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Concerning the Role of Organotin Compounds in Olefin Metathesis Synthesis Structure and Lewis Acidity of [(5-C5Me5)CH3ReCl3].

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Concerning the Role of Organotin Compounds in
Olefin Metathesis: Synthesis, Structure, and Lewis
Acidity of I(qs-CsMes)CH3ReC131**
By Wolfgang A . Herrmann,* Josef K . Felixberger,
Eberhardt Herdtweck, Adolf Scliafer. and Jun Okuda
Dedicated to Professor Heinz Harnisth
on the occasion o f h i s 60th birthday
Tetraorganotin compounds are the most effective cocatalysts for olefin metathesis. Rhenium, after molybdenum
and tungsten, is the most active metal present in catalysts
for this reaction."] A soluble reaction product formed from
ReCI, and Sn(n-C4H,)4 (molar ratio 2 :3), which was not
further characterized, was found in 1971 to be the first rhenium-containing system for olefin metathesis in homogeneous catalysis."] The related heterogeneous system
Re20,/A1203/Sn(CH3)4 even effects the metathesis of
functionalized ole fin^.[^.^^ Although the actual mechanism
of metathesis"' may be regarded as having been established at least for soluble catalysts (olefin cycloaddition to
metal carbene species), this statement does not apply to the
mode of activation of such catalysts by the tetraorganotin
compounds (alkylation vs. reduction).I5' We have therefore
attempted, by means of the readily accessible, simple organorhenium(v) complexes l a , b , to determine the elementary steps involved in the reaction of tin-containing cocatalysts with higher-valent, soluble rhenium compounds and
report herein the synthesis, characterization, and reactivity
of novel alkylrhenium complexes.
ReCl and CH,Re groups.["] The complex [(qsC,Me5)CD,ReC131 ([CD,]-2a. 99.5% labeling), which is obtained analogously from l a and Sn(CD,),, allows the assignment of all CH and C D vibrations, respectively.'"' A
single-crystal X-ray structure analysis of the better crystallizing derivative 2b (Fig. I), despite the disorder of a CI
atom with the CHI group, confirms the expected structure,
namely, a half-sandwich complex with square-pyramidal
co~rdination;~''the analogously synthesized derivative
[(qs-C5Me,Et)CH3ReBr3] has the same geometry in the
crystal but exhibits no disorder.
Fig. I . Molecular crystal structure of 2b. T h e complex forms orthorhombic
crystals (dichloromethane/ri-pentane, -30°C) in the space group Pbca (1.T.
No. 61j [7]. T h e atoms C13 and C are disordered (75 :25).--Selected distances
[pm] a n d angles ["I: Re-Cll 235.4( I). Re-C12 236.6(1), Re-C13 233.0(2), Re-C
229.7(3): CII,Re,C12 80.8( I).-Further details o f the crystal structure investigation may be obtained from the Fachinformationszentrum Energie. Physik,
Mathematik G m b H , D-75 14 Eggenstein-Leopoldshafen 2 ( F R G ) , o n quoting
the depository number CSD-52335, the names of the authors, a n d the journal citation.
+ S n (CH,),
3 a,b
= CH,
= CH,
= C,H,
Scheme I
Treatment of a CH2CIZsolution of l a at room temperature with 1.1 equivalents of tetramethylstannane results in
smooth transmethylation, according to Scheme I , to give,
in addition to trimethyltin chloride ('H-NMR detection),
the new Re" complex 2a as brown, slightly air-sensitive,
and strongly moisture-sensitive crystals. According to elemental analysis and the F D mass spectrum, this substance,
which dissolves in polar organic solvents without undergoing decomposition, has the formula [(C,Me,)CH,ReCI,].
The IR spectrum exhibits, in addition to the band pattern
for the (C,Me,)Re fragment, characteristic bands for the
Prof. Dr. W. A. Herrmann, J. K. Felixberger, Dr. E. Herdtweck,
Dr. A. Schafer, Dr. J. Okuda
Anorgdnisch-chemisches lnstitut der Technischen Universitst Miinchen
Lichtenbergstrasse 4, D-8046 Garching ( F R G )
Multiple Bonds between Main-Group Elements and Transition Metals,
Part 42. This work was supported by Hoechst A G and the Bundesministerium fur Forschung und Techno1ogie.-Part 41: W A. Herrmann, K.
A. Jung, A. SchPfer, H.-J. Kneuper. Atigew Cliem. 99 (1987) 464; Angen'.
Cliem. Inr. E d . Engl. 26 (1987) 464.
