From gallium hydride halides to molecular gallium sulfides

Article abstract of DOI:10.1002/zaac.200400203

Complexes of the type (L)GaHCl₂, with L =tertiary phosphines or pyridines, have been prepared from (HGaCl₂)₂ and the ligands in diethyl ether. The products are stable crystalline solids soluble in common organic solvents. The presence of the Ga-H function has been confirmed by IR and NMR spectroscopy and by single crystal X-ray diffraction, carried out for the 1:1 adducts with L = PCy₃ and PPh₃ (two polymorphs) and for the 2:1 adduct with L = (CH₂PPh₂) ₂ (dppe, two different solvates). The reaction of PVi₃ with (HGaCl₂)₂ gives an insoluble polymer owing to the hydrogallation of vinyl groups by the gallium hydride units (no Ga-H functions are left in the product).Treatment of the complexes (R₃P)GaHCl ₂ with H₂S, metal sulfides or (Me₃Si) ₂S gave only insoluble, ill-defined products. - The 1:1 adduct (L′)GaHCl₂, with L′ = 4-dimethylamino-pyridine, reacts with (Me₃Si)₂S in acetonitrile at ambient temperature to give an only partially sulfur-substituted product of the net formula (L′)GaSH_0.66Cl_0.34. With excess ligand L′, under reflux conditions and after longer reaction times, a pyridine complex of the tetranuclear, molecular gallium sulfide Ga₄S₆ is obtained in low yield. The core of the compound with the composition (L′)₄Ga₄S₆ has an adamantane structure resembling a cluster unit of the binary gallium sulfide polymorphs Ga ₂S₃. The edge-sharing Ga₃S₃ six-membered rings are all in a chair conformation as found previously for the pyridine complexes of the ternary compounds [(L)GaEX]₃(with E = S, Se and X = Cl, Br) and for the bicyclic dication [(L)₆Ga ₄S₅]²⁺. Thermolysis and degradation under mass spectrometry conditions lead to sublimation of L′ and leave amorphous Ga₂S₃. The reaction of (L′)GaCl₃ with (Me₃Si)₂S did not afford any molecular gallium sulfide complex. A comparison of the structural data for (L′)GaCl₃ and (L′)₄Ga₄S₆ suggests a much poorer acceptor character of the gallium sulfide cluster.

Full text of DOI:10.1002/zaac.200400203

From Gallium Hydride Halides to Molecular Gallium Sulfides
Hubert Schmidbaur* and Stefan D. Nogai
Garching, Department Chemie der Technischen Universität München
Received June 2nd, 2004.
Dedicated to Professor Martin Jansen on the Occasion of his 60th Birthday
Abstract. Complexes of the type (L)GaHCl2, with L ϭtertiary
phosphines or pyridines, have been prepared from (HGaCl2)2 and
the ligands in diethyl ether. The products are stable crystalline so-
lids soluble in common organic solvents. The presence of the Ga-
H function has been confirmed by IR and NMR spectroscopy and
by single crystal X-ray diffraction, carried out for the 1:1 adducts
with L ϭ PCy3 and PPh3 (two polymorphs) and for the 2:1 adduct
with L ϭ (CH2PPh2)2 (dppe, two different solvates). The reaction
of PVi3 with (HGaCl2)2 gives an insoluble polymer owing to the
hydrogallation of vinyl groups by the gallium hydride units (no Ga-
H functions are left in the product).Treatment of the complexes
(R3P)GaHCl2 with H2S, metal sulfides or (Me3Si)2S gave only insol-
uble, ill-defined products. Ϫ The 1:1 adduct (LЈ)GaHCl2, with LЈ ϭ
4-dimethylamino-pyridine, reacts with (Me3Si)2S in acetonitrile at
ambient temperature to give an only partially sulfur-substituted
product of the net formula (LЈ)GaSH0.66Cl0.34. With excess ligand
LЈ, under reflux conditions and after longer reaction times, a pyri-
dine complex of the tetranuclear, molecular gallium sulfide Ga4S6
is obtained in low yield. The core of the compound with the com-
position (LЈ)4Ga4S6 has an adamantane structure resembling a clu-
ster unit of the binary gallium sulfide polymorphs Ga2S3. The edge-
sharing Ga3S3 six-membered rings are all in a chair conformation
as found previously for the pyridine complexes of the ternary com-
pounds [(L)GaEX]3(with E ϭ S, Se and X ϭ Cl, Br) and for the
bicyclic dication [(L)6Ga4S5]2ϩ. Thermolysis and degradation un-
der mass spectrometry conditions lead to sublimation of LЈ and
leave amorphous Ga2S3. The reaction of (LЈ)GaCl3 with (Me3Si)2S
did not afford any molecular gallium sulfide complex. A compari-
son of the structural data for (LЈ)GaCl3 and (LЈ)4Ga4S6 suggests a
much poorer acceptor character of the gallium sulfide cluster.
Keywords: Gallium; Gallium hydride halides; Gallium sulfides
Von Galliumhydridhalogeniden zu molekularen Galliumsulfiden
Inhaltsübersicht. Komplexe des Typs (L)GaHCl2, mit L ϭ tertiäre
Phosphine oder Pyridine, wurden aus (HGaCl2)2 und den Liganden
in Diethylether dargestellt. Als Produkte wurden kristalline, stabile
und in den üblichen organischen Lösungsmitteln lösliche Feststoffe
erhalten. Die Anwesenheit der Ga-H-Funktion wurde durch IR-
und NMR-Spektroskopie, sowie durch Einkristallröntgenstruktur-
analysen der Addukte mit L ϭ PCy3 und PPh3 (zwei polymorphe
Formen) und des 2:1-Addukts mit L ϭ (CH2PPh2)2 (dppe, zwei
verschiedene Solvate), bestätigt. Die Reaktion von PVi3 mit
(HGaCl2)2 führte aufgrund der Hydrogallierung der Vinylgruppen
zu einem polymeren Produkt (im Produkt sind keine Ga-H-Funk-
tionen mehr enthalten). Die Behandlung der Komplexe
(R3P)GaHCl2 mit H2S, Metallsulfiden oder (Me3Si)2S ergab ledig-
lich schwerlösliche, undefinierte Produkte. Ϫ Das 1:1-Addukt
(LЈ)GaSH0.66Cl0.34. Die längere Behandlung dieses Produkts mit
überschüssigem Liganden LЈ unter Rückfluß liefert in niedrigen
Ausbeuten den Pyridinkomplex des vierkernigen molekularen Gal-
liumsulfids Ga4S6. Das Grundgerüst der Verbindung (LЈ)4Ga4S6
mit adamantanartiger Struktur ähnelt einem Ausschnitt aus dem
Gitter des binären Galliumsulfids Ga2S3. Die kondensierten Ga3S3-
Sechsringe liegen in der Sesselkonformation vor, wie sie früher be-
reits bei den Pyridinkomplexen [(L)GaEX]3 der ternären Verbin-
dungen (mit E ϭ S, Se und X ϭ Cl, Br) und im bicyclischen Dika-
tion [(L)6Ga4S5]2ϩ gefunden wurden. Thermolyse und Zersetzung
unter massenspektroskopischen Bedingungen führen zur Sublima-
tion von LЈ unter Bildung von amorphem Ga2S3. Die Reaktion von
(LЈ)GaCl3 mit (Me3Si)2S ergab keine molekularen Galliumsulfid-
Komplexe. Ein Vergleich der Strukturparameter von (LЈ)GaCl3
und (LЈ)4Ga4S6 weist auf ein deutlich vermindertes Akzeptorver-
mögen des Galliumsulfid-Clusters hin.
