A study of cation-dependent inverse hydrogen bonds and magnetic exchange-couplings in lanthanacarborane complexes

• Main Authors: Peng-Bo Jin, Qian-Cheng Luo, Yuan-Qi Zhai, Yi-Dian Wang, Yan Ma, Lei Tian, Xinliang Zhang, Chao Ke, Xu-Feng Zhang, Yi Lv, Yan-Zhen Zheng
• Format: Article
• Language: English
• Published: Elsevier 2021-07-01
• Series: iScience
• Subjects: chemistry; inorganic chemistry; molecular inorganic chemistry; magnetism
• Online Access: http://www.sciencedirect.com/science/article/pii/S2589004221007288

Summary: Ten lanthanacarborane complexes were synthesized to study the rare B−Hδ−∙∙∙Mn+ inverse hydrogen bonds (IHBs). The average bonding energy of B−Hδ−∙∙∙Ln3+ is theoretically determined to be larger than 24 kJ/mol, which is comparable to moderately strong hydrogen bonds (21–56 kJ/mol). In addition to NMR and IR, magnetometer was used to study the exchange-coupling interaction via such B−Hδ−∙∙∙Ln3+ IHBs in detail, and the coupling constant is determined to be −2.0 cm−1, which is strong enough to compare with single-atom bridged dysprosium(III) complexes. Two imidazolin-iminato incorporated complexes have shown energy barrier for magnetization reversal larger than 1000 K, and the exchange-biasing effects are evident. Moreover, the bonding strengths of B−Hδ−∙∙∙Mn+ IHBs are cation-dependent. If M = Na, the B−Hδ−∙∙∙Na+ bonding energy is reduced to 14 kJ/mol, and the dimerization process is no longer reversible. The exchange-biasing effect is also disappeared. We believe such a finding extends our knowledge of IHBs.