New multidentate .alpha.-pyridyl ligand. Coordination of bis(2-pyridylmethyl)amine with transition metal ions

Abstract

The synthesis of the tridentate ligand bis(2-pyridylmethyl)amine by reaction of 2-chloromethylpyridine and excess 2-aminomethylpyridine is described, and the proton dissociation constants are reported. The coordination tendencies have been studied potentiometrically (at 25°and µ = 0.10 in KNOs) with Cu(II), Co(II), Ni(II), Zn(II), Cd(II), Mn(II), and Ag(I).Chelation was observed and the corresponding stepwise formation constants and Gibbs free energies are reported. These results are compared with the coordination tendencies of the analogous aliphatic amine, diethylenetriamine. Geometrical considerations for bis (2-pyridylmethyl )amine coordination are discussed. The proton dissociation constants of bis(3-pyridylmethyl)amine are also reported.

Affinity of Polypyridines Towards CdII and CoII Ions: a Thermodynamic and DFT Study

“…[34][35][36][37][38] The set of data presented are the most complete in the literature, independently of the fact that some of them [36] refer to 20°C. The choice seems to be reasonable, as the stability constants available at 25°C, for which enthalpy data are not given, [39,40] are very close to those reported at 20°C.…”

Development of Bis(2‐picolyl)amine–Zinc Chelates for Imidazole Receptors

“…[7] For this purpose bis(2-picolyl)amines (Dpa) 1 ( Figure 1) are well-known tridentate ligands capable of donating three electron pairs to a cationic metal center. [8][9][10] The Dpa geometry and its conformational flexibility gives this ligand a strong affinity for biologically interesting Zn 2+ and Cu 2+ ions, whereas tridentate amine-metal chelation leaves basic coordination places free for counterions. Accordingly, Dpa ligands have been used as such, [11] but more widely as linked ligand units in larger host structures.…”

Spectroscopic Properties, Electrochemistry, and Reactivity of Mo0, MoI, and MoII Complexes with the [Mo(bpa)(CO)3] Unit [bpa = bis(2-picolyl)amine] and Their Application for the Labelling of Peptides

“…Finally, the syntheses of two bioconjugates of [Mo(bpa)(CO) 3 ], in which bpa ligands are covalently linked to the N-termini of an amino acid (Phe-OMe, 8a) and of a dipeptide (Ala-Phe-OMe, 8b), are described. These bioconjugates were comprehensively characterized (including elemental analysis, 1 H, 13 C, and 95 Mo NMR, IR, MS, and electrochemistry). All analytical data supported the proposed constitution and underscore the potential of the Mo-(bpa)(CO) 3 group as a robust marker group in bioorganometallic chemistry.…”

“…Moreover, in contrast to tacn and hydridotrispyrazolylborate, the bpa ligand can easily be derivatized with a (protected) acid functionality, [10,11] which makes binding to biomolecules possible. [11,12] The ligand bpa, first reported by Romary et al, [13] is one of the classical tridentate nitrogen donor ligands in coordination chemistry, but (bpa)metal complexes containing organometallic fragments are relatively scarce. Only four organometallic bpa complexes have so far been structurally characterized by X-ray crystallography: namely, [Rh-(bpa)(cod)]BPh 4 [cod ϭ (Z,Z)-1,5-cyclooctadiene], [14] [Pt(bpa)CH 3 ]Cl, [15] [Pt(bpa)(η 1 -allyl)(CH 3 ) 2 ]Br, [15] and [W(bpa)(η 3 -allyl)(CO) 2 ]PF 6 .…”