Isocarbonyls

In related work, an unusual ytterbium(IIl) complex, [(i7-C5Me5)2-Yb]2[Fe3(CO)7(ja-CO)4], was shown by Tilley and Andersen to contain four isocarbonyl ligands (30). The iron portion of this complex acts formally as a l,3,5-trimetalla-/3-diketonato ligand coordinated to the two Yb(III) ions. 

Under conditions similar to that used with CO, laser-evaporated Be atoms and C02 react during condensation in excess argon to form CO, ArBeO, BeOBe, and two new molecules in a 29 1 ratio that display CO and BeO stretching absorptions, identified as OC-BeO and the isocarbonyl CO-BeO (Equation (3)). 

Fig. 7. Computer-generated drawing of the isocarbonyl species 2,6-Mes2H3C6(THF)2Be-(CO)3Mo(7,5-C5H5).36...

V(py) ][V(CO)6]2 precipitated by adding solid [V(CO)6] to a toluene solution containing an excess of pyridine. By dissolving it in CH2C12, an isocarbonyl-bridged complex... 

D. McIntosh, and G. A. Ozin, Synthesis of Binary Gold Carbonyls, Au(CO)n (n = 1 or 2). Spectroscopic Evidence for Isocarbonyl(carbonyl)gold, a Linkage Isomer of Bis (carbonyl)gold, Inorg. Chem. 16, 51-59 (1977). 

Organolanthanide complexes are coordinately unsaturated and as a result take part in forming mixed complexes with transition metal complexes containing nitrosyl or carbonyl groups. As a result, mixed complexes containing metal-metal bonds or lanthanide-isocarbonyl or isonitrosyl interactions have been characterized. Some typical complexes are given below. 

Isocarbonyl and isonitrosyl linkages to lanthanides are evident in the complexes noted above [256], confirmed by IR spectroscopy. In the Yb complex, an isocarbonyl bridge Yb-OC-Co has been confirmed while in the Iutetium complex Lu-Ru metal-metal bond is present [257]. 

Other compounds containing carbonyl groups are known, involving a transition metal. Most of these feature isocarbonyl linkages. Thus [Cp 2Yb] reacts with Co2(CO)s in THF solution to form [Cp 2Yb(THF)-0-C-Co(CO)3]. A few compounds actually contain metal-metal bonds involving a lanthanide, thus ... 

A similar reaction (see equation 27) has been reported for hexacarbonylvanadium(O). By these reactions, the tetracarbonylcobaltate(-I) and the hexacarbonylvanadate(-I) anions are generated. The crystal and molecular structure of the product of the disproportionation reaction of V(CO)6 with tetrahydrofuran of formula [V(THF)4][V(CO)6]2 has been shown to consist of vanadium(II) octahedrally surrounded by four thf s in the equatorial positions and by two axial carbonyl oxygens from two hexacarbonylvanadate anions resulting in a linear V-O-C-V sequence see Isocarbonyl Complexes). 

Yb(THF)3(CsH4PPh2)2W(CO)4-0.5THF also led to elimination of two THF molecules and conversion to the isocarbonyl-bridged compound.875 Treatment of an equimolar mixture of Na2W(CO)5 and Na2W2(CO)io in DME unexpectedly resulted in the formation of [Na(DME)3]2[W3(CO)i4] without incorporation of lutetium.876 Reactions... 

CO— Bonding. Compounds in the first row in Table I are variously referred to as end-on or isocarbonyls. We have adopted the —CO— terminology to imply the essentially end-on nature of these species, although it must be recognized that these compounds rarely, if ever, contain strictly linear COM arrays. In general —CO— compounds are formed from the interaction of a basic carbonyl moiety with a Lewis or proton acid, repre-... 

The reason for isocarbonyl bridging rather than for Al-tm bonding in these complexes can be found in the interaction of the small and therefore hard group 13 metal A1 with the CO group. The A1 is better suited to the harder basic site in the tm compound, and this is the carbonyl oxygen rather than the metal center. 

Moskovits and Ozin determined the structures of a large number of metal carbonyls produced via matrix co-condensation reactions. They proposed an unusual isocarbonyl structure, OsC—Au—0=C for Au(CO)2, and the... 

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