0000000000459654
AUTHOR
Hans Schmickler
Structure and fluxional behaviour of heptaleneirontricarbonyl and heptalenebis (Irontricarbonyl)
Abstract The synthesis of heptaleneirontricarbonyl ( 4 ) is described. The structures of 4 and of the closely related heptalenebis(irontricarbonyl) ( 3 ) are elucidated by NMR spectroscopy ( 1H and 13C) and by X-ray crystallography. Compounds 3 and 4 are shown by dynamic NMR to undergo an isodynamic 1 ,2-migration of the Fe(CO3)-groups as well as a carbonyl scrambling. The relevant kinetic data allow for a mechanistic discussion of the dynamics and a comparison with other irontricarbonyl complexes.
13C NMR of carbonyl compounds. 3. Structure and dynamics of protonated enones and dienones
Abstract The unsaturated ketones 1 1 – 10 10 were protonated at low temperatures and studied by dynamic 13C NMR spectroscopy. Four interconverting stereoisomers were detected which differ in their conformation with respect to the CO and CC (enone) single bond.
13C NMR of carbonyl compounds -4. Solution conformation of β-ionone and related dienones
Abstract The steric factors relevant for the conformations of β-ionone and structurally related compounds were studied by dynamic n.m.r. and 1 H, 1 H-NOE measurements.
syn-1,6-imino-8,13-oxido[14]annulene
Abstract syn -1,6-Imino-8,13-oxido[14]annulene (1) , an aromatic annulene featuring closely spaced NH and O-bridges, has been synthesized. Contrary to expectation, NH ⋯ O hydrogen bonding in I does not profit from the proximity of the functionalities noticeably.
Doubly charged ions of bridged [4n] annulenes. An evaluation of diatropic ring current effects.
Abstract [4n]Annulenes are transformed into doubly charged ions (dianion, dication) and characterized NMR spectroscopically. The diatropic character of the ionic (4n+2)π-systems is studied as a function of the number of π-electrons.