Manganese(III) porphyrin oligomers as high-relaxivity MRI contrast agents.

Manganese(III) porphyrins (MnPs) as MRI contrast agents (CAs) have drawn particular attention due to their high longitudinal relaxivity (r) and unique biodistribution. In this work, two MnP-based oligomers, MnPD and MnPT, were designed to further improve the relaxivity with ease of synthesis. The two compounds were fully characterized and their nuclear magnetic relaxation dispersion (NMRD) profiles were acquired with a fast field cycling NMR relaxometer.