(LЈ)GaHCl2, mit LЈ
ϭ 4-Dimethylaminopyridin, reagiert bei
Raumtemperatur in Acetonitril mit (Me3Si)2S zu einem teilweise
Schwefel-substituierten Produkt der Nettozusammensetzung
Introduction
particles and larger frameworks [1]. While for several main
group and transition metal sulfides great progress has been
made in providing suitable starting materials and method-
ologies [2], this it not true for group XIII sulfides in general
(B, Al, Ga, In, Tl), and for gallium sulfides in particular.
Binary gallium sulfides are known to have complicated
structures („defect structures“) with poor ordering in many
of its polymorphs [3], and it was only recently that a few
examples of smaller clusters have been introduced which
represent building blocks of larger structures [4].
There is currently an increasing interest in the construction
of well-defined metal sulfides in the form of clusters, nano-
* Prof. Dr. H. Schmidbaur
Department Chemie
der Technischen Universität München
Lichtenbergstr. 4
D-85747 Garching
E-mail: h.schmidbaur@lrz.tum.de
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From Gallium Hydride Halides to Molecular Gallium Sulfides
In previous studies we have investigated the preparation,
structure and derivatization of molecular, trinuclear units
of the stoichiometry [GaSX(L)]3. These complexes feature
six-membered rings (GaS)3 in chair or boat conformations
with halogen substituents X and pyridine ligands L in axial
and equatorial positions at each metal center in various iso-
meric patterns [5, 6]. The six-membered rings can be viewed
as structural units of the gallium sulfide polymorphs with
functional groups that can be used for the design and con-
struction of larger arrays.
In the present account we show that these structural ele-
ments can be further extended to cage-type units including
a molecular gallium sulfide Ga4S6 protected by pyridine li-
gands. It turned out that the pyridine ligands are essential
for the formation and stability of the adducts. All com-
plementary experiments, e.g. with tertiary phosphines as
ligands L, were not successful. A series of complexes of gal-
lium chlorides and hydride chlorides with tertiary phos-
phines were isolated and structurally characterized, as de-
scribed below, but could not be converted into the corre-
sponding gallium sulfide complexes.
shows decomposition only on heating to elevated tempera-
tures (Equation (2)). These observations indicate that the
product is a polymer generated in the hydrogallation of vinyl
substituents by the Ga-H functions.
n (HGaCl2)2 ϩ 2n PVi3 Ǟ [Vi2P(C2H4)GaCl2]2n
(2)
Upon complexation with HGaCl2, the 31P resonances of
most phosphine ligands are shifted upfield relative to the
free ligands, which at first sight may be unexpected, but for
this phenomenon there are parallels in the literature [9, 11].
It appears that metal(III) halides MX3 with larger halogen
atoms X quite generally induce drastic shielding of the at-
tached phosphorus nuclei, while with most other acceptors
the usual deshielding is observed. All other NMR data show
no anomalies.
Treatment of the complexes [(R3P)GaHCl2] with sulfides
[H2S, SHϪ, (Me3Si)2S etc.] did not yield the expected gal-
lium hydride sulfides. Insoluble products were formed the
elemental analysis of which showed no clear stoichiometry.
This route therefore was abandoned and efforts again
turned to the pyridine complexes.
(p-Dimethylamino-pyridine)dichlorogallane [12] was
chosen as the substrate, because its particularly powerful
pyridine donor ligand (LЈ) suggested higher stablity of more
delicate products [6]. This compound was treated with equi-
molar quantities of bis(trimethylsilyl)sulfide in acetonitrile
in the temperature range from Ϫ25 to 25 °C. After 36 h a
colorless precipitate had formed in almost 80 % yield which
was shown to be a mixed sulfide/hydride/chloride of the net
formula [(LЈ)GaSH0.64Cl0.36], indicating incomplete conver-
sion (Equation (3)). It should be noted that the singular
(non-pyridine) hydrogen contained in this product is at-
tached to the gallium and not to the sulfur atom as easily
demonstrated by IR spectroscopy. The compound therefore
should be classified as a gallium(III) sulfide hydride chlo-
ride and not a gallium(I) (hydrogensulfide) chloride.
Preparative Results
Recent investigations have shown that dichlorogallane
[HGaCl2]2 Ϫ owing to its mixed functionality Ϫ is a par-
ticularly useful starting material for the preparation of
mixed gallium chalcogenide halides (GaEX) and their com-
plexes [GaEX(L)]n with E ϭ S, Se and X ϭ Cl, Br. With
ligands L ϭ pyridines, a large family of complexes has been
obtained [5, 6]. Continuing this study, a series of analogous
complexes with other ligands was now prepared.
[HGaCl2]2 is readily available from the reaction of anhyd-
rous [GaCl3]2 with Et3SiH without any solvent. Quantitat-
ive yields of a colorless crystalline, low-melting solid are
obtained after removal of the volatile Et3SiCl by-product
[7, 8]. This dimeric product can be reacted with tertiary
phosphines in the molar ratio 1:2 in diethyl ether to give
high yields of the mononuclear complexes [HGaCl2(L)]
(Equation (1)). With [CH2PPh2]2 (dppe) the 1:2 complex is
formed, which was crystallized as a 1:1 benzene and as a
2:1 diethyl ether solvate. Of (Ph3P)GaHCl2, solvent-free
crystals of a triclinic and a monoclinic polymorph were ob-
tained.
