Pujales Paradela R (2017)
Publication Status: Published
Publication Type: Journal article, Original article
Publication year: 2017
Publisher: ROYAL SOC CHEMISTRY
Book Volume: 46
Pages Range: 1546-1558
Journal Issue: 5
DOI: 10.1039/c6dt04442e
We have reported here a series of ligands containing pentadentate 6,6'-(azanediylbis(methylene)) dipicolinic acid units that differ in the substituent present at the amine nitrogen atom (acetate: H(3)DPAAA; phenyl: H(2)DPAPhA; dodecyl: H(2)DPAC12A; 4-hexylphenyl: H(2)DPAC6PhA). The protonation constants of the hexadentate DPAAA(3-) and pentadentate DPAPhA(2-) ligands and the stability constants of their Mn2+ complexes were determined using pH-potentiometry (25 degrees C, 0.15 M NaCl). The mono-hydrated [Mn(DPAAA)](-) complex (log K-MnL = 13.19(5)) was found to be considerably more stable than the bis-hydrated [Mn(DPAPhA)] analogue (log K-MnL = 9.55(1)). A detailed H-1 and O-17 NMR relaxometric study was carried out to determine the parameters that govern the proton relaxivities of these complexes. The [Mn(DPAC12A)] complex, which contains a dodecyl lipophilic chain, forms micelles in solution characterized by a critical micellar concentration (cmc) of 96(9) mu M. The lipophilic [Mn(DPAC6PhA)] and [Mn(DPAC12A)] derivatives form rather strong adducts with Human Serum Albumin (HSA) with association constants of 7.1 +/- 0.1 x 10(3) and 1.3 +/- 0.4 x 10(5) M (1), respectively. The X-ray structure of the complex {K(H2O)(4)}{[Mn(DPAAA)(H2O)]}(2) shows that the Mn2+ ion in [Mn(DPAAA)](-) is coordinated to the six donor atoms of the ligand, a coordinated water molecule completing the pentagonal bipyramidal coordination environment.
APA:
Pujales Paradela, R. (2017). Developing the family of picolinate ligands for Mn2+ complexation. Dalton Transactions, 46(5), 1546-1558. https://dx.doi.org/10.1039/c6dt04442e
MLA:
Pujales Paradela, Rosa. "Developing the family of picolinate ligands for Mn2+ complexation." Dalton Transactions 46.5 (2017): 1546-1558.
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