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Bonding Attitudes in Crystalline SeF4 and TeF4.

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way. Unsubstituted benzene is so loosely bound to In' that
the adducts could so far not be isolated.
Received: February 6, 1984 [Z 700 IE]
German version: Angew. Chem. 96 (1984) 367
[l] W. E. Silverthorn, Adu. Organomet. Chem. 13 (1975) 47.
[2] E. 0. Fischer, W. Hafner, Z. Naturforsch. B I O (1955) 665.
[31 M. S. Weininger, P. F. Rodesiler, E. L. Amma, Inorg. Chem. 18 (1979) 751
and references cited therein.
[41 H. Schmidbaur, U. Thewalt, T. Zafiropoulos, Angew. Chem. 96 (1984) 60:
Angew. Chem. Int. Ed. Engl. 26 (1984) 76; Organometallics 2 (1983) 1550:
Chem. Ber. 117 (1984), in press.
[5] B. H. Freeland, D. G. Tuck, Inorg. Chem. 15 (1976) 475; P. L. Radloff, G.
M. Papatbeodorou, J. Chem. Phys. 72 (1980) 992.
[6] CI8H2,Br,InZ, M,=789.648: monoclinic, P2,/n, a = 10.624(2), b =
13.384(3), c = 17.697(4) p=94.56(2)" at -4O"C, Y=2508.4 A', Z=4,
p,1~=2.091 g cm-', F(OOO)= 1480: 3946 independent reflections, 783
unobserved (1<2.0o(I): Syntex P21, MoKa. d=O.71069 A, w scan,
1"<3<24"); empirical absorption correction (p=81.24cm-l), based on
y scans of 10 reflections; solution by direct methods (MULTAN);
R=0.047, R,=0.051, atoms other than H anisotropic, H atoms (calculated) constant (SHELX 76),
1.15 e/A'. Further details of the
crystal structure analysis are available on request from the Fachinformationszentrum Energie Physik Mathematik, D-7514 Eggenstein-Leopoldshafen 2, on quoting the depository number CSD 50759, the names of the
authors, and the journal citation.
[7] K. Wade, Adv. Inorg. Chem. Radiochem. 18 (1976) 1: R. E. Williams, ibid.
18 (1976) 67.
[8] P. F. Rodesiler, T. Auel, E. L. Amma, J. Am. Chem. Sac. 97 (1975)
Bonding Attitudes in Crystalline SeF4 and TeF4**
By Riidiger Kniep*, Lutz Korte, Rainer Kryschi, and
Wolfgang Poll
Selenium tetrafluoride: In solution, the SeF, molecule
has a pseudo-trigonal-bipyramidal structure ; with increasing concentration, the molecules become increasingly associated via intermolecular fluorine bridges"]. We have now
succeeded in determining the crystal structure of SeF, and
are able to comment on the type of intermolecular interactions and the molecular structure. From the very beginning,
it could not be ruled out that crystalline SeF, is also polymeric, like TeF4. Since the structure analysis of TeF, reported in the literature[21(film technique) gave only relatively inaccurate bond lengths and angles, we have also redetermined the structure of TeF,, a comparison of the
bonding in SeF, and TeF, thus becoming more informative.
SeF, and TeF, were prepared by reactions of SeO, and
TeO,, respectively, with SF4 in an a u t o . c l a ~ e [ and
~ * ~were
subsequently purified by distillation or vacuum sublimation. In the case of TeF, (m.p. 130"C), single crystals for
the structure analysis were already obtained on sublimation, while in the case of SeF, (m.p. - 10°C) they were cultivated from the melt on the single-crystal diffractometer.
Determination of the lattice parameters and measurement
of the reflection intensities were carried out on both compounds at - 110°C. SeF, and TeF, crystallize with similar
lattice metrics in the space group P2,2,2,; remarkable,
however, is that the c-axis in TeF, is considerably shorter
than that in SeF4I5].
The molecular structure and coordination of the compounds are shown in the top part of Figure 1. In SeF, the
[*I Prof. Dr. R. Kniep, Dr. L. Korte, Dip1.-Chem. R. Kryschi, Dr. W. Poll
Institut fur Anorganische Chemie und Strukturchemie der Universitat
Universitatsstrasse 1, D-4000 Diisseldorf (FRG)
[**I This work was supparted by the Fonds der Chemischen Industrie.
