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Metal-Assisted Reaction of Carbon Disulfide with the УEtriphosФ Phosphane Ligand Synthesis and Structure of [(Etriphos)Fe{S2C(Et2PCH2)2CMe2}](BF4)2.

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exclusively methylated. Such a reaction is realized only with
the triethyl(ethy1idene) homologue ( l b ) , which smoothly affords the 0-alkylated product (3) as shiny golden yellow
crystals, m. p. 84 "C.
MI e
- [E~,P]SO~F
This reaction tendency can be attributed to a steric hindrance of C-alkylation by the methyl ligands on the ylide
carbon and/or to an increase in the electron density on the
acyl oxygen by its donor activity and that of the ethyl groups
on the phosphorus. For the anion of ( l b ) the resonance structure (fb') should be strongly favoredl6l.
(2b): (la), formed on reaction of MeC5H4Mn(CO)3(1.31 g,
6 mmol) with Me3PCH2(1.08 g, 12 mmol) in pentane (15 ml)
at O"C['l, is cooled, together with the solvent, to -78°C.
After addition of MeOS02F (1.37 g, 12 mmol) and warming
to room temperature the pale-yellow crystalline precipitate
of (Zb), [Me4P]S03F and [EtPMe3]S03F is filtered off,
washed with 3 x 5 ml benzene, and dried in a vacuum. Recrystallization from THF/CH,CN (20 ml) affords 0.92 g
(35%) of yellow (Zb), m.p. 99--100°C.
(2c): A suspension of the above mixture of salts in benzene
(40 ml) is treated dropwise at 8°C with a solution of
Me3PCH2(0.45 g, 6 mmol) in benzene (10 ml). After 30 minutes' stirring the insoluble [EtPMe3]S03F and [Me4P]S03F
are filtered off on a frit; the clear reaction solution is then
evaporated down to 15 ml. After addition of pentane (30 ml)
and cooling to O"C, 1.10 g (54%) of golden-yellow (Zc), m.p.
115-117 "C (dec.), crystallizes.
Received: April 2, 1980 [Z 632b IE]
German version: Angew. Chem. 92, 1065 (1980)
Table 1 Spectroscopic data of the carbene-manganese complexes (2a-c) [a].
(2a): 'H-NMR (ChD,)- 6=4.44 (m. 4 ring-H), 1.96 (s. ring-CH,), 4.73 (d,
HC P, ' J ~ ~ r = 3Hz),
4 4.04 (s, OCHI), 0.74 (d, P(CH,)S, 2 J H p c = 13.6 Hz); IR
(ChHh):uCO= 1897 vs, 1827 vs c m - ' [measured in admixture with (Zb)]
f2b): 'H-NMR (CD,CN): 6=4.93 (m, 4 ring-H). 1.93 (s, ring-CH,). 4.36 (s,
OCH'). 1.7 (dq, HCP. ' J ~ c c ~ = 7 . Hz,
6 2J~cp=12.2Hz), 1.33 (dd, CH,CP,
' J ~ c c r = 2 3 Hz), 1.72 (d. P(CH,),, 'Jncp= 14.2 Hz); "P-NMR ([DAI-DMSO):
6=29.9: IR (THF): vCO= 1960 vs, 1895 vs cm '
(Zc). 'H-NMR (ChDh):6=4.44 (m. 4 ring-H). 1.94 ( s . ring-CH,). 2.28 (d, CHIC.
'Jiiccr= 16.2 Hz). 4.00 ( s . OCH,), 0.80 (d, P(CH,)', 'JHCP=13.2 Hz); "C-NMR
(C6D6):6=236.19 (CO), 257.6 (d, C==Mn, 'Jcr=7.77 Hz). 101.9, 82.5, 81.1 and
144 (ring-C-1. -C-2.5. -C-3,4 and -CH,), 58.14 (H,CO), 17.81 (d, CH,C,
' J c ~ r =1x37 Hz). 13.01 (d, CH'P, Jcp=52.16 Hz), 90.61 (d, C i P , Jcr=69.9
HZ); "P-NMR (ChD,,): 6 = -4.49; IR (CoH6): K O = 1898 vs, 1830 vs cm
[t] [MePlSO,F is contaminated with [Me3PEt]S0,F. which is formed by reaction of Me,PCH2 with MeOSO'F.
[2] R. Gompper. H:H. Wagner, Angew. Chem. 88. 389 (1976); Angew. Chem.
Int. Ed. Engl. 15, 321 (1976); B. G. Pearson, J. Songstad. J. Org. Chem. 32,
2899 (1967).
