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A Close Look at Short CCH 3 ⋅⋅⋅Potassium Contacts: Synthetic and Theoretical Investigations of [M 2 Co 2 (μ 3 ‐O t Bu) 2 (μ 2 ‐O t Bu) 4 (thf) n ] (M=Na, K, Rb, thf=tetrahydrofuran)
Author(s) -
Anson Christopher E.,
Klopper Wim,
Li JinShan,
Ponikiewski Lukasz,
Rothenberger Alexander
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200500603
Subject(s) - agostic interaction , trimethylsilyl , crystallography , chemistry , alkali metal , crystal structure , solid state , density functional theory , potassium , metal , stereochemistry , computational chemistry , medicinal chemistry , organic chemistry
Agostic interactions of the type SiCH 3 ⋅⋅⋅M + (M=alkali metal) are frequently mentioned in discussions of solid‐state structures of trimethylsilyl compounds and the purpose of this work was to elucidate if they also exist in the related tert ‐butyl species by using density functional theory. The compounds [M 2 Co 2 (μ 3 ‐O t Bu) 2 (μ 2 ‐O t Bu) 4 (thf) n ] (M=Na, n =2; M=K, n =0; M=Rb, n =1) have been synthesised and their crystal structures determined. Close contacts of methyl groups with K atoms are observed in the solid‐state structure of [K 2 Co 2 (μ 3 ‐O t Bu) 2 (μ 2 ‐O t Bu) 4 ], and calculations of the rotational barrier of a tert ‐butoxy group about the axis through the CO bond were performed. It was shown that apparent short CCH 3 ⋅⋅⋅K distances are in this case a consequence of the packing in the extended solid‐state structure.