Mononuclear organogermanium(IV) catalysts for a [3 + 2] cycloaddition reaction.

Three mononuclear Ge(IV) compounds, [(CH)Ge(CHNO)] (1), [(CH)Ge(CHNO)] (2), and [(CH)Ge(CHNO)] (3), have been synthesized by the reaction of pro-ligands H2L1 (CHNO), H2L2 (CHNO), and H2L3 (CHNO) with (CH)GeCl in the presence of triethylamine. All compounds were characterized by FT-IR spectroscopy and NMR spectroscopy. Single crystal X-ray diffraction analysis shows that the germanium(IV) atom exhibits a five-coordinated geometry in compounds 1 and 2.

Bis(catecholato)germane: an effective catalyst for Friedel-Crafts alkylation reaction.

Bis(catecholato)germane, [Ge(CHO)(HO)] (1), was synthesized by the reaction of catechol and germanium oxide in water according to a reported method. Complex 1 was characterized by FT-IR spectroscopy, NMR spectroscopy and elemental analysis. Complex 1 was employed as a Lewis acid catalyst in the Friedel-Crafts alkylation reaction of indole with various aldehydes and β-nitrostyrene derivatives separately.