
ꢁ145h 51, ꢁ245k 524,
ꢁ185l 519
15 457
ꢁ125h 512, ꢁ205k 520,
ꢁ215l 521
40 585
Reflections collected
Independent reflections
Refinement method
11 472
9372 [Rintꢀ0.0357]
Full-matrix least-squares on F2 [18]
9372/0/372
6713 [Rintꢀ0.1117]
5811 [Rintꢀ0.0782]
Data/restraints/parameters
a
6713/0/336
5811/0/260
Final R indices [I ꢀ2s(I)] R1ꢀ0.0491, wR2ꢀ0.1251
R1ꢀ0.0623, wR2ꢀ0.1272
R1ꢀ0.1228, wR2ꢀ0.1514
0.984
R1ꢀ0.0278, wR2ꢀ0.0455
R1ꢀ0.0564, wR2ꢀ0.0503
0.877
a
R
indices (all data)
R1ꢀ0.0713, wR2ꢀ0.1502
1.028
Goodness-of-fit on F2
Largest difference peak and 1.434 and ꢁ2.097
1.191 and ꢁ1.279
0.653 and ꢁ0.359
ꢁ3
˚
hole (e A
)
Treatment of hydrogen
atoms
Refined with a riding model and common
isotopic temperature factor
Definition of the R values: R1ꢀa jjFojꢁjFcjj/a jFoj; wR2 ꢀ[w a (Fo2 ꢁFc2)2=a w(Fo2)2]1=2 with wꢁ1 ꢀs2(Fo2)ꢂ(aP)2 ꢂbP:
/
a
is the trigonal pyramidal coordination of the antimo-
nido atoms Sb(2) and Sb(2)* (sum of Sb2K and SbK2
angles at Sb(2), respectively Sb(2)* 358.898), which is
very unusual for four-coordinate antimony atoms and
contrasts with the distorted tetrahedral geometry of the
arsenido atoms in [Li(thf)(t-Bu3As2)]2 [11]. This differ-
ence may result from steric effects. The most straight-
forward interpretation for the coordination geometry in
5 is to consider a sp2 hybridization for the Sb(2),
respectively Sb(2)* atoms. Two of the hybrid orbitals
contain the lone pairs of electrons for the coordinative
A common feature of the crystal structures of the
antimonides 2Á
5 and [Ph4Sb3]ꢁ [7] are the relative short
SbÃSb bond lenghts (275.5(1)Á276.7(1) pm). They are
shorter than the SbÃSb single bond lengths in 1
(281.7(2)Á282.1(2) pm) [15] but significantly longer
than a SbÃSb double bond (264.2(1) pm in {2,4,6-
[(Me3Si)2CH]3C6H2}2Sb2 [16]). The shortening may
rather be a consequence of the participation of s orbitals
in the hybridization of the bonding orbitals of the
/
/
/
/
/
/
antimonido atoms than result from (pÁd)p bonding [7].
/
Relative short single bonds were also reported for
complexes containing the [(R2P)2P]ꢁ [10], [R(H)PPR]ꢁ
[12], or [R2PNR]ꢁ [13] ligands.
bond to the potassium ion, one is used for the SbÃ
/Sb
bond. The remaining unhybridized p orbital of Sb(2) is
involved in the bond to the C(9) carbon atom of the t-
Bu group (C(9)Ã
/
Sb(2)Ã
/
Sb(1) 94.88(9), C(9)Ã
/
Sb(2)Ã
/
K(1)* 93.740(9), C(9)Ã
/
Sb(2)Ã
/
K(1) 90.02(9)8). An alter-
3. Experimental
native interpretation would be to assume no hybridiza-
tion at Sb(2) and to consider a p orbital orthogonal to
NMR spectra were run on Bruker DPX 200 spectro-
meter. Chemical shifts are reported in d units (ppm)
the SbÃ
/
Sb bond for the interaction with the K atoms.

H.J. Breunig et al. / Journal of Organometallic Chemistry 660 (2002) 167Á
/
172
171
3.1. Preparation of [Na(L)(t-Bu4Sb3)] (Lꢀ
/
(Me2NCH2CH2)2NMe) (2)
Compound 1 (1.0 g, 1.4 mmol) was reacted for 4 h
with 0.4 g (17.4 mmol) small pieces of Na in 40 ml thf.
Afterwards 0.58 ml (2.77 mmol) (Me2NCH2CH2)2NMe
were added and stirred for 1 h until room temperature
(r.t.). After filtration and removal of the solvent under
reduced pressure 0.08 g of a red solid (82Á
/
88 8C dec.)
was obtained. After recrystallization from C6H6 at 7 8C
1
0.058 g (58%) of 2×
NMR (200 MHz, C6D6): d 1.77 (s, 36H; C(CH3)3), 2.07
2.21 (m,
8H; CH2). 13C-NMR (50MHz, C6D6): d 30.42 (s, 4C;
C(CH3)3), 34.88 (s, 12C; C(CH3)3), 43.14 (s, 1C;
NCH3), 46.02 (s, 4C; N(CH3)2), 56.94 (s, 2C; CH2),
58.35 (s, 2C; CH2).
