Organogallium complexes incorporating tridentate thioetherbiphenolate ligands 2,2′-thiobis(4,6-di-tert-butylphenolate), Stdiol and 2,2′-thiobis(4,6-dimethylphenolate), Smdiol

• Published in: Main group chemistry Vol. 5; no. 1; pp. 61 - 77
• Main Authors: De La Cruz-Burelo, P., Montiel-Palma, V., Oz-Hernández, M.-Á. Muñ
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.03.2006
• Subjects: Gallium complexes; Diol ligands; Diels-Alder catalysis
• ISSN: 1024-1221; 1745-1167
• DOI: 10.1080/10241220600903514

Organogallium(III) thioetherbisphenolate complexes of general formulae SmdiolGaMe-THF (1), StdiolGaMe-THF (2), SmdiolGaMe (3) and StdiolGaMe (4) (Smdiol = 2,2′-thiobis(4,6-dimethylphenolate); Stdiol = 2,2′-thiobis(4,6-diterbuthylphenolate)), were synthesised by methane elimination reactions from GaMe3 and the diol proligands SmdiolH2 and StdiolH2. The molecular structure of 1 is monomeric and shows the Ga centre adopting a trigonal bipyramidal structure with one of the apical positions occupied by the oxygen atom of a coordinated THF molecule. While the solution spectroscopic data of 4 is in support of a monomeric, probably tetrahedral, species its solid state structure shows a polymeric array built upon intermolecular sulphur-to-gallium interactions resulting in a distorted trigonal bipyramid. The Smdiol derivatives 1 and 3 show modest catalytic activities in Diels-Alder cycloaddition reactions of methacrolein and cyclopentadiene. In addition, StdiolGaH (7) is conveniently synthesized from reaction of StdiolGaCl and tBuLi at room temperature. Compound 7 readily hydrolyses in the presence of trace amounts of water leading to StdiolGa(OH) (8) whose solid state structure was determined.