Supramolecular Assembly Formation of Ferrioxamine B and Its Al(III), Ga(III), and In(III) Analogues with Dicyclohexano-18-Crown-6 in Chloroform

Journal Article (Journal Article)

We have shown that the crown ether dicyclohexano-18-crown-6 recognizes the terminal amine group of deferriferrioxamine B (H DFB+) and its Al(III), Ga(III), Fe(III), and In(III) complexes (MHDFB+) by host-guest complex formation. Host-guest formation constants for these supramolecular assemblies in chloroform at 25 °C were determined as follows: log K (H DFB ) = 4.56, log K (A1HDFB ) = 3.48, log K (GaHDFB+) = 3.59, log (FeHDFB ) = 3.67, log K (InHDFB ) = 3.92. Chloroform extraction equilibrium constants (K ) for the extraction of the MHDFB complexes and H DFB in the presence of picrate anion by crown ether were determined as well as distribution constants (K ) between a chloroform and aqueous phase in the absence of crown ether: log K (H DFB ) = 2.89, log K (A1HDFB ) = 2.43, log K (GaHDFB ) = 2.84, log K (FeHDFB+) = 3.05, log K (InHDFB ) = 3.46; log K (H DFB ) = -1.66, log K (AlHDFB ) = -1.05, log K (GaHDFB ) = -0.75, log K (FeHDFB ) = -0.62, log K (InHDFB ) = -0.46. In the series InHDFB , FeHDFB , GaHDFB+, and A1HDFB+ there is increasing hydration in the second coordination shell, as suggested by a linear relationship between log (K ,K ,K ) and 1/r (r = M radius) and M(H O) hydration enthalpy (ΔH ). which consequently increases hydrophilicity (decreases K ) and increases steric hindrance to crown ether host-guest complex formation (decreases K ). Correspondingly, the chloroform extraction constants (K = K ·K ), which depend on chloroform/water distribution (K ) and host-guest complex formation (K ), decrease in the same sequence. We conclude that the protonated amine of the free ligand H DFB and its metal complexes provides a recognition site through formation of a supramolecular assembly with a crown ether. Second coordination shell effects (hydrophilicity) provide a mechanism to discriminate between different M(III) complexes of deferriferrioxamine B. The low K value obtained for deferriferrioxamine B distribution between the hydrophilic and lipophilic phase is consistent with previous reports concerning the therapeutic use of this ligand to remove intracellular iron from patients with iron overload. © 1994, American Chemical Society. All rights reserved. 4 a 4 a a a ex 4 d ex 4 ex ex ex ex d 4 d d d d a ex d i i 2 6 hyd d a ex d a d a 4 d + + + + + + + + + + + + + + + + + 3+ 3+ +

Full Text

Duke Authors

Cited Authors

  • Spasojević, I; Batinfć-Haberle, I; Choo, PL; Crumbliss, AL

Published Date

  • June 1, 1994

Published In

Volume / Issue

  • 116 / 13

Start / End Page

  • 5714 - 5721

Electronic International Standard Serial Number (EISSN)

  • 1520-5126

International Standard Serial Number (ISSN)

  • 0002-7863

Digital Object Identifier (DOI)

  • 10.1021/ja00092a023

Citation Source

  • Scopus