(Me3Si)2S
n (LЈ)GaHCl2
> [(LЈ)GaSH0.064Cl0.36]n (3)
ϪMe3SiCl, Me3SiH
When this product was subsequently reacted with excess
LЈ for another 8 h in boiling acetonitrile, a soluble com-
pound could be extracted from the residue of the reaction
mixture (after removal of the acetonitrile solvent) with di-
chloromethane. This product was finally isolated in the
form of colorless single crystals (from CH2Cl2 at Ϫ30 °C)
in 21 % yield. Another, less pure crop was recovered from
the mother liquor (Equation (4)). The compound was
identified as a tetranuclear complex of the formula
[(LЈ)4Ga4S6] by microanalysis and FAB mass spectrometry.
The parent peak at m/e 959.9 for Mϩ is followed by frag-
ments with the number of ligands LЈ gradually reduced.
The solutions in dichloromethane show one set of proton
resonances for the ligand LЈ suggesting that all four ligands
are equivalent. Thermal decomposition of the solid affords
(HGaCl2)2 ϩ 2 PR3 Ǟ 2 (R3P)GaHCl2
PR3 ϭ PCy3, PEt3
PPh3, 1/2 dppe
(1)
The adducts are colorless air-sensitive liquids (L ϭEt3P) [8]
or solids (L ϭ Cy3P [9], Ph3P, dppe) which are soluble in com-
mon inert organic solvents. The compounds have been identi-
fied by microanalytical and spectral data. The conservation
of the Ga-H function in all products Ϫ except (Vi3P)GaHCl2
Ϫ is readily demonstrated by a strong IR absorption in the
range 1920 Ϫ 1950 cmϪ1 and a broad proton resonance near
5.6 ppm. The complex with trivinylphosphine [10] is also un-
usual in that it is insoluble even in polar organic solvents and
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H. Schmidbaur, S. D. Nogai
a sublimate of the ligand and leaves amorphous gallium
sulfide Ga2S3.
LЈ
6 [(LЈ)GaSH0.64Cl0.36 n
]
>
n [(LЈ)4Ga4S6]
Ϫ2n Љ(LЈ)GaH1.92Cl1.08Љ
(4)
With the existence of (LЈ)4Ga4S6 confirmed, alternative
and potentially improved synthetic pathways were tested.
However, the most obvious precursor molecule, (LЈ)GaCl3,
did not afford any soluble, molecular gallium sulfide com-
plex upon treatment with (Me3Si)2S in boiling acetonitrile
or dichloromethane. Only insoluble products were obtained
which were not characterized any further.
Structural Results
The Gallium Sulfide Complex
Crystals of [(LЈ)4Ga4S6] are monoclinic, space group C2/c,
with Z ϭ 4 formula units in the unit cell. The tetranuclear
molecules have crystallographically imposed point group C2
symmetry with the twofold axis passing through atoms S2
and S4 (Figure 1). The N4Ga4S6 core has an adamantane
structure with a quasi-tetrahedral arrangement of the sulfur
and nitrogen atoms at each gallium atom and almost sym-
metrical Ga-S-Ga bridges. The average of the six indepen-
Figure 1. Molecular structure of (4-Me2N-C5H4N)4Ga4S6 with
atomic numbering (ORTEP, 50 % probability ellipsoids, hydrogen
atoms Ϫ except Ga-H Ϫ and disordered dichloromethane solvent
˚
molecules omitted). Selected bond lengths/A and angles/°:
Ga1-N11 2.007(5), Ga2-N22 2.015(5), Ga1-S1 2.261(2), Ga1-S2 2.246(2),
Ga1-S3 2.258(2); Ga2-S1 2.256(2), Ga2ϪS3 2.239(2), Ga2-S4 2.255(2); S1-
Ga1-S2 115.09(5), S1-Ga1-S3 113.03(7), S2-Ga1-S3 116.39(6), S1-Ga2-S3Ј
114.48(7), S1-Ga2-S4 116.00(5), S3Ј-Ga2-S4 114.56(6), Ga1-S1-Ga2
97.19(8), Ga1-S2-Ga1Ј 96.27(9), Ga1-S3-Ga2Ј 97.74(6), Ga2-S4-Ga2Ј
95.81(9), N11-Ga1-S1 105.74(16), N11-Ga1-S2 104.14(15), N11-Ga1-S3
100.15(14), N21-Ga2-S1 105.65(18), N21-Ga2-S3Ј 102.18(16), N21-Ga2-S4
101.46(17).
˚
dent Ga-S distances is 2.544 A, that of the two Ga-N dis-
˚
tances is 2.016 A. Referring to data of other molecular gal-
lium sulfide compounds, these distances and the Ga-S-Ga
angles between 95.81(9) and 97.76(6)° show that the ada-
mantane unit can be taken as a construction based on six-
membered ring units [Ga3S3] in their chair conformation. It
is interesting to note that all S-Ga-S angles are much larger
than the tetrahedral standard, while the N-Ga-S angles are
correspondingly much smaller. The GaS3 pyramids are thus
rather flat suggesting that the apical donor-acceptor bond-
ing of the pyridine ligand is not very strong, as also indi-
cated by the mass spectra. The ligands LЈ show no struc-
tural anomalies. The crystals contain several partially dis-
ordered molecules of dichloromethane. The plot of the ar-
rangement of the molecules in the unit cell shows the
channels in which the solvent is accommodated. There are
no sub-van der Waals contacts between the molecules (Fig-
ure 2).
Crystals of (LЈ)GaCl3, obtained from acetonitrile at 0 °C,
are orthorhombic, space group Pnma, with Z ϭ 12 formula
units in the unit cell. The asymmetric unit contains one
complete molecule (I) with all atoms in general positions
along with one half of another molecule (II), the second
half of which is generated by a mirror plane (defined by
atoms Cl5, Ga2 andN21, Figure 3). The structure of mol-
ecule I also approaches mirror symmetry (Cs) quite closely,
the plane being defined by atoms Cl1, Ga1 and N11.