0 V C H Verlagspcell.cchaft mhH. 0.6940 We,nheim. 1987
In contrast to the oxidic d'-Re" complexes of the type
[(q5-C5Me,)ReOXZ](X = alkyl, halogen),[x1the aromatic n
ligand of 2b is nearly symmetrically bound to the metal.
As shown by MO analysis of the d'-complexes [(nCsMe5)ReX4] (X =anionic ligand), these complexes can
form singlet/triplet equilibria.["] As a consequence, the metal-bound CH, group of 2a exhibits a strongly temperature-dependent paramagnetic shift in the 'H-NMR spectrum. Whereas the resonance absorption appears at
6= +36.5 (!) at +50"C, it is shifted to higher field with
decreasing temperature and appears at 6= + 13.5 at
- 50°C.
Because of the pronounced flattening of the ReCI,C
pyramid in 2 (sum of angles of ReCI,C in 2b 325"; Fig. I),
complexes of type 2 should allow an additional ligand to
add at the trans position to the n-bonded ring system when
the rhenium(v) centers act as Lewis acids. This is indeed
the case (see Scheme I): for example, 2a reacts with water
in the presence of two equivalents of pyridine to give the
0x0 derivative 3a Your different ligands!),["'] and with trimethylphosphane to give the stable adducts 4a,b,I"' which
presumably have octahedral structures in analogy to the
complex [(q5-CjMej)ReC14(PMe3)],1i'1
which has been
characterized by X-ray structure analysis.
When higher alkyltin compounds are allowed to react
with the tetrachloride l a under otherwise identical conditions, one obtains, in the case of Sn(C,H,), and Sn(nC4H,)4, in addition to the corresponding trialkyltin chlorides, a rhenium(~v)complex, which does not contain the
ethyl or n-butyl groups expected according to Scheme I .
Instead, the product, which is soluble in CH'CI?, has the
0570-08~3/87/0505-0466$ 02.50/0
Angew. Cliem. Inr. E d . Engl. 26 11987) No. 5
formula 5a.Ii'] Its binuclear constitution follows from the
diamagnetism, which requires a direct metal-metal interaction, and from the reaction with trimethylphosphane leading to formation of the paramagnetic Re'" complex 6a.[143
Taking into consideration the liberation of ethylenel
ethane and I-butene/n-butane, respectively (detected by
gas chromatography), the formation of 5a, which involves
reduction (ReV-ReSV),may be explained by a p-hydride
shift and its consequences (Scheme 2): the alkyl intermediate A rearranges to give the hydrido(o1efin) isomer B,
which then undergoes reductive decomposition with olefin
elimination and intermolecular alkane formation; elemental hydrogen does not appear during the formation of 5a.
These findings show that alkyltin compounds of highervalent metal halide systems, although alkylating initially in
a redox-neutral reaction, can subsequently lead to reduction of the transition metal when, sterically and electronically (Lewis acids), the metal allows alkyl rearrangement
processes such as the p-hydride shift to occur. It is interesting that even an excess of Sn(CH3), does not lead to multiple methylation of the tetrachloro complexes l a , b ; the
compound [(q5-CsMes)Re(CH,),] is obtainable, however,
from la via the Grignard route.[i5'
+ A
+LRe-11CH, +
2 L,Re
Scheme 2.
Experimental Procedure
2a: A wspension of I (463 mg, 1.00 mmol) in 20 m L of C H I C l l was treated
at room temperature with Sn(CH,), (0.15 mL, 1.08 mmol) a n d then allowed
to stir for 2 h (N, atmosphere). T h e violet suspension was thereby transformed into a red-brown solution. After removal o f the solvent, the crude
product was washed three times with 10 m L o f n-pentane a n d finally recrystallized from CH,CI,/n-pentane at - 30°C. Yield 375 mg (SSo/o) red-brown,
analytically pure crystals; n o m.p. u p t o 2 5 0 T - 2 b was synthesized analogously: brown-red crystals; m.p. = 135°C (dec.).
[71 Red-brown octahedra: space group Pbca: a = 1247.0(3). h=836.6(1).
c=2854.0(8) pm, n = / ? = y = 9 0 " ; V = 2 9 7 7 x 10'' pm', 2 = 8 : M=456.9.
