ETA(3) AND ETA(6) BRIDGING CATIONS IN THE N,N,N',N'',N''-PENTAMETHYLDIETHYLENETRIAMINE-SOLVATED COMPLEXES OF BENZYLPOTASSIUM AND BENZYLRUBIDIUM - AN X-RAY, NMR, AND MO STUDY

Journal article


Publication Details

Author(s): Hoffmann D, Bauer W, Hampel F, van Eikema Hommes N, Schleyer P, Otto P, Pieper U, Stalke D, Wright D, Snaith R
Journal: Journal of the American Chemical Society
Publisher: American Chemical Society
Publication year: 1994
Volume: 116
Journal issue: 2
Pages range: 528-536
ISSN: 0002-7863


Abstract


The metalation of toluene (PhCH3) with a 1:1 mixture of n-BuLi/MO(t)Bu (M = K,Rb) at ambient temperature affords orange-red powders of benzylpotassium or benzylrubidium. On addition of N,N,N,N'',N''-pentamethyldiethylenetriamine (PMDTA) the precipitates dissolve to give burgundy-red solutions, from which needles of [PhCH2K.PMDTA.0.5PhCH3]n (1) or [PhCH2Rb.PMDTA]n (2) are obtained. X-ray analysis reveals that 1 incorporates half a molecule of toluene per asymmetric unit. In both 1 and 2, the eta3 and eta6 interaction of one M+ cation with two benzyl fragments gives rise to the formation of polymeric chains. The coordination sphere of the cations is completed by one chelating triamine ligand. MO calculations predict multihapto metal carbon interactions to become more important from Li to Cs and substantiate the solid-state results. Ab initio calculations on three different polymers suggest that the array present in the crystal structure is the most stable. The gated decoupled C-13 NMR spectrum of 1 in THF-d8 solution reveals a 1J(C-13,H-1) coupling constant for the benzylic carbon atom which may be interpreted in terms of a mainly planar configuration of the CH2- group in solution.



FAU Authors / FAU Editors

Bauer, Walter apl. Prof. Dr.
Lehrstuhl für Organische Chemie II
Hampel, Frank Dr.
Lehrstuhl für Organische Chemie I
Schleyer, Paul Prof. Dr.
Naturwissenschaftliche Fakultät
van Eikema Hommes, Nico Dr.
Computer-Chemie-Centrum


How to cite

APA:
Hoffmann, D., Bauer, W., Hampel, F., van Eikema Hommes, N., Schleyer, P., Otto, P.,... Snaith, R. (1994). ETA(3) AND ETA(6) BRIDGING CATIONS IN THE N,N,N',N'',N''-PENTAMETHYLDIETHYLENETRIAMINE-SOLVATED COMPLEXES OF BENZYLPOTASSIUM AND BENZYLRUBIDIUM - AN X-RAY, NMR, AND MO STUDY. Journal of the American Chemical Society, 116(2), 528-536. https://dx.doi.org/10.1021/ja00081a013

MLA:
Hoffmann, Daniele, et al. "ETA(3) AND ETA(6) BRIDGING CATIONS IN THE N,N,N',N'',N''-PENTAMETHYLDIETHYLENETRIAMINE-SOLVATED COMPLEXES OF BENZYLPOTASSIUM AND BENZYLRUBIDIUM - AN X-RAY, NMR, AND MO STUDY." Journal of the American Chemical Society 116.2 (1994): 528-536.

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Last updated on 2018-23-06 at 13:23