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Organoosmium Oxides Efficient Syntheses and Structures.

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Table 2. Comparison of the "C NMR data o f 4 , 5. and 6 (75.5 MHz, [D,]THF).
6 (6)
6 (4)
6(5)
6 ( 5 ) - 6 (4)
6 ( 5 ) - - 6( 6 )
c-l
c-2
30.1
30.5
31 0 [a]
0.5
0.9
30.1
30.5
32.8 [a]
2.3
2.7
C-2a
146.2
118.7
112.4
-6.3
- 33.8
c-3
123.1
92.4
73.7 [c]
-28.7
-49.3
c-4
c-5
C-6
C-6a
CO
127.6
93.2
50.3
-42.9
-77.3
127.6
93.2
118.2 [b]
25.0
-9.4
123.1
92.4
126.2 [bj
33.8
3.1
146.2
118.7
73.7 [c]
-45.0
-72.5
235.4
245.7
10.3
[a. b] Interchangeable assignment. [c] The signals in the gated spectrum are clearly differentiated a s singlet (C-6a) and doublet (C-3).
composes above - 60°C to give a metal-containing solid
and cyclobutabenzene (6). Exposure to atmospheric oxygen
resulted in reoxidation to 4.
N M R spectroscopic analysis shows that the solution contains one main component, whose 13C N M R data are most
consistent with 5.Also present are at least two minor components, whose signals partly correspond to isomers of 5. This
is in agreement with the reoxidizability of the products to 4.
Because of the isomeric side products, the ' H N M R spectrum is of little value. The q4 coordination in 5 is shown,
however. by comparing its 13C N M R data with those for
cyclobutabenzene (6) (Table 2). For 5 and 2, the changes in
the chemical shifts of the terminal C atoms (AS = -77.3 and
-72.5, respectively) and the inner C atoms (AS = - 49.3
and - 33.8, respectively) of the coordinated diene unit relative to those of the free ligand are similar. Apparently, the
most strained double bond of the ligand remains preferentially in the coordination sphere of the metal. Similar observations were made earlier for 4,7-dihydroacepentalene complexes." 1'
IR spectra of 2 and 5 in T H F at - 30°C and of 2 at
- IOO'C in KBr were recorded.["] Owing to the increase in
electron density at the metal atom, the carbonyl bands display lower wave numbers than those in the starting materials. Small deviations from the data obtained by Cooper et
for K,[(q4-benzene) Cr(CO),] and by Rieke et aLL4]for
Na,[(q4-naphthalene)Cr(C0),I may be due to differing
measurement conditions and counterions.
This work thus represents the first synthesis and spectroscopic characterization of naphthalene-free solutions of
[(q4-arene)Cr(CO),] dianions whose decomplexed double
bond is not stabilized by an aromatic system. In order to
check whether the absence of stabilization facilitates the
transfer of the Cr(CO), group to other arenes, 2 was allowed
to react with ortho-xylene and 6, both in excess. However,
the Cr(CO), group was not transferred. Therefore, the transfer to naphthalener3] presumably occurs because naphthalene readily undergoes q4 coordination.
Experimentul Procedure
2. Lithium sand (40 mg. 5.7 mmol) was activated on the surface by vigorous
stirring under argon. It was then cooled to -78°C and combined, under a
stream of argon. with a solution of 1 (214 mg, 1.0 mmol) in 4 mL of [D,]THF
cooled to -78 c'. The initially yellow reaction solution turned red after a few
minutes and then brown. The suspension was stirred for 16 h at -78 'C and
then filtercd at -78 C to remove excess lithium sand. The brown-yellow solution is stable for several days under argon at -78'C.
Received: April 9, 1990;
supplemented: September 3, 1990 [Z 3901 I€]
German version: Angeir. Chm?. 102 (1990) 1469
CAS Registry numbers
I . 12082-08-1. 2. 129943-99-3. 4, 99537-78-7; 5, 129944-00-9
[ l ] M. F. Semmelhack, W. Seufert, L. Keller, J. Orgunornet. Chem. 226 (1982)
183.
[2] V. S. Leong. N. J Cooper, J. A m . Chcm. Sor.. 110 (1988) 2644.
