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Linkage of Alkylidyne Carbonyl and Alkyne Ligands at a Tungsten Center to Form a Metallacyclopentadienone and an 3-Oxocyclobutenyl Complex.

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Kennedy, W. McFarlane in I. Mason (Ed.): Multinuclear NMR, Plenum
Press, New York 1987, p. 318.
For a general discussion of '3C-'3C coupling constants: I. B. Stothers:
Carbon-13 NMR Spectroscopy. Academic Press, New York 1972, Chap.
10.
The arguments which have been examined by reviewers are available
upon request from S. Masamune.
For reviews, see a) A. P. Marchand: Stereo Chemical Application of NMR
Studies in Rigid Bicyclic Sysfems, Verlag Chemie International, Dearfield
Beach 1982, Chap. 4; b) I. L. Marshall: Carbon-Carbon and Carbon-Proton NMR Couplings, Verlag Chemie International, Deerfield Beach 1983,
Chaps. 3 and S.
191 a) F. I. Weigert, I. D. Roberts, J . Am. Chem. SOC.94 (1972) 6021; b) I. L.
Marshall, d. E. Miller, ibid. 95 (1973) 8305;c) D. Doddrell, 1. Burfitt, J. B.
Grutzner, M. Barfield, ibid. 96 (1974) 1241; d) M. Barfield, I. Burfitt, D.
Doddrell, ibid. 97(1975) 2631; e) M. Barfield, S . A. Conn, J. L. Marshall,
D. E. Miller, ibid. 98 (1976) 6253; f) M. Stoecker, M. Klessinger, Urg,
Magn. Reson. 12 (1979) 107; g) M. Barfield, ibid. 102 (1980) 1; h) M.
Barfield, J. L. Marshall, E. D. Canada, rbid. 102 (1980) 7; i) S. Berger,
Org. Magn. Reson. 14 (1980) 65;j) M. Klessinger, H. Megen, K. Wilhelm,
Chem. Ber. I I S (1982) 50; k) M. Klessinger, J. Cho, Angew. Chem. 94
(1982) 782; Angew. Chem. Int. Ed. Engl. 21 (1982) 764; 1) S. R. Walter, J.
L. Marshall, C. R. McDaniel, E. D. Canada, M. Barfield, S. R. Walter,
ibrd. I05 (1983) 4185; m) M. Barfield, S. R. Walter, rbid. 105 (1983)4191;
n) E. W. Della, P. E. Pigou, ibid. 106 (1984) 1085; a) E. W. Della, H.
Gangodawila, P. E. Pigou, J . Org. Chem. 53 (1988) 592.
ucts from which purple complex 5 and orange complex 6
were isolated in 26 and 13% yield, respectively."'] The molecular structure of complex 5 is shown in Figure 1.["] The
tungsten center, the former carbyne and carbonyl ligands,
Me3Pf
I
CH,CI,
4d, 2OoC
C
0
By Andreas Mayr,* Ken S . Lee, and Bart Kahr
The reactivity between metal-carbon triple bonds and
carbon-carbon triple bonds is complex. High-valent alkylidyne metal complexes interact with alkynes to give metallacyclobutadienes, which-depending on the system-may
be activated towards alkyne metathesis,]'] insertion of a
second alkyne to give cyclopentadienyl ligands,lZ1or the
formation of cyclopropenyl metal complexes.131The lowvalent carbyne alkyne metal complex 1 was proposed
as an intermediate in the formation of a cyclopropenyl
metal complex.[41 The low-valent metal carbynes
[M(CR)Br(C0),lfS1 were shown to induce the polymerization of acetylenes (M = W)I6l and to give annelated phenols in reactions with a p d i y n e s (M = Cr,
We have
recently described evidence for the existence of low-valent
carbyne alkyne tungsten complexes of the type 2 and facile protonation to give the carbene alkyne tungsten complexes 3.@IHere we report the reaction of a low-valent carbyne carbonyltungsten complex with alkyne in the absence
of proton sources to give a novel metallacyclopentadienone and a metal q3-oxocyclobutenyl complex.
w).[']
(a)
4
Ph
Ph
I
5 Ph
Linkage of Alkylidyne, Carbonyl, and Alkyne
Ligands at a Tungsten Center to Form a
Metallacyclopentadienoneand an
q3-Oxocyclobutenyl Complex**
-
PhC,H
r3.3
CI-W=C-Ph
6
Ph
and phenylacetylene combine to form a metallacyclopentadienone ring, a cyclic metal carbene. The intraring distances indicate the presence of fairly localized n bonds.