131 Me3PCH2 is immediately removed from the reaction mixture as
141 The ethyl groups guarantee high stabilization of the phosphoniurn moiety.
151 Space group Pca2,; a = 1770(1), b=795.4(3), c = 1187.7(6); 2=4
V = 1672 X 10" pm'; p (talc)= 1.34 g/cm3. Syntex P2JXTL. Mo,,.-radiation
(graphite monochromator, A =71.069 pm), 1077 structure factors (F,it3.90),
[6] U. Schuberr, J. Organomet. Chem. 185, 373 (1980).
171 B. Zimmer-Gasser, D. Neugebauer. U . Schubert. H. H. Karsch, Z . Naturforsch. 8 3 4 , 1267 (1979).
[a] 6 Values rel. TMS int. ('H, "C) and H3P0, ext. ("P). I3C- and "P-NMR 'Hdecoupled
The composition and structure of (2a-c) and (3) are confirmed by elemental analysis and by IR and NMR spectra
(cf. Table 1). In the case of (Zc) its constitution was also confirmed by an X-ray structure analysis (cf. Fig. I)[']. This
shows that the bonding in (2c) is best described by two resonance forms.
,OM e
Fig. I . Structure of (Zc) in the crystal (important bond lengths in [pm]). Bond angles: Mn-C10-010
123.5(7), Mn-ClOC11 129.0(8), OlO-C1OC11 107.6(9),
117.7(8)O 171.
(24 differs from the C5H5(CO),Mn-carbene complexes
known so far (resonance form A)['] in that the length of the
Mn-Ccarbenebond is extended by 7-10 pm, that of the C,,,.
pm, and that the methyl group on 010 is
no longer located in the coordination plane of the carbene
carbon. The carbene carbon is electronically stabilized according to resonance form B, mainly by the ylide function;
the methoxy group no longer participates'']. Accordingly, the
CIO-C11 bond has strong double bond character, while the
P-C11 bond (176.6 pm) is markedly longer than the corresponding bonds in phosphorus ylides. For comparison: The
bond lengths in [(Me3P)3C]12are 175 pm (formal
bond order: 1.33)l91.
Metal-Assisted Reaction of Carbon Disulfide with
the "Etriphos" Phosphane Ligand
Synthesis and Structure of
By Claudio Bianchini, Andrea Meli, Annabella Orlandini,
and Luigi Sacconi[''
By reaction of CS2 with hydrated iron(I1) tetrafluoroborate
in the presence of (neopentanetriyltris(diethy1phosphane)
("Etriphos") ( l ) , we have obtained the iron(1i) complex
[(Etriphos)FeZ](BF& (2),where Z is the unprecedented sixmembered heterocyclic zwitterion 1,1,3,3-tetraethyl-5,5-dimethyl-I ,3-diphosphonia-2,2-cyclohexanedithiolate.
( I ) , etriphos
bond by 7-8
Angew. Chem. Inr. Ed. Engl. 19 (1980) No. 12
['I Prof. Dr. L. Sacconi, Dr. C. Bianchini, Dr. A. Meli, Dr. A. Orlandini
lstituto di Chimica Generale e Inorganica dell'Universita, Laboratorio
39 Via J. Nardi, 1-50132 Firenze (Italy)
0 Verlag Chemie, GmbH. 6940 Weinheim. 1980
$ 02.50/0
An X-ray structural investigation"] on compound (2) (Fig.
1) has shown that the iron atom is five-coordinated by the
three phosphorus atoms of the Etriphos ligand and by the
two sulfur atoms of the zwitterion in a distorted square
I31 F. Busolo, R. G. Pearson: Mechanisms of Inorganic Reactions. Wiley, New
York 1967.
141 M. Bacci, S. Midollinr, P. Stoppioni, L. Socconi, Inorg. Chem. / 2 , 1801
151 W. Hewerrson, H. R. Watson. J. Chem. SOC.(962. 1490.
Reversal of Stability in the Benzene/Dewar-Benzene
By Giinther Maier and Klaus-Albert Schneiderl'l
Dedicated to Professor Karl Dimroth on the occasion of
his 70th birthday
In all previously investigated cases121the valence isomers
of benzene and its derivatives under normal
higher in energy than the aromatic parent molecules. We
have now found that crowding of very bulky groups can
make the Dewar-benzene isomer more stable than the partner with an intact benzene ring.
Despite the great steric hindrance, tetra-tert-butylcyclobutadienel4]reacts smoothly with acetylenedicarboxylate, even
at room temperature, to give the symmetric Dewar-phthalate
(1) (colorless crystals, m. p. 94-97 "C, 83%).
Figure I. Perspective view of the complex cation [(Etriphos)FeZ]" (2) (ORTEP
diagram). Important bond lengths and bond angles: Fe-P(1-3)=
150.1(2), S2-Fe-P2=
= 77.8(2), St -C-S2
= 101.7(9)" (11.
