f-Element complexes with benzyl and cyclohexyl substituted trihydroborates

IF 2.4 3区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Polyhedron Pub Date : 2025-01-16 DOI:10.1016/j.poly.2025.117408

Joshua C. Zgrabik, Peter A. Zacher III, Scott R. Daly

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引用次数: 0

Abstract

Actinide complexes containing the simplest borohydrides (BH₄)¹⁻ and (MeBH₃)¹⁻ can exhibit remarkably highly volatility, which creates unique hazards and handling challenges, especially when making measurements on solid samples under vacuum. Here we describe efforts to prepare new actinide borohydride complexes with attenuated volatility by adding bulkier benzyl (Bn) and cyclohexyl (Cy) substituents to boron. Reactions of ThCl₄, UI₃(thf)₄, and NdI₃ with the mixed alkali metal salt Li/K(BnBH₃)(thf)_n yielded Th(BnBH₃)₄(thf)₂, U(BnBH₃)₄(thf)₂, and K[Nd(BnBH₃)₄], respectively. Notable amongst these, the reaction with UI₃(thf)₄ proceeds via oxidation of U(III) to U(IV) despite the presence of reducing borohydride ligands. Similarly, reactions of the same metal halides with four equivalents of Li(CyBH₃)(Et₂O)_n yielded Th(CyBH₃)₄, U(CyBH₃)₄(thf)₂, and [Li(Et₂O)₃][Nd(CyBH₃)₄]. Single crystal X-ray diffraction studies of the M(BnBH₃)₄(thf)₂ complexes with M = Th and U confirmed their formulations. The complexes have approximate D_2d point group symmetry and adopt bicapped hexagonal antiprismatic coordination geometries with axial thf ligands and κ³-BnBH₃ ligands bound in the equatorial plane. K[Nd(BnBH₃)₄] and [Li(Et₂O)₃][Nd(CyBH₃)₄], which were prepared for comparison to U(III) complexes that were unsuccessfully targeted, were also structurally characterized to reveal complex anions with tetrahedral arrangements of trihydroborate ligands bound to Nd(III). Crystals obtained for Th(CyBH₃)₄ and U(CyBH₃)₄(thf)₂ were not suitable for XRD studies, but ¹H and ¹¹B NMR spectra were consistent with their formulations. Collectively, these complexes represent rare examples of structurally characterized f-element trihydroborate complexes with carbon substituents other than methyl.

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来源期刊

Polyhedron 化学-晶体学

CiteScore

4.90

自引率

7.70%

发文量

515

审稿时长

2 months

期刊介绍： Polyhedron publishes original, fundamental, experimental and theoretical work of the highest quality in all the major areas of inorganic chemistry. This includes synthetic chemistry, coordination chemistry, organometallic chemistry, bioinorganic chemistry, and solid-state and materials chemistry. Papers should be significant pieces of work, and all new compounds must be appropriately characterized. The inclusion of single-crystal X-ray structural data is strongly encouraged, but papers reporting only the X-ray structure determination of a single compound will usually not be considered. Papers on solid-state or materials chemistry will be expected to have a significant molecular chemistry component (such as the synthesis and characterization of the molecular precursors and/or a systematic study of the use of different precursors or reaction conditions) or demonstrate a cutting-edge application (for example inorganic materials for energy applications). Papers dealing only with stability constants are not considered.