Light-controlled switching of the spin state of iron(III).
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30420598.
- Also identified by DOI 10.1038/s41467-018-07023-1 and PMC identifier 6232099.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Controlled switching of the spin state of transition metal ions, particularly of Fe<sup>II</sup> and Fe<sup>III</sup>, is a prerequisite to achieve selectivity, efficiency, and catalysis in a number of metalloenzymes. Here we report on an iron(III) porphyrin with a photochromic axial ligand which, upon irradiation with two different wavelengths reversibly switches its spin state between low-spin (S = <sup>1</sup>/<sub>2</sub>) and high-spin (S = <sup>5</sup>/<sub>2</sub>) in solution (DMSO-acetone, 2:598). The switching efficiency is 76% at room temperature. The system is neither oxygen nor water sensitive, and no fatigue was observed after more than 1000 switching cycles. Concomitant with the spin-flip is a change in redox potential by ~60 mV. Besides serving as a simple model for the first step of the cytochrome P450 catalytic cycle, the spin switch can be used to switch the spin-lattice relaxation time T<sub>1</sub> of the water protons by a factor of 15.
Medical subject headings
- Iron
- Light