The W-C(1) distance is similar to the value of the tungsten-carbon double bond (1.97(2) A) in the related alkylidene alkyne tungsten complex 3, alkyne = Ph&, and the
W-C(8) distance may be compared to the W-CHzCMe3
bond length (2.258(9)
in 7 (dmpe = bis(dimethy1phos-
A)
[W(CCMe3)(CHCMe3)(CH2CMe,)(dmpe)]
7
phino)ethane).['*' The C(9)-C(30) bond length is close to
the aFcepted value for carbon-carbon double bonds
(1.34 A) and the C(l)-C(30) as well as the C(8)-C(9) distances are in the range of Csp2-Csp2single bonds (1.48
Fairly localized double bonds have also been found in the
molecular structure of an organic cy~lopentadienone,['~~
supporting the formal analogy with the metallacyclopentadienone ring in 2.
The q3-oxocyclobutenyl complex 6 is formally derived
from 5 by extrusion of tungsten from the metallacycle. I3C
A).
[MO(CM~)(.~~~-C,H,)(P~C,P~)~P(OM~),I,~
1
[W(CPh)Cl(CO)(alkyne)(PMe3)2]
2
[W(CHPh)Cl,(alkyne)(PMe,),l
3
Reaction of 419] with excess phenylacetylene (15 equiv.)
in dichloromethane [Eq. (a)] generates a mixture of prod-
:211
[*] Prof. A. Mayr
[**I
Department of Chemistry
State University of New York at Stony Brook
Stony Brook, NY 11 794 (USA)
K. S. Lee, B. Kahr
Department of Chemistry
Princeton University
Princeton, NJ 08544 (USA)
This work was supported by the National Science Foundation (CHE8 6 17472).
1730
0 VCH Verlagsgesellschaji mbH. 0-6940 Weinheim, 1988
Fig. 1. Molecular structure of 5 . Important distances [A] and angles ["I:
W-C(I) 2.00(1), W-C(8) 2.28(1), W-C(16) 2.05(1), W-C(17) 2.04(1), W-CI
2.430(1), W-P(1) 2.508(3), W-P(2) 2.522(3), C(1)-C(30) 1.49(2), C(9)-C(30)
1.37(2), C(S)-C(9) 1.52(2), C @ - O 1.23(1); C(l)-W-C(8) 76.0(4), W-C(1)C(30) 119.8(7), C(l)-C(30)-C(9) 120(1), C(S)-C(9)-C(30) 110.1(9), W-C(8)C(9) 113.9(7), C(1)-W-CI 157.5(3); C(B)-W-~entroid[C(16)-C(17)] 174.5,
P(l)-W-P(2) 157.8(1); dihedral angle formed by the planes W-C(1)-C(2) and
W-C(16)-C(17) 92.2.
OS70-0833/88/1212-1730 $ 02.50/0
Angew. Chem. Int. Ed. Engl. 27 (1988) No. 12
NMR resonances at 6= 181.2 (CO), 59.4 (JCH= 195.8 Hz,
CH), 67.2, and 57.3 (CPh) are assigned to the carbon atoms
of the oxocyclobutenyl ring. Signals at 6= 193.2 (Jcp= 12.5
Hz, CPh) and 184.6 (JCH= 196.8 Hz, Jcp= 17.0 Hz, CH) are
observed for the phenylacetylene ligand.l'O1
, When reaction (a) was conducted with PhI3C=CH, the
label was found to be distributed equally between the CPh
groups in the metallacyclopentadienone ring of 5 and the
oxocyclobutenyl ligand of 6 . Since the two CPh groups in
the symmetrically substituted oxocyclobutenyl ligand['41of
6 may exchange between equivalent sites by simple dynamic processes, we tested whether interconversion of
compounds 5 and 6 may provide a mechanism for scrambling the label in complex 5 . Pure samples of 5 and 6 were
heated in toluene. Compound 5 underwent conversion to 6
irreversibly. This reaction proceeds at 100°C in about one
hour, but is too slow at room temperature to account for
formation of 6 in reaction (a).["] Consequently, compounds 5 and 6 form independently in reaction (a). To
account for these results we propose a mechanism involving the initial coupling of carbyne and alkyne ligands to
give metallacyclobutadiene and metal cyclopropenyl intermediates. Insertion of carbon monoxide into the metallacyclobutadiene could generate the metallacyclopentadienone."61 Insertion of carbon monoxide into a metallacyclobutene to give a metallacyclopentanone was recently
rep~rted.['~J
Carbonyl insertion of the cyclopropenyl
ligand may initiate formation of the oxocyclobutenyl
complex. This latter type of reactivity is well established
for cyclopropenyl carbonylmetal complexes.['*]
Since metal carbenes are postulated as the active species
in acetylene polymerization,161the transformation of tungsten carbynes into tungstenacyclopentadienones represents
a possible pathway for the formation of acetylene polymerization catalysts from carbonylmetal carbynes. Metallacyclopentadienones may also be considered as intermediates on the way to phenols from carbonylmetal carbynes
and a,o-diynes.['I Insertion of a second acetylene unit into
the metallacycle followed by reductive elimination would
generate the organic ring system.
