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Intramolecular Mobility in CS2 Complexes of Manganese.

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analogously by addition to trans-I ,3-pentadiene. The cycloaddition proceeds exclusively as shown below, affording the
1 -pyrazolines in the isomeric ratio 1 : 1 (NMR integration).
( 4 c j and ( 4 t) decompose thermally ( 3 G 6 0 " C )and photochemically ( O T , n-pentane, Pyrex filter, Hanau T Q 150) with
formation of trans-l-(trans-l-hexenyl)-2-vinylcyclopropane
( I j and 6-butyl-1,4-cycloheptadiene (3 j . trans-I-(trans-1 -Propenyl)-2-~inylcyclopropane
( I a j and 6-methyl-I ,4-cycloheptadiene ( 3 u ) are obtained in an analogous way from (512)
and ( 5 t ) .
(4c) + (41)
A, hv
N,- ( 1 )
A
hv
f
41.5%
55.57'0
(2)
-
(3)
[ I ] L. Jarnicke, D . G . Muller, Fortschr. Chem. Org. Naturst. 30, 61 (1973).
[2] J. ff. Law, Acc. Chem. Res. 4, 199 (1971).
[3] The transformation can be achieved photochemically only by photosensitized irradiation with short-wave UV: W Pickenhagen, F . Nbf; G . Ohloff.
P . Muller, J.-C. Perlberger, Helv. Chim. Acta 56, 1868 (1973).
[4] M . Schneider, J . Rebell, J. Chem. SOC. Chem. Commun. 1975, 283; M .
Schneider, Angew. Chem. 87, 717 (1975); Angew. Chem. Int. Ed. Engl.
14, 707 (1975).
[S] Prepared by dehydration (KHSO+, 160°C) of 3-octen-1-01(from acrolein
and n-pentylmagnesium bromide) and subsequent fractional distillation.
Small amounts of the cis form are isomerized to the / r a m form by
I,-catalyzed irradiation.
[6] R. E. Moore, J . A . Pettus, Jr., J . Mistysyn, J . Org. Chem. 39. 2201
(1974); G. Oh/off; W Pickenhagen, Helv. Chim. Acta 5 2 , 880 (1969).
171 The irradiation was carried out directly in the NMR apparatus (Bruker
HX 90 R with modified probe) using a quartz light guide; lamp: Philips
SPIOOOW; filter UGl.
58.5%
44.5qo
Intramolecular Mobility in CS2 Complexes of Manganese[**l
By M a x Herberhold, Margot Suss-Fink, and Cornelius G.
Kreiter"]
A
hv
35%
6 570
60%
40%
All spectroscopic data of the natural products ( 1 ) and
( 3 ) , readily accessible in this way, were identical with those
of the compounds isolated and obtained by multistep synthesis[6*71.
(I a ) and (3 a ) have been unequivocally identifiedL4].
Low-temperature photolysis of ( 4 c j ( 4 t ) at -45"C'71 affords
exclusively ( 1 j and cis-I -(trans-I -hexenyl)-2-~inylcyclopropane (2). In an analogous way the low-temperature photolysis
of ( 5 c ) + ( 5 t ) leads to ( I a ) and cis-l-(trans-l-propenyl)-2vinylcyclopropane ( 2 n ) . The novel compounds ( 2 ) and (2a)
are stable for several hours up to -20°C. and rearrange
quantitatively at G 2 0 " C into the 1,4-cycloheptadienes (3)
and (3 a), respectively. Both reactions can be followed directly
by 'H-NMR spectroscopy by observing the allylic protons
of (3) (6=2.18 and 2.86 ppm) and (3a) (6=2.25 and 2.83
PPm).
+
Considerable speculation still surrounds the coordinative
bonding of carbon disulfide in transition metal complexes[']
since the structures of only few molecules are known. We
have made the surprising observation that the two cyclopentadienylmanganese complexes CpMn(C0)2(CS2) ( I ) and
[CpMn(C0)2]2(CS2)(2) give temperature-dependent NMR
spectra. Thence it is concluded that:
1) The mononuclear complex ( I ) possesses an $-coordinated CS2 ligand which undergoes hindered motion in solution.
2) The dinuclear complex (2 j contains a new kind of CSz
bridge and is a fluxional molecule.
v ( C . 0 ) 2 0 1 2 , 1 9 5 7 ern-'
(THF)
V(C-0)
2021,1969;
1 9 2 8 , 1 8 7 1 cm-' ( T H F )
Experinzental:
A solution of N-allyl-N-nitrosourea (69) in triethylene glycol (50 ml) is added dropwise with stirring at 20°C and 15
torr to a solution of sodium (69) in triethylene glycol (I00
ml). The 3-diazo-1-propene that is formed (ca. 10 mmol,
0.7 g) is condensed at -78°C in a cold trap containing 30
mmol trans-I ,3-octadiene or -pentadiene. The resulting deepred mixture is stored at +4"C until completely decolorized
(ca. 4 days), taken up in n-pentane and washed with ice-water
to remove the pyrazole. After drying, all volatile components
are distilled off at OoC/l5 torr. The pyrazolines ( 4 c ) + ( 4 t )
(1.5 mmol) or ( 5 c) + ( 5 t) (1.4 mmol) so obtained are photolyzed at 0°C without further purification in a forced circulator
(Hanau T 150, pyrex filter) or thermolyzed in n-heptane at
30--60"C. After distillation, the products (1) and ( 3 ) , or
(la) and (3a), are isolated by gas chromatography (3 m
10% OV17 on Chromosorb W).
