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Analysis of 13 C and 17 O Chemical Shift Tensors and an ELF View of Bonding in Fe 2 (CO) 9 and Rh 6 (CO) 16
Author(s) -
Kaupp Martin
Publication year - 1996
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19961290509
Subject(s) - chemistry , crystallography , octahedron , chemical bond , atomic orbital , density functional theory , molecular orbital , anisotropy , cluster (spacecraft) , bent molecular geometry , molecule , electron localization function , electron , chemical shift , stereochemistry , computational chemistry , crystal structure , physics , quantum mechanics , organic chemistry , computer science , programming language
Carbon and oxygen chemical shift tensors for bridging and terminal carbonyl ligands in Fe 2 (CO) 9 and Rh 6 (CO) 16 were calculated by sum‐over‐states density‐functional perturbation theory (SOS‐DFPT). Agreement with experimental 13 C shift tensors is excellent, and 17 O 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 δ 33 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 Rh 6 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 B 6 H 6 2‐ .