Received: May 30, 1988 [Z 2788 IE]
German version: Angew. Chem. 100 (1988) 1798
[ I ] M. R. Churchill, J. W. Ziller, J. H. Freudenberger, R. R. Schrock, Organomelallics 3 (1984) 1554.
[2] J. Okuda, R. C . Murray, J. C. Dewan, R. R. Schrock, Organometalks 5
(1986) 1681.
[3] R. R. Schrock, S. F. Pedersen, M. R. Churchill, I. W. Ziller, Organometallics 3 (1984) 1574.
[4] F. J. Feher, M. Green, A. G. Orpen, J. Chem. SOC.Chem. Commun. 1986.
291.
151 E. 0. Fischer, G. Kreis, Chem. Ber. 109 (1976) 1673.
[61 T. J. Katz, T. H. Ho, N.-Y. Shih, Y.-C. Ying, V. I. W. Stuart, 1.Am.
Chem. SOC.106 (1984) 2659.
171 T. M. Sivavec, T. J. Katz, Tetrahedron Left. 26 (1985) 2159.
[8] A. Mayr, K. S. Lee, M. A. Kjelsberg, D. Van Engen, J. Am. Chem. Soc.
108 (1986) 6079.
[9] A. Mayr, M. F. Asaro, M. A. Kjelsberg, K. S . Lee, D. Van Engen, Organomeraliics 6 (1987) 432.
[lo] Preparative thin layer chromatography on silica under Ar at O T ;
eluant, CHZC12/ethylacetate 9 :I.
5 : 'H NMR (250 MHz, CDCI,): 6= 12.00 (m, 1 H; HC-CPh), 8.33 (t,
I H, 4 J ~ i i = 2 . Hz;
1 CH); ''C NMR (62.9 MHz, CDCla, 233 K): 6=284.5
(m, W=C), 217.5 (C=O), 200.3 (PhCSCH), 193.0 (JcH=194 Hz;
PhCECH), 158.6 ( J c ~ = 1 5 6Hz; CH), 157.7 (CPh); "P NMR (101.2
MHz, CDCI,, 298 K): 6 = - 12.6 (Jwp=182 Hz; PMe,); IR (CH2C12):
VC-,,= 1597 cm-'.
6: 'H NMR (250 MHz, CDCL): 6 = 10.74 (m, 1 H; HCEPh), 4.50 (d,
1 H, J r l j =11.7 Hz; CH), 1.77 (d, 9H, JpH=8.7 Hz; PMe3), 1.36 (d, 9 H ,
J P H = S .Hz;
~ PMe,); ''C NMR(62.9 MHz, CDCI,, 233 K): see text; "P
NMR (101.2 MHz, CDCI,): 6- -11.1 (m; 2PMe3); IR (CH2CI,):
GC-, = I663 cm - ' ; satisfactory C,H analysis.
Angew.
