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Dimerization of S6O to S12O2 Crystal Structure Analysis of S12O2╖2SbCl5╖3CS2.

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torted trigonal SbSe3 pyramids, i.e. +-tetrahedra, two different dinuclear Sb2Se4units are observed, representing the czsand trans-configuration of two SbSe3 pyramids linked to
each other via a common edge. This simple linkage resulting
in surprisingly small isolated units is so far unique in the
structural chemistry of compounds of trivalent antimony.
particularly striking value of 168" for two SSSS torsional angles, which exceeds the values found so far for sulfur homocycles by 45 The principal molecular parameters are shown
in Figure 1. The 0 atoms occupy axial positions relative to a
mean plane through the S I 2ring. The SbCls groups and the
bridging 0 atoms have a n almost octahedral geometry. Only
van der Waals interactions occur with the CS2 molecules not
shown in Figure 1.
A mixture of anhydrous barium acetate, antimony, and selenium (molar ratio Ba(CH,C00)2: S b : Se = 1:1: 10) is fused
at 600 " C under argon in a n alumina crucible. After cooling,
the sintered mass is finely ground in a mortar, then heated
again to 650 "C, maintained at this temperature for 2 h, and
finally allowed to cool slowly over a period of 12 h. The regulus is broken up and the excess of selenium removed by
sublimation in a vacuum at 320 "C, leaving behind dark-gray
prismatic crystals.
Received: September 27. 1979 [Z 437 IEJ
German version: Angew Chem. 92, 310 (1980)
CAS Registry number:
Ba,Sb4Se, ,. 73377 52-3
[ I ] H . A. Grux H. Schiifer. 2. Naturforsch. B 27. 735 (1972); Z . Anorg. Allg.
Chem. 414, 211 (1975); G. Diffmur. H.Schafer. 2. Anorg. Allg. Chem 437,
183 (1977); 441. 93. 98 (1978); K . Volk. P. Bickert, R. Kolmer. H. Schafer. Z.
Naturforsch. B 34, 380 (1979); B. Eisenmunn. H. Schafer, ibid. B 34, 383
(1979). K Volk, H. Schufer, ibid. B 33, 827 (1978); B 34. 172 (1979). B 35. in
(21 Orthorhombic. space group Pnnm. a = 891.7(3), b= 2797 6(7). c=927.6(3)
pm. 2 = 4 . p,,,l,=5.47.
pczp= 5.45 g/cm'; four-circle diffractometer PWI 100.
w scan, p = 233.4 cm I . no absorption correction, 3559 symmetry-independent reflections; solution by direct methods (Program SHELX-76, G. M.
Sheldrrck. Program for Crystal Structure Determination, University of Cambridge. England). refinement to R = 0.0936 for all observed reflections.
Fig. 1. Internuclear distances [pm] and torsional angles ["I of
S,202-2SbC15.3CS~f/). The torsional angles to the 0 atom are
S 6 Sl S2 0: 87 4" and 54 S3 S2 0 9.6" (S6' IS obtained by reflection
of S6 in the inversion center).
Dimerization of S60to Siz02:
Crystal Structure Analysis of S,,0,.2 SbCI,-3CS2['1
By Raw Steudel, Jiirgen Steidel, and Joachim Pickardt['l
cyclo-Hexasulfur monoxide is formed on oxidation of S,
with trifluoroperacetic acid1']. However, it has not yet been
obtained as crystals large enough to permit determination of
its molecular structure. An attempt to prepare better crystalline adducts of S 6 0 with SbCls by analogy with numerous
sulfoxide-metal c o m p l e ~ e s [ ~
(at - 50 " C in CS2)
orange crystals of Sl2OZ.2 SbC15- 3 CS2 (I); their X-ray structure analysis'4' provides the first information about the structure of a cyclo-polysulfur dioxide.
