Insights into the crystal structure and optical property for complexes of iminodiacetic-terpyridine

IATPY, a multidentate ligand with strong coordination ability was prepared by connecting iminodiacetic acid with phenylterpyridine, and its Ir(III), Zn(II) and Tb(III) complexes were synthesized in solution or by solvothermal method. The iminodiacetic group on IATPY will be substituted by solvent molecules under weakly basic condition. Coordination reactions will take place between Zn(II) and Tb(III) with IATPY under weakly acidic condition solvothermally. With the contribution from water molecules, a variety of intermolecular hydrogen bonds are formed that make IATPY parallelly arranged in crystals, resulted in intense pi - pi stacking and induced its absorption and emission spectra obtained in solution dramatically different from that in solid state. With the participation of terpyridine moiety and carboxyl groups simultaneously, coordination polymers [Zn(IATPY)](n) and [Tb-2(IATPY)(3)](n) were obtained when Zn(NO3)(2) and Tb(CH3COO)(3) reacted with IATPY. Intense pi-pi stacking effects can be observed in the crystal structures of [Zn(IATPY)](n) and [Tb-2(IATPY)(3)](n,) which influence their optical properties in solid state.