[3] V. S. Leong. N J. Cooper, Organomeralli~s7 (1988) 2058.
Ang~ir.Chem h i t .
Ed. Engl. 29 (1990) N o . 12
141 R. D. Rieke. W. P. Henry, J. S.Arney, Inor,?. Chem. 26 (1987) 420.
[5] L.-N Ji, M. E. Rerek, F. Basolo. Orgnnome/u//ic.c.3 (1984) 740.
[6] E. 0 . Fischer, K. Ofele, Chem. Bcr. YO (1957) 2532.
[7] N M R data for dianions 2 and 5 (counterions Lie). 2. ' H N M R (200 MHz.
[D,]THF, - XO'C): 6 = 1.57 [br.s. 2H. 1(4)-H]. 4.65 [br.s, 2 H . 2(3)-H].
5.15 [br.s, 2H. 5(6)-H]. " C NMR (75.5 MHz, [D,]THF. - 80 C ) .
6 = 55.6 [d, C-1(4). 'J(C,H) = 150 f 2 Hz]. 87.5 Id, C-2(3), 'J(C.H) =
I63 & 2 Hz]. 124 5 [d. C-5(6). 'J(C,H) = 154 f 2 Hz], 245.8 (s. CO). 5.
I3C N M R (75.5 MHz, [D,]THF, - 80-C): 6 = 31 0 (t, C-I/C-2.
'J(C.H) = 135 Hz). 32.8 (t. C-l/C-2, 'J(C.H) = 134 Hz). 50.3 (d, C-4.
'J(C.H) = 149 Hz), 73.7 (d. C-3. 'J(C,H) = 167 Hz), 73.7 (s, C-6a). 112.4
(s. C-2a). 118.2 (d, C-5/C-6. 'J(C,H) = 155 Hz). 126.2 (d. C-Sic-6,
'J(C,H) = 154 Hz), 245.7 (s. CO). I n addition to the signals assigned to 5.
other weaker signals are present and are probably due to isomers of 5 .
[S] a ) H. G. Wey, H Butenschon, J. Organomel. Chem. 350 (1988) C8: b)
H. G. Wey. P. Betz, H . Butenschon. Chein. Ber.. in press.
(91 D. E. F. Gracey, W R. Jackson, W. B. Jennings, S. C. Rennison, R Spratt.
J. Chem. Soc. 5 1969, 1210.
[lo] a ) H. Butenschon, A. de Meijere. Tetrohedriron 42 (1986) 1721. b) Angeir.
Chem. 96 (1984) 722: Ang<,U. Chen?. h l . Ell. Engl. 23 (1984) 707.
[I I] Only the positions of the Carbony1 bands are given. 2 i R (THF. - 30 C ) :
C[cm-']= 1845m, 1810m, 1790s. 1765s, 1765m, 1735m. 1710m.
1665 m. The bands at 1845. 1735, and 1665 c m - ' disappear after only i<
few seconds, whereas !he other bands given here as well as those of the
starting material at 1960 and 1885 cm- become more intense. I R (KBr,
- l00'C): ,:[cm-'] = 3500 br. 3020 m, 2920 m, 2740 m. 1792 s, 1759 s,
1724s. 1 5 1 0 ~ 1. 4 8 0 ~ 1445m,
.
1300m. 1180m. 1155m. 1025s. 750m.
678 m, 635 m, 535 m. 4 : i R ( T H E - 30 C ) . O[cm-'] = 1842m. 1795 m.
1790m. 1750m, 1735m, 1708 m, 1665 m. The bandsat 1842.1790, 1735,
and 1665 c m - ' disappear after only a few seconds, whereas the other
bands given here a s well as those of the starting material at 1957 and
1878 c m - ' become more intense.
