Cobalt(II), nickel(II), and copper(II) complexes of 14-membered hexaazamacrocycles: synthesis and characterization

Abstract

Cobalt(II), nickel(II), and copper(II) complexes containing 5,12-di(4-bromophenyl)-7,14-dimethyl-1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-dione (H₂L¹) and 5,12-diphenyl-7,14-dimethyl-1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-dione (H₂L²) have been synthesized. All complexes were characterized by elemental analysis, MALDI TOF-MS spectrometry, and electronic absorption spectroscopy. The crystal structures of two compounds, [Cu₂(H₂L¹)Cl₄]_n and [NiL²], were determined by X-ray powder diffraction. In the polymeric [Cu₂(H₂L¹)Cl₄]_n, the Cu₂Cl₄ units and H₂L¹ molecules are situated on inversion centers. Each Cu(II) has a distorted trigonal-bipyramidal coordination environment formed by N and O from H₂L¹ [Cu–N 2.340(14) Å, Cu–O 1.952(11) Å], two bridging chlorides [Cu–Cl 2.332(5), 2.279(5) Å] and one terminal chloride [Cu–Cl 2.320(6) Å]. In the [NiL²] complex, the Ni(II) situated on inversion center has a distorted square-planar coordination environment formed by four nitrogens from L² [Ni–N 1.860(11), 1.900(11) Å].

Graphical Abstract

Keywords:

• Co(II), Ni(II), and Cu(II) complexes
• Nitrogen-containing heterocycles
• Hexaazamacrocycles
• Semicarbazide

Additional information

Funding

Funding. We acknowledge the financial support from the Russian Foundation for Basic Research [grant number 12-03-00927-a] and a grant from the President of the Russian Federation for Young Candidates of Sciences [grant number MK-699.2012.3].