Synthesis, crystal structures and electrochemical properties of CuII and NiII complexes with hexadentate ligands containing thioether-amido-pyridyl donor set

An unusual square planar open-lock shaped copper(II) metallaligand obtained from a hexadentate amine–amide–phenol ligand

“…The potentially hexadentate, but functionally tetradentate, salicylamide ligand of triethylenetetramine, L was prepared in 80% yield in a single pot condensation reaction of trien with ethylsalicylate in a 1 : 2 molar ratio. 1 H and 13 C NMR spectral assignments for L are consistent with the proposed formulation of the ligand. The IR spectrum of the ligand shows peaks around 1590 cm -1 , which are characteristic of imine C=O functions.…”

“…IR spectra were obtained on a Perkin-Elmer 883 spectrometer (200-4000 cm -1 ) prepared as KBr pellets. 1 H and 13 C NMR spectra were obtained on a Bruker AC 200 NMR spectrometer using TMS as the internal standard. Solution electrical conductivity was measured using a Unitech type UI31C digital conductivity metre with a solute concentration of about 10 -3 M. Electronic spectra were recorded on a Shimadzu UV/Vis/NIR 3100 (190-3200 nm) (1 cm quartz cell) spectrometer.…”

“…Only a few octahedral complexes of copper(II) are known with acyclic hexadentate ligands. [10][11][12][13] Two other possible mononuclear complexes 2 and 3 are not obtained here, of which 3 is nonmetallaligand type CuO 2 N(amide) 2 complex. Complex 4 bears a pendant bidentate amido-phenolate group which is not involved in coordination and we anticipated that certain reactions centred at these functionalities might lead to systems available for further assembly by complexation.…”

Highly Selective and Sensitive Membrane Sensors for Copper(II) Ion Based on a New Benzo‐Substituted Macrocyclic Diamide 6,7,8,9,10‐Hexahydro‐2H‐1,13,4,7,10‐benzodioxatriazacyclopentadecine‐3,11(4H,12H)‐dione

“…Based on geometry optimization results, the Cu 2 -N and Cu 2þ -O distances were calculated as 1.92 and 1.95 , respectively. These distances are normal for the coordination of copper(II) to ligands [39].…”

Structural effects of potentially hexadentate N4O2, N4S2 or N6 ligands involving pyridine, amine and ether or thioether donors: crystal structure of copper(II) and zinc(II) complexes †

“…These distances are comparable with those of copper() compounds having the same geometry with CuN 4 chromophore. 32, 33 Neither of the ether oxygen atoms coordinates to the copper center. A six membered chelate ring containing two coordinated ether oxygen atoms may be unsuitable for copper() ion.…”