Stepwise C–H bond activations and assembly of binuclear Ln3+ species coordinated by a hexaanionic anti-η5:η5-dibenzopentalene-bridged bis(carbazolyl) framework
Abstract
New binuclear rare-earth complexes [(μ 2 -η 5 :η 5 ;κ 2 :κ 2 -N,C-L)Ln2(THF)4] (Ln = Y 3+ (1Y), Tb 3+ (1Tb), Dy 3+ (1Dy), Er 3+ (1Er)) containing a hexaanionic dibenzopetalenebridged bis(carbazolyl) framework were obtained via spontaneous self-assembly in the reactions of Ln(CH2SiMe3)3(THF)2 with equimolar amount of 3,6-di-tertbutyl-1,8-bis(phenylethynyl)-9H-carbazole. Two Ln 3+ ions are -anti-η 5 :η 5 -coordinated with the dianionic dibenzopentalene fragment resulting from a series of successive intramolecular ortho-CH activations in the phenyl rings of the ethynyl substituents followed by intermolecular dimerization involving Ln-C Ar bond addition to a C≡C triple bond. Magnetic investigations show that 1Dy behaves as a genuin single-molecule magnet (SMM) with relaxation dynamics described by a multicomponent model dominated at high temperature by an Orbach process, yielding an effective barrier of 689 cm -¹. In contrast, 1Tb and 1Er exhibit only field-induced slow magnetic relaxation at low temperature. Ab initio calculations reveal a substantially larger crystal-field splitting and stronger axial anisotropy for Dy³⁺ than for Er³⁺ analogue. Weak antiferromagnetic interactions between the lanthanide centers were identified with J = -0.23 cm -¹ for 1Dy, -0.06 cm -1 for 1Tb, and -0.28 cm -¹ for 1Er. This indicats that the slow magnetic relaxation is governed primarily by single-ion crystal-field effects rather than exchange coupling.
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BibTeX
@article{zakaria2026stepwise,
title = {{Stepwise C–H bond activations and assembly of binuclear Ln3+ species coordinated by a hexaanionic anti-η5:η5-dibenzopentalene-bridged bis(carbazolyl) framework}},
author = {Hamza Zakaria and Gautier Félix and Dmitry Lyubov and Max Kallio and Veacheslav Vieru and Anna Vologzhanina and Rinat Aysin and Yannick Guari and Joulia Larionova and Alexander Trifonov},
journal = {Dalton Transactions},
year = {2026},
month = jun,
doi = {10.1039/d6dt01110a},
url = {https://hal.science/hal-05768860v1},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Stepwise C–H bond activations and assembly of binuclear Ln3+ species coordinated by a hexaanionic anti-η5:η5-dibenzopentalene-bridged bis(carbazolyl) framework
AU - Hamza Zakaria
AU - Gautier Félix
AU - Dmitry Lyubov
AU - Max Kallio
AU - Veacheslav Vieru
AU - Anna Vologzhanina
AU - Rinat Aysin
AU - Yannick Guari
AU - Joulia Larionova
AU - Alexander Trifonov
PY - 2026
DA - 2026/06/23
JO - Dalton Transactions
DO - 10.1039/d6dt01110a
UR - https://hal.science/hal-05768860v1
AB - New binuclear rare-earth complexes [(μ 2 -η 5 :η 5 ;κ 2 :κ 2 -N,C-L)Ln2(THF)4] (Ln = Y 3+ (1Y), Tb 3+ (1Tb), Dy 3+ (1Dy), Er 3+ (1Er)) containing a hexaanionic dibenzopetalenebridged bis(carbazolyl) framework were obtained via spontaneous self-assembly in the reactions of Ln(CH2SiMe3)3(THF)2 with equimolar amount of 3,6-di-tertbutyl-1,8-bis(phenylethynyl)-9H-carbazole. Two Ln 3+ ions are -anti-η 5 :η 5 -coordinated with the dianionic dibenzopentalene fragment resulting from a series of successive intramolecular ortho-CH activations in the phenyl rings of the ethynyl substituents followed by intermolecular dimerization involving Ln-C Ar bond addition to a C≡C triple bond. Magnetic investigations show that 1Dy behaves as a genuin single-molecule magnet (SMM) with relaxation dynamics described by a multicomponent model dominated at high temperature by an Orbach process, yielding an effective barrier of 689 cm -¹. In contrast, 1Tb and 1Er exhibit only field-induced slow magnetic relaxation at low temperature. Ab initio calculations reveal a substantially larger crystal-field splitting and stronger axial anisotropy for Dy³⁺ than for Er³⁺ analogue. Weak antiferromagnetic interactions between the lanthanide centers were identified with J = -0.23 cm -¹ for 1Dy, -0.06 cm -1 for 1Tb, and -0.28 cm -¹ for 1Er. This indicats that the slow magnetic relaxation is governed primarily by single-ion crystal-field effects rather than exchange coupling.
SN - 1477-9226
SN - 1477-9234
ER -