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FeCoMoWS(AsMe2)Cp2(CO)7 The First Cluster to Contain Four Different Metal Atoms.

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IS] Older data given i n the literature on the lormation of"p~,lythioanion\" [cl: I;.
!1i0?7mit7. A . Mullcr, Coord. Cheni. Rev. 1 0 . 79 (I973)j. which we intend i n ve\tigating \ysteniatically. are in need of revision since the possibility 01 red o pri)cesre\
(strongly temperature dependent owing to the high activation
energy 141) taking place simultaneou\ly ha\ not been taken into convdcration
161 Space group Pcd?,. 0-29202 (5). h=h.54h ( 1 ) . c = IO.X75 ( 2 ) A: hee
S l i d d n ~ h4. . Mullw. C I (11, Inorg. Cheni.. i n prea\.
FeCoMoWS(AsMe,)Cp,(CO),: The First Cluster to
Contain Four Different Metal Atoms[**]
By Felix Richter and Heinrich Vahrenkamp1'I
The directed synthesis of clusters is still in its infancy"'.
and especially in the case of heteroclusters there are but few
preparative pathways which owe their success more to strategy than to chance''1. We discovered such a pathway in the replacement of carbonylcobalt groups by other organometallic
fragments"'. A detailed study of this reaction has provided
an entry to a new class of compounds by leading to the synthesis of the first cluster to contain four different metal
of the p.,-bridged complex ( 1 ) into (4)
the straightforward substitution product (2) previously described was found to be converted into a further isolable intermediate (3)[41. This intermediate under mild conditions
underwent not only elimination to give the trinuclear FeCoMo cluster (4) but also aggregation to form the tetranuclear
FeCozMo cluster having the skeleton (5)"'. A corresponding
reaction sequence starting from (4) and the organometallic
base Cp(CO),W AsMe,lhl led-as planned-to the tetranuclear cluster named in the title to which we assign the tetrahedral FeCoMoW skeleton (6)"'.
AsCH, groups by the appearance of two signals at 6 = 1.72
and 1.74, as well as the two distinct cyclopentadienyl ligands
by the occurrence of two broad signals at 6=4.36 and 4.86
(benzene, TMS int. std.). The CO stretching bands (in cyclohexane 2003 m, 1987 vs, 1946 m, 1888 w, 1811 w, 1779 w,
1769 cm- w) indicate the presence of terminal and bridging
carbonyl ligands. Owing to the different nature of each corner of the tetrahedral skeleton, compound (6) is chiral, like
the starting compound (4).
The bridging ligands AsMe, and S which permit the directed synthesis of (6) may prove obstructive in studies of the
chemical properties of this novel tetranuclear cluster since
they tend to "shield" the metal atoms. The versatility of (6)
(each metal atom coordinated in a different way, six different metal-metal bonds) nevertheless makes it a stimulating
object of study.
Cp(CO),W AsMe, (0.43 g, 0.98 mmol) are heated under reflux for 1 d in benzene (20 ml). After evaporation to dryness
the product is crystallized from a small volume of benzene/
hexane (1 : 1) at - 35 "C;yield 0.35 g (42%) of (6), black crystals, m. p. 135 "C.
Received: February 26. 1979 [Z 220 1E]
German version: Angew. Chem. 91. 566 (1979)
CAS Registry numbers:
(/), 22364-22-3: (2). 68185-54-6; (3). 70576-10-2; (4). 68185-55-7: /5), 70576-33-9:
(6). 70623-72-2; Cp(CO),W AsMe,, 52456-36-7
[ I ] H. Vuhrmkuntp. Struct. Bonding (Berlin) 32, I 11977).
121 W L. Gludfdrer. G. L. Groffrui.. Adv. Organomet. Chem 18. in press.
[ 31 F. Rich/er. H. Rrwnch. H. VuhrenAump. Angew. Chem. 00. 915. 916 ( l Y 7 X ) :
Angew Chem. Int. Ed. Engl. 17. Xh3. Xh4 (197X); .I Organmiet. Chem 166.
C5 (1979)
[ 41 l3) was characteri7ed by crystallography: iiwnoclinic. PZ,/c. < I = 1576 ( ( 7 ) .
h = 1136 9(2). c = 1346.0(4) pm. p=Y3.91(3) . 3137 independent retleclions.
K = 0.04 I .
[ 51 In the crystalline state. the molecules 0 1 15) havc three C O bridge5 triclinic.
P i . o = ~ o x . s ( ~ h=
) . 1464.2(5). (.=x620(4) pni. ( ~ = ~ 0 . 4 7 ( 3p=
) . 101.45(3).
y=72.70(3) . 3015 independent rellections. R =O.O69.
161 W. Muli.\rh, M. Kuhn. Angew. Chem. K6, 51 (1974). Angew. Chem Int. l:d.
kngl /3.84 ( 1974).
[ 7) Structure asigned by analogy with (S).C r y t a l structure determination of (6)
precluded by the crystals' turning amorphous (apparently without deconipw
sition) in the X-ray heam.
tion, and Carbene Reactions'**]
By Manfred Regitz, Annernarie Heydt, and Berndt Weher"'
The composition of compound (6) has been established by
complete elemental analysis and FD mass spectrometry. Its
'H-NMR spectrum reveals the nonequivalence of the two
lndividual cases of electrophilic substitution at carbon of
diazomethyl compounds, such as acylation with acyl chlorides. have been known for a long time"'; however. generalization of this reaction (halogenation, nitration. metalation,
and alkylation) was accomplished only recently[". lntroduction of Hiickel-aromatic cations as electrophiles opens up
new vistas.
Model reactions between the diazomethylphosphoryl compounds (3a) and (36/1'1 in dichloromethane/triethylamine
(route B ) , or preferably their silver derivatives (2a) and
[ * ] Prof. Dr H. Vahrenkamp. DiplLChem. F. Richter
Chemibches Lahoratorium der Universitit
Alhert\trase 21. 11-7XDO Freihurg (Germany)
[ **I This work wa\ wpported by the Deutsche Forschungsgemeinschaft and the
Fonds der Chemischen Indu\trie. We are grateful to Ur. K. S/einhuch. Marhurg.
for the ma\\ \peelrum.
[ **I Studie, of D i a i o Compounds and ATides. Part 34. This work was supported
by the Deutsche Forschungsgemeins~ha1tand the Fonds der Cheniirchen Industrie. -Part 33: M Regirr. A. M . 7 u r f i k . H Herdr. Synthesi\. in press.
A n g e r . ('hem. Inr. Ed. Engl.
IK 1107Y) No. 7
0 Verlug Chrmie. G m b H .
Prof. Dr. M. Rcgit7. DipL-Chcm. A. Heydt. Dr. B. Weber
Fachbereich Chemie der Universitit
D-6750 Kaiserslautern (Germany)
6 9 4 0 Wernheim. IY7Y
05 7 f / - ( / H l . l /7Y/0707-0>.3 / $ 02.XJ/O
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fecomows, clusters, first, metali, atom, four, contain, different, cp2, asme2
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