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Metal-Promoted Cyclotrimerization of a 3-Phosphaalkyne Formation of Vanadium-Complexed Valence Isomers of a 1 3 5-Triphosphabenzene.

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[ I ] P Binger, R. Milczarek, R. Mynott, M. Regitz, W. Rosch, Angew. Chem.
98 (1986) 645; Angew. Chem. Int. Ed. Engl. 25 (1986) 644; P. B. Hitchcock, M. J. Maah, J. F. Nixon, J. Chem. SOC.Chem. Commun. 1986.
[2] E. Fluck, G. Becker, 8 . Neumuller, R. Knebl, G. Heckmann, H. Riffel,
Angew. Chem. 98 (1986) 1018; Angew. Chem. Int. Ed. Engl. 25 (1986)
[3] G. W. Parshall: Homogeneous Catafysrs. Wiley, London 1980, p. 165.
141 The formal cyclotrimerization of PI has also been demonstrated. 0. J.
Scherer, H. Sitzmann, G. Wolmershluser, Angew. Chem. 97 (1985) 358;
Angew. Chem. lnt. Ed. Engl. 24 (1985) 351.
[ 5 ] E. W. Abel, M. A. Bennett, R. Burton, G. Wilkinson, J. Chem. Soc. 1958.
161 G. Becker, G. Gressner, U.Uhl, 2. Naturforsch. 836 (1981) 16; G. Becker, 2. Anorg. Allg. Chem. 430 (1974) 66.
171 The isotope distribution patterns of all fragment ions were computer
[S] F. A. Cotton, G. Wilkinson. Aduanced Inorganic Chemistry. 4th ed., Wiley, London 1980, p. 1074; Anorganische Chemie, 4th ed., Verlag Chemie, Weinheim 1982, p. 1094f.
191 R. Bartsch, P. B. Hitchcock, M. F. Meidine, J. F. Nixon, J. Organomer.
Chem. 266 (1984) C41.
(101 K. Dimroth in A. R. Katritzky, C. W. Rees (Eds.): Comprehensiue Heterocyclic Chemistry, Vol. I . Pergamon, Oxford 1984, p. 506.
gands,".'' reaction of 1 and the Cp,Zr fragment (prepared
in situ) affords a 1,3-diphosphabicyclo[l.l.O]butane-2,4diylzirconium complex.131Free or complexed cyclotrimers
of h3-phosphaacetylenes141were previously unknown.'***1
Herein we report a metal-promoted cyctotrimerization of a
Reaction of tert-butylphosphaalkyne 1 with the naphthalenevanadium complex 2,15'which is a suitable source
of Cp*V fragments (Cp* = q5-pentamethylcyclopentadienyl), results in liberation of naphthalene in an exothermic
reaction and formation of a new organovanadium complex
as dark brown crystals having the composition
[Cp*V(PCtBu)J 3 (MS, elemental analysis). At room temperature, 3 readily reacts with 1 mol of C O yielding complex 4 (MS, elemental analysis) as dark green crystals.
Metal-Promoted Cyclotrimerization of a
A3-Phosphaalkyne: Formation of
Vanadium-Complexed Valence Isomers of a
1,3,5-Triphospha benzene* *
By Roman Milczarek. Wolfgang Riisseler, Paul Binger, *
Klaus Jonas, Klaus Angermund, Carl Kriiger, and
Manfred Regitz
tert-Butylphosphaacetylene 1 undergoes cyclodimerization on q5-cyclopentadienyl metal complexes: Whereas
reaction of 1 and cyclopentadienylbis(ethene)cobalt results in the formation of a h3-1,3-diphosphacyclobutadienecobalt complex with displacement of the ethene li-
[*I Priv.-Doz. Dr. P. Binger, Dr. R. Milczarek, Dr. W. Riisseler,
Prof. Dr. K. Jonas, Dr. K. Angermund, Prof. Dr. C. Kriiger
Max-Planck-lnstitut fur Kohlenforschung
Kaiser-Wilhelm-Platz I , D-4330 Miilheim a. d. Ruhr
Prof. Dr. M. Regitz
Fachbereich Chemie der Universitat
Erwin-Schrodinger-Strasse,D-6750 Kaiserslauiern
[**I This work was supported by the Stiftung Volkswagenwerk.