Received: January 17, 1977 [Z 651 1E]
German version: Angew. Chem. 89. 187 (1977)
CAS Registry numbers:
( I ) , 50265-47-9: ( I a ) , 61649-93-2; ( 2 ) , 50265-49-1; (Za), 61688-32-2: ( 3 ) .
22735-58-6; ( 3 ~ ) 61689-14-3:
.
(4c), 61649-94-3: (4t), 61688-33-3; ( j c ) .
61649-95-4; ( 5 t ) , 61688-34-4; 3-diazo-l-propane, 2032-04-4; trons-1,3-octadiene, 39491-65-1 ; rrans-1,3-pentadiene, 2004-70-8
Angew. Chem. I n t . Ed. Enql. I6 ( 1 9 7 7 ) N o . 3
Compounds ( I ) and (2) can be prepared by photolysis
of CpMn(C03) in tetrahydrofuran solution (THF) and subsequent reaction of the labile THF complex CpMn(C0)2(THF)
with CS2[21:
In solution ( I ) slowly loses CS2 to form (2). Contrary
to earlier reports[31,we were unable to observe the reverse
reaction.
The compositions of (1 j and ( 2j are confirmed by elemental
analysis and mass spectra. Their structures follow from NMR
[*I Doz. Dr. M. Herberhold, DipLChem. M. Suss-Fink, Doz. Dr. C. G.
Kreiter
Anorganisch-chemisches Institut der Technischen Universitat
Arcisstrasse 21, D-8000 Miinchen 2 (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft
and the Fonds der Chemischen Indnstrie. M . Sliss-Fink is indebted to
the Cusanus Foundation for a graduate study grant.
193
and IR spectra, which indicate a pronounced acceptor capacity
of the CS2 ligandc4]. We assume that CS2 is coordinated
like an olefin via a C=S double bond in (1 ); on complexation,
the molecule which is linear in the free state should experience
bending, such as has been detected by X-ray analysis of
(Ph,P),M(CSZ) (M =Pt, Pd)[51.
Table 1. ‘H- and I3C-NMR spectra of the CS2 complexes ( I ) and ( 2 ) .
(I)
(2)
310
231
169
5.10
310
210
179 [b]
4.89
5.33, 3.74
92.5
92.6
87.9
83.6, 92.7
229.3
228.4 (x)
230.2 (n)
231,s
252.7
254.1
228.1 (x)
229.0 (x)
234.4 (a)
251.5
~~
[a] In ID,]-acetone; 6 values [ppm] us. TMS int.
[h] In [Db]-acetone/THF.
A rigid molecule having the structure (I) must contain
two non-equivalent CO ligands; however, only one CO signal
is observed down to 220 K in the 13C-NMR spectrum. The
expected signal splitting confirming structure ( I ) is not
observed until below ca. 200 K. This reversible splitting can
be explained in terms of a hindered rotation of the CS2 ligand
about the axis of the coordinative bond which becomes slower
with decreasing temperature(AGtg0=9.5+0.1 kcal/mol; AG*
values of 8 to 12 kcal/mol are characteristic for the analogous
rotation of monoolefin ligands in C P M ~ ( C O ) ~
complexes[61).
L
In addition to two e 0 bands which are shifted slightly
relative to those of ( I ), the IR spectrum of the dinuclear complex (2) contains two additional G O stretching absorptions. It may be deduced from their relatively low frequency
that ( I ) is bonded as a donor ligand uia a lone pair of
the non-coordinated sulfur atom to another [CpMn(C0)2]
fragment. In contrast to the dithiocarboxylato-bridged complexes (3)[’”] and (4)[7bl, (2) appears to contain a true carbon
disulfide bridge.
Procedure[’] :
(Carbon disuIfde)dicarbonyl(rpcyclopentadienyl)rnanganese
(1)[2’:
To CpMn(C0)2(THF)[91
(1.5 mmol) at -20°C is added
cooled pentane (80 ml). After addition of CS2 (2 ml) the
solution is slowly warmed to room temperature and stirred
for 5 min. The solvent is drawn off at - 20°C and CpMn(CO),
sublimed off at room temperature under high vacuum. The
residue is taken up in cooled pentane; after filtration (G3
frit) the solvent is drawn off at -20°C and compound ( I )
dried in vacuo at -10°C. Orange-red crystals, dec. at ca.
65°C (under argon); yield 0.10 g (27%).
