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Interactions in Molecular Crystals, 118. The Sodium(benzo‐15‐crown‐5) Salt of 2, 6‐Di( tert ‐butyl)‐4‐methylphenol, a Sodium Phenolate with an Extremely Short Na + …O − Distance: Structure and Density Functional Calculations
Author(s) -
Bock Hans,
Dienelt Rüdiger,
Näther Christian,
Havlas Zdenek
Publication year - 1997
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.19971301029
Subject(s) - chemistry , sodium , 15 crown 5 , crown ether , mulliken population analysis , monoclinic crystal system , crystallography , alkali metal , tetrahydrofuran , salt (chemistry) , inorganic chemistry , solvent , ion , molecule , medicinal chemistry , crystal structure , organic chemistry
The structure of crystals, isolated in low yield, from the attempted metallation of diphenylmethane in tetrahydrofuran solution containing benzo‐15‐crown‐5 at a sodium metal mirror is determined, surprisingly, to be the sodium (benzo‐15‐crown) salt of 2,6‐di( tert ‐butyl)‐4‐methylphenol, an antioxidative stabilizer to prevent ether peroxide formation. The structure of the solvent‐shared contact ion pair (monoclinic P 2 1 /n, Z = 4, R 1 = 0.06) proves a strong Na + …O − interaction at the extremely short distance of only 216 pm, a sixfold O‐coordination of the Na + cation in a pentagonal pyramid, and a hemispherical distortion of the crown ether. Density functional calculations at the B3LYP/6‐31G * level, based on the structural data, reproduce, within a one‐dimensional hypersurface approach, the rather short Na + …O − distance, and predict Mulliken charges of +0.32 for Na′ and ‐0.71 for 0 − , as well as a considerable polarization of the trialkyl phenolate anion.