Syntheses, structures and electrochemical properties of complexes of nickel(II) with triethylenetetramine and bidentate nitrogen donor co-ligands

Octahedral copper(ii)-diimine complexes of triethylenetetramine: effect of stereochemical fluxionality and ligand hydrophobicity on CuII/CuIredox, DNA binding and cleavage, cytotoxicity and apoptosis-inducing ability

Stereochemical fluxionality of octahedral [Cu(trien)(diimine)]²⁺complexes determines the Cu^II/Cu^Iredox potential, DNA binding affinity, ROS generation, cytotoxicity and apoptosis-inducing ability.

Crystal structures of (1,4,7,10-tetra-aza-cyclo-dodecane-κ(4) N)bis-(tri-cyano-methanido-κN)nickel and (1,4,7,10-tetra-aza-cyclo-dodecane-κ(4) N)(tri-cyano-methanido-κN)copper tri-cyano-methanide

The structures of two mononuclear transition-metal complexes with tri-cyano-methanide (tcm(-)) and 1,4,7,10-tetra-aza-cyclo-dodecane (cyclen) ligands, [Ni(C4N3)2(C8H20N4)], (I), and [Cu(C4N3)(C8H20N4)](C4N3), (II), are reported. In the neutral complex (I), the nickel cation is coordinated by one cyclen ligand and two monodentate N-bound tcm(-) anions in a distorted octa-hedral geometry. The tcm(-) ligands are mutually cis. The Cu(II) atom in (II) displays a distorted tetra-gonal-pyramidal geometry, with the four N-donor atoms of the cyclen ligand in the equatorial plane, and one tcm(-) anion bound through a single N atom in an axial site, forming a monocation. The second tcm(-) molecule acts as a counter-ion not directly coordinating to the copper cation. In both (I) and (II), extensive series of N-H⋯N and C-H⋯N hydrogen bonds generate three-dimensional network structures.

[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.