(p-Carbon disuIfde)bis[dicarbonyl(q-cyclopentadieny1)rnanguiiese] (2)I2I:
CS2(2 ml) is added to the red solution of CpMn(C0)2(THF)
formed on photolysis of CpMn(CO), (0.306 g, 1.5 mmol)
in THF and the mixture stirred for 2 h. CpMn(CO), and
( I ) are washed out of the residue of the reaction solution.
Recrystallization from ether gives dark red ( 2 ) , dec. at ca.
118°C (under argon): yield 0.13 g (40%).
Received: December 13, 1976 [Z 634a IE]
German version: Angew. Chem. 89, 191 (1977)
CAS Registry numbers:
(1),49716-49-6; I Z ) , 61483-85-0; CpMn(CO)2(THF),12093-26-4; 13C, 1476274-4
Review: 1 . S. Butler, A . E. Fenster, J. Organomet. Chem. 66, 161 (1974).
Both ( 1 ) and ( 2 ) were first observed in the reaction of the cyclooctene
complex CpMn(CO)2(C8H14)[9] with CS2 and characterized by their
IR solution spectra (in CSJ [3]. However, ( I ) could not he isolated;
( 2 ) was formed in only minute amounts and was mistaken for a dimer
of ( I ) .
[31 A. E . Fenster, I . S . Butler, Inorg. Chem. 13, 915 (1974).
141 M . Herberhold, M . Siiss-Fink, Angew. Chem. S9,192(1977); Angew. Chem.
Int. Ed. Engl. 16, 194(1977).
I
Kaskiwagi,
151 R. Mason, A. I . M . Rae, J. Chem. SOC.A 1970, 1767; ‘
N. Yasuoka, 7: Ueki, N . Kasai, M . Kakudo, S. Takakaski, N . Hagikara,
Bull. Chem. SOC.Jpn. 41. 296 (1968).
[6l H. Alt, M . Herberhold, C. G . Kreiter, H . Strack, J. Organomet. Chem.
102, 491 (1975); and references cited therein.
171 a) J . E. Ellis, R . 19: Fennel/, E. A . Flom, Inorg. Chem. 15, 2031 (1976);
b) J. M . Lisy, E . D. Dobrzynski, R. J . Angelici, J . Clardy, J. Am. Chem.
SOC.97, 656 (1975).
All operations performed under argon. A mercury vapor lamp ( Q 700,
Quarzlampengesellschaft Hanau) was used for the photolysis of
CpMn(CO)3. Yields not optimized.
~ 9 3E. 0. Fischer, M . Herberhold, Experientia Suppl. I X , 259 (1964).
PI
PI
(31
14 i
At room temperature the two differently coordinated
[CpMn(C0)2] moieties cannot be distinguished in the ‘Hand * ,C-NMR spectra of (2): only one signal each is registered
for the Cp and CO ligands (Table 1). An intramolecular motion
is clearly taking place in which the two [ c ~ M n ( C 0 ) ~
frag]
ments rapidly exchange their sites and functions. This “degenerate o/. bond isomerization” is completely frozen at 210 K,
and line shape analysis of the ‘H-NMR cyclopentadienyl
signals affords AG:50= 12.4+0.1 kcal/mol. At even lower
temperature (ca. 180 K) the rotation of the CpMn(C0)2(CS2)
“ligand” is also seen to be frozen in the I3C-NMR spectrum,
only the CO signal of the C ~ M n ( c 0 )fragment
~
engaged
in olefinic complexation undergoing splitting.
In contrast to ( 2 ) , the iron complex (3) does not give
a temperature-dependent ‘H-NMR spectrum. Two cyclopentadienyl signals are always observed, until the complex decomposes into [CpFe(CO)2]2 and CS2 at ca. 370 K.
194
Acceptor Function of q2-Bonded CS2 Ligands[**]
By Max Herberhold and Margot Siiss-Fink[*]
Carbon monoxide is regarded as the prototype of all “acceptor ligands”. There are only few two-electron ligands which
surpass CO in its ability to withdraw charge from a central
metal; apart from CS and PF3 these also include dienophilic
olefins such as tetracyanoethylene (TCNE) and maleic anhydride (MA). We have now discovered that q’-coordinated carbon disulfide is also a stronger acceptorthan CO. This follows
from the IR and ‘H-NMR spectra of the cyclopentadienyl( 1 )[‘I,
manganese
complexes
CpMn(C0)2(CS2)
[*] Doz. Dr. M. Herberhold, DipLChem. M. Suss-Fink
Anorganisch-chemisches lnstitut der Technischen Universitat
Arcisstrasse 21, D-8000 Munchen 2 (Germany)
I**]This work was supported by the Deutsche Forschungsgemeinschaft
and the Fonds der Chemischen Industrie. M . Siiss-Fink is indebted
to the Cusanus Foundation for a graduate study grant.
-
Aiiqrw.
Chein. Int. Ed. Engl. 16 (1977) No. 3
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