Interactions of CyMe4 ‐BTBP ligand with lanthanides and actinides: Insights from ESI‐MS and DFT calculations

AbstractElectrospray Ionization Mass Spectrometry (ESI-MS) technique and density functional theory (DFT) calculations were combined to study the formation of the complexes of lanthanides (Ln  = La, Ce, Nd, Sm, Eu, Yb) and actinides (UO22+, Th4+) with CyMe4-BTBP (6,6 ′-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo-[1,2,4-]triazin-3-yl)-[2,2′]bipyridine) to understand the mechanisms during the extraction process. Mass spectrometry titrations showed the formation of the complexation in acetonitrile. For lanthanides, only 1:2 complexes ([Ln(L)2]3+, [Ln(L)2(CH3CN)]3+), [Ln(L)2(NO3)]2+) were found at low [Ln]/[L] concentration ratios, whereas the 1:1 complexes ([Ln(L)(NO3)2]+) were observed when the [Ln]/[L] concentration ratio reached 1.0. For uranyl complexes, 1:1 complex ([UO2L(NO3)]+) was the only species within the measuring range. Th4+ complexes had two compositions: 1:1 and 1:2, in which 1:2 species was the dominant complex. Collision-induced dissociation (CID) was employed to characterize the fragmentation process. The fragmentation process was unfolded sequentially on both sides of CyMe4-BTBP ligand with the loss of alkyl groups and cleavage of triazinyl rings. The CID results of CyMe4-BTBP complexes revealed a slight difference depending on the metal center. The DFT calculations showed that the stable complexes formed in acetonitrile solution were consistent with the ESI-MS results.

Source: Journal of Mass Spectrometry - October 31, 2023 Category: Chemistry Authors: Qi ‐Qi Zhang, Yang Liu, Shu‐Ping Tan, Yan Chen, Jie Gao, Xin‐Yue Liang, Wei‐Qun Shi, Yong‐Gang Zhao Tags: RESEARCH ARTICLE Source Type: research