It should be noted that the Ga-N distances in the GaCl3
Figure 2 Packing of the molecules(LЈ)4Ga4S6 in the unit cell (LЈ ϭ
p-dimethylamino-pyridine).
stronger donor-acceptor interactions in the former, i.e.
weaker bonding of LЈ at the gallium sulfide cluster. It has
already been pointed out that the GaS3 pyramid in the gal-
lium sulfide complex is rather flat (with large S-Ga-S angles,
average 114.9°), whereas in the gallium chloride complex
˚
adduct of LЈ [1.948(2) and 1.946(3) A for molecules I and
II, respectively] are significantly shorter than those in the
˚
Ga4S6 adduct [2.011(5) and 2.022(5) A] indicating much
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From Gallium Hydride Halides to Molecular Gallium Sulfides
Figure 3 Molecular structure of (LЈ)GaCl3 with atomic numbe-
ring. The atoms Cl5, Ga2, N21, C24 and N22 of Molecule II reside
on a mirror plane. Molecule I also closely approaches mirror sym-
˚
metry. (Hydrogen atoms are omitted). Selected bond lengths/A and
angles/°:
Figure 5 Molecular structure of (Cy3P)GaHCl2 with atomic num-
bering (hydrogen atoms Ϫ except Ga-H Ϫ omitted). Selected bond
lengths/A and angles/° for the major component of two disor-
Ga1-N11 1.948(2), Ga1-Cl1 2.1609(7), Ga1-Cl2 2.1628(7), Ga1-Cl3
2.1614(7), Ga2-N21 1.946(3), Ga2-Cl4 2.1539(9), Ga2-Cl5 2.158(1); N11-
Ga1-Cl1 109.86(6), N11-Ga1-Cl2 104.82(6), N11-Ga1-Cl3 106.56(6), Cl1-
Ga1-Cl2 110.99(3), Cl1-Ga1-Cl3 111.91(3), Cl2-Ga1-Ga3 112.35(3); N21-
Ga2-Cl4 106.85(5), N21-Ga2-Cl5 108.44(9), Cl4-Ga1-Cl5 110.41(3), Cl4-
Ga2-Cl4Ј 113.63(7).
˚
dered molecules:
Ga1-C1 2.182(2), Ga1-Cl2 2.200(2), Ga1-P1 2.432(1), Ga1-H1 1.46(5); Cl1-
Ga1-Cl2 105.76(7), Cl1-Ga1-P1 110.92(6), Cl2-Ga1-P1 102.24(7), Cl1-Ga1-
H1 115(2), Cl2-Ga1-H1 114(2), P1-Ga1-H1 107(2).
the Cl-Ga-Cl angles are closer to the tetrahedral standard
(average 111.7°).
Crystals of (Cy3P)GaHCl2 (m.p. 174 °C with decompo-
sition, solvent-free from diethyl ether) are monoclinic, space
group Cc, with Z ϭ 4 formula units in the unit cell. The
molecules have the staggered conformation predicted by
calculations, but the GaHCl2 part is disordered over two
sites (Figure 5). The Ga-H hydrogen atom of the major
component was tentatively assigned to a residual electron
density. The resulting refined geometry agrees reasonably
well with those of other Ga-H compounds reported in the
literature (Exp. Part). The hydrogen atom of the minor
component was calculated with an idealized geometry using
the Ga-H distance of the major component as a reference
parameter.
The Dichlorogallane Complexes
The structure of the complex (Et3P)GaHCl2 [8] which is a
liquid at room temperature has not been determined exper-
imentally, but was calculated using standard quantum-
chemical methods (Exp. Part). The result is shown in Figure
4. The molecule has a staggered, ethane-like conformation.
Crystals of (Ph3P)GaHCl2were obtained from diethyl
ether in two solvent-free polymorphic forms, one mono-
clinic (space group P21/n, Z ϭ 4) and one triclinic (space
¯
group P1, Z ϭ 2). The latter was found to crystallize from
diethyl ether, if excess PPh3 was present in the solution. The
molecular structures in both polymorphs are very similar
(Figure 6) with differences arising only from variations in
the conformative orientations as shown in the superposition
presented in Figure 7. The Ga-H hydrogen atoms of both
polymorphs were calculated in idealized positions account-
ing for a probable disorder of the HGaCl2 unit similar to
the one found in the structure of (Cy3P)GaHCl2 (Exp.
Part).
Crystals of [(dppe)(GaHCl2)2](C6H6), (m.p. 203 °C, from
benzene/pentane), are monoclinic, space group C2/c, with
Z ϭ 4 formula units in the unit cell. The two halves of the
molecule are related by a center of inversion located midway
between the C3-C3Ј bond (Figure 8). As in some of the
previous examples, the HGaCl2 units are disordered over
Figure 4 Calculated molecular structure of (Et3P)GaHCl2 with
atomic numbering. Selected bond lengths/A and angles/°:
Ga1-Cl1 2.1976, Ga1-Cl2 2.1978, Ga1-P1 2.4355, Ga1-H1 1.5570; Cl1-Ga1-
Cl2 112.95, Cl1-Ga1-P1 98.16, Cl2-Ga1-P1 98.24, Cl1-Ga1-H1 116.42, Cl2-
Ga1-H1 116.42, P1-Ga1-H1 110.94.
˚
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H. Schmidbaur, S. D. Nogai
ometry using the Ga-H distance of the major component
as a reference parameter (Exp. Part).
Figure 6 Molecular structure of (Ph3P)GaHCl2 in the monoclinic
form with atomic numbering. (Hydrogen atoms Ϫ except Ga-H Ϫ
omitted). Selected bond lengths/A and angles/°:
Ga1-Cl1 2.1982(7), Ga1-Cl2 2.1913(7), Ga1-P1 2.4038(6), Ga1-H1 1.51 (fi-
xed); Cl1-Ga1-Cl2 106.60(3), Cl1-Ga1-P1 103.92(3), Cl2-Ga1-P1 104.73(3),
Cl1/Cl2/P1-Ga1-H1 113.6 (fixed).
Figure 8 Molecular structure of [(dppe)(GaHCl2)2] in the benzene
solvate (1:1) with atomic numbering. There is a center of inversion
midway between atoms C3 and C3Ј. Hydrogen atoms Ϫ except Ga-
˚
˚
H Ϫ are omitted. Selected bond lengths/A and angles/° for the
major component of two disordered molecules:
Ga1-Cl12.1841(9), Ga1-Cl2 2.2056(8), Ga1-P1 2.426(1), Ga1-H1 1.48(3);
Cl1-Ga1-Cl2 111.45(4), Cl1-Ga1-P1 104.22(3), Cl2-Ga1-P1 96.93(3), Cl1-
Ga1-H1 91.15(1), Cl2-Ga1-H1 113(1), P1-Ga1-H1 112(1).
