Manisyl-substituted polypyridine coordination compounds: Metallo-supramolecular networks of interdigitated double helices assembled via CH...pi and pi-pi interactions.

A series of ML(2) coordination compounds of manisyl-substituted 2-pyridin-2-yl-1,10-phenanthrolines (pherpys) and 2,2':6',2''-terpyridines (terpys) with Fe(ii), Co(ii), Ni(ii), Cu(ii), Zn(ii), Ru(ii), and Os(ii), were synthesized. The pyridyl-phenanthroline-metal complexes form isomorphous crystals (space group Pcca), except for the zinc complex, which is isostructural but not isomorphous (space group P2(1)/c). Traces of the Ru complex induce the Zn complex to crystallize in the Pcca modification. Terpyridine complexes are isostructural but divided into two subgroups (Pnna and C2/c). Within the crystal lattice, the dications arrange into two-dimensional sheets of interdigitated left- and right-handed double helices via CHpi and pi-pi interactions of the pendant manisyl functionalities. All of the complexes exhibit weak ligand charge transfer (LCT) emission in solution at room temperature and the osmium complexes possess an emissive metal to ligand charge transfer (MLCT) state.