New 2-pyridyl polyamines. Synthesis, spectra, and proton dissociation constants

Abstract

The synthesis of di-(2 -pyridylmethyl) amine, Z-aminoethyl-(2-pyridyimethyl) amine, di-(2-2'-pyridylethyl) amine, 3-aminopropyl-(2-2'-pyridylethyl) amine, 2-2'-pyridylethyl-(2-pyridylmethyl) amine. and 3-aminopropyl-(2-pyridylmethy1)amine is described. Their infrared and n.m.r. spectral characteristics are described, and their trihydrochlorides and dipicrates have been prepared. The three proton dissociation constants have been rigorously determined in each case by potentiometric titration at 25" and p 0.1 0 in potassium nitrate.ALTHOUGH the synthesis of a number of 2-pyridyl amines and polyamines has been de~cribed,l-~ several new polyamines were required for a planned long-range study of the role of x-bonding4p5 during chelation reactions. These amines, which must satisfy rigid molecular-structure requirements, comprise pairs containing one and two 2-pyridyl groups, respectively. The compounds reported here include di(2-pyridyl-methy1)amine (I), 3-aminopropyl-(2-2'-pyridylethyl)amine (IV), 2-2'pyridylethyl-(2-pyridylmethyl)amine (V) , and 3-aminopropyl-(2-pyridylmethyl)amine (VI) .Although di-(2-2'-pyridylethyl)amine (111) and 2-aminoethyl-(2-pyridylmethyl)amine (11) have been r e p~r t e d ,~,~ they have been synthesized here by different routes, which are reported together with spectra, dissociation constants, derivatives, and other new data.

Complexation of the N,N′,O-donor ligand N-trans-(2′-hydroxycyclohexyl)-2-aminomethylpyridine

“…The values of the protonation constants (6.8, 2.2) are comparable with those found for similar compounds, including 1 (pK a values of 8.1 and 2.8) and 2-aminomethylpyridine (8.5 and 2.1). Values for two closely related dipyridineamine compounds bis(3-pyridinemethyl)amine (7.1, 3.9 and 2.9) [28] and N,N 0 -bis(2-picolyl)ethane-1,2-diamine (8.2, 5.4 (amines) and 2.0 (first pyridine)) [29] are also similar to those for 2, as anticipated.…”

“…Unlike 1, the tridentate N,N 0 ,N-chelate (2) is well-known and as a result is wellcharacterized [1][2][3][4][5][6][7][8][9][10][11][12], with an established coordination chemistry. Protonation and stability constants were reported at an early stage in its development as a ligand [11,12], but may lack the precision available with modern experimental facilities and computational packages.…”

“…The focus in this work is on determination of stability constants of metal complexes of 1, with some complexes of 1 characterized by X-ray crystal structures. Further, stability constants were determined for Cu(II) complexation of N,N-bis(2-pyridylmethyl)amine (2), which has one aliphatic and two aromatic nitrogen atoms able to coordinate to metal; it is a versatile tridentate ligand whose complexes with a range of transition metals have been reported [9][10][11][12][13][14][15][16]. (1).…”

Synthesis and characterization of new trinuclear copper complexes

“…To a three-neck 250 mL round bottom flask equipped with a stir bar and a rubber septum was added in the following order under argon: 2,4,6-tris(bromomethyl)mesitylene (1.0 g, 2.51 mmol), 125 mL ethyl acetate, bis((2-pyridyl)ethyl)amine [21] (2.3 g, 10.1 mmol), 200 mg KI, and di-isopropylethylamine (2.0 mL, 11.5 mmol). After several minutes of stirring under argon, a white precipitate was formed.…”

Chiral Quadridentate Ligands Derived from Amino Acids and Some Zinc Complexes Thereof

“…The following workup was performed under ambient laboratory conditions unless stated otherwise. The bis(picolyl)glycine 1 [30] and bis(picolyl)amine 5 [52,53] were synthesized according to published procedures. -Lys(Z)ϪOMe⋅HCl (2b) was purchased from Nova Biochem, -PheϪOMe⋅HCl (2a) from Bachem.…”