Crystals of [(dppe)(GaHCl2)2](Et2O)2 (from diethyl
¯
ether) are triclinic, space group P1, with Z ϭ 1 formula unit
in the unit cell. The structure of the adduct (also point
group Ci) is very similar to that described for the benzene
solvate. The Ga-H hydrogen atom was calculated in an ide-
alized position (Exp. Part).
Discussion
The present work has again demonstrated that pyridines
appear to be the ideal ligands for molecular gallium(III)
halides and chalcogenides. In particular pyridines with
strong electron-donating substituents, such as 4-dimeth-
ylamino-pyridine LЈ, can be employed to stabilize even the
binary gallium sulfide in a tetranuclear form Ga4S6 with an
adamantane structure. This structure features exclusively
the six-membered rings Ga3S3 in chair conformation which
are also characteristic of the bulk gallium sulfide poly-
morphs Ga2S3.
The Ga-N bond lengths and the average Cl-Ga-Cl/S-Ga-
S angles indicate that donor-acceptor bonding is weaker at
Ga4S6 than at the strong acceptor GaCl3. It is for this rea-
son that the ligand LЈ can be readily eliminated on heating,
but concurrently the remaining Ga4S6 cages undergo poly-
merization.
The synthetic route involves reaction of (LЈ)GaHCl2 with
(Me3Si)2S which first affords a mixed gallium “hydride
chloride sulfide” which finally can be converted into the
product by reaction with excess ligand LЈ in boiling aceto-
nitrile. The simple metathesis reaction of (LЈ)GaCl3 with
Figure 7 Superposition of the molecules (Ph3P)GaHCl2 in the tri-
clinic and monoclinic polymorphs.
two orientations with a hydrogen and a chlorine atom
changing positions. The members of the molecular chain
are all in staggered all-trans conformations leading to an
extended (stretched) structure. The Ga-H hydrogen atom of
the major component was located and refined, that of the
minor component was calculated with an idealized ge-
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From Gallium Hydride Halides to Molecular Gallium Sulfides
(Nujol on KBr): 1920 cmϪ1 (ν Ga-H). NMR (C6D6, 25 °C) 1H:
0.9-2.4, m, 33H, Cy; 5.1, br. s, 1H, GaH. 13C: 26.0, s, C-4; 27.2, d,
J 10.4 Hz, C-3/5; 29.3, s, C-2/6; 31.2, d, J 15.6 Hz, C-1. 31P: 0.9,
br. s.
(Me3Si)2S does not afford any soluble gallium sulfide com-
plexes.
Pyridines have previously been found to dissolve readily
the ternary gallium chalcogenide halides GaEX to form tri-
nuclear complexes with six-membered ring structures (E ϭ
S, Se; X ϭ Cl, Br) [5, 6]. With tertiary phosphines, these
ternary compounds show no reaction. Similarly, treatment
of the (L)GaHCl2 complexes with sulfides gave only ill-de-
fined, insoluble substitution products, probably because not
only the halogen atoms but also some of the tertiary phos-
phines L are substituted by sulfide leading to a cross-linking
of the molecular units.
The intermediates of the sulfide substitution reactions,
the aforementioned mixed “gallium(III) sulfide hydride
chloride complexes” have the hydrogen atom attached to
gallium(III) as a hydride and not to sulfur in a gallium(I)
hydrogensulfide chloride. It should be noted that there is no
literature on a ternary compound of the net composition
GaSH or its complexes. Since no gallium(I) compounds
have been encountered in the present and previous studies it
appears that the “GaSH” involved under the experimental
conditions chosen for this work is to be classified as a gal-
lium(III) hydride sulfide Ga(S)(H) and not a gallium(I) hy-
drogensulfide Ga(SH).
(Triphenylphosphine)dichlorogallane(III): As described above,
from (HGaCl2)2 (1.67 g, 5.89 mmol, 30 ml Et2O) and Ph3P (3.09 g,
11.8 mmol, 30 ml Et2O); colorless, air-sensitive, triclinic crystals,
m.p. 202-205 °C; 4.76 g (97 % yield). Found C 53.25, H 3.96, Cl
17.38, P 7.37; calcd. for C18H16Cl2GaP (403.92): C 53.52, H 3.99,
Cl 17.55, P 7.67 %. IR (KBr): 1940 cmϪ1 (ν Ga-H). NMR (C6D6,
25 °C) 1H: 5.84, br. s, 1H, GaH; 6.87-7.00, m, AAЈBBЈCX, 9H,
CH-3/4/5; 7.46-7.54, m, AAЈBBЈCX, CH-2/6. 13C: 129.6, d, J
10.3 Hz, C-3/5; 132.0, d, J 2.6 Hz, C-2/6; 134.0, d, J 11.3 Hz, C-1;
C-4 not detected. 31P: Ϫ8.8, br. s. [Note: Crystals from diethyl ether
are triclinic; crystals from diethyl ether containing excess Ph3P
are monoclinic.]
[Bis(diphenylphosphino)ethane]-P,PЈ-bis[dichlorogallane(III)]: As
described above, from (HGaCl2)2 (1.70 g, 6.00 mmol, 20 ml Et2O)
and (CH2PPh2)2 (dppe) (2.39 g, 6.00 mmol, 20 ml Et2O); colorless,
air-sensitive crystals, m.p. 202-205 °C; 3.80 g (93 % yield). Found:
C 45.93, H 3.91, Cl 20.45, P 8.95; calcd. for C26H26Cl4Ga2P2
(681.69): C 45.81, H 3.84, Cl 20.80, P 9.09 %. IR (KBr): 1951 cmϪ1
1
(ν Ga-H). NMR (C6D6, 25 °C) H: 2.48, br. s, 2H, CH2; 6.17, br.
s, 1H, GaH; 6.96, m, AAЈBBЈCX, 6H, CH-3/4/5; 7.36, m,
AAЈBBЈCX, 4H, CH-2/6. 13C: 22.3, br. s, CH2; 129.2, br. s, C-3/5;
130.2, br. s, C-2/6; 133.1, m, AXXЈ, C-1. C-4 not detected. 31P:
Ϫ10.4, br. s.
