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Co5(CO)11(PR2)3 A Novel Type of Pentanuclear Cluster.

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A,
Experimmtul
(+)-Cataline,(+)-(5):Asolutionof( + ) - ( 4 ) ( 1 g)in trifluoroacetic acid (TFA) is treated dropwise with stirring at - 15 "C
with a solution of VOF3 (0.7g) in TFA (25ml) (deep blue
to red-violet coloration). The mixture is stirred for 2 h at
- 15 to - 10°C and, after removal of the cold-bath, for a
further 1 h at room temperature. The TFA is then removed
at 2O0C/7O torr and the residue treated with cold aqueous
NH3 solution and extracted with CHCI3. After drying over
Na2S0, and removal of solvent the residue is taken up in
ether and filtered. Subsequent crystallization affords 646 mg
(61 %) ( + ) - ( 5 ) .
central C O ~ ( C Ounit
) ~ are 2.41-2.47
of those bridged by
phosphorus to the outer Co atoms 2.76-2.81 A, and of the
unbridged C o - C o bonds 2.89 and 2.92 A. The nonbonding
Co..-Co distance is 3.21 A.
Received: June 23, 1977 [Z 784 IE]
German version: Angew. Chem. 89, 739 (1977)
CAS Registry numbers:
( k)-( 1 ~ ) 1699-51-0;
.
(?)-<lb), 26642-09-1 ; (-)-( I b ) , 4747-98-2; ( t ) - ( 2 u ),
5630-1 1-5: (+)-(2h). 39945-40-9; (+_)-(Zb).HBr, 63569-46-0; (+)-(20),
21848-62-4;(+ )-fZb).HBr, 63599-49-5; ( + ) - ( Z h ) N-acetyl deriv., 14787-63-4:
i k H 3 u J . 57236-98-3; (+_)-(3u).HBr, 63569-47-1; ( i ) - ( 3 a ) acetate,
63598-88-9; (T)-f30). 63569-48-2; (?)-(3b).HBr, 63569-49-3; ( + ) - ( 3 b )
TrifluorWdCetdte. 63569-50-6; ( + ) - ( 3 b ) 0,N-diacetyl deriv , 63569-51-7;
( + ) - ( 3 b ) , 63598-89-0; ( + ) - ( 3 b ) 0,N-diacetyl deriv., 63598-90-3; ( + ) - ( 4 ) ,
475-81-0; ( - ) - ( 4 ) , 38325-02-9; (+J-(5), 38764-84-0; (+J-(5) acetate,
38726-63-5; (-)-(.5),
63598-91-4; ( +J-(6). 63598-92-5; VOF3, 13709-31-4
S.M . Kupchun, Om P . Dhinyrtr. Chuny-Kyu Kim, J . Org. Chem. 41, 4049
(1976), and literature cited therein.
All the compounds synthesized were characterized by IR, NMR, MS,
and partly by elemental analysis. Yields refer t o crystallized products.
a ) ( + )-Cataline, ( + ) - ( 5 ) , was isolated from Gfaucium Ffurrrm Cr. cur.
Vrstituni: I . Ribns. J . Sueirusu, I.. Cusicdo, Tetrahedron Lett. 1972, 2033.
b) O u r synthesis of cataline was carried out at the beginning of 1974;
J. Hartmslein, G. Sutzingrr, DOS 2625 116.1 (1976), Goedecke AG;
c) D. Ho.\kiiio, H.Horu, M . Ogawa, B. Umezartu have reported an alternative synthetic entry to (f)-cataline: J. Chem. Soc. Chem. Commun.
1Y75. 306; Chem. Pharm. Bull. (Japan) 23, 2578 (1975); d ) Acetylation
affords the acetate having m.p. 169--170°C. For ( + ) - c a t a h acetate
a melting point of 91-92°C has been quoted [3a].
H . Corrodi, E. Hurdegger, Helv. Chim Acta 39, 889 (1956).
a ) M. Toiniru, S.-7: Lu. S . 4 . Wung. C.-H. Lee, H.-7: Shih, Yakugaku
ZasshiXX. 1143(1968);Chem. Abstr. 70,48850b(1969); b ) C . Cusuyruiidr,
G. Fcrruri, Farmaco 25, 442 (1970).
L. Custedo. R. Suan. A . Morrriiio, Heterocycles 3, 449 (1975).
,-
Fig. I . Molecular structure(1eft)and heavy-atom skeleton(right)of Cos(CO),
IP(CH3)zll ( I ) .
