Exploring Spin‐Orbit Effects in a [Cu6Tl]+ Nanocluster Featuring an Uncommon Tl−H Interaction

• Published in: Chemistry : a European journal 2024-05, Vol.30 (25), p.e202400390-n/a
• Main Authors: Hertler, Phoebe R., Yu, Xiaojuan, Brower, Jordan D., Nguyen, Thuy‐Ai D., Wu, Guang, Autschbach, Jochen, Hayton, Trevor W.
• Format: Article
• Language: English
• Subjects: Chemical equilibrium; cluster compounds; copper; Density functional theory; hydrides; Magnetic resonance spectroscopy; Metal hydrides; Nanoclusters; NMR spectroscopy; thallium
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202400390

Reaction of [CuH(PPh3)]6 with 1 equiv. of Tl(OTf) results in formation of [Cu6TlH6(PPh3)6][OTf] ([1]OTf]), which can be isolated in good yields. Variable‐temperature 1H NMR spectroscopy, in combination with density functional theory (DFT) calculations, confirms the presence of a rare Tl−H orbital interaction. According to DFT, the 1H chemical shift of the Tl‐adjacent hydride ligands of [1]+ includes 7.7 ppm of deshielding due to spin‐orbit effects from the heavy Tl atom. This study provides valuable new insights into a rare class of metal hydrides, given that [1][OTf] is only the third isolable species reported to contain a Tl−H interaction. The [Cu6Tl]+ cluster, [Cu6TlH6(PPh3)6][OTf], exhibits a rare Tl−H orbital interaction, as ascertained by 1H NMR spectroscopy and density functional theory (DFT) calculations. According to DFT, the 1H chemical shift of the Tl‐adjacent hydride ligands includes 7.7 ppm of deshielding due to spin‐orbit (SO) effects mainly originating from the heavy Tl atom, which represent an important confirmation of SO effects in heavy element main group hydrides.