Organoosmium Oxides:
Efficient Syntheses and Structures **
By Wolfgang A . Herrmunn,* Stefun J. Eder. Paul Kiprof;
Kristin Rypdul, and Petru Watzlowik
The little explored organometallic oxides['] offer application in homogeneous and heterogeneous catalysis, for example in the oxidation and metathesis of olefins and in aldehyde
olefination.['] The synthesis of compounds of general formula R,M,O, has so far been left largely to chance, since the
usual oxide and halide precursors are not easily alkylated
because they are strong oxidants. An exception is the methylation of dirhenium h e p t a ~ x i d e , ~although
'~
extension to
[*] Prof. Dr. W A. Herrmann, S. J. Eder, P. Kiprof, P. Watzlowik
Anorganisch-chemisches lnstitut der Technischen Universitit Munchen
Lichtenbergstrasse 4, W-8046 Garching (FRG)
Dr. K. Rypdal[+]
Department of Chemistry, University of Oslo
P. 0 Box 1033 Blindern. N-0315 Oslo 3 (Norway)
[ ' 1 Electron diffraction analysis
[**I Multiple Bonds between Main-Group Elements and Transition Metals,
Part 84. This work was supported by the Fonds der Chemischen industrie
(doctoral fellowship lo S. J. E.) and the Deutsche Forschungsgemeinschaft. Part 83: I. A. Degnan, W. A. Herrmann. E. Herdtweck. Ch<,n?.Bcv.
123 (1990) 1347.
VCH VL.rlug.sp;esel/.schufimbH, W-6940 Weinheim. 1990
0570-0833/9011212~1445S 3.50f . 5 l J
1445
1
lb
I
'
5
2c
c
1
0
lb
I
IZnR2
.".I
4
3b
Scheme 1. Synthesis of selected new organoosmlum oxides. All compounds were characterized by elemental analyss; for further data see [7-9, 11, 121
even closely related osmium tetraoxide is not possible. Here
we describe a simple, generalizable synthetic procedure, as
exemplified by organoosmium oxides. It is based on the selective alkylation of glycolate complexes of metals in high
oxidation states.
Alkylosmium oxides of unpredictable composition are
formed in poor yields upon direct alkylation of osmium(vrr1)
For example, treatment of OsO, ( l a ) with dimethylzinc affords tetramethyl(oxo)osmium(vI) (2 a) in only
19 % yield (Scheme l).[4g1
Only recently was a more efficient
synthesis of a tetraalkylosmium oxide described.I5]
On the other hand, reaction of dimethylzinc and the airstable glycolate complex 1b, obtained by treatment of 1 a
with 1,2-ethanediol (> 95 % yield),[61 affords the methyl
compound 2 a in 60 % yield as a red solid that sublimes under
vacuum without d e c o m p ~ s i t i o n . ~
Compound
~"~
2 a, the simplest alkylosmium oxide so Far, has a square-pyramidal
molecular structure of symmetry C, in the gas phase (Fig. 1).
It is resistant to both oxidation and reduction: the cyclovoltammetric half-wave potentials are 2.2 V (irreversible)
and - 1.58 V (reversible), respectively, versus Ag/AgCl in
acetonitrile. Diethylzinc reacts with 1a to give the ethyl compound 2 b, which decomposes above - 60 "C and preferentially loses n-butane, ethane, and ethylene at room temperat~re.I'~]
Fig. 1. Gas-phase structure of tetrdmethyl(oxo)osmium(vi) determined by
electron diffraction. Selected bond lengths [pm] and angles ["I: 0s-C 209.6(3).
C-H 111.0(4), 0 s - 0 168.1(4); Cl-Os-C2 81.8(4), CljC2jC3jC4-0s-0 112.2(5),
0s-C-H 109(1); 0-0s-C-H 24.(8).
1446
q ) VCH Verla~s~esi~llrchaftf~
m h H , W-6940 Weinheim,I Y Y O
The synthetic principle--exchange of a glycolate chelating
ligand for two alkyl groups R+an be extended in a straightforward fashion to complex 1 c. As shown in Scheme 1, this
reaction affords the dimethylosmium(v1) compound 3 a in
55% yield.1sa1Complex 3a has a nearly undistorted octahedral molecular structure in the crystal with trans 0x0 and cis
methyl groups (Fig. 2.) It is resistant to alkylzinc com-
C2
C
c1
c12
C16
c13
C15
C14
Fig. 2. Molecular structure of dimethyl(dioxo)bis(pyridine)osmiurn(vI) (3a) in
the Crystdl (ORTEP plot without H atoms). Selected bond lengths [pm] and
angles ['I: 0 s - 0 1 172.3(3), 0 s - 0 2 171.5(3), 0s-C1 207.8(6), Os-C2 208.4(6),
0s-Nl 232.8(5), O S - N 233.2(4);
~
0 1 - 0 s - 0 2 164.8(2), C I - O S - C ~87.3(2), N1Os-N2 SS.9(1)[131.
