American Chemical Society
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Formation and Structure of Gas-Phase Lanthanide(III) Cyanobenzyne Complex (η2‑4-CNC6H3)LnCl2, Obtained via Both the Single- and Dual-Ligand Strategies

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journal contribution
posted on 2024-03-03, 17:03 authored by Qian Wang, Songpeng Wan, Jinhao Zhou, Haiying Fu, Xiuting Chen
The lanthanide(III) cyanobenzyne complexes (η2-4-CNC6H3)LnCl2 (Ln = La–Lu except Eu; Pm was not examined) were generated in the gas phase using an electrospray ionization mass spectrometry coupled with collision-induced dissociation (CID) technique. For all lanthanides except Sm, Eu, and Yb, (4-CNC6H3)LnCl2 can be generated either via a single-ligand strategy through consecutive CO2 and HCl losses of (4-CNC6H4CO2)LnCl3 or via a dual-ligand strategy through successive CO2/C6H5CN or 4-CNC6H4CO2H and CO2 losses of (4-CNC6H4CO2)2LnCl2. For Sm and Yb, although only reduction products LnCl3 were formed upon CID of (4-CNC6H4CO2)LnCl3, (4-CNC6H3)LnCl2 were obtained via the dual-ligand strategy without the appearances of other products. CID of (4-CNC6H4CO2)EuCl3 and (4-CNC6H4CO2)2EuCl2 gave EuCl3 and the cyanophenyl complex (4-CNC6H4)EuCl2, respectively, in both of which the +III oxidation state of Eu was reduced to +II. Density functional theory (DFT) calculations reveal that (4-CNC6H3)LnCl2 are formally described as Ln(III) cyanobenzyne complexes, (η2-4-CNC6H3)LnCl2, with the dianionic cyanobenzyne ligand (4-CNC6H32–) coordinating to the Ln(III) centers through two Ln–C σ bonds, which is in accordance with their reactivities toward water. Benzyne and substituted benzyne complexes (XC6H3)LuCl2 (X = H, 3-CN, 4-F, 4-Cl, and 4-CH3) were also synthesized in the gas phase via the single- and dual-ligand strategies.