The structure and bonding of ( 1 ) are in many respects
unusual. Firstly, ( I ) is the first Lewis-base-bridged cluster
containing more than four metal atoms[41. Further, such an
edge-bridged trigonal pyramid in pentanuclear clusters is new;
previously only the trigonal bipyramid[',
the tetragonal
pyramidr4-'I, and the double triangle[71have been observed.
Finally, the metal-metal bonds in ( 2 ) are explainable neither
by simple application of the I %electron rule nor by the skeleton
electron counting method[s]. Only the valence bond notation
with the two resonance formulas ( l a ) and (Zb) providesa somewhat acceptable picture of the bonding. It gives all cobalt
atoms the krypton configuration and assigns the bond order
' / 2 to the unbridged Co-Co
bonds. It is then understandable
that these two bonds are distinctly longer than normal
unbridged Co-Co bonds.
N
CO~(CO
,(PR213,
)~
A Novel Type of Pentanuclear
Cluster[**]
By Egbert Keller and Heinrich VahrenkampI*]
The reaction of complexes of secondary phosphanes with
n-ally1 complexes involving elimination of propene has previously led to phosphorus-bridged dinuclear and trinuclear
complexes containing metal-metal bonds[']. We have now
tried to utilize this reaction scheme for the synthesis of a
compound containing a Co-Ni bond. On reacting q3C 3 H 5 C ~ ( C 0 ) 3with (CO)3Ni-PMe2H
we surprisingly
1(PMe2)3
)~
obtained the pentanuclear cobalt cluster C O ~ ( C O
(I ). The mechanism of formation of this product is unclear;
its formation is, however, consistent with our observation[']
that the aggregation of polynuclear base-bridged complexes
increases with decreasing number of terminal ligands.
The composition and structure of the new compound (I )['I
could be unequivocally determined only by a crystal structure
analysis[31.As seen in Figure 1 , the arrangement of the cobalt
atoms has to be described as a n edge-bridged trigonal
pyramid in which the lengths of the Co-Co bonds in the
[*] Prof. Dr. H. Vahrenkamp, DipLChem. E. Kellei
Chemisches Laboratorium der Universitat
Albertstrasse 21, D-7800 Freiburg (Germany)
I"*] This work was supported by the Deutsche Forschungsgemeinschaft,
the Fonds der Chemischen Industrie, and the University Computing Center
at Freiburg.
Angew. Chem. Int. Ed. Engl. 16 (1977) No. 10
(10)
ilb)
The structure of ( 1 ) is a further example showing that
phosphorus bridging leads to unusual polynuclear complex
geometries['. 'I. A systematization of these geometries, however, requires the discovery of further examples.
Experimentul
A mixture of (CO)3Ni-PMe2H (4.0g, 20mmol) and q3C 3 H s C ~ ( C 0 ) (3.7
3 g, 20 mmol) is stirred for 1 d without
solvent. 280 ml of gas (propene, CO) is evolved. The highly
viscous oil remaining after removal of 1.9 g of volatile
reaction products (mainly Ni(CO),) is extracted with benzene
(20ml) and theextract chromatographed on a silica gel column
(2 x 100cm). Initial elution with benzene/hexane (I :4) gives
a dark-green compound which has not yet been identified.
Next, with benzenehexane (1 :2) a dirty-green fraction is
obtained which after concentration by evaporation and
subsequent slow recrystallization from benzene affords 220 mg
(7 %) of black (I ), m.p. 166-1 67°C (dec.).
Received: July 8, 1977 [Z 782 IE]
German version: Angew. Chem. 89, 738 (1977)
73 1
CAS Registry numbers:
( 1 A 63588-51-2; (CO)3Ni-PMe,H,
63548-46-9; q3-C3H,Co(CO),, 12144-
85-3
[l] B. C. Benson, R . Jackson, K . K . Joshi, D . T. Thompson, Chem. Commun.
1968.1506: E . Krller, H . Vuhrenknmp, Chem. Ber. 110,430 ( 1 977); Angew.
Chem. 89, 568 (1977); Angew. Chem. Int. Ed. Engl. 16, 542 (1977).
[2] Correct elemental analyses, ‘H- and 3’P-NMR, IR, and mass spectra
were obtained.