On exposure to air, the initially clear crystals of ( I ) turn
cloudy within 1 min as a result of efflorescence with liberation of CS2, and ultimately form a yellow oil. In CS2 at room
temperature partial decomposition is already detectable after
10 min, yielding SOCl2, SO2, S8, and SbC13 (SO2 possibly by
hydrolysis of SOCl2).
The asymmetric SO stretching vibration of the SI2O2ligand was observed at 940 cm ' in the IR spectrum (CS2 solution); the symmetrical SO vibration expected in the Raman
spectrum has not yet been detected.
The SI2O2.2SbClsmolecules occupy lattice sites of C,
symmetry. The conformation of their ring differs drastically
showfrom that of cyclo-dodecasulfur S I z(D3d~ymmetry)'~],
ing striking variations in the SS internuclear distances and a
Valence angles
S2 Sl S6
s1 s 2 s 3
s2 s3 s4
ss s4 s 3
94.4( 1 )
103.9(1 )
S5 S6
S6 S S
s2 0
s2 0
l01.6( 1)
Formation of the centrosymmetric S ,202
molecule, which
is still unknown in the free state, from S 6 0 can be explained
in terms of a dipolar addition:
The chair conformation of the six-membered rings of the
two S 6 0 components can still be seen in SIZO2.
Thus dimerization of a sulfur ring has now been observed for the first
Prof Dr. R. Steudel, DiplLCbem. J. Sieidel. Priv.-Doz. Dr. J. Pickardt
Insutul fur Anorganische und Analytische Chemie der Technischen Universitat
Sekr. C 2, Strasse des 17. Juni 135, D-1000 Berlin 12 (Germany)
Angew. Chem. Int. Ed. Engl. 19 (1980) No. 4
Freshly distilled SbCI, (0.5 ml) is added to a stirred solution of p-S,Om (500 mg, 2.40 mmol) in dried CS2 (100 ml)
prepared at - 10 "C, and the mixture is immediately cooled
to - 50 "C. After one week, crystals of (1) (150 mg; 10%)precipitate which are isolated at - 30 " C on a glass frit, washed
with pentane ( - 30 "C), and dried in uacuo. The crystals release CS2 in the final step; they should therefore be stored in
the mother liquor at - 5 0 ° C (where they can be kept for at
least 5 weeks).
0 Verlug Chemie, GmbH. 6940 Weinheim, 1480
OS 70-0833/80/0404-0,25
$ 02.50/0
3 25
Received: October 19, 1979 [ Z 421 IE]
German version: Angew. Chem. 92, 313 (1980)
[ I ] Sulfur Compounds, Part 64.-Part 63: H:J.
Maude. R. Steude/. 2. Anorg.
Allg. Chem.. in press
[2] R. SreudeL J. Sreidel. Angew. Chem. 90, 134 (1978): Angew Chem. Int. Ed.
Engl. 17. 134 (1978).
131 I. Lindquisl: Inorganic Adduct Molecules of 0x0-Compounds. Springer-Verlag. Berlin 1963.
141 Space group P2,/n, a = 11589(5), b = 1833.3(9). c=935.9(5) pm.
p=114.86(4)". pirlr =2.29 g ' c m ' ( - IlS"C), 2 = 2 . 3020 reflections measured at - 115 "C (Syntex P2,). R=0.046 (anisotropic temperature factors).
151 A. Kuroglu. E. H e h e r . Angew. Chem 78. 1021 (1966); Angew. Chem. Int.
Ed. Engl. 5, 965 (1966).
the Sn -0 bonds, affording the tricyclic intermediate (2).
Subsequent addition of a few drops of water cleaves the labile Sn -N bonds[51and releases the macrocyclic dicarbamates (3).Applying this procedure macrocyclic dicarbamates
(3a), n = 6I6j, and (B),
n = 5, have been prepared in a simple
two step process. The compounds gave correct analyses and
characteristic spectra in agreement with the assigned structures. Compound (3a) was in addition characterized by a single crystal X-ray structure analysis (Fig. 1).
