Synthesis, Characterization, Crystal Structure, and hybrid DFT Computation
of Antimony(III) Chloride Diazide, SbCl(N
3
)
2
Thomas M. Klapo
È
tke*, Heinrich No
È
th, Thomas Schu
È
tt, and Marcus Warchold
Munich, Department of Chemistry, Ludwig-Maximilians University
Received September 11th, 2000.
Abstract. SbCl(N
3
)
2
was synthesized by the reaction of two
equivalents of sodium azide with SbCl
3
in CH
2
Cl
2
.The
structure of the compound was determined by X-ray struc-
ture determination. SbCl(N
3
)
2
crystallizes in the monoclinic
space group C2/c with a = 11.694(4), b = 7.751(4) and
c = 12.241(5) A
Ê
, b = 100.45(1)°, with 8 formula units per unit
cell. The SbCl(N
3
)
2
molecules show interactions to form
chains. The frequencies obtained by Raman and infrared
spectroscopy were assigned to the normal modes of the
SbCl(N
3
)
2
molecules in comparison with computational re-
sults.
Keywords: Antimony; Azides; Crystal structure; hybrid DFT
Synthese, Charakterisierung, Kristallstruktur und hybrid-DFT-Berechnung
von Antimon(III)-chlorid-diazid, SbCl(N
3
)
2
Inhaltsu
È
bersicht. SbCl(N
3
)
2
wurde durch die Umsetzung von
zwei Øquivalenten Natriumazid mit SbCl
3
in CH
2
Cl
2
synthe-
tisiert. Die Struktur der Verbindung wurde durch RoÈntgen-
strukturanalyse bestimmt. SbCl(N
3
)
2
kristallisiert in der mo-
noklinen Raumgruppe C2/c mit den Gitterkonstanten
a = 11.694(4), b = 7.751(4) und c = 12.241(5) A
Ê
, b = 100.45(1)°,
mit 8 Formeleinheiten in der Elementarzelle. Die SbCl(N
3
)
2
-
MolekuÈ le bilden Ketten durch zwischenmolekulare Wechsel-
wirkungen. Die durch Raman- und Infrarot-Spektroskopie
erhaltenen Banden wurden den Normalschwingungen der
SbCl(N
3
)
2
-MolekuÈ le zugeordnet und mit berechneten Ergeb-
nissen verglichen.
Introduction
Recently we have been studying the reactions of var-
ious group 15 elements with silver azide, sodium azide
or trimethylsilyl azide [1±4]. In 1996 we reported on
the synthesis of the first binary antimony azide species
Sb(N
3
)
3
[5]. However we were unable to grow suitable
crystals for X-ray diffraction of Sb(N
3
)
3
. The structural
characterization of antimony azide species was so far
only possible when organic ligands were present, except
for the ternary antimony(V) species (SbCl
4
N
3
)
2
[6].
The structure of the molecules {[(PN
t
Bu)
2
(N
t
Bu)
2
]-
SbN
3
} [7], [(CH
3
)
3
SbN
3
]
2
O [8], Me
2
SbN
3
[9] and
[(C
6
H
5
)
3
SbN
3
]
2
O [10] could be solved by X-ray diffrac-
tion. The weak crystallization tendency of Sb(N
3
)
3
prompted us to find a better crystallizing antimony
azide species having a minor azide content. Here we re-
port on the synthesis, the spectroscopic properties and
the crystal structure of the first mixed halide pseudoha-
lide antimony(III) species, SbCl(N
3
)
2
.
Results and Discussion
SbCl(N
3
)
2
was prepared by the reaction of two
equivalents of sodium azide with SbCl
3
in CH
2
Cl
2
at
room temperature. After filtration and removing the
solvent under dynamic vacuum a colorless solid
remained. Recrystallization from the same solvent at
±30 °C gave single crystals suitable for the X-ray
measurements.
Crystal Structure of SbCl(N
3
)
2
The crystal structure at ±90 °C reveals that SbCl(N
3
)
2
forms isolated molecules in which the antimony atom
including the lone pair of electron is surrounded in a
pyramidal fashion by two nitrogen atoms and one
chlorine atom. The N1±Sb±N4 angle is 90.5(3)°, the
N1±Sb±Cl1 angle is 91.0(2)° and the N4±Sb±Cl1 angle
is 88.7(2)°. The molecular unit is shown in Fig. 1. Ta-
ble 1 shows the experimental and calculated bond
lengths and angles of the SbCl(N
3
)
2
unit. The Sb±N
distances (2.15 A
Ê
) are in good agreement with the
reported Sb±N distances of other antimony azides
[6±10].
The azide ligands in SbCl(N
3
)
2
are different. One
azide unit shows a ªnormalº behavior with an N4±N5
distance of 1.22(1) A
Ê
and an N5±N6 distance of
1.13(1) A
Ê
, while the other azide unit shows unrealistic
Z. Anorg. Allg. Chem. 2001, 627, 81±84 Ó WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001 0044±2313/01/62781±84 $ 17.50+.50/0 81
* Prof. Dr. Thomas M. KlapoÈ tke,
Department of Chemistry, Ludwig-Maximilians-University,
Butenandtstr. 5±13 (D),
D-81377 Munich, Germany
e-mail: tmk@cup.uni-muenchen.de