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An Unusual Carbonyl Chemical Shift in a Carbonylhexairidium Cluster: A Combined Solid‐State NMR and DFT Approach (Eur. J. Inorg. Chem. 22/2007)
Author(s) -
Chierotti Michele R.,
Garlaschelli Luigi,
Gobetto Roberto,
Nervi Carlo,
Peli Giulia,
Sironi Annalisa,
Della Pergola Roberto
Publication year - 2007
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200790053
Subject(s) - chemistry , chemical shift , solid state nuclear magnetic resonance , anisotropy , cluster (spacecraft) , computational chemistry , density functional theory , electromagnetic shielding , crystallography , nuclear magnetic resonance , quantum mechanics , physics , computer science , programming language
The cover picture shows the structure and the 13 C NMR spectrum of [Ir 6 (CO) 15 ] 2− at 173 K. It features an unprecedented μ 2 ‐bridging carbonyl low frequency shift; the resonances of the terminal μ 1 ‐carbonyl groups are placed at higher frequencies. This unusual trend has been explained by combined use of DFT calculations and solid‐state NMR parameters, such us chemical shift tensors and shielding anisotropies. The scalar and Spin‐Orbit (SO) relativistic two‐component Zero‐Order Regular Approximation (ZORA) methods have been employed in the geometry optimization and NMR chemical shift calculations, respectively. The large SO contribution (26.6 ppm) to the 13 C chemical shifts of the μ 2 ‐bridging CO groups accounts for the position of the experimentally observed resonance. This work outlines the importance of the SO evaluation in cases of atoms connected to heavy metal atoms. Details are discussed in the article by L. Garlaschelli, R. Gobetto et al. on p. 3487 ff.