[3] Monoclinic, P2,/c, Z = 4 ; a=9.974(4), h=15.192(2). c = 18.981(3)6.,
p = 105.79(3)”; 3617 reflections corrected forabsorption, R=0.041.
[4] Cf. P . Chini, G. Longoni, V. G. Albano, Adv. Organomet. Chem. 14,
285 (1976); H . Vahrenkump, Struct. Bonding 32, 1 (1977).
[5] C. R. Eady, B. F . G . Johnson, J . Lewis. B . E . Reicherr, G . M . Sheldrick,
J. Chem. SOC.Chem. Commun. 1976, 271.
[6] K . Jodden, H . C. i’on Schnering, H . Schafer. Angew. Chem. 87, 594
(1975); Angew. Chem. Int. Ed. Engl. 14, 570 (1975).
[ 7 ] H . Vahrenkamp, L. F . Dahl, Angew. Chem. 81, 152 (1969); Angew. Chem.
lnt. Ed. Engl. 8, 144 (1969).
[XI K . Wade, Adv. Inorg. Chem. Radiochem. 18, I (1976).
[9] R. J . Haines, R . Mason, J . A. Ztibretn, C. R . Nolre, J. Cbem. SOC.
Chem. Commun. 1972,990.
ABSTRACTS
carbonyl group.-3) The thiocarbonyl group has a greater
volume than the carbonyl group.-A. Ohno compares the
reactions of thiocarbonyl and carbonyl compounds from this
vantage point. [Thiones in S . Oae: Organic Chemistry of
Sulfur. Plenum Press, New York 1977, pp. 189-229; 145
references]
[Rd 965 IE]
Tellurophene ( I ) and related compounds is the title of a
survey by F. Frinquelli, G. Marino, and A . Taticchi. The term
“related compounds” not only covers derivatives of tellurophene but also applies to furan, thiophene, and selenophene,
Polymerizations proceeding via free radicals and initiated by
light have become increasingly important in recent years owing
to their practical significance in the printing industry and
in the production of printed circuits and coatings. A . Ledwith
gives an account of the polymerizations of methyl methacrylate
initiated by various amine-fluorenone combinations and light.
[Photoinitiation of Polymerisation. Pure Appl. Chem. 49,
43 1-441 (1977); 36 references]
[Rd 970 IE]
Thiols (mercaptans), as all chemists know, have an extremely
unpleasant odor. This repulsive property may have precluded
a thorough study of this class of compounds, although no
organism is able to live without them. In a review, A . Ohno
and S. Oae compare and contrast the physical properties
of the thiols with those of their oxygen analogs, describe
the syntheses and reactions of thiols, and discuss some of
their biological functions. [Thiols in S. Oae: Organic Chemistry of Sulfur. Plenum Press, New York 1977, pp. 119-187;
250 references]
[Rd 964 IE]
Thiocarbonyland carbonyl groups differ in the following properties: 1) The x electrons of a thiocarbonyl group are more
strongly localized at the sulfur than the TI electrons of a
carbonyl group at the oxygen. The thiocarbonyl C atom therefore carries a greater positive charge than the carbonyl C
atom.-2) Unpaired electrons on the thiocarbonyl sulfur are
more readily removed than those on the carbonyl oxygen,
i.e. the thiocarbonyl group is more easily ionized than the
732
whose properties are compared quantitatively with those of
tellurophene. [Tellurophene and Related Compounds. Adv.
Heterocycl. Chem. 21, 119-1 73 (1977); 109 references]
[Rd 976 IE]
Thienopyridines, i. e. compounds of type (I) to (6), command
theoretical interest as systems having one ring with a surfeit
of 7c electrons and the other with a deficiency of 71 electrons.
Numerous substances of this class have also been synthesized
in the search for new pharmaceuticals; apart from derivatives
of type ( I ) and ( 2 ) , which occur in high-sulfur oil shales,
Nm
N\
(4)
(5)
N
C
S
16)
thienopyridines have not yet been found in nature. J . M .
Barker has written a review of the syntheses, reactions, and
properties of these compounds. [The Thienopyridines. Adv.
Heterocycl. Chem. 21, 65-1 18 (1977); 150 references]
[Rd 975 IE]
Angew. Chem. Int. E d . Engl. 16 (1977) No. 10
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