[***I Note added by the editorial staff: A related cyclotrimerization in which
a 1,3,5-triphosphabenzene derivative is formed in the coordination
sphere of molybdenum I S also reported in this issue: A. R. Barron, A.
H. Cowley, Angew. Chem. 99 (1987) 956; Angew. Chem. In! Ed. Engl.
26 (1987) 907.
0 VCH Verlagsgesellschafr mbH. 0-6940 Wernheirn. 1987
Fig. 1. Top: Molecular structure of 3. C2SH42P.,V,0=9.664(2), b= 17.935(3).
c = 16.015(1) I\,B= 101.91(l)o, V=2716.0 I\',&.,,,cd= 1.19 g cm-',p(MoK,,)=
5.36 cm-', 2 = 4 , space group P2,/n, 6537 measured reflections ( + h , + k ,
+ I ) (averaged according to point group symmetry 2/m), 6120 unique reflections, 4424 observed ( I > 20(I)), empirical absorption correction (min, 0.861 ;
max, 1.083), 262 refined parameters, R =0.043, R,, =0.050. Selected distances
[A] and angles ["I: V-PI 2.382(1), V-P2 2.437(1), V-P3 2.702(1), V-CI 1.849(3),
V-ClI 1.993(3), PILP3 2.206(1), PLC6 1.845(3), PI-CI 3.047(3), P2-CI
1.850(3), P2-C6 1.904(3), P2-CIl 1.842(3), P3-C6 1.915(3), P3-CI1 1.937(3);
C6-Pl-P3 55.6(1), C6-PI-V 87.3(1), P3-PI-V 72.1(1), C1 I-P2-C6 88.9(1), C I I P2-Cl 98.1(1), CII-P2-V 53.3(1), C6-P2-C1 104.6(1), C6-P2-V 84.4(1), CI-P2V 48.8(1), C I I-P3-C6 85.9(1), CI 1-P3-P1 99.5(1), CI I-P3-V47.4(1), C6-P3-PI
52.6(1), C6-P3-V 77.1(1), PILP3-V 57.0(1), P2-CI-V 82.4(1), P3-C6-P2 91.9(1),
P3-C6-P1 71.8(1), P2-C6-PI 107.2(1), P3-CII-P2 93.2(1), P3-CIl-V 86.9(1),
P2-Cl I-V 78.8(1) [6].-Bottom: Molecular structur? of 4 . C2,H,20P3V,
a=18.525(1),b=15.674(1),~=9.555(1)~, V = 2 7 7 4 . 4 A 3 , ~ E . , l r t l = 1 . 2 3 g c m - 1 ,
p(MoK,.)=5.31 c m - ' , 2 = 4 . Space group Pnma, 4489 measured reflections
( + ) I , + k , + I ) (averaged according to point group symmetry mmm), 4135
unique reflections, 2995 observed reflections ( I > 2 ~ ( 1 ) ) .154 refined parameters, R=0.040, R,,=0.047. Selected distances [A] and angles ["I: V-PI
2.459(1), V-CI 2.17112). PI-CI 1.801(2), PLC6 1.886(1), P2-Cl 1.859(2), P2C6 1.878(3); C6-PI-V 83.3(1), C6-PI-CI 88.0( I), V-PI-CI 58.9(1), C6-P2-CI
86.6(1), CI*-P2-CI 102.6(1), P2-CI-V 85.8(1), P2-CI-PI 94.3(1), V-CI-PI
75.8(1), P2-C6-P1 91.0(1), PI*-C6-P1 105.2(2) 161.
