82763-96-0Relevant academic research and scientific papers
CHIMIE DES METALLOLES DU GROUPE IV. SYNTHESE DE METHYLSILOLES PAR THERMOLYSE D'ESTERS DE SILACYCLOPENTENE-4 OLS-3 ET COMPLEXES η4-FER TRICARBONYLES
Dubac, Jaques,Laporterie, Andre,Iloughmane, Hafida
, p. 295 - 312 (2007/10/02)
Thermolysis of esters of silacyclopent-4-ene-3-ols Me2CH=CR-CR'(X)H2 (R,R'=H or Me; X=OC(O)NHPh, OC(S)SMe) leads to 1,1-dimethylsilole (1), 1,1,3-trimethylsilole (2) or 1,1,3,4-tetramethylsilole (3).The thermally unstable S-methylxanthates decompose involving both competitive β-C-H and β-C-Si eliminations.With N-phenylcarbamates a regioselective C-H elimination on an endocyclic carbon, leads to the expected siloles 1-3, is mainly observed.A one pot synthesis of 3, the first methylsilole stable as a monomer, from the corresponding alcohol (X=OH, R=R'=Me) and phenyl isocyanate is described. 1,1,3,4-Tetramethylgermole (4) is similarly obtained.The relative stability of the methylsiloles, their ability to form Diels-Alder dimers and to isomerize into a transoid diene, is discussed.In this respect, the strong influence of C-methyl groups on the stabilization of the tetramethylsilole, as in the case of the 1,1,3,4-tetramethylphospholium ion, is made possible.The principal characteristisc of NMR and mass spectra of methylsiloles 1-3 and those of their stable tricarbonyliron complexes are studied.
Electronic structure of group 14 (η4-metallole)tricarbonyliron complexes
Guimon,Pfister-Guillouzo,Dubac,Laporterie,Manuel,Iloughmane
, p. 636 - 641 (2008/10/08)
Some methyl derivatives of metalloles R2XC4H4 (X = C, Si, Ge) and their tricarbonyliron complexes have been prepared in order to study the influence of both the group 14 elements and complexation effects on the electronic structure of the diene ring using photoelectron spectroscopy (UPS, He I, He II). Strong electron donation from iron to the metallole ligand has been demonstrated. This transfer, which is the result of participation of the lowest vacant orbital of the ring (3b1) in the highest occupied orbital (HOMO) of the complex, shows that these compounds have a certain aromatic character.