pounds, but undergoes smooth alkylation on treatment with
the Grignard reagent Me,SiCH,MgCl in a redox-neutral
fashion and with retention of the cis configuration (!) (70%
yield).[g1Organometallic oxides with different alkyl ligands
are thus accessible for the first time by a direct and stereoselective reaction. Reaction of 1 c with bis(trimethvlsilv1- methyl) zinc gives complex 3 b18b](Scheme I), which was also
characterized by X-ray structure analysis.r101
In vacuum, complex 3 a loses one molar equivalent of
pyridine and affords the formally fivefold coordinated com-
o570-0~33/9O/f21Z-1446
8 3.50+.25/0
Angew. Chem. Int. Ed. Engl. 29 (1990) No. 12
plex [OsO,(CH,),(py)]. In the solid state, the latter complex
forms the trinuclear compound 4, which is octahedrally coordinated at osmium and has the same empirical formula
(45 % yield). The crystal structure (Fig. 3) is unusual in that
an unsymmetrical, nearly planar Os,O, six-membered ring,
held together by 0 - 0 s donor bonds, is present.["] However, these bonds stabilize only the solid-state structure.
They are so weak that, even in chloroform o r benzene, only
monomers are present (vapor pressure osmometry). Addition of pyridine results in conversion of 4 back to 3a.
04
c1
[3] W. A. Herrmann, J. G. Kuchler. J. K. Felixberger. E. Herdtweck. W. Wagner, Angew. Chc,m. 100 (1988) 420; Angrw. Chem. Int. Ed Engl. 27 (198X)
394.
[4] a) A. S . Alves, D. S . Moore, R. A. Andersen. G. Wilkinson, Po/rhedron I
(1982) 83; b) R. P. Tooze, P. Stavropoulos, M. Motevalli, M . B. Hursthouse, G. Wilkinson, J Chem. Soc. Chem. Commun. 1985, 1139; c) P.
Stavropoulos, P. G. Edwards, T. Behling. G. Wilkinson, M. Motevalli,
M. B. Hursthouse, J Chem. Sue. Dalton Truns. 1987,169;d) P. Stavropou10s. P. D. Savage, R. P. Tooze, G. Wilkinson, B. Hussain, M. Motevalli.
M. B. Hursthouse. ibid. 1987. 557; e) C. J. Longley, P. D. Savage. G.
Wilkinson, B. Hussain. M. B. Hursthouse, Polyhedron 7(1988) 1079;f) K .
Mertis, G. Wilkinson, J. Chem. Soc. Dalton Trans. 1976, 148X; g) S . J.
Eder, Diplomurbrit, Technische Universitat Munchen 1989.
[5] [OsO(CH,SiMe,),] has a structure analogous to 2 a and is formed in 54%)
yield from [OsO,CI,]'": R. W. Marshman, W. S . Bigham, S . R. Wilson,
P. A. Shapley, Orgunometailics 9 (1990) 1341.
[6] a) R. J. Collin, J. Jones, W. P. Griffith, J. Chem. Soc Dalton Truns. 1974,
1094; b ) R . Criegee, Jusrus Liebigs Ann. Chrm. 522 (1936) 75; c ) R .
Criegee, B. Marchand, B. Wannowius, h i d . 550 (1942) 99.
[7] a) 2a: Red needles after sublimation under high vacuum onto a cold finger
(O"C),m.p.74~'C.IR[cm~']v(OsO)
= 1013 vs(Cs2),994vs. br(KBr). 'H
NMR (270 MHz, [D,]toluene. 20 "C): 6 = 2.74 (s). "C NMR (67.9 MHz.
[DJtoluene, 20' C): 6 = 23.91. EI-MS (70 eV, L920s):molecular ion at m / ;
268 (Me,
16%). " 0 NMR (C,D,, 20°C. external standard H,O): 6 =
512. b ) 2 b . Orange crystals, stable at -78 'C. ' H NMR (400 MHz, CDCI3,20'C):6 =4.03(q.-'J(H,H) = 7 . 3 H z , 8 H ; C H 2 ) , 1.51 (t, 12H;CH,).