0570-0833/87/0909-0908 3! 02.50/0
Angew Chem Int. Ed. Engl 26 (1987) No. 9
The crystal structure analyses of 3 and 4 show that, in
both compounds, the three phosphaalkynes are bound to
the vanadium center as valence isomers of 2,4,6-tri-fert-butyl- 1,3,5-triphosphabenzene (Fig. 1). The C3P3 ligand in
complex 3 can be derived from a 1,3,5-triphosphaprismane in which no bonding interaction between P1 and C1
or between CI and C11 (see Fig. I, top) is present. In complex 4, the C3P3 ligand is unequivocally bound as 1,3,5triphospha-Dewar-benzene (Fig. 1, bottom).
In contrast to 4, complex 3 exhibits dynamic behavior
in solution. At 20"C, a broad signal for P-1 and P-3 at
S= -58.2 is observed in the 31P-NMR spectrum; only at
- 100°C is it split into two doublets at 6 =
140.4 and
-234.4 (JPp=219 Hz). The signal for P-2, on the other
hand, is temperature independent, appearing at 6 = - 130.9
at 20°C and - 135.8 at - 100°C. Therefore, at room temperature a rapid valence isomerization occurs, which can
be described, for example, by the structural formulas 3a
and 3b. The small differences between the bond lengths in
the C,P,V framework of 3a (see caption to Fig. 1, top),
however, indicate that other valence isomeric structures
exist, such as those found for the structurally similar P:"
and that these must be considered for a complete
description of the structural dynamics. In the 3'P-NMR
spectrum of the carbonyl complex 4, the P-l and P-3 signals are observed at 6= -22.4 (d, Jpp=6.0 Hz) and that
for P-2 at S= +84.4 (t); both are temperature independent.
It is remarkable that 1 and 2 react to form vanadium
complexes of valence isomers of 1,3,5-triphosphabenzene,
since reaction of 2 (Cp instead of Cp*) with diphenylacetylene affords a C p vanadium complex containing
n-bonded hexaphenyIbenzene.lK1A possible reason for this
is the strong tendency of two-coordinate phosphorus in
phosphaalkenes to undergo transformation to the more
stable three-coordinate form,''I but it is not clear what role
the transition metal and the C p or Cp* ligands play.
IS] K. Jonas, W. Riisseler, C. Kriiger, E. Raabe, Angew. Chem 98 (1986)
902; Angew. Chem. Int. Ed. Engl. 25 (1986) 925.
[6] Further details of the crystal structure investlgation may be obtained
from the Fachinformationszentrum Energie, Physik. Mathematik
GmbH, D-7514 Eggenstein-Leopoldshafen2 (FRG). on quoting the depository number CSD-52458, the names of the authors, and the journal
[7] a) M. Baudler, Angew. Chem. 94 (1982) 520; Angew. Chem. int. Ed. Engl.
21 (1982) 492; b) H. G. von Schnering, rbid. 93 (1981) 44 and 20 (1981)
[8] W. Riisseler, Disser/ation. Universitat Bochum 1986.
191 See, e.g., the thermal 2-Dewar-phosphinine- I-Dewar-phosphinine
rearrangement: K. Blatter, W. Rosch, U.-J. Vogelbacher, J. Fink, M. Regitz, Angew. Chem. 99 (1987) 67; Angew. Chem. Inr Ed. Engl. 26 (1987)
[lo] G . Becker, G. Gresser, W. Uhl, Z . Naturforsch. 836 (1981) 16: improved
procedure: W. Rosch, U. Hess, M. Regitz, Chem. Ber. 120 (1987). in
C-S Bond Cleavage in a
n-Thiophene Ruthenium Complex**
By Johannes W. Hachgenei and Robert J. Angelici*
Catalytic hydrodesulfurization (HDS), the process by
which sulfur is removed from crude oil by treatment with
hydrogen over a Mo-Co(y-A1203) catalyst, is practiced industrially on a very large scale.['' However, little is understood about the mechanism of this process, especially for
the thiophene-containing organosulfur compounds, which
are the most difficult to desulfurize.[21 As a model for the
possible reaction of n-adsorbed thiophene with hydride
hydrogen bound to the surface of the HDS catalyst, we
previously[31allowed [Mn(C0)3(qs-thiophene)](S03CF3)to
react with hydridometalates (HFe(C0): and HW(C0):)
and obtained the hydride adduct 1 .
