Optimized structures of Cr2(CO)6+ with three different symmetries by density functional calculation
✍ Scribed by Takao Wada; Satoru Nishio; Takayuki Yada; Satoshi Hayashi; Akiyoshi Matsuzaki; Hiroyasu Sato; Hisayoshi Kobayashi; Tokio Yamabe
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 440 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0268-2605
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✦ Synopsis
Density functional calculations have been made on a binuclear metal carbonyl ion Cr 2 (CO) 6 found in our laser ablation-molecular beam (LAMB) experiment. Optimized structures are calculated for three different conformations: T33 of D 3d symmetry with three terminal carbonyl groups on each chromium atom, B2T22 of D 2h symmetry with two bridging carbonyl groups and two terminal carbonyl groups on each chromium atom, and B4T11 of D 4h symmetry with four bridging carbonyl groups and one terminal carbonyl group on each chromium atom. The most stable conformation is T33 which is 36.76 and 286.44 kJ mol À1 lower in energy than B2T22 and B4T11, respectively. The difference of conformation exerts a significant influence on the internuclear distance between chromium and the carbon of terminal CO, but hardly on the Cr-Cr bond length. For B2T22 and B4T11, longer C-O distances for bridging carbonyls compared with those for terminal ones indicate effective p * -back donation from the chromium atom to the bridging carbonyl groups. Furthermore, the relative abundance of Cr 2 (CO) n (n = 0-6) observed in our previous experimental study can be explained qualitatively by comparison of the excess energy produced in the formation of a Cr -Cr bond with the CO dissociation energy of Cr 2 (CO) 6 .