ISSN:
0009-2940
Keywords:
Sterically overcrowded organosilicon molecules
;
Radical cation dynamics
;
Silicon compounds
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Structures and Molecular Properties of Sterically Overcrowded Molecules, 37[1]. - Hexakis(trimethylsilylmethyl)benzene C6[CH2Si(CH3)3]6Both the low first vertical ionization energy of only 7.40 eV, determined by PE spectroscopy for C6[CH2Si(CH3)3]6, and the blocked substituent rotation in its radical cation as proven by ESR/ENDOR spectroscopy suggest considerable steric over-crowdedness. To further substantiate this interpretation of the molecular properties, the crystal structure (hexagonal R3, Z = 2) has been determined at 100 K. Accordingly, the bulky trimethylsilyl groups are arranged alternatingly above or below the C6-ring plane, out of which the methylene C centers are twisted by ±9°. Due to the angles CCSi widened to 115°, however, the intramolecular distances C(H)=(H)C between non-neighboured methyl groups of 443 and 452 pm even slightly exceed their van der Waals radii sum of 400 pm and thus avoid severe spatial congestion.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19931261011