Under more forcing conditions, (L)GaHCl2 complexes
(with L ϭ pyridine or phosphine) can undergo reductive
elimination of molecular hydrogen to give dinuclear gal-
lium(II) compounds of the formula (L)Cl2Ga-GaCl2(L). To
date, no such elimination of molecular hydrogen was ob-
served in the gallium(III) hydride sulfide systems.
Reaction of trivinylphosphine with dichlorogallane(III): As de-
scribed above, (HGaCl2)2 (0.70 g, 2.47 mmol) is treated with Vi3P
(0.56 g, 5.00 mmol) in 20 ml of diethyl ether at Ϫ78 °C. On warm-
ing the reaction mixture a colorless precipitate is formed which
cannot be redissolved in organic solvents and decomposes upon
heating without melting; 0.98 g (78 % yield). Found: C 28.71, H
4.30, Cl 27.27, P 10.36; calcd. for C6H10Cl2GaP (253.75): C 28.40,
H 3.97, Cl 27.94, P 12.21 %. The IR spectrum (Nujol on KBr)
shows no absorption for a ν Ga-H stretching vibration.
Experimental Part
Tetrakis(4-dimethylamino-pyridine)tetragallium(III) hexasulfide:
(4-Dimethylamino-pyridine)dichlorogallane (1.04 g, 3.92 mmol)
[12] is reacted with bis(trimethylsilyl)sulfide (0.70 g, 3.94 mmol) in
30 ml of acetonitrile at Ϫ25 °C for 3 h. The reaction mixture is
allowed to warm to room temperature over a period of 12 h and
kept at 20 °C for another 24 h. The colorless precipitate is filtered
off, washed with 2x20 ml of hexane and dried in a vacuum. The
solid product melts and decomposes over a broad temperature in-
terval (0.72 g, 78 % yield). Found: C 34.95, H 4.62, N 11.42, S
13.88, Cl 5.46, Ga 29.49; calcd. for (C7H10N)GaSCl0.36H0.64: C
35.42, H 4.52, N 11.80, S 13.51, Cl 5.38, Ga 29.37 %. IR (Nujol
on KBr): 1890 cmϪ1 (ν Ga-H).
0.502 g (2.11 mmol) of this product is suspended in 25 ml of a satu-
rated solution of 4-dimethylamino-pyridine in acetonitrile and
heated to reflux for 8 h. The reaction mixture is filtered at 70 °C
and the solvent removed from the filtrate in a vacuum. The residue
is dissolved in 40 ml of dichloromethane and the solution cooled
to Ϫ30 °C for crystallization of the colorless product, 0.105 g, 21 %
yield. Found: C 35.56, H 4.50, N 11.60; calcd. for C28H40N4Ga4S6
(959.9) C 35.03, H 4.02, N 11.67 %. MS (FAB): m/e 959.9 [Mϩ].
NMR (CD2Cl2, 20 °C) 1H: 3.01, s, 6H, Me; 6.55 and 8.45, m,
AAЈBBЈ, 2H each, CH-2/6 and CH-3/5. Upon thermolysis a subli-
mate of 4-dimethylamino-pyridine is obtained and X-ray amorph-
ous gallium sulfide (containing no carbon, nitrogen or hydrogen,
and with a correct gallium and sulfur analysis) remains.
General: All preparative experiments were carried out in an atmos-
phere of dry, pure nitrogen. Solvents were dried, distilled and satu-
rated with nitrogen, glassware was oven-dried and filled with nitro-
gen. Standard equipment was used throughout. Dichlorogallane
was prepared following a published procedure [7, 8]. All other
chemicals were commercially available.
(Triethylphosphine)dichlorogallane(III): The molecular structure
of (Et3P)GaHCl2 [8] was calculated with the TURBOMOLE suite
of programs on the RI-MP2 level with a SV(P) basis set (split val-
ence quality with a polarization function for all non-hydrogen
atoms) [13].
(Tricyclohexylphosphine)dichlorogallane(III): Freshly prepared
(HGaCl2)2 (0.84 g, 2.98 mmol) is dissolved in 15 ml of diethyl ether
at Ϫ25 °C and Cy3P is added as a solution in diethyl ether (1.67 g,
5.95 mmol, 40 ml Et2O) with stirring. A precipitate forms, which is
filtered and washed with 2x20 ml of diethyl ether. Remaining sol-
vent is evaporated in a vacuum. Additional crystalline product is
obtained by slow cooling of the combined filtrates to Ϫ78 °C: Col-
orless, air-sensitive crystals, m.p. 174 °C (decomposition); 2.33 g
(93 % yield). Found C 51.37, H 8.19, Cl 16.57, P 7.11; calcd. for
C18H34Cl2GaP (422.07) C 51.22, H 8.12, Cl 16.80, P 7.34 %. IR
Z. Anorg. Allg. Chem. 2004, 630, 2218Ϫ2225
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2223

H. Schmidbaur, S. D. Nogai
(4-Dimethylamino-pyridine)trichlorogallium(III): Anhydrous (GaCl3)2
(1.80 g, 5.11 mmol) is dissolved in dichloromethane (20 ml) and LЈ
(1.25 g, 10.22 mmol) is added. The reaction mixture is stirred for
2 h and subsequently the volume of the solution is reduced to one
half in a vacuum. Cooling of the remainder solution to Ϫ78 °C
leads to the deposition of the colorless, crystalline product; 2.96 g
(98 % yield, m.p. 103-104 °C). Found: C 28.28, H 3.30, N 9.29, Cl
35.66; calcd. for C7H10Cl3GaN2 (298.25): C 28.19, H 3.38, N 9.39,
Cl 35.66 %. NMR (C6D6, 25 °C) 1H: 2.07, s, 6H, Me; 5.55 and
7.38, m, AAЈBBЈ, 2H each, C6H4. 13C: 38.7, s, Me; 107.0, 143.6
and 155.9, all s, for C-3/5, -2/6 and -4, respectively.
