<i>trans</i> ‐Configured Ligands Boost Spin Crossover to Room Temperature in Mononuclear Fe(II) Complexes
Seven new mononuclear complexes [Fe(aqin)<sub>2</sub>(NCS)<sub>2</sub>] (1), [Fe(aqin)<sub>2</sub>(NCSe)<sub>2</sub>] (2), [Fe(aqin)<sub>2</sub>(NCBH<sub>3</sub>)<sub>2</sub>] (3), [Fe(2-pic)<sub>2</sub>(NCS)<sub>2</sub>] (4), [Fe(2-pic)<sub>2</sub>(NCSe)<sub>2</sub>] (5), [Fe(2-pic)(NCBH<sub>3</sub>)<sub>2</sub>] (6), [Fe(tpa)(NCBH<sub>3</sub>)<sub>2</sub>] (7), [aqin = 8-aminoquinoline, 2-pic = 2-picolylamine, tpa = tris(2-pyridylmethyl)amine)] are investigated. Structurally, except for 3, which affords a trans-configuration, all the complexes adopt a cis-configuration. Their propensity to crystallize without any solvent molecules facilitates the study of the influence of the "pure" ligand on spin-crossover (SCO) characteristics. Magnetically, 1, 2, and 4 remain in the high-spin state, and 3, 5, 6, and 7 display SCO with transition temperatures T<sub>1/2</sub> of approximately 310, 162, 262, and 400 K, respectively. The T<sub>1/2</sub> values of all the complexes except 3 follow the sequence of ligand-field strength, whereas the T<sub>1/2</sub> value of 3 is increased to room temperature, beyond that of the whole cis-[Fe(2-pic)<sub>2</sub>(NCE)<sub>2</sub>] family. Theoretical modeling based on the harmonic approximation via Gaussian and periodic DFT+U+D3 calculations via the QE reveals that the lower distortion effect of the trans-configuration resulted in the LS stabilization increasing T<sub>1/2</sub>.
Authors
- Zihan Yan (ORCID: https://orcid.org/0000-0001-5298-4839)
- Zhao‐Yang Li (ORCID: https://orcid.org/0000-0002-0952-9862)
- Yanhui Shi
- Xiguang Han (ORCID: https://orcid.org/0000-0003-2469-4572)
- Jing‐Wei Dai
- Yan Kong (ORCID: https://orcid.org/0000-0001-6680-0260)
- Xin Chen (ORCID: https://orcid.org/0000-0001-8234-0292)
- Yingying Wu (ORCID: https://orcid.org/0000-0003-4014-0254)
- Feng‐Lei Yang (ORCID: https://orcid.org/0000-0002-8684-353X)
- FU Guang-wen
Institutions
- Jiangsu Normal University (CN)
- Centre National de la Recherche Scientifique (FR)
- Nankai University (CN)
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (FR)
Publication Details
- Journal
- Chemistry - An Asian Journal
- Published
- 2025-07-21
- DOI
- https://doi.org/10.1002/asia.202500638
- Citations
- 1
- Primary Topic
- Magnetism in coordination complexes
- Type
- article
- Field-Weighted Citation Impact
- 0.43
Funders
- National Natural Science Foundation of China
- Jiangsu Normal University