/
C6H6 formed as red crystals. H-
Fig. 3. ORTEP-like representation of a section of the structure of 3×
/
0.5C6H6 (H atoms omitted) at 30% probability showing the atomic
(s, 12H; N(CH3)2), 2.10 (s, 3H; NCH3), 2.15Á
/
numbering scheme. Bond lenghts (pm) and angles (8): K(1)Ã
383.3(6), K(1)*ÃSb(1) 415.7(4), K(1)*ÃSb(3) 399.7(6), Sb(2)Ã
276.65(11), Sb(1)ÃSb(2) 276.3(3), SbÃC 221.3(11)Á
287.9(10)Á297.4(9), K(1)ÃSb(2)ÃSb(3) 130.24(5), K(1)Ã
120.97(8), Sb(1)ÃSb(2)ÃSb(3) 87.60(5), Sb(2)ÃSb(1)Ã
102.2(3), Sb(3)Ã 99.7(3)Á103.0(3), C(1)Ã
Sb(2)Ã
105.0(4), C(9)ÃSb(3)ÃC(13) 104.7(4), Sb(3)*ÃK(1)ÃSb(2) 130.24(10),
Sb(1)*ÃK(1)ÃSb(2) 121.03(8), Sb(2)ÃSb(1)ÃK(1)* 104.09(8), Sb(2)Ã
Sb(3)ÃK(1)* 108.12(6), CÃSb(1)ÃK(1)* 104.0(3)Á135.6(3), CÃSb(3)Ã
K(1)* 113.8(3)Á124.3(3), NÃK(1)ÃN 60.3(3)Á61.7(3), C(1)ÃSb(1)Ã
Sb(2)ÃSb(3) 125.03, C(5)ÃSb(1)ÃSb(2)ÃSb(3) 126.87, C(9)ÃSb(3)Ã
Sb(2)ÃSb(1) 137.16, C(13)ÃSb(3)ÃSb(2)ÃSb(1) 114.94.
/Sb(2)
/
/
/Sb(3)
/
/
/
225.1(11), K(1)Ã
Sb(2)ÃSb(1)
101.6(3)Á
Sb(1)ÃC(5)
/
N
/
/
/
/
/
/
/
/
/
C
/
/
/
C
/
/
/
/
/
/
/
3.2. Preparation of [K(L)(t-Bu4Sb3)] (Lꢀ
/
/
/
/
/
/
(Me2NCH2CH2)2NMe) (3)
/
/
/
/
/
/
/
/
/
/
/
/
To a solution of 1 (1.0 g, 1.4 mmol) in 40 ml thf 0.3 g
(7.7 mmol) small pieces of K were added and stirred
with reflux for 1 h. At this temperature 0.43 ml (2.1
/
/
/
/
/
/
/
/
/
/
mmol) (Me2NCH2CH2)2NMe were added and the redÁ
/
brown solution further stirred until r.t., than filtered
through a frit covered with kieselguhr. Removal of the
solvent under reduced pressure gave 0.76 g (68%) of 3 as
a redÁ
/
brown solid (90Á
/
110 8C dec.). Crystals of 3×
/
0.5C6H6 suitable for X-ray analysis were grown by
1
cooling solutions of 3 in C6H6 at 7 8C for 1 day. H-
NMR (200 MHz, C6D6): d 1.81 (s, 36H; C(CH3)3), 2.10
(s, 12H; N(CH3)2), 2.14 (s, 3H; NCH3), 2.26Á2.34 (m,
/
8H; CH2). 13C-NMR (50 MHz, C6D6): d 24.80 (s, 4C;
C(CH3)3), 34.89 (s, 12C; C(CH3)3), 43.61 (s, 1C;
NCH3), 45.73 (s, 4C; N(CH3)2), 56.40 (s, 2C; CH2),
57.83 (s, 2C; CH2).
