Macrocyclic complexes of Fe(III) with mixed hydroxypropyl and phenolate or amide pendants as T₁ MRI probes.

ABSTRACT: High-spin Fe(III) complexes of 1,4,7-triazacyclononane (TACN) with mixed oxygen donor pendants including hydroxypropyl, phenolate or amide groups are prepared for study as T₁ MRI probes. Complexes with two hydroxypropyl pendants and either amide (Fe(TOAB)) or phenolate (Fe(PTOB)) groups are compared to an analog with three hydroxypropyl groups (Fe(NOHP)), in order to study the effect of the third pendant on the coordination sphere as probed by solution chemistry, relaxivity and structural studies. Solution studies show that Fe(PTOB) has two ionizations with the phenol pendant deprotonating with a pK_a of 1.7 and a hydroxypropyl pendent with pK_a of 6.3. The X-ray crystal structure of [Fe(PTOB)]Br₂ features a six-coordinate complex wit

SUBMITTER: Kras EA 

PROVIDER: S-EPMC10897765 | biostudies-literature | 2024 Feb

REPOSITORIES: biostudies-literature