Snap-shots of cluster growth: structure and properties of a Zintl ion with an Fe3 core, [Fe3Sn18]4

Zi-Sheng Li; Wei-Xing Chen; Harry W T Morgan; Cong-Cong Shu; John E McGrady; Zhong-Ming Sun

doi:10.1039/d3sc04709a

Snap-shots of cluster growth: structure and properties of a Zintl ion with an Fe₃ core, [Fe₃Sn₁₈]⁴

Chem Sci. 2023 Dec 2;15(3):1018-1026. doi: 10.1039/d3sc04709a. eCollection 2024 Jan 17.

Authors

Zi-Sheng Li¹, Wei-Xing Chen², Harry W T Morgan¹, Cong-Cong Shu², John E McGrady¹, Zhong-Ming Sun²

Affiliations

¹ Department of Chemistry, University of Oxford South Parks Road Oxford OX1 3QR UK john.mcgrady@chem.ox.ac.uk.
² State Key Laboratory of Elemento-Organic Chemistry, Tianjin Key Lab for Rare Earth Materials and Applications, School of Materials Science and Engineering, Nankai University Tianjin 300350 China sunlab@nankai.edu.cn.

Abstract

The endohedral Zintl-ion cluster [Fe₃Sn₁₈]^4- contains a linear Fe₃ core with short Fe-Fe bond lengths of 2.4300(9) Å. The ground state is a septet, with significant σ and π contributions to the Fe-Fe bonds. The Sn₁₈ cage is made up of two partially fused Sn₉ fragments, and is structurally intermediate between [Ni₂CdSn₁₈]^6-, where the fragments are clearly separated and [Pd₂Sn₁₈]^4-, where they are completely fused. It therefore represents an intermediate stage in cluster growth. Analysis of the electronic structure suggests that the presence of the linear Fe-Fe-Fe unit is an important factor in directing reactions towards fusion of the two Sn₉ units rather than the alternative of oligomerization via exo bond formation.