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Gavara-Edo M, Valverde-Muñoz FJ, Muñoz MC, Elidrissi Moubtassim S, Marques-Moros F, Herrero-Martín J, Znovjyak K, Seredyuk M, Real JA, Coronado E. Design and Processing as Ultrathin Films of a Sublimable Iron(II) Spin Crossover Material Exhibiting Efficient and Fast Light-Induced Spin Transition. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:9591-9602. [PMID: 38047182 PMCID: PMC10687866 DOI: 10.1021/acs.chemmater.3c01704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 12/05/2023]
Abstract
Materials based on spin crossover (SCO) molecules have centered the attention in molecular magnetism for more than 40 years as they provide unique examples of multifunctional and stimuli-responsive materials, which can be then integrated into electronic devices to exploit their molecular bistability. This process often requires the preparation of thermally stable SCO molecules that can sublime and remain intact in contact with surfaces. However, the number of robust sublimable SCO molecules is still very scarce. Here, we report a novel example of this kind. It is based on a neutral iron(II) coordination complex formulated as [Fe(neoim)2], where neoimH is the ionogenic ligand 2-(1H-imidazol-2-yl)-9-methyl-1,10-phenanthroline. In the first part, a comprehensive study, which covers the synthesis and magnetostructural characterization of the [Fe(neoim)2] complex as a bulk microcrystalline material, is reported. Then, in the second part, we investigate the suitability of this material to form thin films through high-vacuum sublimation. Finally, the retainment of all present SCO capabilities in the bulk when the material is processed is thoroughly studied by means of X-ray absorption spectroscopy. In particular, a very efficient and fast light-induced spin transition (LIESST effect) has been observed, even for ultrathin films of 15 nm.
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Affiliation(s)
- Miguel Gavara-Edo
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
| | | | - M. Carmen Muñoz
- Departamento
de Fisica Aplicada, Universitat Politècnica
de València, Camino de Vera s/n, Valencia 46022, Spain
| | - Safaa Elidrissi Moubtassim
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
| | - Francisco Marques-Moros
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
| | | | - Kateryna Znovjyak
- Department
of Chemistry, Taras Shevchenko National
University of Kyiv, 64/13,
Volodymyrska Street, Kyiv 01601, Ukraine
| | - Maksym Seredyuk
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
- Department
of Chemistry, Taras Shevchenko National
University of Kyiv, 64/13,
Volodymyrska Street, Kyiv 01601, Ukraine
| | - José Antonio Real
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
| | - Eugenio Coronado
- Instituto
de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán
2, Paterna 46980, Spain
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Zhang Y. Surface-Induced Electronic and Vibrational Level Shifting of [Fe(py) 2bpym(NCS) 2] on Al(100). MATERIALS (BASEL, SWITZERLAND) 2023; 16:6150. [PMID: 37763428 PMCID: PMC10532516 DOI: 10.3390/ma16186150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023]
Abstract
It is essential that one understands how the surface degrees of freedom influence molecular spin switching to successfully integrate spin crossover (SCO) molecules into devices. This study uses density functional theory calculations to investigate how spin state energetics and molecular vibrations change in a Fe(II) SCO compound named [Fe(py)2bpym(NCS)2] when deposited on an Al(100) surface. The calculations consider an environment-dependent U to assess the local Coulomb correlation of 3d electrons. The results show that the adsorption configurations heavily affect the spin state splitting, which increases by 10-40 kJmol-1 on the surface, and this is detrimental to spin conversion. This effect is due to the surface binding energy variation across the spin transition. The preference for the low-spin state originates partly from the strong correlation effect. Furthermore, the surface environment constrains the vibrational entropy difference, which decreases by 8-17 Jmol-1K-1 (at 300 K) and leads to higher critical temperatures. These results suggest that the electronic energy splitting and vibrational level shifting are suitable features for characterizing the spin transition process on surfaces, and they can provide access to high-throughput screening of spin crossover devices.
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Affiliation(s)
- Yachao Zhang
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Education University, Guiyang 550018, China
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