• Gallium;
  • Subvalent compounds;
  • Macrocycles;
  • Element–element interactions;
  • Supramolecular chemistry


Treatment of the tetraalkyldigallium compound R2Ga–GaR2 (1) [R = CH(SiMe3)2] with functionalized dicarboxylic acids (2,2′-bipyridyl-3,3′-dicarboxylic acid, 2,2′-iminodibenzoic acid, 2,2′-dithiodibenzoic acid) resulted in the formation of large heterocycles in which two Ga–Ga bonds were bridged by two dicarboxylato spacer ligands. Each Ga–Ga bond was bridged by two carboxylate groups in an almost ideal perpendicular arrangement that favors the formation of macrocyclic structures. The N–H groups of the imino-bridged compound pointed towards the center of the molecule and formed a network of hydrogen bonds through interactions with carboxylate oxygen atoms. Both disulfur groups of the dithio derivative adopted an ideal coplanar arrangement and came into relatively close contact, which might indicate a weak closed-shell bonding interaction between the sulfur atoms.