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Multiple Bonds between УNakedФ Lead and Transition MetalsЧThe First Example.

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Multiple Bonds between "Naked" Lead and
Transition Metals-The First Example**
By Wolfgang A . Herrmann, * Heinz-Josef Kneuper, and
Eberhardt Herdtweck
Dedicated to Professor Max Schmidt on the occasion of
his 60th birthday
Methods for the directed synthesis of complexes containing multiple bonds between transition metals appeared, until recently, to be better developed than those
for the synthesis of analogous compounds between transition metals and substituent-free ("naked") main-group elements. This is true, above all, for compounds with the
more electropositive elements of the fourth to sixth main
groups."' From the pioneering investigations of Huttner et
al., Weiss et al., Herberhold et al., and Legzdins et aI.,[',21it
was expected that a strong tendency of formation should
exist for this class of compounds and that such compounds
might undergo a wide variety of reactions.['.'] At present,
the elements germanium, tin, arsenic, antimony, sulfur, selenium, and tellurium (coordination numbers 2 and 3 with
linear, bent, or trigonal-planar frameworks) are known to
exist without substituents in the bridge position of organometallic complexes and to be bonded through multiple
bonds to organometallic fragments. We have succeeded,
for the first time, in binding divalent lead via two cumulative double bonds to a transition metal.
Whereas the hydride route is suitable for the coupling of
substituent-free germanium atoms with organometallic
f r a g r n e n t ~ , [ ' ~ ~this
~ ~ ~strategy
fails for the heavier homologue lead, probablyon account ofthe instabilityofthe binary hydride. Lead(i1) dichloride appeared to be a more
promising precursor, even though it was not expected to be
completely transformed into the substituent-free maingroup ligand in the presence of organometallic complexes.
We therefore allowed the substitutionally labile solventcomplex [(q'-C,H,)Mn(CO),(thf)]
(thf = tetrahydrofuran)
to react with lead(i1) chloride. After column chromatographic work-up of the crude product (silica gel, 15"C),
we obtained the Mn2Pb complex 2 in ca. 20% yield.r412 is
a relatively light- and oxygen-sensitive deep reddish brown
compound which is nonetheless stable in air u p to ca.
130°C for a short period of time. Conclusive statements
regarding the mechanism of formation of 2 are not yet
possible, particularly since the reaction occurs with the
precipitation of appreciable amounts of finely divided
2 is not formed upon reaction of the organometallic presursor with elemental lead, even when the lead is transformed into a reactive form by high-performance ultra-
sound dispersion.['] Possibly, dichloroplumbanediyl complexes are formed in the first step; in the case of germanium(1i) chloride, the mono- and binuclear dichlorogermanediyl complexes [(q5-C,H,)Mn(CO)2(GeC12)] (as solvent adduct) and [(p-GeCI,){(q'-C,H,)Mn(CO),J2] (solvent
free) are isolable species.[61In the present case, 2 might result from consecutive halogen abstraction from labile intermediates of this type.
According to a single-crystal X-ray structure determination, 2 is the first complex containing a substituent-free
lead atom that is bonded to a transition metal via multiple
bonds. The three-atom MnPbMn structural unit is essentially linear (177.2(1)"), so that no contact exists between
the manganese atoms, and the bridging element lead is dicoordinated (Fig. 1).
Fig. I . ORTEP plot of the molecular structure of ~-lead-bis[dlcarbonyI(rlscyclopentadienyl)manganese] 2 in the crystal. The ellipsoids of thermal vibration correspond to SO% probability; the positions of the hydrogen atoms
are calculated. Crystals obtained from diethyl ether/dichloromethane, 294 K,
142d, Z = 8 , a = 1585.4(2), c=1210.3(2) pm; V=3042x 10' pm': Enraf-Nonius CAD4, VAX I1/730; R = 0.022, Rw=0.028.--Se1ected distances [pm] and
angles["]: Mn-Pb 246.3(1), Mn-CI 185.7(8), Mn-CZ l81.3(7), C I - 0 1 1 Il.1(8),
(22-02 I13.6(7): Mn-Pb-Mn* 177.2(1), Mn-CI-OI 174.1(6), Mn-C2-02
173.9(7), CI-Mn-C2 93.0(3), Pb-Mn-C1 89.9(2), Pb-Mn-C2 91.3(2), torsion
angle CI-Mn-Mn*-CI* -22.2(5), C2-Mn-Mn*-CIS - IIS.2(S).-Further details of the crystal structure investigation are available on request from the
Fachinformationszentrum Energie, Physik, Mathematik GmbH, D-75 14 Eggenstein-Leopoldshafen 2 , by quoting the depository number CSD 5 1613,
the names of the authors, and the journal citation.
On the basis of the bonding proposed for the formally
[(p-Ge){(q5C,R,)Mn(CO),),] ( R = H , CH,; Mn-Ge 218-220 pm),[3a.c.d1
cumulative multiple bonds having triple-bond character
and involving the lead atom should be present.['] The
MnPb distances (245.9(1) pm) justify this view: MnPb single bond lengths (ca. 265-270 pm) may be fairly reliably
estimated by extrapolation of known structural data.Ia1 For
the MnPb double bonds, distances at least 20 pm shorter
are expected, which should, at the same time, be about
2 0 p m longer than analogous MnGe double bonds. This
[*] Prof. Dr. W. A. Herrmann, H.-J.
