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Distorted Sandwich Compounds [1]Ferrocenophanes and [2]Ruthenocenophanes.

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HIGHLIGHTS
Distorted Sandwich Compounds:
[ l]Ferrocenophanes and [2]Ruthenocenophanes**
Max Herberhold*
lic compounds are potential monomers for ringopening pol!.nierization. and strained metallocenophanes have
consequcntl) attracted interest as precursors for polymcrs containing iI;insition metals such as Fe or R u in the cage of sanduich unit\ t h a t are incorporated into the macroinolecule.[llThe
propensity towards polyinerization depends on the ring strain.
;IS may be seen for the sila[ii]ferrocenophanes['] fc[ (SiMe,),,]
with / r = I ( I ) and / I = 2 (2). Whereas 1 polymerizes i n the melt
above I30 C ' to give silaferrocenylene polymers.[312 requires
temperatures above 350 C to undergo ring-opening polymerization.l'.
Nevertheless. i t is easy to oxidize fc[(SiMel),] 2 to
I .3-bis( diinet ti).lsila)-2-oxa-[3]ferroceiiophane fc[ (SiMel)lO]
uhich. like te[(SiMcZ),]3, is strain-free and therefore not prone
t o poI!iiieriL;ltion."
es. for example in the series 4-6. To date [Ijtkrrocenophanes
containing elements of the second row of the periodic table
(E = B. C. N . 0) as bridges have noi been synthesized. The
smallest bridging element possible appears to be sulfur. and the
Fe
SiPhZ
PPh
Fe
Fe
0
S
L3
fc[SiPhZ] (red)
4 Pal
fc[PPh] (red-purple)
171
a = 269"
a = 192"
b= 167 3"
p = 40"
B = 99 l( 3) "
1598"
p = 32 3"
O = 90 7(2)O
1s.
fc[S] (violet)
6 151
(x = 31 05(10)"
i i = 156 9(1)"
p= 288,291"
t)= 89 03(9)"
(Very similar an les
are given in ref$bl)
fc[SiMe,]
fc[Si2Me4]
1
u = 20 8(5)"
2
"'
6 = 164 74(8)"
a = 4 19(2)"
(4 3" 121)
6 = 176 48(3)"
The ring strain i n [ l]ferrocenophanes. which contain just a
single bridging atom as it link between the two cyclopentadienyl
ligand\. i b coineniently described by the tilt angle c1 o f the rings
a n d the defortnaiion angle (iat the metal between the midpoints
o f t h e rings. (Fig. 1, cf. ref. [ 3 ] ) The
.
tilt angle c1 increases as the
size (ix. the co\alent radius) ofthe bridging element E decreas-
new thia[l]ferrocenophane fc[S] 6. prepared by Ian Manners
and co-workers,[5Jholds the present world record thr the largest
tilt angle in [l]ferrocenophanes with x = 31.05( 10) . The conformation of the two cyclopentadienyl rings in 1 atid 4 - 6 is almost
exactly eclipsed.
As expected, the ring strain is reduced when the bridging atom
is ;I heavier homologue. a s for example in diphenylgerma[llferrocenophane fc[GePh,] ( X = 16.6. (5 = 170. /i= 32.5, and
11 = 90.6 )("l and in the substituted phenylarsa[ 1 jferrocenophane
f~'[AsPh] (fc' = (C,H,)Fe(C,H,R).
R = CHMeNMe?; x =
22.9. Ci =162.5. /I = 32.8. and (I = X7.90(7) )."I Apparently
only u single inetalla[l]ferrocenophane has been structurally
characterized: f~[Zr(C,H,rBu)~l7 (3 = 6.0. t i :
177.27(8) ):['I
the inetal-metal separation. tl(Fe-Zr) = 796.21(5) pin. might
indicate a weak bonding interaction.
