ISSN:
0009-2940
Keywords:
Density functional theory
;
Electron localization function
;
NMR chemical shift tensor
;
Transition-metal carbonyl clusters
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Carbon and oxygen chemical shift tensors for bridging and terminal carbonyl ligands in Fe2(CO)9 and Rh6(CO)16 were calculated by sum-over-states density-functional perturbation theory (SOS-DFPT). Agreement with experimental 13C shift tensors is excellent, and 17O shift tensors are predicted. The reduced anisotropy values of the shift tensors for the bridging compared to terminal carbonyl ligands are due to large deshielding contributions to δ33 from non-bonding or bridge-bonding orbitals. Comparison to recent computational results for a series of unusual piano-stool and bent-sandwich group-4 complexes is made. The electronic structures of the clusters are discussed by using plots of electron localization functions (ELF). Bonding electrons within the Rh6 cluster are mainly localized on the unbridged octahedral faces. This leads to a heterocubane-like arrangement of ELF maxima above all octahedral faces (four bridging CO ligands, four M-M 3-center-bonding maxima), in analogy to previous results for B6H62-.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19961290509
