Ni(II) complexes of 4′-(2-pyridyl)-2,2′:6′,2″-terpyridine: Structure of mono- and bis-chelates containing anion⋯π interactions

The mono- and bis-Ni(II) chelates of 4′-(2-pyridyl)-2,2′:6′,2″-terpyridine (L) having the molecular formula [[Ni(L)(H2O)3](NO3)2]3[Ni(L)(NO3)(H2O)2](NO3) · 5H2O (1) and [Ni(L)2](PF6)2 · 2H2O (2), respectively, are synthesized. The structural, optical and magnetic characteristics are determined. The asymmetric unit of (1) contains three [Ni(L)(H2O)3]2+ (1a) and one [Ni(L)(NO3)(H2O)2]+ (1b) species along with five water molecules and seven nitrate ions. In both 1a and 1b, the bivalent nickel has pseudo-octahedral mer-N3O3 and in 2, mer-N3N3 environments. The molecular packing reveals the presence of water–nitrate ion network, (NO3-)⋯π interaction in 1 and F⋯π interaction in 2 and water dimer in both. Both 1 and 2 exhibits d–d transitions in visible and intra-ligand charge transfer (ILCT) in UV regions. The emission spectra are of π → π∗ character for λex = 345 nm.

The Ni(II) chelates of 4′-(2-pyridyl)-2,2′:6′,2″-terpyridine (L) having the molecular formula [[Ni(L)(H2O)3](NO3)2]3[Ni(L)(NO3)(H2O)2](NO3) · 5H 2O (1) and [Ni(L)2](PF6)2 · 2H2O (2) are synthesized. The structural, optical and magnetic characteristics are determined. The molecular packing reveals the presence of water–nitrate ion network, (NO3-)⋯π interaction in 1 and F⋯π interaction in 2 and water dimer in both.Figure optionsDownload as PowerPoint slide