Benzene chromium tricarbonyl revisited: Theoretical study of the structureand dynamics of (eta(6)-C6H6)Cr(CO)(3)

The electronic effects of the chromium tricarbonyl fragment on the structur e of the benzene ring of (eta(6)-C6H6)Cr(CO)(3) is investigated theoretical ly using ab initio molecular orbital calculations with electron correlation included by using both Moller-Plesset second-order calculations and densit y functional theory. The results of the calculations showed that the solid- state structure of alternating long and short carbon-carbon distances in th e benzene ring is a result of the orientation of the Cr(CO)(3) fragment wit h respect to the benzene ring in which the carbonyl groups lie over the mid point of alternate carbon-carbon bonds of the benzene ring, called the stag gered conformation. A different distortion of the benzene ring is observed even in the eclipsed conformation in which the carbonyls Lie over alternate carbon atoms of the benzene ring. The results of these calculations indica te that the distortion of the benzene ring in (eta(6)-C6H6)Cr(CO)(3) is a r esult of the electronic influence of the Cr(CO)(3) fragment on the benzene ring. (C) 2000 John Wiley & Sons, Inc.