Chromium cyclooctatetraene complex

Another aspect of the chemistry of M(CO) fragments that the computed molecular orbital diagram could help to explain was the structure of the cyclooctatetraene complexes of iron and chromium tricarbonyl.10 Chromium tricarbonyl was shown to have three relatively low-lying vacant orbitals, with the right spatial characteristics to be able to accept electron donation from three of the double bonds of cyclooctatetraene, and accordingly adopts the r geometry shown in Figure 10.4. In iron... 

Among the compounds that form complexes with silver and other metals are benzene (represented as in 9) and cyclooctatetraene. When the metal involved has a coordination number >1, more than one donor molecule participates. In many cases, this extra electron density comes from CO groups, which in these eomplexes are called carbonyl groups. Thus, benzene-chromium tricarbonyl (10) is a stable compound. Three arrows are shown, since all three aromatic bonding orbitals contribute some electron density to the metal. Metallocenes (p. 53) may be considered a special case of this type of complex, although the bonding in metallocenes is much stronger. 

CgHg, 1,3,5,7-Cyclooctatetraene, lithium complex, 28 127 lutetium complexes, 27 152, 153 CgH NO, Benzoyl isocyanide, chromium complex 26 32, 34, 35 CgHg04, Phthalic acid, rhodium complex, 27 291... 

The binuclear complexes of chromium and vanadium, (21), exhibit restricted rotation of the cyclooctatetraene (COT) ring below 2(X)K. In related cyclooctatriene ligand complexes a diamagnetic-paramagnetic equilibrium exists suggesting Cr—Cr multiple bonding. Olefin rotation, in addition to other dynamic processes, has been reported in the (p-benzo-quinone)copper(I) complexes (22). The complex dismutates in solution according to the equilibrium 2[Cu(bq)L] [LCu(p-bq)CuL]+ bq. Intra-... 

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