T = 2 5 " C : p,.,,,,,=2.038 g c m - ' : fit,,,,=1744; CAD4 (Enraf-Nonius),
graphite monochromator, A =0.7107 A (Mok,J, measuring range:
I " S H S 2 5 " , / ( m a x ) = 6 0 s , h(O/l4), k(0/9), /(-33/33): 5844 measured
reflections, of which 728 were not observed, 2591 unique reflections,
1816 unique reflections with I > 3.0m(/) used for refinement, structure
solution by Patterson methods: all non-hydrogen atoms refined anisotropically, H atoms calculated at ideal positions a n d included i n the calculation of structure factors: empirical absorption correction, p = 87.93
cm - I ; R = Z(ll&,l- IF,II)/ZIfi,I=O.O29: R,,=[Zw(l&,I - lFJ)'/XwF~,]'~'=
0.028, G O F = [Zw(lF,,I - IF,I)'/(NO - NV)]' = 3.3 I6 ( w = I /o'(F,,)):
Ae,,/A'= 1.32.
[8] W. A. Herrmann, E. Herdtweck, M. Floel, J. Kulpe, U. Kdsthardt, J
Okuda, PoirJiedron. in press.
[9] P. KubiCek, R. Hoffrnann, Z. Havlas, Organome/al/ics I (1982) 180.
[lo] 3a: I R ( K B r , c m - ' ) . l 2 0 3 m ( G R e C H , ) ; 2 9 7 8 m , 2 9 5 5 m , 2 9 1 5 m , 2 8 9 3 m
(vCH); 1460 m (sh) ( 6 C H ) : 1389 m, 1378 s, 1040 s (sh) (VCC): 963 vs,
951 vs (vReO): 365 w, 343 s (vReCI) ' H - N M R (400 MHz, C,.D,, 30°C):
G(ReCH,)=2.75 (s, 3 H ) , G(C,(CH,),)= 1.54 (s. I5H). " C I ' H J - N M R
(100.4 MHz, C,D,,, 30°C): S(C,Me,)= 103.65, G(C,(CH;),)= 10.79,
S ( R e C H , ) = - 11.04. E L M S (70 eV; '"Re/"Cl):
m / z 388 ( M 9 , 50'%r),
373 ([M-CHIIo, 100%), 337 ( [ M - C H I - HCl]o, 90%). Correct C,H.CI
elemental analyses.
[ I I ] 4a: Dark brown crystals, m.p.= 138°C (dec.). IR (KBr, cm . I ) : 3000 m,
2980 m, 2915 s ( v C H ) ; 1490 m, 1455 m, 1420 m ( 6 C H ) ; 1372 s, 1022 m
(vCC): 1288 s, 970 vs (sh) (PMe,); 305 m (sh) (vReCI); 1005 rn, 870 w,
730 m, 680 m, 370 w (without assignment). ' H - N M R (270 MHz, C , D , ,
20°C): S ( P C H , ) = 1.562 (d, 9 H ; 'J(H,P)= 11.7 Hz); G(ReCH,)= 1.536
(d, 3 H ; 'J(H,P)= 14.7 Hz); 6(Ci(CH,),)= I 4 9 1 (s, I5H). " P I ' H / - N M R
( 3 6 4 3 MHz. C,,D,, 20°C: ex!. H,PO,): is=6.70 (P). " C ( ' H I - N M R (67.8
G(C5Meij= 108.03,
ii(ReCH,)= 15.37.
6(P(CHx),)= 15.12 (d: 'J(P,C)=39.9 Hz], G(C,(CH,),)= 10.63. E l - M S
(70 eV; '"Re/"CI): m / z 517 ( M O - H ; correct isotope pattern). Correct
C,H,CI,P elemental analyses.
[I21 W. A. Herrrnann, E. Voss. U. Kusthardt. E. Herdtweck, J . Oryanomrf.
Chem. 254 (1985) C 3 7 .
1131 5a: Dark brown crystals: no melting point u p to 250°C. IR (selected:
KBr, c m 335 vs/305 s (vReCI); 1485 s/1450 s ( 6 C H ) : 1375 vs/1025
vs (sh) ( K C ) ; 1 0 7 8 . m . ' H - N M R (270 MHz, CD,Cl,. -50°C):
S ( C H , ) = 1.85 ( s ) . E l - M S (70 eV, "'Re/''CI): m / z 427 ([C,MerReCI,]'",
30"/0), 392 ([CiMeiReCI,I", 5%). 355 ([CiMe,ReCI,-2 HCl]". IOO'YO), 36
(IHCI]", 3So/o). Correct C,H,CI elemental analyses.-The formulation o f
this compound a s a dimeric species also results from the ohcervaiion
that it can be reduced to the structurally characterized Re"' complex o f
W. A. Herrmann. R. A. Fischer,
composition ((iii~CiMei)Re(~~-CI)Cl]::
E. Herdtweck, unpublished results.
[I41 6a: Brown crystals, m.p.= 163°C (dec.). IR(se1ected. KBr, cm I ) : 275 s.