{'HI ',CNMR (100.5 Hz, CDCI,, 20'C): 6 = 40.30 (CH,), 20.29 (CH,).
41 %).
CI-MS ( 1 9 2 0 s )mi;
. 324 (Me,
[XI a) 3a: Red-brown, air-stable crystals, m.p. % 235 "C. Red-brown cubes of
dimensions 0.64 x 0.38 x 0.36 mm obtained from CS, solution ( - 25 C);
systematic absences, h0l (I = 2n 1). 0k0 ( k = 2n 1); space group, monoclinic, P , /c (No. 14). Lattice constants after least-squares refinement
from 25 reflections at large diffraction angles. u = 674.0(1). h = 1479.4(2).
L' = 1355.1(2) pm, /3 = 92.27( < l)", V = 1350 x 10, pm'; empirical formula, C,,H,,N,O,Os (410.5); 2 = 4; F,, =776. P(calcd) = 2.02 g cm-',
Enraf-Nonius CAD-4 diffractometer, Mo,. radiation 0. =71.073 pm).
graphite monochromator; T = 23 2 3 "C: measuring range, 1.0 < 0 <
25.0'; o scan; scan width, (1.00 0.30 t a n 0 ) f 25% before and after
each reflection for background determination; r(max), 60 s; 2695 mea2082 unlque reflections, 237 reflections
sured reflections ( + h , k,
with I > 2.0 o(f)suppressed; 155 parameters after full-matrix least squares
refinement; R = CIIF,I - l~ll/F,l= 0.035; R, = [Z w(llFnl - IF,
= [ x \ ~ ( ( / F-l IF,ll)2/NO-NV)]"2 = 1.964nur
E W ( F ~ ( ~=]0.030;GOF
"~
M' = l/02(Fn).
Structure solution: Patterson methods, difference Fourier
technique; empirical absorption correction, p = 94.5 cm- ', nine reflections; no decomposition; extinction, I; = 0.2525 x lo-', corrected: hydrogen atoms calculated for ideal geometry (d(C-H) = 95 pm) and included in
the calculation of the structure factors with a collective isotropic temperature factor per C atom but not refined. Anomalous dispersion was laken
into consideration. Shiftierror < 0.01 in the last cycle of refinement; resid1.10e0Afor99pmand - 1.10e,A-3 for 104pm
ualelectrondensity,
distance from osmium atom. IR (CS,)[cm-'] v(Os0) = 866 (vs. 'H NMR
(270 MHz, C,D,, 20°C): 6 = 3.92 (s. 6 H , CH,). 8.84 (m, 4H. CH). 6.79
(m. 2 H ; CH), 6.57 (m. 4 H ; CH). I3C NMR (100.5 MHz. C,D,%.20'C):
6 = -7.37 (4, 'J(C,H) = 130 Hz; CH,) 147.24 (0).138.20 ( p ) , 124.15 (m).
" 0 NMR (54.2 MHz, C6H,/C,H,N, 2 0 T , external standard H,O):
6 = 617, b)3b: brown crystals. ' H NMR (400MHz. CD,CI,, 20'C):
+
+
+
Fig. 3. Structure of trimeric dimethyl(dioxo)(pyridine)osmium(vI) (4) in the
crystal (ORTEP plot without H atoms). Selected bond lengths [pm] and angles
["I: Osl-01 173.5(3), O s l - 0 2 171.7(4), O s l - 0 3 231.2(4), Os3-01 244.5(4), OslN1 232.4(6). Osl-C1 203.3(8), Osl-C2 207.0(7); 0 1 - O s l - 0 2 164.3(2), C1-OslC2 89.1 ( 3 ) . 0 1 - 0 s l - 0 3 81.9(2), O s l - 0 1 . 0 ~ 3 153.1(3)[13].
The constitution of the glycolate ligands may be used to
control the selectivity of alkylation. The bulky bispinacolate
complex l b reacted with Zn(CH,), to give the dimethyl
compound 5, also characterized by an X-ray structure analysis,Iiol in 55% yield.[12]The second chelating ligand here is
only removed upon treatment with Grignard reagents
(Scheme I). This approach represents a second way to obtain
mixed alkylated osmium oxides.