ment with reference data. The Ga-H hydrogen atoms of the minor
components were calculated in ideal positions with Ga-H distances
derived from the corresponding major components. In the structure
refinements of both polymorphs of (Ph3P)GaHCl2 and of [(dppe)-
(GaHCl2)2](Et2O)2 also relatively high residual electron densities
occurred, roughly in the space segments where the hydride ligands
were expected. Together with significantly unequal anisotropic
thermal displacement parameters for Cl1 and Cl2 in the triclinic
polymorph of (Ph3P)GaHCl2 this indicated a disorder similar to
the one discussed above. The Ga-H hydrogen atoms of both poly-
morphs of (Ph3P)GaHCl2 and of [(dppe)(GaHCl2)2](Et2O)2 there-
fore were calculated in ideal positions with a mean Ga-H distance
based on information held in the Cambridge Structural Database
(version 5.25, April 2004 release) [15]. The search fragment used
consisted of a four-coordinate gallium atom attached to a singly-
coordinate hydrogen atom. The 138 data listed in this compilation
Crystal Structure Determinations:
Specimens of suitable quality and size of [(4-Me2N-Py)4Ga4S6], (4-
Me2N-Py)GaCl3, (Cy3P)GaHCl2, (Ph3P)GaHCl2 (one monoclinic
and one triclinic polymorph), [(dppe)(GaHCl2)2](C6H6) and
[(dppe)(GaHCl2)2](Et2O)2 were mounted on the ends of quartz fib-
ers in inert perfluoropolyalkylether and used for intensity data col-
lection on a Nonius DIP2020 diffractometer, employing graphite-
monochromated Mo Kα radiation. The structures were solved by
a combination of direct methods (SHELXS-97) and difference-
Fourier syntheses and refined by full matrix least-squares calcu-
lations on F2 (SHELXL-97) [14]. The thermal motion was treated
anisotropically for all non-hydrogen atoms. After an initial struc-
ture solution and refinement of (Cy3P)GaHCl2 and [(dppe)-
(GaHCl2)2](C6D6) high residual electron densities in appropriate
distances and angles suggested a disorder of the HGaCl2 groups
over two sites in both structures. The subsequent refinement of split
atom models gave satisfactory results for both structures with site
occupation factors of 87.6 and 91.3 % for the major components
in (Cy3P)GaHCl2 and [(dppe)(GaHCl2)2](C6D6) respectively. To
prevent closely neighbouring atoms from becoming non positive
definite, all Ga-Cl distances were restrained to be equal within a
˚
gave a mean Ga-H distance of 1.51 A. The C-H hydrogen atoms
were located and refined with isotropic displacement parameters in
all structures except [(4-Me2N-Py)4Ga4S6] where they were calcu-
lated in ideal positions and allowed to ride on their parent atoms
with fixed isotropic contributions. The Flack parameter for (Cy3P)-
GaHCl2 is 0.006(10). The structure of [(4-Me2N-Py)4Ga4S6] con-
tains disordered solvent molecules, which were partially taken into
account by the SQUEEZE method [16] (Solvent Accessible
3
˚
Volume: 970.7 A containing 35 electrons per cell). Absorption cor-
rections for [(dppe)(GaHCl2)2](Et2O)2, (Cy3P)GaHCl2 and
(4-Me2N-Py)GaCl3 were carried out using DELABS, as part of the
PLATON [16] suite of programms. Further information on crystal
data, data collection and structure refinement are summarized in
Tables
1 and 2, CCDC reference numbers 225439 and
244202Ϫ244207.
Acknowledgement. This work was generously supported by Fonds
der Chemischen Industrie (FCI) and by Deutscher Akademischer
Austauschdienst (DAAD). Professor P. Pyykkö (University of
Helsinki) and Dr. U. Monkowius (TUM) are thanked for assistance
with the quantum chemical calculations.
˚
standard deviation of 0.01 A. The Ga-H hydrogen atoms of the
major components in both structures were attributed to residual
electron densities. The refined Ga-H distances are in good agree-
Table 1 Crystal Data, Data Collection, and Structure Refinement of [(4-Me2N-Py)4Ga4S6], (4-Me2N-Py)GaCl3 and (Cy3P)GaHCl2.
[(4-Me2N-Py)4Ga4S6]
(CH2Cl2)3.86؉x
(4-Me2N-Py)GaCl3
(Cy3P)GaHCl2
Empirical formula
M
C31.88H47.73Cl7.73Ga4N8S6
1288.04
monoclinic
C2/c
10.3839(2)
39.335(1)
14.4037(5)
94.821(1)
5862.5(3)
1.459
C7H10Cl3GaN2
298.24
orthorhombic
Pnma
7.3898(1)
28.6487(4)
16.6420(2)
90
3523.25(8)
1.687
C18H34Cl2GaP
422.05
monoclinic
Cc
16.7490(5)
9.5296(3)
13.0925(4)
98.212(2)
2068.28(1)
1.355
Crystal system
Space group
˚
a/A
˚
b/A
˚
c/A
β/°
3
˚
V/A
ρcalc/g cmϪ3
Z
4
12
4
F(000)
2585
24.14
143
1776
29.84
143
888
16.62
143
µ (Mo-Kα)/cmϪ1
T/K
Refls. measured
Refls. Unique
Refined parameters /restraints
R1 [IՆ2σ(I)]
wR2a)
159925
3603
287 / 12
0.0521
0.1298
a ϭ 0.451
b ϭ 61.7951
0.744 / Ϫ0.731
72813
3284
244 / 0
0.0270
30932
3759[Rint ϭ 0.056]
364 / 10
0.0370
0.0695
0.0871
Weighting scheme
a ϭ 0.0332
b ϭ 4.0385
1.612 / Ϫ0.460
a ϭ 0.0000
b ϭ 1.0445
0.452 / Ϫ0.502
Ϫ3
˚
σfin(max/min)/eA
2
a) wR2ϭ {Σ[w(Fo2-Fc2)2]/Σ[w(Fo2)2]}1/2; w ϭ 1/[σ2(Fo2)ϩ(ap)2ϩbp]; p ϭ (Fo ϩ 2Fc2)/3.
2224
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Z. Anorg. Allg. Chem. 2004, 630, 2218Ϫ2225

From Gallium Hydride Halides to Molecular Gallium Sulfides
Table 2 Crystal Data, Data Collection, and Structure Refinement of (Ph3P)GaHCl2, (Ph3P)GaHCl2, [(dppe)(GaHCl2)2](C6H6) and [(dppe)-
(GaHCl2)2](Et2O)2.
