Synthesis, structures and properties of dinuclear cadmium(II) complexes based on polybenzimidazole binucleating ligands

OFF–ON–OFF fluorescent response of N,N,N′,N′-tetrakis(1-isoquinolylmethyl)-2-hydroxy-1,3-propanediamine (1-isoHTQHPN) toward Zn2+

1-isoHTQHPN exhibits OFF–ON–OFF fluorescent response toward increasing concentration of Zn²⁺ions due to the specific intramolecular excimer formation in a mononuclear complex.

[μ-N,N'-Bis(2-amino-eth-yl)ethane-1,2-diamine-κ(4)N(1),N(1'):N(2),N(2')]bis-{[N,N'-bis-(2-amino-eth-yl)ethane-1,2-diamine-κ(4)N,N',N'',N''']cadmium} tetra-kis-(perchlorate)

The centrosymmetric dinuclear cadmium title complex, [Cd(2)(C(6)H(18)N(4))(3)](ClO(4))(4), was obtained by the reaction of N,N'-bis-(2-amino-eth-yl)ethane-1,2-diamine (trien) with Cd(NO(3))(2)·4H(2)O and sodium perchlorate in methanol. The Cd(II) cation is coordinated by four N atoms of a non-bridging trien ligand and by two N atoms of a bridging trien ligand in a slightly distorted octa-hedral coordination geometry. The bridging ligand shares another two N atoms with a neighboring symmetry-equivalent Cd(II) cation. The structure displays C-H⋯O and N-H⋯O hydrogen bonding. The perchlorate anion is disordered over two sets of sites in a 0.854 (7): 0.146 (7) ratio.