Strukturen sterisch überfüllter Moleküle, 39 [1,2]
2014
Bock, H. | Meuret, J. | Bats, J. W. | Havlas, Z.
1,4-Bis(trimethylsiloxy)benzene has been crystallized both by vacuum sublimation and from «-heptane solution, which each yielded colourless plates with identical monoclinic unit cell dimensions (P₂/n, Z = 4). The conformation of C[ symmetry shows the two (H₃C)₃SiO-substituents to be conrotationally twisted around the O-(C₆H₄)-O axis by dihedral angles o f ± 60°. According to the photoelectron spectroscopic ionisation pattern and its Koopmans’ assignment, IEⱽₙ = -εJᴬᴹ ¹, by AM 1 eigenvalues, the gas phase structure should also be of C, symmetry. The results of geometry-optimized MNDO , AM 1 or PM 3 calculations for the monosubstituted derivative H₅C₆-OS i(CH₃)₃ are compared with respect to the quality of their fit to the measured data.
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