Syntheses with Metalloid Derivatives: Preparation
of Macrocyclic Dicarbamates
By Abraham Shanzer, Nava Shochrt, Dov Rabinovich,
and Felix Frolow[*l
The difficulty in directing condensation reactions to provide ring products in preference to polymeric materials represents the major barrier towards the efficient synthesis of
macrocyclic structures['! In order to overcome this barrier
various cyclization procedures have been recommended: dilution[2"l and double activation methodsIZbl,and the use of
or metal templates["]. We have found an alternative method, in which metalloid derivatives serve as
covalent templates for the construction of ring compounds
from acyclic precursors. Once the construction of the organic
shell has been completed, the metalloid template is easily removed by mild hydrolytic cleavage of the weak metalloidheteroatom bond. The feasibility of this approach will be demonstrated in this communication by the preparation of macrocyclic dicarbamates from ethylene glycol and diisocyanates using dibutyltin as covalent template.
2 BunSnO +2HO-CH&Hz-OH
2 O=C=N-(CH&- N=C=O
The synthetic sequence involves condensation of ethylene
glycol with dibutyltin oxide to give the known distannoxane
derivative (l)I3I.Treatment of the latter with organic diisocyanates results in insertionr4]of the N-C group between
Dr. A. Shanzer [ I. Dipl-Chem. N. Shochet
Department of Organic Chemistry. The Weizmann Institute of Science
Rehovot (Israel)
Dr. D. Rabinovich, Dr. F. Frolow
Department of Structural Chemistry, The Weizmann Institute of Science
Rehovot (Israel)
[ * ] Author to whom correspondence should be addressed.
0 Verhg Chemie, GmbH. 6940 Weinherm. I Y X O
Fig. 1. Crystal structure of (30). The measurements were performed on an EnrafNonius CAD-4 diffractometer with MaK,. radiation; space group C2/c,
a=16.805(1). b=8.452(1). c=17.067(1)
p=104.88". V=2342.5 A', 2 = 8 ,
p,,,,=1.32 g/cm'. P < , ~ . =1.31 g/crn3: 2531 independent reflections(es27"), solution by direct methods (MULTAN). refinement to R =0.039, torsion angles:
C32 C O l
C04 C07
N10 C12
0 1 4 C15
C18 0 2 1
C22 N24
C26 C29
- 58.6"
C 0 7 N10
C12 0 1 4
C15 C18
0 2 1 C22
N24 C26
C29 C32
COl C 0 4
- 53.1"
- 98.8"
- 99.5"
- 58.7"
The two carbonyl oxygen atoms in (3a) are almost perpendicular to the equatorial plane of the molecule and their deviations above or below this plane are equal (1.48 8).This
arrangement of the carbonyl groups, which define a n internal polar cavity, seems to be typical for such structures.
an alternatLikewise, in cyclic peptides such as er~niatin[~I
ing orientation of the carbonyl oxygen atoms above and below the plane of the ring is also observed.
The formation of the cyclic dicarbamates (3) from distannoxane (1) and diisocyanates indicates the dual function of
the metalloid template as activating and guiding unit. Activation is achieved by the electropositive character of the tin,
which increases the nucleophilicity of its attached functional
groups"]. Stereochemical guidance, on the other hand, is inferred by the rigidity of the ring structure. The latter directs
condensation reactions to proceed intramolecularly and
thereby reduces competitive polymerization processes. Direct
condensation of ethylene glycol with hexamethylene diisocyanate (160-170 " C ,8-20 h, dilution technique) has been
reported to yield less than 5% of the desired macrocyclic
product (3a)I'I.
The exclusive formation of the macrocyclic dicarbamate in
preference to the tetracarbamate deserves particular attention. Insertion of diisocyanates into the distannoxane (1)
could apriorz occur by either of the two alternative pathways
A or B (Scheme 1).
S (l2.50/0
Angew. Chem. Int. Ed. Engl 19 (1980) No. 4
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crystals, structure, dimerization, analysis, s12o2, 3cs2, 2sbcl5, s6o
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