Experimental Procedure
3: 1 (2.5 g, 25 mmol) [lo] in 10 mL of T H F was added to a solution of 2
(2.3 g, 7.3 rnmol) [S] in 30 m L of T H F at room temperature; the solution
gradually heats u p to boiling accompanied by a color change from dark red
to brown. After stirring for I h at 20°C, all volatiles were removed at 0.1 torr
and then most of the naphthalene was sublimed off at 20"C/0.01 torr. The
residue was dissolved in 35 mL of hexane; the crystals precipitating at
- 78°C were filtered off and the residual naphthalene was removed at 0.001
torr. A second recrystallization from a small amount of hexane gave 1.53 g
(43%) of 3 (nearly black crystals, m.p. = 121 "C).
4 : A solution of 3 (0.95g, 1.95mmol) in 1 5 m L of hexane absorbed
1.95 mmol of CO in 1 h at 2 0 T , the solution turning green. The green crystals separating out near the end of the reaction were filtered off and recrystallized from ca. 5 m L of diethyl ether at -30°C.After washing with a small
amount of cold pentane and drying at 0.1 torr, 0.9 g (90%)of 4 (decomp. at
125°C) was obtained.
We now find that the reaction of 2 (Cp=q-CsH5)L41
hydrides (LiAIH,, 3, and NaBHEt,) also results in the formation of a hydride adduct, 4. However, an X-ray crystal
of 4 (Fig. 1) shows that, in contrast to
1 , a C-S bond has been cleaved to give a butadiene
Received: May 21, 1987 [Z 2251 IE]
German version: Angew. Chem. 99 (1987) 957
[I] P. Binger, R. Milczarek, R. Mynott, M. Regitz, W. Rosch, Angew. Chem.
98 (1986) 645; Angew. Chem. Inf. Ed. Engl. 25 (1986) 644.
[2] P. B. Hitchcock, M. J. Maah, H. F. Nixon, J . Chem. SOC.Chem. Commun. 1986, 137.
[3] P. Binger. B. Biedenbach, C. Kriiger, M. Regitz, Angew. Chem. 99 (1987)
798; Angew Chem. Int. Ed. Engl. 26 (1987) 764.
[4] Of interest in this connection is the recently described synthesis of a
1,3,5-triphosphabenzene,which, however, contains two hS phosphorus
atoms: E. Fluck, G. Becker, B. Neumiiller, R. Knebl, G. Heckmann, H.
Rittel, Angew. Chem. 98 (1986) 1018: Angew. Chem. I n / . Ed. Engl. 25
(1986) 1002; cf. the complex stabilization of cyclo-P, (hexaphosphabenzene): 0. J. Scherer, H. Sitzmann, G. Wolmershauser, Angew. Chem. 97
(1985) 358: Angew Chem. I n / . Ed. Eng(. 24 (1985) 351.
Anyew Chrm I R I Ed Engt 26 (1987) No 9
[*] Prof. Dr. R. J. Angelici, Dr. J. W. Hachgenei
Department of Chemistry and Ames Laboratory,
Iowa State University
Ames, IA 5001 1 (USA)
Ames Laboratory is operated for the U.S. Department of Energy by
Iowa State University under Contract No. W-7405-Eng-82. This research
was supported by the Office of Basic Energy Sciences, Chemical
Sciences Division. We thank Prof. R . A . Jucobron and D. Wintergrass
for their help with the X-ray diffraction analysis.
0 YCH Verlagsgesellschaft mbH, 0-6940 Wernherm. 1987
0570-0833/87/0909-0909$ 02 50/0
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promote, valence, metali, formation, triphosphabenzene, complexes, isomers, phosphaalkyne, vanadium, cyclotrimerization
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