The Dolinar group specializes in the development of new, magnetically interesting compounds, specifically in the fields of MRI contrast agents and single molecule magnetism.
Redox Switchable Gd MRI Contrast Agents
Development of MRI contrast agents that respond to the different chemical environments present in various tissues and cells remains a challenge for synthetic chemists. Strategies that have been employed to address this problem include altering the substituents on the ligand in order to tune where the MRI agent localizes within the body as well as the development of pH and redox switchable compounds. In redox-switchable MRI contrast agents, different levels of oxygen content and reactive oxygen species (ROS) present in cells leads to oxidation or reduction of the contrast agent, altering its magnetic behavior and leading to different degrees of contrast in the MRI image.
The seven unpaired electrons and magnetic isotropy of Gd(III) ions makes them for exceptionally useful as MRI contrast agents. While Gd(III) itself is not redox active in vivo, we can design Gd(III) compounds that posses a redox active moiety. These groups can undergo a redox event in the presence of ROS in the cell altering the magnetic response of the MRI contrast agent, ultimately allowing the oxygen concentration of cells to be probed.
Single Molecule Magnets Featuring Metal-Metal Bonds Between High-Spin Transition Metals and Lanthanides
Single Molecule Magnets (SMMs) are molecular compounds that exhibit magnetic memory and have the potential to be utilized as magnetic bits in next generation information storage devices. SMMs are much smaller than the magnetic bits currently used in commercially available hard drives. Thus, SMMs have the potential to greatly improve storage density of information storage devices. In such molecules, magnetic anisotropy gives rise to a thermal barrier to magnetic relaxation, resulting in their magnetic memory behavior Current state of the art SMMs only exhibit magnet memory at cryogenic temperatures (< 80 K), limiting their commercial viability. This limitation arises largely from magnetic relaxation phenomena such as quantum tunneling of magnetization (QTM), which serves to circumvent the thermal barrier.
Research in the Dolinar group explores the synthesis of transition-metal lanthanide metal-metal bonded compounds in which the transition metal is paramagnetic. We predict that such compounds will have high degrees of magnetic coupling, which can reduce QTM and subsequently increase the operating temperature of SMMs.