211860-73-0Relevant academic research and scientific papers
Synthesis, structural characterization, and bonding analysis of (η4-1-azadiene)Fe(CO)3 complexes: Consequences of the electronic structure on molecular and crystal properties
Imhof, Wolfgang,G?bel, Angela,Braga, Dario,De Leonardis, Piero,Tedesco, Emilio
, p. 736 - 747 (2008/10/08)
A series of 1-azadiene ligands as well as the corresponding (η4-azadiene)Fe(CO)3 complexes have been synthesized and structurally characterized by means of single-crystal X-ray diffraction. At the molecular level, the 1-azadiene assumes a trans conformation as free ligand, while a cis coordination is found in the organometallic complexes. In the coordinated ligand the H(C3) hydrogen is found nonplanar with respect to the C-C-C-N plane. A molecular orbital analysis has been carried out by means of extended Hu?ckel calculations. The electronic origin of the out-of-plane position of the 1-azadiene hydrogen atom H(C3) has been justified in terms of a better π*-back-bonding between the 1-azadiene and Fe(CO)3 molecular fragments. A comparison of cis and trans conformations of the ligand has also been performed. The organometallic crystals show the presence of a large number of hydrogen bond interactions of the C-H- - -O type involving CO-ligand acceptors. Hydrogen bonding of the azadiene moiety is always realized by the hydrogen atom at the C-N double bond and the hydrogen atom in α-position with respect to the imine group.
Synthesis, Molecular Structure, Fluxional Behavior, and Tricarbonyliron Transfer Reactions of (η4-1-Azabuta-1,3-diene)tricarbonyliron Complexes
Knoelker, Hans-Joachim,Baum, Gerhard,Foitzik, Norbert,Goesmann, Helmut,Gonser, Peter,Jones, Peter G.,Roettele, Herbert
, p. 993 - 1007 (2007/10/03)
The η4-1-azabuta-1,3-diene)tricarbonyliron complexes 10 are easily prepared in high yield by condensation of the corresponding arylamines 7 with the cinnamaldehydes 8 and subsequent ultrasound-promoted complexation of the resulting 1-azabuta-1,3-dienes 9 with nonacarbonyldiiron. The complexes 10 are shown to represent excellent reagents for the transfer of the tricarbonyliron fragment onto cyclohexa-1,3-diene (1a). The structural characterization for the complexes 10 is achieved by IR, 1H-NMR, and 13C-NMR spectroscopy, as well as X-ray crystallography of 10b, 10c, and 101. Using variable temperature 13C-NMR spectroscopy the fluxionality of the complexes 10a, 10b, 10c, 10e, and 2 is investigated and the activation barrier for the turnstile rotation of the tricarbonyliron fragment is determined. The transfer reaction and the structural factors influencing the transfer of the tricarbonyliron fragment are extensively investigated.