Kneuper, Dr. E. Herdtweck
Anorganisch-chemisches lnstitut
der Technischen
Lichtenbergstrasse 4, D-8046 Garching (FRG)
Multiple Bonds between Main Group Elements and Transition Metals,
Part 23. This work was supported by the Rundesministerium fur Forschung und Technologie, the Deutsche Forschungsgemeinschaft, and
the Fonds der Chemischen 1ndustrie.-Part 22: W. A. Herrmann, E.
Voss, U. Kiisthardt, E. Herdtweck, J. Organomet. Chem. 295 (1985)
0 VCH Verlagrgesellschafc mbH. 0-6940 Weinheitn, 1985
Fig. 2. Anticlinal conformation of the Mn2Pb compound 2 in the crystal
(projection along the MnPbMn axis).
0510-0833/8S/I2I2-1062 S 02.50/0
Anyen' Chem. lnr. Ed. Engl. 24 (1985) No. 12
continues the trend for lead chemistry observed by Huttner
et al. for the germanium and tin complexes [(F~E)(W(CO),),] (W=Ge 250.2, W=Sn 270.2 pmf2"I).
Of the possible conformers discussed earlier,[3d' only the
anticlinal form is found for the lead complex 2 in the crystal ; the antiperiplanar conformation (trans orientation of
the C5Hi ligands) is not observed (Fig. 2).
Lead is the heaviest main-group element to be combined
with transition metals so far.
Received: August 7, 1985 [Z 1422 IE]
German version: Angew. Chem. 97 (1985) 1060
[I] Review5 and literature: a) W. A. Herrmann in B. L. Shapiro (Ed.): Organomerallir Compounds: Synthesis, Structure. and Theory, Vol. I , Texas A
& M University Press, College Station, TX, USA 1983, p. 383 ff; b) W. A.
Herrmann. Angew. Chem. (1986), in press.
121 Recent work: a) G. Huttner, U. Weber, B. Sigwarth, 0. Scheidsteger, H.
Lang, L. Zsolnai. 3. Organomet. Chem. 282 (1985) 331; b) W. A. Herrmann, J. Rohrmann, H. Noth, C . K. Narula, 1. Bernal, M. Draux, ibid. 284
(1985) 189.
[3] a ) W. Gade, E. Weiss. 3. Organomet. Chem. 213 (1981) 451; b) W. A.
Herrmann, J. Weichmann, U. Kiisthardt, A. Schafer, R. Horlein, C .
Hecht, E. Voss. R. Serrano, Angew. Chem. 95 (1983) 1019; Angew. Chem.
I n t . Ed. Engl. 22 (1983) 979; Angew. Chem. Suppl. 1983, 1543; D. Melzer,
E. Weiss, J . Organomet. Chem. 263 (1984) 67; d) J. D. Korp, I. Bernal. R.
Horlein, R. Serrano, W. A. Herrmann, Chem. Ber. 118 (1985) 340.
[4] Spectroscopic characterization: 1R (KBr, v(CO), [cm -'I): 1959 (w), 1921
(s). I891 (s), 1839 ( s ) ; (THF): 1966 (br. s), 1938 (m, sh), 1905 (m), 1860
(w).-'H-NMR (90 MHz, +28"C, [DaITHF): S=4.58 (s, CSHS).-"C
NMR (+28"C, [D,]THF): S=78.7 (C5H,).-EI-MS: m / z 560 ( M + ,
"''Pb). -- A correct elemental analysis ( C , H, Mn, 0 , Pb) was obtained for
the pure substance.
IS] Heat Systems Ultrasonics, Inc., Model W-375.
[6] a) P. Jutzi, W. Steiner, Chem. Ber. 109 (1976) 3473; b) W. A. Herrmann,
H.-J. Kneuper. E. Herdtweck, unpublished (synthesis and X-ray structure
analysis of [(~-GeC12)((r15-CiHs)Mn(C0)2]~]:
P i ; Mn-Ge 235.7( I),
238.7( I ) pm.
[7] N. M. Kostic, R. F. Fenske, J . Organomet. Chem. 233 (1982) 337.
[XI MnGe single-bond lengths lie in the range 243-250 pm (e.g.,
[(CO),MnGeH,], 249 pm) and are therefore 20-30 pm longer than the
cumulative MnGeMn multiple bonds in complexes of type 2 (Ge instead
of Ph). The I"(2") covalent radii are taken to be 122 ( 1 12) pm for Ge, 140
(130) pm for Sn, and 144-150 (134-140, estimated) pm for Pb; the covalent radius (144 pm) obtained from the structure of Pb2Me6 (Pb-Pb 288
pm) appears to be a lower limit. Cf. A. F. Wells, Structural Inorganic
Chemisrrr. 5th ed., Clarendon Press, Oxford, England 1984.-Estimated
covalent radii in organomanganese(1) complexes of the I($C,R,)Mn(CO),] series: 130-133 ( l a ) , ca. 120 (2"). ca. 109 pm (3"). cf. [3dl,
footnote 19).
