Details

Autor(en) / Beteiligte

• Zhang, Xiuhui
• Li, Qian-shu
• Xie, Yaoming
• King, R Bruce
• Schaefer, 3rd, Henry F

Titel

Beyond the metal-metal triple bond in binuclear cyclopentadienylchromium carbonyl chemistry

Ist Teil von

• Dalton transactions : an international journal of inorganic chemistry, 2008-01 (35), p.4805-4810

Ort / Verlag

England

Erscheinungsjahr

2008

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The cyclopentadienylchromium carbonyls Cp(2)Cr(2)(CO)(n) and Cp*(2)Cr(2)(CO)(n) (Cp = eta(5)-C(5)H(5) and Cp* = eta(5)-Me(5)C(5); n = 3, 2) have been studied by density functional theory using the B3LYP and BP86 functionals. Triplet and singlet structures are found for Cp(2)Cr(2)(CO)(3), with the triplet isomer having an apparent Cr[triple bond]Cr triple bond (2.295 A by BP86) and predicted to have a lower energy than the singlet isomer having an apparent Cr[quadruple bond]Cr quadruple bond (2.191 A by BP86). Quintet, septet, and singlet structures, as well as a highly spin contaminated triplet structure, were found for the dicarbonyl Cp(2)Cr(2)(CO)(2). In all of the Cp(2)Cr(2)(CO)(n) (n = 3, 2) structures the carbonyls are asymmetric semi-bridging groups, typically with differences of 0.3-0.5 A between the shortest and longest M-C distances. Very little difference was found between the structures and energetics of the corresponding Cp and Cp* derivatives. These DFT studies suggest that the reported unstable photolytic decarbonylation product of Cp*(2)Cr(2)(CO)(4), characterized only by its infrared nu(CO) frequencies, is the singlet isomer of the tricarbonyl Cp*(2)Cr(2)(CO)(3).