Carboxy Ester Hydrolysis Promoted by a Dicopper(II) Macrocyclic Polyamine Complex with Hydroxypropyl Pendant Groups

Abstract

A dinuclear Cu II complex containing a hexaaza macrocyclic ligand bearing two 2-hydroxypropyl pendants, 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxypropyl) . The protonation constants of Cu 2 L were determined by potentiometric titration, and it was found that the alcoholic hydroxypropyl group of the complex Cu 2 L exhibits low pK a values of pK a1 = 7.31, pK a2 = 7.83 at 25°C. The hydrolysis kinetics of 4-nitrophenyl acetate (NA) promoted by the title

Bis{1-[bis(2-aminoethyl)amino]propan-2-ol}nickel(II) bis(perchlorate)

“…(2007). E63, m2754 [https://doi.org/10.1107/S1600536807050386] Transition-metal polyamine complexes with hydroxypropyl pendant group play important roles in hydrolytic metalloenzymes (Xia et al,2001;Huang et al,2004). The syntheses of such complexes acting as model compounds for hydrolytic metalloenzymes have attracted much attention (Li et al,2002).…”

17 Macrocyclic coordination chemistry

“…The stability and decomposition kinetics of Cu II complexes of the novel azacyclophane receptors 2,6,10,13,17,21-hexaaza [22]- (2,6)-pyridinophane (L 1 ), 2,6,9,12,15,19-hexaaza [20]- (2,6)-pyridinophane (L 2 ) and 2,6,9,12,15,19-hexaaza [20]metacyclophane (L 3 ) have been investigated and compared with their open chain ligand analogues. The Cu II ion can perform a 'slippage' motion through the macrocyclic cavity, driven by pH changes.…”

“…11 The macrocycle adopts a variety of conformations in order to accommodate the supramolecular constructs, formed by the oxo-anions and solvent molecules as the relative proportions of interacting species are altered. In a related study, the halide binding properties of the two well known polyazamacrocycles [12]aneN 4 (L 22 ) and [18]aneN 6 have been investigated. 12 [18]aneN 6 was generally found to bind two anions within the macrocyclic cavity.…”

“…12 [18]aneN 6 was generally found to bind two anions within the macrocyclic cavity. In the adducts formed by L 22 , the anions and solvent of crystallization do not sit within its cavity, instead preferring to occupy positions outside the macrocycle. In most cases, chloride and bromide adopt trigonal-pyramidal coordination motifs with various degrees of distortion from a regular geometry.…”

“…The hydrolysis kinetics of 4-nitrophenyl acetate promoted by this complex have also been studied, with the pH-rate profile corresponding to a sigmoidal curve. 22 The coordination chemistry of an octa-aza macrocycle, L 34 , containing four pyrrole and four Schiff base donors, towards late first row transition metals has been reported. Binuclear complexes with Ni II , Cu II , Zn II and Cu I were prepared and characterized (Fig.…”