The glycolate derivatization-possibly
with reduction
(Scheme 1) -has proven useful in the efficient synthesis of
alkyl(oxo) complexes of osmium in medium and high oxidation states. I t is superior to the methods used so far with
respect to yield, selectivity, and generizability. The route to
a thorough exploration of this class of substances is thus
open, and we have applied this technique to metals other
than osmium.['4'
Received: July 26, 1990 [Z 4095 IE]
German version: Angew. Chem. 102 (1990) 1460
CAS Registry numbers.
l a . 20816-12-0; 1 b, 54260-55-8; 1 b, 52782-38-4; l c . 39019.05-1; 2a. 13014961-0; 2b. 130149-63-2; 2e, 130149-64-3. 3a, 130149-65-4; 3b, 130149-67-6: 4,
130149-66-5: 5, 130149-62-1.
+ + n,
+
6=0.07(s,18H;CH,),4.14(s,4H;CH,),8.58,7.40(2m,2~4H;CH),
7.80 (m, 2 H ; CH). "C NMR (100.5 MHz. CD,CI,, 20 'C): 6 = 0.34
(CH,), 4.11 (CH,), 124.6, 138.4, 148.3(CH).
[9] 2 c : brown oil. I R ( C S , ) [cm-'1: v(Os0) = 1005 vs. ' H NMR (400 MHz.
CDCI,. 20'C): 6 = 4.10 (d, 'J(H.H) =7.9 Hz; 2H: CH,). 3.45 (d,
2J(H.H)=7.3 Hz,2H;CH,).2.99(s.6H;OsCH3),0.09(s.18H:SiCH,).
{'H}I3C NMR (100.5 MHz, CDCI,, 20°C): b = 40.81 (t, 'J(C,H) =
124 Hz; CH,), 24.86 (4. 'J(C.H) = 132 Hz; OSCH,), 1.11 (t. 'J(C.H) =
119 Hz; SiCH,). El-MS (70eV. 1920s):mi; 412 (Me,
7%).
(101 W. A. Herrmann, P. Kiprof, unpublished results. 1990.
[l I] 4. Dark, air-stablecrystals. m.p. 83'C ; sublimation at 80 "C/ ca.
Torr
afforded red-brown prisms of dimensions 0.38 x 0.26 x 0.20 mm: no systematic absences; space group, triclinic. Pi (No. 2). Lattice constants after
least-squares refinement from 25 reflections at high diffraction angles:
u = 972.6(1),
b = 1090.9(1).
c = 1415.0(1) pm,
a = 8 5 03(<1),
/3 = 76.41(1). 7 = 67.71(1)'; V = 1350x 10'pm'.
empirical formula.
C,,H,,N,O,Os, (994.1); 2 = 2, F,,, = 912; e(calcd) = 2.44 gem-): Enraf-Nonius CAD-4 diffractometer, Mo,, radiation ( . = 71.073 pm),
graphite monochromator; T = 23 f 3 "C; measuring range, 1.O < 0 < 250 ; w scan; scan width, (0.90 0.30 tan 0) _+ 25% before and after each
reflection for background determination; t(max) 60 s; 5028 measured reflections (- h , i - k , f l ) . 4394 unique reflections, 4394 reflections with
I > 0.0 o(0 used. 299 parameters, full-matrix least-squares refinement,
R = C(IIF,I - IF~I~EIF,I
= 0.048; R, =
NF,I - IF,II)~E ~ ~ I K J ~
= 0.042; GOF =
w(llFol - lFc11)2/(NO-NV)]"2= 3.951 mit )L' =
l/aL(FO).
Structure solution: Patterson methods, difference Fourier tech
+
[I] Reviews: a) F.Bottomley, L. Sutin, Adv. Orgunomet. Chem. 28 (1988) 339;
b) W A. Herrmann, Angew. Chem. iUO(1988) 1269; Angebr. Chem. Int. Ed.
Engl. 27 (1988) 1297.
121 W. A. Herrmann. J Orgunornet. Chem. 382 (1990) 1. and references cited
therein.