Some metal complexes with disulfido ligands containing
only one quaternary phosphonium atom have already been
reported['], but no ring closure within the zwitterion has previously been observed. Definite conclusions have not been
reached about the cleavage of a carbon-phosphorus bond in
the third chain of the Etriphos rest.
The title compound (2) seems to be the first example of a
five-coordinate iron(r1) complex lying in a singlet ground
state. Its diamagnetism can be ascribed to the very high 2 no
value of the P3S, donor
even higher than that of the
P4Br set in the complex [Fe(P4)Br]BPh4,which shows a singlet-triplet spin state e q u i l i b r ~ i m [ ~ ~ .
(P4 = Ph2P(CH2)2PPh(CH&PPh(CH2)2PPh2)
Table I. Spectral data of the compounds (/), (2). and (3). IR [cm 'I;UV [nm],
am ax(^) in cyclohexane: NMR: 6 values rel. to TMS (p=prrmary, q=quaternary).
All operations are performed under N2 and with oxygenfree solvents. CS2 is bubbled for 30 min through a hot mix(2 mmol) in dichloromethane (40 ml) and
ture of
Fe(BF&.6H20 (1 mmol) in ethanol (30 ml). The reaction
mixture is maintained at reflux temperature for one hour.
The resulting dark green solution is concentrated to give
green crystals which are recrystallized from dichloromethane/ethanol; yield 40%.
Received: May 13, I980 (Z 633 IE]
German version: Angew. Chem. 92, 1055 (1980)
[I] Philips PW 1100 automatic diffractometer. Crystallographic data for the
complex: a=18.964(7), b=18.016(7), c=14.033(5) A. /3=109.1(1)". monoclinic, space group P2,/c, Z=4. The structure was refined from 1936 observed reflections with 2s 3u(1) to R =0.074 and Rw =0.073 respectively.
121 T V Ashworth, E Singleton, M Luing, J. Chem. Soc. Chem. Commun. 1976.
875; G. R. Clark, T. J. Collins, S. M . James, W R. Roper, K. G. Town, ibrd.
1976, 475; P. V. Yaneff, Coord. Chem. Rev. 23, 183 (1977).
When (1) is heated to 120°C a new, unsymmetrical Dewar-benzene isomer (3) is formed (colorless crystals, m. p.
51%) with another arrangement of the substituents. The structures assigned to (1) and (3) follow from the
spectra (see Table 1) and the finding that both bicycles are
0 Verlug Chemie, G m b f f ,6Y40 Weinheim, 1980
(1): IR (CCb): 1730, 1715 (C--zO), 1627 (C -.C); UV: 256 (2500). MS: m/
e=418.3083 (calc.), 418.3079 (obs.); 'H-NMR (CDCL): 1.37 (18H), 1.39 (18H),
3.78 (6H); "C-NMR (CDICII): 32.4 (p), 32.7 (p), 33.5 (q), 34 6 (q), 51.6 (p), 78.4
(4). 152.3 (q), 158.7 (9). 165.0 (C ..O)
(2): 1R (Film): 1730. 1715 (C- 0); UV: 305 (4050). 265 (14600) (51; MS: m /
e=418.3083 (calc.), 418.3063 (obs.); 'H-NMR(CD2C12):1.44(18H), 1.47 (18H).
3.64 (6H); "C-NMR (CDzC12): 34 8 (p), 362 (p), 41.0 (q), 46.5 (9). 52.0 (p).
129.2 (q), 142.6 (q). 160.1 (4).171 1 (C-0)
13): 1R (CCL): 1734, 1720 (C-0).
1620 (C-C1; U V 235 (1650); MS m/
e=418.3083 (calc.), 418.3120 (obs.): 'H-NMR (CDCI,): 1.18 (9H [a]), 1.30 (9H),
1.33 (9H). 1.37 (9H). 3.68 (3H). 3.85 (3H); "C-NMR (C2D2CI,). 29.5 ( p [b]),
30.2 (p). 30.4 (p). 32.2 (p), 32.7 (4). 34.1 (4). 34.6 (q). 34.8 (q), 51.1 (p). 51.7 (p),
59.4 (q). 75.9 (4). 136.0 (q), 153.9 (q), 156.3 (q), 165.8 (4). 171.0 ( C ~ - 0 173.4
[a1 At room temperature broad, at 120°C In C2D2C14sharp. [bl At room temperature scarcely visible. at 100°C sharp.
Prof. Dr. G. Maier. DiplLCbem. K.-A. Schneider
Institut fur Organische Chemie der Universitat
Heinrich-Buff-Ring 58, D-6300 Giessen (Germany)
S 02.50/0
Angew. Chem. Int. Ed. Engl. 19 (1980) Nu. I 2
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bf4, assisted, reaction, disulfide, ligand, structure, synthesis, уetriphosф, 2cme2, et2pch2, metali, phosphane, etriphos, s2c, carbon
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