0 Veriaa Chemie GmbH. 0-6940 Weinheim. 1984
Fig. 1. Top: Molecular structure and coordination in SeF, and TeF, with
bond lengths (standard deviations 0.006 and 0.005 A, respectively). Bond angles (standard deviations 0.3 and 0.2", respectively): FISeF2 96.9, FlSeF3
85.7, FelSeF4 87.2, FlSeF3' 171.0, FlSeF4' 77.1, F2SeF3 85.5, F2SeF4 87.5,
F2SeF3' 78.5, F2SeF4' 169.5, F3SeF4 169.3, F3SeF3' 86.3, F3SeF4' 102.5,
F4SeF3' 100.3, F4SeF4' 83.6, F35eF4' 108.6, SeF3Se' 150.1, SeF4Se"
139.9.-FlTeF2 86.8, FlTeFe3 87.6, FlTeF4 83.9, FITeF4' 162.5, F2TeF3
84.2, F2TeF4 161.3, F2TeF4' 88.2, F3TeF4 79.2, F3TeF4' 75.3, F4TeF4' 95.9,
TeF4Te' 154.1.-Bottom: Polymeric structure in TeF, and position and sequence of monomers in a corresponding section of the SeF, structure (schematic representation).
selenium is bonded to four fluorine atoms in such a way
that, with the pair of electrons on the selenium atom also
taken into consideration, a distorted pseudo-trigonal bipyramid with longer axial Se-F bonds results. In accord
with the electron pair repulsion (VSEPR) model the
Fa,-Se-Fa, array is not linear but angular (169.3"), with
the Se-Fa, bonds tilting away from the lone pair on Se; in
the same way, the F,,-Se-F,,
angle is smaller than 120".
The coordination of neighboring molecules in the second
sphere is increased via the axial fluorine atoms (distorted
octahedral fluorine coordination); according to the size of
the F. Se distance, the intermolecular interactions are to
be rated as being so weak that they do not significantly influence the bonding in the SeF, molecule. The bonding in
TeF, is different (see also r21).Here the tellurium is bonded
to five fluorine atoms (distorted tetragonal pyramid), two
of which (cis-oriented in the tetragonal plane) bridge a further neighboring tellurium atom each. The bridge bonds,
are, however, distinctly shorter than the intermolecular
F. .Se contacts in SeF,. It is to be expected that the lone
pair on the tellurium completes a pseudo-octahedral coordination of the central atom; consistent with this expectation the tellurium atom is located 0.3 A below the plane of
the four fluorine atoms. The differences in the bonding in
crystalline SeF, and TeF, can be ascribed to the respective
degrees of hybridization of the chalcogen, and can be described in terms of sp3d (SeF,: pseudo-trigonal-bipyramidal) and sp3d2states (TeF,: pseudooctahedral). The polymeric structure of TeF, in the [OlO] direction and the position and sequence of SeF, monomers (also in the [OlO] di-
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Anaew. Chem. Int. Ed. E n d . 23 (1984) No. 5
rection) in a corresponding section of the SeF, structure
are reproduced schematically at the bottom of Figure 1.
The shortening of the c-axis in TeF, is due to the strong
fluorine bridges within the polymeric structural assemblage. The fundamental similarity of the arrangements of
the structural units of SeF, and TeF, in the [OlO] direction
also exists in the three-dimensional crystal arrays. The possibility of a structural transformation in SeF, by a closer
(pressure-induced) proximity of the axial fluorine atoms to
selenium atoms of neighboring molecules cannot be ruled
The chemical similarity of SeF, and SFJ6] seems to be
further confirmed by the-albeit up to - 160°C disordered-crystal structure of SFL7', from which a formation of
fluorine-bridged associates in crystalline SF4 is not to be
Received: August 26, 1983;
supplemented: March 23, 1984 [Z 532 IE]
German version: Angew. Chem. 96 (1984) 351
- Mo2
[l] K. Seppelt, Z. Anorg. Allg. Chem. 416 (1975) 12.
[2] A. J. Edwards, F. I. Hewaidy, J . Chem. SOC.A1968, 2977.
[3] A. L. Oppegard, W. C. Smith, E. L. Muetterties, V. A. Engelhardt, J. Am.
Chem. Soc. 82 (1960) 3853.
[4] D. Lentz, H. Pritzkow, K. Seppelt, Inorg. Chem. 17 (1978) 1926.