The Chemistry and Antibiotic Activity of the
Toadstool Agaricus xanthoderma (Agaricales)**
By Sabine Hilbig. Thomas Andries. Wolfgang Steglich, *
and Timm Anke
Dedicated to Professor Hans Grisebach on the occasion
of his 60th birthday
Fruit-bodies of the toadstool Agaricus xanthoderma
Gen. stain intense chrome-yellow when bruised and develop a phenol like odor. Treatment with alkalis turns the
flesh orange-yellow. Extracts of the toadstool exhibit a
[*I Prof. Dr. W. Steglich, DipLChem. S. Hilbig, T. Andries,
lnstitut fur Organische Chemie und Biochemie der Universitat
Gerhard-Domagk-Str. I , D-5300 Bonn I (FRG)
Prof. Dr. T. Anke
Lehrbereich Biotechnologie der Universitat Kaiserslautern
Paul-Ehrlich-Strasse 22, D-6750 Kaiserslautern (FRG)
Antibiotics from Basidiomycetes, Part 22. This work was supported by
the Deutsche F0rschungsgemeinschaft.-Part 21: T. Anke, J. Heim, F.
Knoch. U. Mocek, B. Steffan, W. Steglich, Angew. Chem. 97 (1985) 714;
A n g e c C h m . tnr. Ed. Engl. 24 (1985) 709.
Anyew Chcm Inr. Ed. Engl. 24 11985) N o . 12
0 VCH Verlagsgesellschaft mbH,
strong antibiotic activity, which Atkinson"' ascribed to a
photolabile compound "psalliotin". Later, work-up of the
methanolic extract in the presence of sodium sulfite afforded "agaricin", which exhibits strong antibiotic and
cancerostatic properties.'*] In neither case was the active
substance chemically characterized in detail. First insights
into the chemistry of A . xanthoderma were gained by Gill
and S t r a ~ c h , [who
~ l were able to isolate phenol, hydroquinone, 4,4'-dihydroxyazobenzene, and 4,4'-dihydroxybiphenyl from the ethanol extract. In this communication we describe the elucidation of the structures of compounds
which are responsible for the antibiotic activity and the
yellow discoloration of the fungus. When fruiting bodies
of A . xanthoderma are extracted with cold ethyl acetate
and the extracts are carefully concentrated by evaporation
and chromatographed at 0-3"C, an intense yellow zone
can be separated. Further chromatographic separation furnishes agaricone l l 4 I (yield 5 x
which according to
its mass spectrum has the empirical formula C l o H ,I NzO
and which in its 'H-NMR spectrum shows signals typical
of a -(CH2)3- unit, as well as signals in the aromatic reg i ~ n . [ ' ~The characteristic MS fragments m / z 107
( C C ~ H ~ N O106
) , (CCiHdNO), 94 ( C J b O ) , 93 (GHsO), 84
(C4HsN2),and 83 (C4H7N2)indicate structure 1 , which has
been confirmed by synthesis. The butyrolactim methyl ester was allowed to react with W(4-benzyloxypheny1)hydrazine hydrochloride in methanol to give the hydrochloride
of the pyrrolidonehydrazone 2 (yield 75%), which upon
hydrogenolysis with Pd/carbon in methanol afforded the
crystalline hydrochloride of 3 .I4]
= CH&&
When 3 is dissolved in water and treated with sodium
hydrogencarbonate the solution immediately turns yellow
in color on being exposed to air. Oxidation proceeds especially smoothly upon addition of sodium periodate: 1 can
be recovered by extraction with ethyl acetate; it is identical
in all respects with the yellow pigment from A . xanthoderma. It can therefore be assumed that the toadstool contains leucoagaricone 3 which is oxidized to 1 by atmospheric oxygen (oxidases) when the fruiting body is damaged.[61
When fresh fruit-bodies are extracted with S02-saturated methanol and all chromatographic steps are carried
out under argon at 0-3"C, a colorless chromogen (yield
can be separated from large amounts of mannito1 after chromatography on Sephadex LH 20 (eluent methanollwater 9 : 1) and repeated further chromatography
on LichroPrep RP8 (eluent: water). The separation can be
monitored by spot testing with K,[Fe(CN),]/NaHCO, solution (orange-yellow color reaction !). The chromogen,
called xanthodermin by us,141gives a positive ninhydrin
reaction and shows signals typical for a glutamic acid residue as well as a signal in the aromatic region of the ' H N M R spectrum. This finding and the fact that ions containing three nitrogen atoms occur in the mass spectrum of
the peracetyl derivative would suggest the structure of a
y-glutamyl-N'-(4-hydroxyphenyl)hydrazide 4 for the chromogen. This has been confirmed by synthesis. In the case
of the a-benzyl ester of N-(benzyloxycarbony1)-L-glutamic
acid the y-carboxy group was converted in 70Y0 yield i n t o
0-6940 Weinheim. 1985
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