Angrn . Chiw lni Ed. EngI. 29 (1990) N o . 12
[x
!I>
VCIf Verlu~.sge.srll.~ci~u~r
mbH, W-6940 Weinheim. 1990
[x
0570-0833/9f)~1212-1447$ 3.50+ .25!U
1447
I ~ ~
nique: empirical absorption correction, bi = 141.5 cm-l. eight reflections.
decomposition, - 18.9% f in 77 3 h for tlireecontrol reflections. isotropic correction, extinction. i: = 0.3526 x lo-'. corrected: hydrogen atoms
caculated for ideal geometry (d(C-H) = 95 pm) and included in the calculation of the structure factors with a collective isotropic temperature factor
per C atom but not refined. Anomalous dispersion was taken into consideration Shiftlerror < 0.01 in the last cycle of refinement: residual electron
2.58 e , , k 3 for 85 pm and - 2.77 e,&' for 91 pm distance
density:
from osmium atoin. IR [cm-'1: I ~ O S O=) 904 vs (CS,). X68 vs (KBr).
' H N M R (400 MHL, C,D,, 20 C): 6 = 3.91 (s. 6 H : CH,) 8.35 (m, 2 H :
CH). 6.79 (m. I H: CH). 6.51 (m, 2 H : CH). ( ' H ) ' ' C N M R (100.5 MHz.
C,D,. 20 C). 6 = - 10.74 (CH,). 124.6, 139.0, 147.1 (CH). "ONMR
(54.2 MHz. C,H,. 20'C. external standard H,O): 6 =745. FD-MS
(CH,CI,, "*Os): mlz 333 (monomer; rel. int ll'h).
[12] 5. red crystals, dcc. above ca. 150 C, sublimable at 50 Ci760 Torr. IR
(KBr) [cm-'] (e(0sO. term.) = 950 vs. v(Os0. ester) = 634 m. ' H NMR
(400 MHz. C,D,. 20 C): 6 = 0.93 ( s , 6 H ; CCH,), 1.27 ( s . 6 H : CCH,),
3.87 ( s . 6 H : OSCH,). "CNMR (100.5 MHz. C,D,. 20 C): 6 = 18.28
(OsCH,), 24.63 (CCH,). 25.80 (CCH,). 90.94 (CCH,) "ONMR
(54.2 MHz. pentane, 20 C. external standard H,O): B = 675. El-MS
(70eV. i920s):m i ; ( M @ ,5 % )
(131 Further details of the crystal structure investigation o f 3 a and 4 may be
obtained rrom the Fachinformationszentrum Karlsruhe, Gesellschaft fur
wissenschaftlich-technische Information inbH, D-7514 Eggenstein-Leopoldshafen 2 (FRG), on quoting the depository number CSD-54862, the
names of the authors and the journal citation.
[14] W. A. Herrmann, P. Watzlowik. P. Kiprof, unpublished results 1990.
+
which is almost unchanged from the Raman line of elemental
Br, (317 cm-I). No BrF stretching vibration could be seen.
In the case of CsF . Br,, we succeeded in growing single
crystals and carrying out an X-ray analysis (Fig. 1). Much to
our surprise the compound is a cesium fluoride intercalation
compound with Br, as guest. The NaC1-typecesium fluoride
lattice has opened along the (100) planes and the Br, molecules are stacked between the planes. The cesium and fluorine atoms are arranged in an eclipsed manner along [IOO],
resulting in a primitive tetragonal cell. The Br-Br distance of
232.4pm is only slightly longer than that in elemental
bromine (228 pm) and the Br . . F' contacts (252.1 prn) are
about 4 0 % longer than a normal Br-F bond (180 f 10 pm).
Any covalent bonding here must be very weak.
CsF-Br,, an Alkali-Metal Halide Intercalation
Compound **
By Darryl D. DesMarteau.* Thomas Grelbig,
Sun-ffee ffwang, and Konrad Seppelt
Cesium fluoride is one of the strongest fluoride catalysts,
since it combines a very large cation and a very small anion
in a simple NaC1-type lattice. Therefore, the salt has a strong
tendency to "increase" the size of its anion by forming intermediate or permanent anionic fluoride complexes. There are
a large number of complex cesium fluorides CS:AF:,
where
A can be almost any element of the periodic system. Many
of their structures are known.