[5] Crystallographic data: SeF,: 1220 (1378) reflections: R = 5.9%; P212121:
a=5.169(1), b=5.548(1), c=11.345(2) A; Z = 4 ; pCal,=3.16 g/cm3.TeF,: 1525 (1608) reflections, R=6.0%; P212121;a=5.214(4), b=6.229(5),
c=9.414(7) A; Z = 4 ; p,.,,=4.37 g/cm3. Further details of the crystal
structure investigation are available from the Fachinformationszentrum
Energie Physik Mathematik, D-7514 Eggenstein-Leopoldshafen 2, on
quoting the depository number CSD 50827, the names of the authors,
and the journal citation.
[6] K. Seppelt, Angew. Chem. 91 (1979) 199; Angew. Chem. Int. Ed. Engl. 18
(1979) 186.
[7] L. Korte, Dissertation, Universitat Dusseldorf 1983.
M03 - M o l 2681111
Fig. 1. ORTEP plot of the complex anions at the positions A and B in the
asymmetric unit of crystals of 1 [4] (distances in pm). Further details of the
crystal structure determination are available on request from the FachinforMixed Crystals Containing
mationszentrum Energie Physik Mathematik, D-7514 Eggenstein-Leopoldsthe Diamagnetic Complex [ M O ~ ( S O ~ ) ( S ~ ) ( Cand
N ) ~ ~ ~ "hafen 2, on quoting the depository number CSD 50676, the names of the authe Paramagnetic Complex I M O ~ ( S O ~ ) ( S ~ ) ( C N ) , ~ ~thors,
~ and the journal citation.
By Achim Muller*, Werner Eltzner, Rainer Jostes,
Hartmut Bogge, Ekkehard Diemann, Jurgen Schirnanski,
and Heiko Lueken
In the crystal, the complexes l a and l b are located at
Paramagnetic multinuclear and, particularly, binuclear
crystallographically independent positions A and B
complexes of the heavy transition metals (4d and 3d ele(Fig. 1). The structures of l a and l b differ only slightly; in
ments) are rare. We have now been able to isolate a
both complexes each molybdenum atom is surrounded by
compound which contains the isostructural anions
an approximately pentagonal-bipyramidal array of four
[ ( M O " ' ~ ' ~ ) ~ ( S O ~ ) ( S ~ ) ( Cl aN ) ~(paramagnetic)
CNe and three sulfur atoms of the bridging ligands
l b) ~
together in a
and S:Q[51. However, markedly different Mo-Mo
mixed crystal compound.
are observed for the positions A and B (279.0
Passage of oxygen into an aqueous solution of
and 268.4 pm, respectively). Since the greater Mo-Mo dis[ ( M O " ' ) ~ ( S ) ~ ( C N 2["leads
) ~ ] ~ ~ to the formation of a blackish
tance is to be expected for l a (see below), this complex obviolet mixed-crystal compound of the composition & + x viously preferably occupies the position A ; but since the
[ ( M ~ ' " ~ ' ~ ) z ( ~ ~ ~ ) ( ~ z ~ ~ ~ ~ ~--x.
s 4l H~z 0~ ~ ~ ~ ' ~ ~ z ~ ~ ~ z ) ( ~ z ) ( ~ ~ ) ~ l ~
crystal contains only ca. 30% of la, the geometric parame1 (x = 0.3) l l 3 ] . 1 was characterized magnetochemically
ters cannot exclusively arise from l a , at least in the case of
and spectroscopically (ESCA, ESR, IR, UV/VIS/NIR),
and by an X-ray structure analysis (Fig. l)',].
By ESCA measurementsL6]it was possible to demonstrate that mixed valence Mo species are present in 1.
Moreover, from the hyperfine structure of the ESR spec[*] Prof. Dr. A. Miiller, Dr. W. Eltzner, Dr. R. Jostes, Dr. H. Biigge,
Dr. E. Diemann, J. Schimanski
trum (solution of 1 in water, addition of Na2S03[71,room
Fakultat fur Chemie der Universitat
temperature) it unequivocally follows that an unpaired
Postfach 8640, D-4800 Bielefeld 1 (FRG)
electron in l a interacts with the nuclear spin of two chemiProf. Dr. H. Lueken
cally equivalent Mo atoms (95Moand 97Mo with I = 5/2).
Institut fur Anorganische Chemie der Technischen Universitat
The measured parameters ij= 2.012 and x(95Mo)= 19.2 G
Paul-Ernst-Str. 4, D-3392 Clausthal-Zellerfeld (FRG)
Angew. Chem. Int. Ed. Engl. 23 (1984) No. 5
0 Verlag Chemie GmhH, 0-6940 Weinheirn, 1984
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bonding, attitudes, crystalline, sef4, tef4
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