Amino-phenol complexes of Fe(III) as promising T1 accelerators

Abstract

Iron(III) complexes with N,O-ligands are compounds of high interest because they can be applied in catalysis and play an important role in living organisms, e.g., as models of catechol dioxygenase. Several N,O-ligands were studied: their synthesis, iron(III) complexation and the potential of the latter as T 1 -MRI contrast agents. A route to the tetrapodal N 3 O 2 -naphthyl ligand was investigated. The resulting iron complex was obtained in 26% total yield and its relaxivity value was moderate (r 1 = 1.03 in water and 2.54 s À1 mM À1 in serum). Thus, phenyl isomeric salan complexes were obtained. These complexes differed in charge (positive and neutral) and in the presence of polar hydrogen-bonding substituents. The highest relaxivities (r 1 = 2.39 in water and 5.37 s À1 mM À1 in serum) were obtained for the Fe(III) cationic complex with MeO groups in the ligand. EPR studies confirmed a high spin configuration of rhombically distorted Fe(III) complexes. ª 2014 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Novel Magnetic Elastic Phase-Change Nanodroplets as Dual Mode Contrast Agent for Ultrasound and Magnetic Resonance Imaging

“…The particles were also able to speed up the ultrasonic wave and carry the potential of dual-modal imaging [ 55 ]. Cationic Fe (III) has also been found to decrease T1 relaxation time [ 56 ]. Yoon et al reported Fe (III)-melanin microbubbles as T1 MR and ultrasound contrast agents [ 57 ].…”

Bulky alkylaminophenol chelates with high potential for functionalization

“…2,4-di(tert-butyl)phenol, propane-1,3-diamine, and paraformaldehyde. While reductive elimination of salicylaldehyde and propane-1,3-diamine led to N,N 0bis(hydroxybenzyl)propane-1,3-diamine [19], the Mannich reaction led to cyclization and formation of N,N 0 -disubstituted 1,3-diazine 4, which was well identified by X-ray analysis (Scheme 5) [27,28]. Therefore, the route as described above from 3-aminopropan-1-ol via chlorination is a reasonable alternative that successfully leads to the desired N,N-bis(hydroxybenzyl)-N-propanamines.…”

Folate-assisted targeted photocytotoxicity of red-light-activable iron(iii) complex co-functionalized gold nanoconjugates (Fe@FA-AuNPs) against HeLa and triple-negative MDA-MB-231 cancer cells

“…[9][10][11][12][13][14][15] The non-labile and photo-activable complexes of biocompatible metals like iron make them a suitable choice for photochemotherapeutic applications. [16][17][18][19] However, octahedral iron(III) complexes of π-donor (e.g. phenolate-O or carboxylate-O) ligands exhibit a reduced energy gap between the e g * (LUMO) and t 2g (HOMO) MOs, resulting in typical low-energy ligand-to-metal charge transfer (LMCT) transitions in the range 450-600 nm.…”