In the reactions of fluorinated nitriles with bromine in the
presence of CsF, the C s F was found to absorb bromine,
which was not readily removed at room ternperature.['*'I
Subsequent investigation revealed that CsF can absorb both
Br, and I, to form complexes in which the ratio CsF:X, is
1 : I and 2:1.[31 The CsF.Br, complex is very effective in
oxidizing fluorinated nitriles and imines to N-bromo derivatives as well as in converting N-CI bonds into N-Br bonds
in N,N-dichloroamines." - 3 1 This reactivity, combined with
the novelty of the CsF-halogen complexes, made their structure determination of interest.
The halogen-rich 1 : 1 phases are formed with excess halogen at room temperature, and the 2: 1 materials can be prepared by prolonged pumping at lo-' mbar on the 1 : I
phases. The supposition that the 1 : 1 materials might contain
the polyhalide ions [Br-Br-F]' and [I-I-FIO (cf. Br?, BrFF,
IClF, CI,F') was not in accord with the Raman spectra of
CsF-Br,, since it shows only one line at i;= 292.5 c m - ' ,
[*] Prof. D D. DesMarteau, S.-H Huang
Department of Chemistry. Clemson University
Clemson, SC 29631 (USA)
Prof. K . Seppelt, T. Grelbig
Institut fur Anorganische und Analytische Chemie der freien Universitit
Fabeckstrasse 34-36, D-1000 Berlin 33 (FRG)
['*I
Fig. 1. Crystal structure o f C s F . Br, (two adjacent unit cells). The orange crystals were grown from CsF in a large excess of elemental bromine at 80°C in a
glass ampoule over four weeks. Enraf-Nonius CAD-4 diffractometer.
T = - 153'C, Mo,,. graphite monochromator, 4 2 8 scan, DIFABS absorption correction. SHELX. full matrix, P4/nimn? (No. 123). u = 417.7(2),
c =736.4(2) pm. V = 128.5 x 10' pm', Z = 1. Reflections: 886 measured, 287
independant, 264 with I > 341) within 2 5 0 i 4 0 . R = 3.15, R, = 2.6. Further details of the crystal structure investigation are available on request from
the Fachinformationszentrum Karlsruhe, Gesellschaft fur wissenschaftliche
und technische Information mbH. D-7514 Eggenstein-Leopoldshafen2
(FRG). on quoting the depository number CSD-54259. the names of the authors. and the journal citation.
If one considers the NaCl lattice to be very stable, this
reaction is very surprising. But Madelung lattice energy calculations (MAPLE)t4] on CsF show that cleavage along
(100) results in loss of only 6 % of the energy; which explains
the cleavability parallel to (100) for such crystals. If entropic
terms are disregarded, this small loss of electrostatic energy
could be compensated for by even very weak Br . . . F' interactions, which could amount to only a few kJ mol-'.
The coordination of the CsQ ions is square planar and the
Cs' . . Fa distance of 300.1 pm in cesium fluoride is reduced to 294.0 pm in CsF . Br,. This is virtually identical to
the CsQ . . F@distance of 293.6 pm in the high-pressure CsF
(CsCI-type) modification (48 k b ~ ) . [If~ the
] bromine atoms
at a distance of 388 pm are included in the coordination of
CsQ, the coordination number is 12 and the coordination
polyhedron a square-based column.
Whether these features are retained in CsF.1, and whether
the 2: 1 phases are intercalates where only every second layer
is filled remain speculation until structural data are available.
This work was supported by the Fonds der Chemischen Industrie and the
Alexander von Humboldt Stiftung. We thank Prof. G. M e w r . Hannover,
for help with the MAPLE calculations.
1448
Q VCH V ~ . r l u g . s ~ ~ ~ . s e l lmhH.
~ c h u / ~W-6940 Weinh<>.irn,
1990
0570-0833!90~1212-1448
.$3.50+ .25jO
Received. July 2. 1990 [Z 4048 IE]
German version: Angeii. Chern. 102 (1990) 1519
Angels. Chem. I n t . Ed. Engl. 29 119901 No. 12
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