A mononuclear cobalt(III) complex of the ligandN,N′-bis(pyridin-2-ylmethyl)pyrazine-2,3-dicarboxamide

Abstract

In the complex, bis­[N,N′‐bis­(pyridin‐2‐yl­methyl)­pyrazine‐2,3‐dicarbox­amide]­cobalt(III) tris­(perchlorate) aceto­nitrile 3.5‐solvate, [Co(C18H16N6O2)2](ClO4)3·3.5CH3CN, the result of the reaction of Co(ClO4)2 with the ligand N,N′‐bis­(pyridin‐2‐yl­methyl)­pyrazine‐2,3‐dicarbox­amide, the CoII atom has been oxidized to CoIII and has a slightly distorted octahedral coordination geometry. In each ligand, one amide NH proton has been transferred to a non‐coordinated pyridine ring, thereby producing a zwitterion. This proton is hydrogen bonded to the carbonyl O atom of the adjacent deprotonated (pyridin‐2‐yl­methyl)­amide substiutent involved in coordin­ation.

Control of molecular architecture by use of the appropriate ligand isomer: a mononuclear “corner-type” versus a tetranuclear [2 × 2] grid-type cobalt(iii) complex

“…As in 1•12.75MeCN, the planes of the pyrazine rings in 2•2EtOH are not coplanar with the planes of the respective pyridine rings, instead forming an average angle of 51.7°. The Co III -N amide and Co III -N py distances in 2•2EtOH are around 0.02-0.05 Å longer than in the related compound of H 2 L pm ,13 and are more similar to those found in 1•12.75MeCN. The uncoordinated amide groups of 2•2EtOH are still N-protonated and are almost perpendicular to the respective pyrazine ring mean planes (average angle of 82.8°).…”

“…A similar mononuclear cobalt(III) complex of the lower ligand homologue H 2 L pm has recently been described by Stoeckli-Evans and co-workers. 13 The zwitterionic ligands of 2•2EtOH are formed through relocation of a former N-H amide proton from the coordinating terdentate half of the ligand to the pyridine nitrogen atom of the non-coordinating half of the ligand. This effectively results in the blockage of the latter as a chelating site.…”

Structural variation in copper(i) complexes with pyridylmethylamide ligands: structural analysis with a new four-coordinate geometry index, τ4

“…[Cu(HL) 2 ]PF 6 (1). Crystallographic analysis of mononuclear 1 indicates that it consists of one Cu(I) ion, two neutral HL ligands, and a PF 6 anion (Fig.…”

“…Mass spectra were recorded on a Q-TOF quadrupole time-of flight mass spectrometer (Micromass, Manchester, UK) equipped with a Z-spray electrospray ionization (ESI) source. 1 H NMR spectra were recorded on a Varian 300 MHz spectrometer using deuterated solvent as an internal standard. Elemental analyses were carried out by Atlantic Microlabs, Norcross, GA. Electrochemical measurements were performed with a C-3 CV-50W instrument (Bioanalytical Systems Inc.).…”

Copper(I) Coordination Chemistry of (Pyridylmethyl)amide Ligands

“…Pyridyl amide ligands have garnered interest because of their biomimetic potential and their variable ligation modes. − These ligands have been shown to bind in a wide variety of coordination modes, including the anionic amidate form 1,2,4-6,8-11 and the neutral amide form. − ,, While we are particularly interested in examples of Cu II complexes with polydentate amide ligands, ,− ,, numerous other transition-metal pyridyl amide or pyridyl amidate complexes have also been reported. ,,, Among the various reported transition-metal complexes with pyridyl amide ligands, several have been specifically used as biomimetic models, , while others have produced interesting supramolecular and/or polymeric structures. ,, Only a few examples of pyridyl amide ligands coordinated to Cu I ions have been reported …”