Understanding Antiferromagnetic and Ligand Field Effects on Spin Crossover in a Triple-decker Dimeric Cr(II) Complex

22 May 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Two possible explanations for the temperature-dependence of spin crossover (SCO) behavior in the dimeric triple-decker Cr(II) complex ([(C5Me5)Cr(P5)Cr(C5Me5)]+) have been offered. One invokes variations in antiferromagnetic interactions between the two Cr(II) ions, while the other posits the development of a strong ligand-field effect favoring the low-spin ground state. We perform multireference electronic structure calculations based on multiconfiguration pair-density functional theory to resolve these effects. We find quintet, triplet, and singlet electronic ground states, respectively, for the experimental geometries at high, intermediate, and low temperatures. The ground-state transition from quintet to triplet at intermediate temperature derives from increased antiferromagnetic interactions between the two Cr(II) ions. By contrast, the ground-state transition from triplet to singlet at low temperature is attributable to increased ligand-field effects, which dominate with continued variations in antiferromagnetic coupling. This study provides quantitative detail for the degree to which these two effects can act in concert for the observed SCO behavior in this complex and others subject to temperature dependent variations in geometry.


Spin crossover
Bimetallic complexes
Ligand field
Multireference methods

Supplementary materials

Supporting Information
The supporting information contains results of preliminary calculations additional numerical data, optimized geometries, orbitals, results for preliminary magnetic anisotropy calculations accounting for the effects of spin-orbit coupling, and tables for the absolute total energies.


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.