A. Pinkerton, P. Carrupt, P. Vogel
1978
Citations
0
Influential Citations
37
Citations
Journal
Inorganica Chimica Acta
Abstract
Abstract The photoreaction of 5,6-dimethylene-7-oxabicyclo [2.2.1]hept-2-ene(1) with Fe(CO)5 yields initially the dihapto-tetracarbonyl iron complex (3), which reacts further to give a dihapto-tetracarbonyl-tetrahapto- tricarbonyl complex (C8H8O)Fe2(CO)7 (4) The molecular structure of 4 has been determined by X-ray crystallagraphy. Both the Fe(CO)4 and Fe(CO)3 groups are in exo position with respect to the roof-shaped triene. The ligand is bound through its lone double bond to an equatorial position of a substituted trigonal-bipyramidal Fe(CO)4L moiety and through its diene group to two basal positions of a tetragonal pyramidal Fe(CO)3L2 moiety. Hydrogen atom positions have been determined in the last cycles (final residual R = 0.023). H(Z) atome deviate by 39° from the diene plane away from the metal and H(E) atoms deviate by 11° towards the metal. H atoms of the lone CC double bond deviate by 34° from the C(1)C(2)C(3)C(4) plane away fromthe metal. The structures of complexes 3,4 and(C8H8O)Mo(CO)3 (7) in solution were deduced fromtheir 1H NMR data and the unknown geometries of ligands 1 and 5,6-dimethylenebicyclo[2.2.1] hept-2-ene (2) were simulated by MINDO¦3. Deoxygenation of the ligand is observed in the presence of Fe2(CO)9 in benzene at 60 °C, giving o-quinodimethane complexes 5 and 6, 5 being also obtained by direct thermolysis of complex 4.