4
fc[Zr( CsH4tBu)~l
7 Pi
u=60"
6 = 177 28(8)"
MCp2
8a M = Fe ( d = 332 prn)
8b M = R u ( d = 368 prn)
8c M = 0 s ( d = 371 pm)
Whereas it h i r number of [ I]ferrocenophane\ are now available. the isolation of the first [llruthenocenoph~ine.rc[SiMe,],
was mentioned onl! in 19Y4.r'1 and the first [2]1-u~Iienocenoph~tnes
have been described by Ian Manners and his group only recent-
HIGHLIGHTS
ly. ' l o , ''I As the intramolecular ring-ring distance in the parent
metallocenes MCpz 8a-c expands on going from ferrocene to
ruthenocene and osmocene, the distortion in the corresponding
[1]- and [2]metallocenophanes must similarly increase. This
might explain why dimethyldichlorosilane Me,SiCI, reacts with
1,l'-dilithioferrocene fcLi, to give fc[SiMe,] 1,[''] while the corresponding reaction with 1.1'-dilithioruthenocene rcLiL leads
preferentially to oligomers and polymers. The binuclear bis(dimethylsila)[l .l]metallocenophanes 9a,b were prepared by
a different route [Eq. (a)];['31 it is conceivable that small
amounts of the strained mononuclear monomers fc[SiMe,] 1
and r~[SiMe,]['~are formed under these conditions as well.
e
2
S
I
M
e
?
e
LI
LI
+ 2 MCl2. nL
e S i M e 2
- 4 LlCl
M
____)
(THV
&s,
n
S
GS
e S i M e 2
(M = Fe , nL = 2thf,
9a : fc(SiMe,),fc
M = Ru , nL = 4dmso)
9b rc(SiMe2)2rc1131
14
R = H : fc[S,] "'I
-CMe2
M
I
(R = H, nBu, Wu)
a=
285"
S = 177.7"
macromolecules 14; again substituents on the rings are required to obtain soluble products. When 4-tert-butyl-I ,1',2,2bis(l.2,3-trithia[3])ferrocenophane(15) is used as the
monomer, giant three-dimensional networks contain(a)
ing disulfide bridges can be obtained.[2']
In spite of the synthetic achievements in the chemistry of distorted sandwich compounds, some questions still remain open. Thus, points of discussion are
the disturbed intramolecular interactions between
e-,
[MI
/
&E
15
M
n
13
In all cases (2, 10- 12) where analogous [2]ferrocenophanes
and [2]ruthenocenophanes have been structurally characterized,
the ruthenium complex is always the more strained.[l3] As expected, an almost linear correlation exists between the distortion
angles a and 6 in [I]- and [2]metallocenophanes.
6Yb
- nBu3PS
*
M
*SiMe2
M
.
16
E = S, Se, Te
[MI = metal complex fragment
I
eCb
eCMe2
eSiMe2
IOa : M = Fe
a = 21.6(5)"
l l a M=Fe""
a = 23'
S = 163.4(6)"
12a : M = Fe
a = 4.19(2)"
'= 176.48(3)"
10b . M = Ru
a = 29.6(5)"
6 = 159.3(2)"
l l b : M= Ru"~]
a = 30.6/31.5"
S = 159.21158.3"
12b : M = Ru [''I
a = 7.8(5)"
6 = 174.2(2)"
(two independent
molecules in the cell)
monomer fc[S] 6 is expected to lead to poly(ferroceny1ene sulfide) [fcsln. A yellow product Of this
was Obtained
earlier from the reaction of 1,l'-diiodoferrocene fcI, with the
copper salt of 1,l'-dimercaptoferrocene fc(SCu), in boiling pyridine;"71 it is insoluble in all common
The presence Of
substituents on the rings is amarentlv necessary to obtain
tractable sulfur-bridged ferrocene polymers, which might be
new materials with special properties due to the regularly arranged Fe centers.
A modified ring-opening polymerization leading to POIY(ferrocenylene disulfide) [fcS,], 14 (R = H) was discovered by T. B.
Rauchfuss and co-workers [Eq. (b)] . [ 1 y - 2 2 1 Starting from the
unstrailled 1'2'3-trithia[31ferrocenophanes
13, abstraction Of
the central sulfur atom using PnBu, generates one-dimensional
I
Y
. I
iron and the cyclopentadienyl rings or the possible contacts of
iron to the bridge elements. An attractive synthetic target for the
near future will be the preparation of polymeric materials with
different metals, either from metalla[l]ferro~enophanes[~.
231 or
from [3]ferrocenophanes 16, which contain transition metal
complex fragments in the bridge system (cf. ref. [24]).
German version: A I ~ , ~ EChew.
I I . . 1995, 107, 1985-1987
Keywords: iron compounds . metallocenophanes . polymerization ruthenium compounds . sandwich complexes
to 7iuii.siritin Meld-Bused P o l i ~ m ~ (rAs d v . Orgonomet. Chcm. 1995, 37.
