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Naked Phosphorus Atoms as Trigonally Planar Coordinated Bridge Ligands.

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of the phosphorus atoms in 2, indicated by the &(("P)value, was proven by an X-ray structure analysis (Fig. 1).
Naked Phosphorus Atoms as Trigonally Planar
Coordinated Bridge Ligands**
By Heinrich Lung, Laszlo Zsolnai, and Gottfried Huttner*
Dedicated to Professor Ernst Otto Fischer on the occasion
Fig. 1. Molecular structure of the complex 2, a compound with trigonally
of his 65th birthday
planar coordinated phosphorus atoms. Further details of the crystal structure
investigation are available on request from the Fachinformationszentrum EnCompounds in which a phosphorus atom is p3-bonded
ergie Physik Mathematik, D-7514 Eggenstein-Leopoldshafen, on quoting the
to three transition-metal centers in a trigonal planar coordepository number CSD 50601,the names of the authors, and full citation of
dination have so far never been described. Since it was
the journal.
found that complexes with planar threefold bridging arsThe tetranuclear complex 2 has almost C2-symmetry.
enic atoms are accessible by reaction of haloarsanediyl
The two P atoms each lie in a plane with their three nearest
complexes with organometallic nucleophiles['I, we atneighbor atoms (maximum deviation 5.0 pm); the interplatempted the synthesis of trigonally planar coordinated p3nar angle for Fel-PI-Fe2 and Fel-P2-Fe2 is 94.1". The
phosphorus in a similar way.
vacant p-orbital of the phosphorus is predominantly filled
Indeed, the complex 2 could be obtained as the first
by back-bonding from manganese donor orbitals: the mancompound containing this structural element by reductive dehalogenation of ( T ~ ~ - C ~ H ~ ) M ~ ( C1Owith
) ~ P B ~ ~ganese-phosphorus bond, with a length of 210 pm, is even
shorter than the corresponding bonds in phosphinidene
complexes, which are similarly shortened by manganesedn-phosphorus-pn interactions['].
2 (34%)
2 dissolves in n-pentane or toluene, yielding wine-red
solutions. Crystals of 2 exhibit the metallic luster characteristic of the chromophoric system of metal complexes
containing trigonally planar coordinated elements of the
fifth main group[']. The composition of 2 is confirmed by
elemental analysis and by the mass spectrum. IR and 'HNMR spectra are consistent with a hindered rotation
about the P-Mn axes. The 3'P-NMR spectrum indicates
an unconventional structure; it shows a singlet at 6=977,
i.e. with the largest downfield shift known so far. Only
"phosphinidene" complexes exhibit similarly extreme signal positions [ ( I ~ ~ - C ~ H ~ ) M ~ ( C O ) ~ ] 6~ =
P 884)19].
bonding system in which the P atom is involved in phosphorus-pdmetal-dx interactions-with its low-lying LUMOS[~."~,
due to the "weak" n-bonding-apparently increases the paramagnetic contribution to the chemical shift
to a considerable extent. The trigonal-planar environment
[*I Prof. Dr. G. Huttner, H. Lang, L. Zsolnai
Lehrstuhl fur Synthetische Anorganische Chemie der Universitat
Postfach 55 60, D-7750 Konstanz (Germany)
[**IThis work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen lndustrie.-We thank Prof. Dr. Marianne
Baudler and Dr. J. Hahn, Universitat Koln, for the "P-NMR measurements.
Q Verlag Chemie GmbH, 6940 Weinheim, 1983
Received: July 5, 1983
German version: Angew. Chem. 95
The complete version of this communication
Angew. Chem. Suppl. 1983,
[Z 444 IE]
(1983) 1016
appears in:
[I] G. Huttner, B. Sigwarth, J. von Seyerl, L. Zsolnai, Chem. Ber. 115 (1982)
121 B. Sigwarth, L. Zsolnai, 0. Scheidsteger, G. Huttner, J. Organomer.
Chem. 235 (1982)43; and references cited therein.
[4j G. Huttner, H.-D. Muller, A. Frank, H. Lorenz, Angew. Chem. 87 (1975)
714;Angew. Chem. Inf. Ed. Engl. 14 (1975)705.
[7] N.M. KostiC, R. F. Fenske, J . Orgonomet. Chem. 233 (1982)337.
191 H. Lang, G. Huttner, unpublished.
[lo]G. Huttner, J. von Seyerl, M. Marsili, H . 4 . Schmid, Angew. Chem. 87
(1975)455;Angew. Chem. Int. Ed. Engl. 14 (1975) 512.
Diphosphorus, :P=P:, as Eight-Electron Ligand**
By Heinrich Lang, Laszlo Zsolnai, and Gottfried Huttner*
Dedicated to Professor Ernst Otto Fischer on the occasion
of his 65th birthday
It was already demonstrated some time ago that the Pz
and As, molecular homologues of dinitrogen can be stabilized as side-on bonded 4x-donor ligands in carbonylcobalt
complexes C O ~ ( C O ) ~(E=P,
E ~ As). We have now found
[*] Prof. Dr. G. Huttner, H. Lang, L. Zsolnai
Lehrstuhl fur Synthetische Anorganische Chemie der Universitat
Postfach 5560, D-7750Konstanz (Germany)
[**IThis work was supported by the Deutsche Forschungsgemeinscbaft and
the Fonds der Chemischen Industrie.
0570-0833/83/1212-0976 $02.50/0
Angew. Chem. Int. Ed. Engl. 22 (1983) No. 12
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planar, bridge, atom, coordinated, naked, trigonal, ligand, phosphorus
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