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oai:figshare.com:article/34032142 2026-09-30T12:09:21Z category_1 category_4 category_915 category_7 category_12 category_16 category_272 category_873 category_64 category_135 portal_63 item_type_6 month_year_09_2026

Direct Evidence of a La–Te Bond and Bonding Regime Differences for Ln–C and Ln–Te in [K(18-Crown 6)(Cp″₂LnTe₃)] (Ln = La, Ce, and Nd) Cedric Y. Reitz (25143781) David Frick (25143784) Elena Pross (25143787) Emily M. Reynolds (2887028) Constantin Wansorra (19846836) Sven M. Schenk (25143790) Jacob A. Branson (20780620) Hanna Kaufmann-Heimeshoff (25143793) Mary Blankenship (25143796) Julius Wolf (25143799) Dirk Hauschild (5860238) Jörg Göttlicher (1606540) Ralph Steininger (1606876) Stefan Mangold (1606870) Ruwini S. K. Ekanayake (5706326) Bianca Schacherl (10291589) Lothar Weinhardt (1345440) Clemens Heske (1345434) Cristian Celis-Barros (1561687) Harry Ramanantoanina (1593310) Peter W. Roesky (1549540) Tonya Vitova (1694806) Biophysics Biochemistry Physical Sciences not elsewhere classified Medicine Cell Biology Physiology Environmental Sciences not elsewhere classified Chemical Sciences not elsewhere classified Cancer Computational Biology multielectron reducing agents higher delocalization index frontier molecular orbitals driven covalency regime density functional theory 2 –</ sup ray spectroscopic approaches bonding regime differences bond critical point ln – c 2 </ sub ln – te c interaction tellurium bonding ray scattering f </ te bond together enable tellurium chain qtaim analysis predominantly localized predominantly electrostatic participation within mechanistic interpretation heavier lanthanides experimentally resolve direct evidence cp ″ complementary ligand centered x Using nonclassical divalent lanthanide precursors as multielectron reducing agents, complexes [K(18-crown-6)(Cp″₂LnTe₃)] with Ln = La, Ce, and Nd; Cp″ = 1,3-bis(trimethylsilyl)cyclopentadienyl were synthesized and investigated to elucidate the mechanism of lanthanide-tellurium bonding and the role of 4<i>f</i>-element electron density in stabilizing small chalcogenide chains. Density functional theory (DFT) reveals that the frontier molecular orbitals of these complexes are predominantly localized on the [Te₃]^2– fragment, while the trivalent lanthanide ions stabilize the tellurium chain through weak but measurable metal–ligand interactions. To experimentally resolve these interactions, we focus on complementary ligand- and metal-centered X-ray spectroscopic approaches. Ln L₃-edge high-resolution XANES (HR-XANES) and valence-band resonant inelastic X-ray scattering (VB-RIXS) demonstrate that the Ln-Te/C interaction has substantial Ln 5d orbital contributions, particularly for the Ln-Te bond, and remain largely constant across the three complexes. DFT-based bond analysis provides a mechanistic interpretation of these trends. The Ln–C interaction exhibits increasing electron density at the bond critical point and a higher delocalization index (QTAIM analysis) from the lighter to the heavier lanthanides, reflecting enhanced Ln 4<i>f</i> participation within an energy-driven covalency regime. The Ln–Te interaction is predominantly electrostatic, with meaningful orbital contributions arising mainly from Ln 5<i>d</i> participation within an orbital-overlap-driven covalency regime. These results demonstrate that the Ln–C and Ln–Te bonding in the present complexes follow fundamentally distinct covalency mechanisms, which together enable the stabilization and isolation of the small [Te₃]^2– fragment chain. 2026-09-30T00:00:00Z Text Journal contribution 10.1021/jacs.6c06838.s001 https://figshare.com/articles/journal_contribution/Direct_Evidence_of_a_La_Te_Bond_and_Bonding_Regime_Differences_for_Ln_C_and_Ln_Te_in_K_18-Crown_6_Cp_sub_2_sub_LnTe_sub_3_sub_Ln_La_Ce_and_Nd_/34032142 CC BY-NC 4.0