305 s, 320 vs (vReC1): 950 vs, 965 vs, 1282 s, 1290 s. 1370 m (PMe,)
E l - M S (70 eV, '"'Re/''CI): m / z 503 (molecular ion, 5%), 468 ([M-CI],
30%). 433 (IMo-ZCll, 15%). 356 ([C,,,H,,ReCII@, l00%). Correct
C,H,CI,P elemental analyses.
[ i s ] M. Floel, E. Herdtweck, P. Harter, J. Kulpe, W A. Herrmann. Angrfi,.
Chem. 99 (1987), Angen. Chem. Int. Ed. Engl. 26 (1987). in press.
3a: A suspension of 2a (160 mg, 0.36 mmol) in 10 m L of toluene was allowed
to react at 25°C with a solution of HIO (6.5 pL, 0.36 mmol) a n d pyridine
(58 pL, (1.72 mmol) in I m L o f tetrahydrofuran (THF). After stirring for 2 h
under N2, the brown reaction solution was filtered t o separate the precipitated pyridinium hydrochloride a n d then concentrated. Addition o f a layer
of n-pentane resulted in t h e precipitation at - 30°C of 8 4 mg (60%) of black
crystal\: m.p.= 174°C.
Received: December 23, 1986 [Z 2029 IE]
G e r m a n version: Angew Chem. 95 (1987) 466
[ I ] Reviews: R. H. Grubbs, Prog. Inorg. Chem. 24 (1978) I : T. J. Katz, Ad".
Oryanomet. Cliem. 16 (1977) 283.
[Z] J. A. Moulijn, C. Boelhouwer, Cl7em. Commun. 1571. 1170.
(31 E. Verkuijlen. F. Kapsteijn, J C. Mol, C . Eoelhouwer, J. Chem. SOC.
Chrm Commun. 1977. 198; J. C. Mol, E. F. G. Woerlee, ibid. 1575.
[4] J. <. Mol, J Mol. Coral. 15 (1982) 35.
[5] E. L. Muetterties, Inorg. Chem. 14 (1975) 951.
[h] 2 a : IR (KBr, cm '; *: bands for C D , derivative): 1198 m (6ReCHI), 745
m (yReCH,): 3000 2-m/*2256, 2958 w-m/*2203, 2912 w-m/*2098
(iX'H): 1482 s ( 6 C H ) ; 1378 vs, 1018 s (vCC); 330 vs (vReCI). F D - M S
(('H2< 1:: "'Re/"CI):
m / z 442 (M3,lOO"/o: correct isotope pattern). ' H N M R (270 MHz. CDCI,, 20°C): G(ReCH,)=27.98 (s, 3 H ) ,
,S(('.ICHl)\)=2.41 (s. 15H); chemical shift o f the rhenium-bound C H ,
group stronely temperature dependent (cf. text). "CI'HI-NMR (67.8
MHz. CIX'I,. 20°C): &(CiMe,)= 143.8, S(C.(CH,),)= 16.0. cS(ReCHlj
1101 unambiguously assignable. Correct C,H,CI elemental analyses.
[Ph4PI,[Sb218]: Weak Interactions between
Phenyl Groups of the Cation and
Antimony Atoms of the Anion**
By Siegfried Pohl,* Wolfgang Saak, and Detlev Haase
Arene-SbC13 adducts have already been well documented."." In the last few years numerous comparable
complexes of galliurn(i),['l tin(it), and l e a d ( i ~ ) ,as
~ ~well
of halides of trivalent elements of the fifth main group['-']
with neutral arenes have also been synthesized or characterized for the first time. We report here on the complex
[Ph,P]z[SbZIJ. 2C H JCN
A i i g ~C'hrm
lnt Ed. Engl. 26 11587) No 5
in which we found similar interactions characteristically
revealing that the phenyl groups of the cation function as
Prof. Dr. S. Pohl, W. Saak, D. Haase
Fachbereich Chemie d e r Universitat
Carl-von-Ossietzky-Sirasse, D 2 9 0 0 Oldenburg ( F R G )
This work was supported by the Fonds d e r Chemischen lndustrie
0 VCH Verlag~gesellrchafrmhH. D-6540 Weinheim. 1987
0570-0833/87/0505-067 $ 02.50/0
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acidity, c5me5, structure, synthesis, metathesis, compounds, olefin, role, concerning, organotin, lewis, ch3recl3
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