Coordination polymers built from metal tripyrrin units

This account summarizes recent advances in the coordination chemistry of tripyrrins and related ligands with a special emphasis on the structural chemistry of coordination polymers with such ligands. The tripyrrin ligand is unique in supporting the formation of 1D- and 3D-supramolecular structures from pentacoordinate transition metal ions due to an effective blockage of their sixth coordination site. Linear coordination polymers have been observed with a multitude of bidentate and tridentate bridging ligands like trifluoroacetate, azide, thio- and selenocyanate, and higher order pseudohalides. Homo- and heterodimetallic species have been obtained by the use of cyanometallates and could be characterized structurally in two cases. Besides the covalent coordination bonds, several secondary interactions like hydrogen bonding and a-stacking were found to support these coordination polymers and are demonstrated to allow the preparation of species with functionalized inner surfaces. Copyright (C) 2008 Society of Porphyrins & Phthalocyanines.