Chem. Int. Ed. Engl. 27 (1988) No. I2
[Ill 5 : Orthorhombic, Pcab (standard Pbca, No. 61), a = 13.381(5),
V=5916(3)
2=8, p ( M 0 ~ ~ ) = 4 3 . 5
b=20.903(5), ~=21.151(7)
cm-', pC,,,,=1.56 g cm-3. All intensity measurements were made at
175+ 3 K on a Nicolet R3m four-circle diffractometer by applying MOK*
Of 5214 unique reflections with 3 ° 5 2 8 5 0 0
radiation (/1=0.71069
and h , k , l 2 0 , 3702 with IFo1230(Fo)were considered observed after applying Lorentz, polarization, and empirical absorption corrections. The
structure was solved by standard heavy-atom techniques and refined by
least-squares methods. All hydrogen atoms were located at idealized positions except H(17) and H(30) which were located in the final difference Fourier map and fixed. R=0.058, R,=0.054, GOF= 1.33. The
near W. Further
highest peak in the final difference map (2.5 e k3)
details of the crystal structure investigation can be obtained from the
Fachinformationszentrum Energie, Physik, Mathematik GmbH, D-75 14
Eggenstein-Leopoldshafen 2 (FRG), by quoting the depository number
CSD-53295, the names of the authors, and the journal citation.
[I21 M. R. Churchill, W. J. Youngs, Inorg. Chem. 18 (1979) 2454.
[13] A. Nishinaga, T. Itahara, T. Matsuura, A. Rieker, D. Koch, K. Albert,
P. B. Hitchcock, J. Am. Chem. SOC.100 (1978) 1826.
[I41 The molecular structure of an adduct of 6 with trifluoromethanesulfonic
acid has been determined by X-ray diffraction analysis. It features a
symmetrically substituted diphenyloxocyclobutenyl ligand: B. Kahr, unpublished results.
I151 Complexes 5 and 6 could also be generated in a 1 :2 ratio (as determined by 'H NMR) by reaction of [W(CPh)CI(CO)(PMe,),(py)J with excess PhC2H in CH2C12at 0°C for I h.
[16] Formation of 5 by sequential coupling of the carbyne ligand with carbon monoxide and phenylacetylene (via a ketenyl intermediate) would
place the label only at C(1).
1171 N. J. Conti, W. M. Jones, Organometallics 7 (1988) 1666.
[IS] W. A. Donaldson, R. P. Hughes, J. Am. Chem. SOC.I04 (1982) 4846.
A,
A',
A).
Structure, Magnetochemistry and Biological
Relevance of [Mn403C14(O A ~ ) ~ ( p y ) a~ lComplex
,
with S=9/2 Ground State**
By Qiaoying Li, John B. Vincent, Eduardo Libby,
Hsiu-Rong Chang, John C.Huffman, Peter D. W. Boyd,
George Christou,* and David N . Hendrickson*
Two to four Mn ions serve as the active site for catalyzing the oxidation of two molecules of H 2 0 to give one molecule of O2 during photosynthesis."] Two research groups
independently reported an EPR signal for the S2 state of
this site near photosystem I1 (PS II).['l This signal, comprising a g=2 feature structured with 16-19 Mn hyperfine
lines and a subsequently identified g = 4 feature, was
shown to be consistent with a tetranuclear Mn:"MniV
site.l3] The g = 2 feature has been assigned to a low-lying
S = 1/2 excited state, and the g = 4 feature to either the
S=3/2 ground state of the same Mnii'MniV siteL4]
or to an
S = 3 / 2 state of a different conformation of this site.151
These assignments are still matters of active discussion vis
a vis detailed saturation, temperature dependence and
sample history studies.
As part of our efforts to model this site, we recently reported the preparation of the first Mni"MniV complex 1.I6I
(H21m)2[Mn,03C16(HIm)(OAc)3]~3/2MeCN
1, HIm
=
imidazole, HJm@ = imidazolium cation
[*] Prof. Dr. G. Christou, J. B. Vincent, E. Libby, Dr. J. C. Huffman
Department of Chemistry and the Molecular Structure Center
Indiana University
Bloomington, IN 47405 (USA)
Prof. Dr. D. N. Hendrickson, Q. Li, H.-R. Chang,
Dr. P. D. W. Boyd ['I
School of Chemical Sciences, University of Illinois
Urbana, IL 61 801 (USA)
[I'
[**I
On sabbatical leave from the Chemistry Department of the University of
Auckland, Auckland (New Zealand).
This work was supported by the U.S. National Institutes of Health (GM
39083 and HL 13652).
Q VCH Verlagsgesellscha~mbH, 0-6940 Weinheim. 1988
0570-0833/88/1212-173I $ 02.50/0
1731
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linkage, forma, complex, carbonyl, alkynes, metallacyclopentadienone, oxocyclobutenyl, tungsten, alkylidyne, center, ligand
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