(Ph3P)GaHCl2
(Ph3P)GaHCl2
[(dppe)(GaHCl2)2]
(C6H6)
[(dppe)(GaHCl2)2]
(Et2O)2
Empirical formula
M
C18H16Cl2GaP
403.90
monoclinic
P21/c
12.5720(1)
11.1633(2)
12.9621(2)
90
90.270(1)
90
C18H16Cl2GaP
403.90
C32H32Cl4Ga2P2
759.76
Monoclinic
C2/c
15.5980(2)
12.3725(2)
18.2083(3)
90
107.767(1)
90
C34H46Cl4Ga2O2P2
829.89
Crystal system
Space group
triclinic
triclinic
¯
¯
P1
P1
˚
a/A
9.3578(4)
9.8923(4)
10.3752(5)
107.468(2)
95.163(2)
93.847(2)
907.94(7)
1.477
8.9950(2)
10.7604(3)
11.9444(4)
88.321(2)
68.165(2)
68.287(2)
989.12(5)
1.393
˚
b/A
˚
c/A
Ͱ/°
β/°
γ/°
3
˚
V/A
1819.15(5)
1.475
4
3346.35(9)
1.508
4
ρcalc/g cmϪ3
Z
2
1
F(000)
816
18.87
143
408
18.91
143
1536
20.46
143
426
17.41
143
µ (Mo-Kα)/cmϪ1
T/K
Refls. measured
Refls. Unique
Refined parameters /restraints
R1 [IՆ2σ(I)]
wR2a)
39424
3176 [Rint ϭ 0.035]
259 / 0
0.0318
0.0816
a ϭ 0.0380
b ϭ 1.9075
1.229 / Ϫ0.496
27871
3137 [Rint ϭ 0.063]
260 / 0
0.0480
0.1049
a ϭ 0.0170
b ϭ 2.5972
1.125 / Ϫ0.568
38753
2910 [Rint ϭ 0.038]
264 / 7
0.0258
0.0695
a ϭ 0.0277
b ϭ 3.6298
0.460 / Ϫ0.317
21949
3388[Rint ϭ 0.031]
288 / 0
0.0404
0.1091
a ϭ 0.0573
b ϭ 1.0010
1.390 / Ϫ0.711
Weighting scheme
Ϫ3
˚
σfin(max/min)/eA
2
a) wR2ϭ {Σ[w(Fo2-Fc2)2]/Σ[w(Fo2)2]}1/2; w ϭ 1/[σ2(Fo2)ϩ(ap)2ϩbp]; p ϭ (Fo ϩ 2Fc2)/3.
[7] a) H. Schmidbaur, W. Findeiss, E. Gast, Angew. Chem. 1965,
77, 170; Angew. Chem. Int. Ed. Engl. 1965, 4, 152; b) E. S.
Schmidt, A. Schier, N. W. Mitzel, H. Schmidbaur, Z. Natur-
forsch. 2001, 56b, 337.
[8] S. Nogai, H. Schmidbaur, Inorg. Chem. 2002, 41, 4770.
[9] F. M. Elms, G. A. Koutsantonis, C. L. Raston, J. Chem. Soc.,
Chem. Commun. 1995, 1669.
[10] a) L. Maier, D. Seyferth, F: G. A. Stone, E. G. Rochow, J.
Am. Chem. Soc. 1957, 79, 5884; b) U. Monkowius, S. Nogai,
H. Schmidbaur, Organometallics 2003, 22, 145; c) U. Monkow-
ius, S. Nogai, H. Schmidbaur, J. Chem. Soc., Dalton Trans.
2003, 987.
References
[1] a) C. P. Collier, T. Vossmeyer, J. R. Heath, Ann. Rev. Phys.
Chem. 1998, 49, 371; b) I. Dance, K. Fisher in Progress in
Inorganic Chemistry, Karlin, K. D.; Ed., Vol 41, p. 637, 1994;
c) B. Krebs, G. Henkel, Angew. Chem. 1991, 103, 785; Angew.
Chem. Int. Ed. Engl. 1991, 30, 769; d) B. Krebs, D. Voelker,
K.-O. Stiller, Inorg. Chim. Acta 1982, 65, 101; e) A. J. Downs,
Chemistry of Aluminium, Gallium, Indium, and Thallium,
Blackie Academic & Professional, Glasgow, 1993.
[2] a) H. Pfistner, D. Fenske, Z. Anorg. Allg. Chem. 2001, 627,
575; b) V. N. Soloviev, A. Eichhöfer, D. Fenske, U. Banin, J.
Am. Chem. Soc. 2001, 123, 2354.
[11] M. Sigl, A. Schier, H. Schmidbaur, Z. Naturforsch. 1998,
53b, 1301.
[3] a) A. F. Wells, Structural Inorganic Chemistry, 5. Ed., Oxford
University Press, pp. 763, 1987; b) H. Hahn, W. Klinger, Z.
Anorg. Allg. Chem. 1949, 259, 135; c) J. Goodyear, G. A. Steig-
mann, Acta Crystallogr. 1963, 16, 946; d) G. Collin, J. Flahaut,
M. Guittard, A. Loireau-Lozach, Mat. Res. Bull. 1976, 11,
285; e) A. Tomas, M. P. Pardo, M. Guittard, M. Guymont, R.
Famery, Mat. Res. Bull. 1987, 22, 1549.
[4] a) N. Zheng, X. Bu, P. Feng, J. Am. Chem. Soc. 2003, 125,
1138; b) N. Zheng, X. Bu, B. Wang, P. Feng, Science 2002,
298, 2366.
[12] S. Nogai, A. Schriewer, H. Schmidbaur, Dalton Trans. 2003,
3165.
[13] a) R. Ahlrichs, M. Bär, M. Häser, H. Horn, C. Kömel, Chem.
Phys. Letters 1989, 162, 165; b) F. Weigend, M. Häser, Theor.
Chem. Acc. 1997, 97, 331; c) F. Weigend, M. Häser, H. Patzelt,
R. Ahlrichs, Chem. Phys. Letters 1998, 294, 143.
[14] G. M. Sheldrick, SHELX-97, Programs for crystal structure
analysis, University of Göttingen, Germany, 1997.
[15] a) F. H. Allen, Acta Crystallogr., Sect. B 2002, 58, 380; b) I.
J. Bruno, J. C. Cole, P. R. Edgington, M. Kessler, C. F. Macrae,
P. Mc Cabe, J. Pearsons, R. Taylor, Acta Crystallogr., Sect. B
2002, 58, 389.
[5] S. Nogai, A. Schier, H. Schmidbaur, Z. Naturforsch. 2001,
56b, 711.
[6] S. Nogai, H. Schmidbaur, Dalton Trans. 2003, 2488.
[16] A. L. Spek, Acta Crystallogr. 1990, A40, 194.
Z. Anorg. Allg. Chem. 2004, 630, 2218Ϫ2225
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 2004 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
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