Metallo-gels and organo-gels with tripodal cyclotriveratrylene-type and 1,3,5-substituted benzene-type ligands

The cyclotriveratrylene-type ligands tris(4-[4-methyl-2,2'-bipyridyl] methyl)cyclotriguaiacylene 1 and tris(isonicotinoyl) cyclotriguaiacylene 2 form metallo-gels with Cu(II) and Ag(I) (for 1 only), while tris(3-(3-pyridyl)-1-thiourea) cyclotriguaiacylene 3 is a low molecular weight gelator (LMWG) for 2,2,2-trifluoroethanol. Benzene-1,3,5-tricarboxylic acid tris(4-hydroxyquinoline) ester 4 is a LMWG for acetone, while 1,3,5-tris(2-quinoline-methoxyl) benzene 5 forms Cu(II) metallo-gels. All gels have fibrous structures and show different thermal behaviour. Aside from the hydrogen bonding organo-gel of 3, an important intermolecular interaction within these gels is likely to be pi-pi stacking interactions. Crystal structures of a geometric isomer of 4 and of a discrete [Ag-2(5)(2)](2+) complex are also reported herein.