168); I. Manners. Pho.\phorus Su/fiir Silicon 1994, 93/94. 143-151
I3 1
~
[?] V, V, Dementrev. F, Cervantes-Lee. L, parkany,, H , Sharma, K , H. pannell,
M. T. Nguyen. A. Didz. Orgunotn~ru//ics1993, 12, 1983-1987.
[3] W. Finckh. B:Z. Tang. D. A. Foucher, D. B. Zamble. R. Ziembinski. A.
Lough. I. Manners, OrgunomrlciNic.t 1993, 12, 823-829.
[4] C. Angelakos. D. B. Zamble. D. A. Foucher. A . J Lough. 1 Manners. Inorg.
Chrrn 1974. 33. 1709 1718
151 J. K. Pudelski. D. P. Gates, R. Rulkens, A. J. Lougli, 1. Manners, Angrn..
Chem. 1995. 107. 1633-1635: A n g e a . Clieni. In(. Ed. €ng/. 1995, 34. 15061508.
[6] a ) H. Stoeckli-Evans. A G. Osborne, R. H. Whiteley. H e h . Cliim. Acru 1976.
SY. 2402-2406: b) J. O r g m i o ~ n Climi.
~~.
1980, 1Y4. 91-101
[7] 1, R, Butler, w,R, Cullen. F. W. 8, Einstein, S, J, Ret[ig. A, J Willis.
Orpunonieto/lrc.\ 1983, 2, 1% 135.
[ X I R. Broussier. A. Da Rold. B. Gautheron. Y. Drornree, Y Jeannin, Inorg. Chem.
1990, 29. 1 8 1 7 ~
1822.
~
[9] J. M. Nelson, A. J. Lough. 1. Manners. Phosp/iorti\ Su/jur Siiicon 1994, Y3jY4.
361 -362.
HIGHLIGHTS
IlO] .I. M. Nelson, A . 1. Lough. I . Manners. Angaw. C/imi. 1994. 106. 1019 1021:
/l/rg<,It. C ~ / i < , m1/11, Ed Engl. 1994. 33. 989-991.
[ I l l .I M. N e l w n . A J. Louph. I. Manners, OrRunomelo//ic.\ 1994. 13, 3703-3710.
[ I ? ] .4.
B. Fischcr. J B. Kinney. R. H. Staley. M. S. Wrighton, J. Am. Chem So<.
1979. 101. 6501 -6506.
1131 M. Herberhold. Th. Birtl. Z. Nuturforsch. 1995. 50h. in press.
[14] .I. M. Nelson, tl. Rengel, 1. Manners. J A m . C/iem.So<. 1993, 115. 7035-7036.
[15] M. Burke L:iing. K. N . Trueblood. A r m Criwullogr. 1965. 19. 373- 381
[16] W Milius. LJnivei-sit:it Bayreuth. unpublished results.
[I71 .I. C W. Chien. R 0. Gooding. C. P. Lillya. Po/ym. Murrr. Sci. Eng. 1983, 49.
107 111
[ I X ] B R . Davi<. I.Bernal. J Cri.sr. Mol. Strurl. 1972. 2, 107 114.
[19] P. F. Brandt. T. B. Rauchfuss. J An?. Chiwi. Soc. 1992. 114. 1926 1Y27.
[20] D. L. Compton, T. B. Rauchfuss. Poli,m. P r e p . ( A ~ IC'/ILWI
.
So..Dii,. Pu/wn.
Chefn.) 1993, 34, 351 -543.
[21] C. P. Galloway. T. B. Rauchfuss. Angfw. C/iiw. 1993. 10.5. 1407 1409. Atige11'.
Chain. Int. Ed. En& 1993. 32. 1319- 1321.
[22] T. B. Rauchfuss. C. P. Galloway, Phosphorus Sulfur S i / i i o ! i . 1994, 93:94. 117
128.
[23] R. Broussier. A. Da Rold. M. Kubicki. B. Gautheron. h//.
Soi.. Chini. Friincr
1994, 131, 951-958.
[24] M , Herberhold, Farrociwophunc Cornpounrlt Conriiinin~qI ~ r r r r o i ~ l m n r ninl . ~Fivrocpne.p. Hornopwous Cutcrlwis - O r p n i c Swrhcsi>- Mir/n.iu/.\ S c i e n w (Eds. :
.A. Togni. T. Hayashi). VCH, Weinheim. 1995. pp. 219 27X.
Woollins, J. D. (ed.)
Inorganic Experiments
1994. XV, 286 pages
with 86 figures and
8 tables.
Hardcover. DM 148.00
ISBN 3-521-29235-1
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