Fe-Fe bonding in the rhombic Fe4 cores of the Zintl clusters [Fe4E18]4- (E = Sn and Pb)

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

doi:10.1039/d4sc00165f

Fe-Fe bonding in the rhombic Fe₄ cores of the Zintl clusters [Fe₄E₁₈]^4- (E = Sn and Pb)

Chem Sci. 2024 Feb 28;15(13):4981-4988. doi: 10.1039/d4sc00165f. eCollection 2024 Mar 27.

Authors

Wei-Xing Chen¹, Zi-Sheng Li², Harry W T Morgan², Cong-Cong Shu¹, Zhong-Ming Sun¹, John E McGrady²

Affiliations

¹ 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.
² Department of Chemistry, University of Oxford South Parks Road Oxford OX1 3QR UK john.mcgrady@chem.ox.ac.uk.

Abstract

We report here the synthesis and characterization of two endohedral Zintl-ion clusters, [Fe₄Sn₁₈]^4- and [Fe₄Pb₁₈]^4-, which contain rhombic Fe₄ cores. The Fe-Fe bond lengths are all below 2.5 Å, distinctly shorter than in the corresponding Cu clusters, indicating the presence of Fe-Fe bonding. Subtle differences in the structure of the Fe₄ core between the two clusters suggest that the change in tetrel element causes a change in electronic ground state, with a very short Fe-Fe bond length of 2.328 Å present across the diagonal of the rhombus in the lead case.