3.3. Preparation of [K(L)(t-Bu3Sb2)] (Lꢀ
/
(Me2NCH2CH2)2NMe) (5)
Fig. 4. ORTEP-like representation of 5 at 30% probability showing the
atomic numbering scheme. Bond lenghts (pm) and angles (8): K(1)Ã
Sb(2) 356.55(9), K(1)ÃSb(2)* 359.26(11), Sb(1)ÃSb(2) 276.13(10), SbÃ
222.6(4)Á225.0(3), KÃ 282.9(3)Á288.9(3), K(1)ÃSb(2)ÃK(1)*
101.37(3), Sb(2)ÃK(1)ÃSb(2)* 78.63(3), Sb(1)ÃSb(2)ÃK(1) 113.85(2),
Sb(1)ÃSb(2)ÃK(1)* 143.669(18), Sb(1)ÃSb(2)ÃC(9) 94.88(9), Sb(2)Ã
Sb(1)Ã 100.01(1)Á103.53(9), C(1)ÃSb(1)ÃC(5) 102.77(14), C(9)Ã
Sb(2)ÃK(1)* 93.70(9), C(9)Ã
/
The reaction of 1.0 g (1.4 mmol) 1 with 0.3 g (7.7
mmol) K in 40 ml of thf for 2 h was performed in an
analogous way to the synthesis of 3. After addition of
0.88 ml (4.2 mmol) (Me2NCH2CH2)2NMe and further
stirrring for 1 h at r.t. the reaction mixture was filtered
and the solution concentrated to 15 ml. Cooling at 7 8C
/
/
/
C
/
/
N
/
/
/
/
/
/
/
/
/
/
/
/
/C
/
/
/
/
/
/
Sb(2)Ã
/
K(1) 90.02(9).
for 1 day gives 0.46 g (53%) of 5 as orange crystals (80Á
/
1
90 8C dec.). MS (CIneg, NH3): 415 (100) [t-Bu3Sb2]ꢁ.
1H-NMR (200 MHz, C6H6): d 1.55 (s, 18H; C(CH3)3),
1.57 (s, 9H; C(CH3)3), 2.11 (s, 12H; N(CH3)2), 2.17 (s,
referenced to C6D5H (7.15 ppm, H) and C6D6 (128.0
ppm, 13C). Mass spectra were recorded on Finnigan
MAT CH7 (A) spectrometer. The pattern of antimony-
containing ions was compared with theoretical values.
The reactions and manipulations were performed in an
inert atmosphere of Ar using dried solvents distilled
under Ar. cyclo-(t-Bu4Sb4) (1) was prepared according
to reported procedures [17].
3H, NCH3), 2.34Á
2.46 (m, 8H, CH2). 13C-NMR (50
/
MHz, C6D6): d 30.52 (s, 4C; C(CH3)3), 31.03 (s, 2C,
C(CH3)3), 34.99 (s, 12C; C(CH3)3), 35.61 (s, 6C,
C(CH3)3), 43.26 (s, 1C; NCH3), 46.12 (s, 4C;
N(CH3)2), 57.05 (s, 2C; CH2), 58.45 (s, 2C; CH2).

172
H.J. Breunig et al. / Journal of Organometallic Chemistry 660 (2002) 167Á172
/
Wheatley, D.S. Wright, J. Chem. Soc. Chem. Commun. (1998)
2485.
4. Supplementary material
[5] A. Bashall, M.A. Beswick, N. Choi, A.D. Hopkins, S.J. Kidd,
Y.G. Lawson, M.E.G. Mosquera, M. McPartlin, P.R. Raithby,
A.A.E.H. Wheatley, J.A. Wood, D.S. Wright, J. Chem. Soc.
Dalton Trans. (2000) 479.
Crystallographic data have been deposited with the
Cambridge Crystallographic Data Centre, CCDC nos.
184805Á
/
184807 for compounds 5, 3×
/
0.5C6H6 and 2×
/
[6] M. Westerhausen, Ch. Guckel, M. Warchhold, H. Noth, Orga-
¨
¨
C6H6. Copies of this information may be obtained free
of charge from The Director, CCDC, 12 Union Road,
nometallics 19 (2000) 2393.
[7] R.A. Bartlett, H.V. Rasika Dias, H. Hope, B.D. Murray, M.M.
Olmstead, P.P. Power, J. Am. Chem. Soc. 108 (1986) 6921.
[8] G. Becker, A. Munch, C. Witthauer, Z. Anorg. Allg. Chem. 492
¨
Cambridge CB2 1EZ, UK (Fax: ꢂ44-1223-336033; e-
/
mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
(1982) 15.
[9] J. Ellermann, W. Bauer, M. Schutz, F.W. Heinemann, M. Moll,
¨
Monatsh. Chem. 129 (1998) 547.
[10] I. Kovacs, H. Krautscheid, E. Matern, E. Sattler, G. Fritz, W.
Acknowledgements
Honle, H. Borrmann, H.G. von Schering, Z. Anorg. Allg. Chem.
¨
622 (1996) 1564.
[11] A.M. Arif, R.A. Jones, K.B. Kidd, J. Chem. Soc. Chem.
Commun. (1986) 1440.
The support of this work by the Deutsche For-
schungsgemeinschaft is gratefully acknowledged.
[12] M.A. Beswick, A.D. Hopkins, L.C. Kerr, E.G. Mosquera, J.S.
Palmer, P.R. Raithby, A. Rothenberger, D. Stalke, A. Steiner,
A.E.H. Wheatly, D.S. Wright, J. Chem. Soc. Chem. Commun.
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¨
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