Wan Songpeng, Gong Yu, Chen Xiuting
National Key Laboratory of Thorium Energy, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China.
University of Chinese Academy of Sciences, Beijing, China.
Rapid Commun Mass Spectrom. 2025 Aug 15;39(15):e10054. doi: 10.1002/rcm.10054.
The lanthanide hydrocarbyl complexes often exhibit exceptional performance in organic synthesis, catalytic process, and small molecule activation, and they generally exhibit several valuable differences in reactivity which can be influenced by the metal center and its oxidation state. Decarboxylation of metal carboxylate precursor is a powerful means to obtain multitudinous organometallic complexes which are well suited for gas-phase investigation by employing electrospray ionization mass spectrometry (ESI-MS) experiments in combination with density functional theory (DFT) calculations.
The (CHCO)LnCl and (CHCO)LnCl (Ln = Sm, Eu, and Yb) precursor anions were produced in the gas phase via ESI of LnCl and CHCONa mixtures in methanol. Collision-induced dissociation (CID) technique was employed to obtain (CH)LnCl and (CH)LnCl via fragmentation reactions of lanthanide acetate chloride anions. Activation of water molecule by (CH)LnCl or (CH)LnCl via CH or H release was investigated by ion-molecule reaction (IMR) experiments. With the support of DFT calculations, the influences of lanthanide center and its oxidation state were also explored.
(CH)LnCl was generated via decarboxylation of (CHCO)LnCl (Ln = Sm, Eu, and Yb) upon CID, while (CHCO)LnCl underwent consecutive two-step CO/CH or one-step CHCO·and CO losses to give (CH)LnCl . All three (CH)LnCl anions spontaneously reacted with HO to form Ln (OH)Cl accompanied by methane release, and the reaction extent is generally following as (CH)SmCl > (CH)EuCl > (CH)YbCl . For (CH)EuCl with HO, there was minor (CHO)EuCl produced through hydrogen loss reaction as well. Three (CH)LnCl anions reacted much more quickly than (CH)LnCl with HO via CH loss, and the reactivity enhancement extent is following as Yb > Eu > Sm, which agrees well with Ln-C bond elongation trend from (CH)LnCl to (CH)LnCl . Moreover, (CH)SmCl and (CH)YbCl rather than (CH)EuCl underwent H loss reaction with HO, which is on the contrary with the cases of (CH)LnCl .
The reactivity of the methyllanthanide chloride complexes towards water is significantly influenced by the lanthanide center and its oxidation state. In general, the methyllanthanide (II) chloride complexes (CH)LnCl is much more reactive than the methyllanthanide (III) chloride complexes (CH)LnCl . Besides, the reactivity of (CH)LnCl is following as Sm > Eu > Yb, while that of (CH)LnCl is Eu > Sm ≈ Yb.
镧系烃基配合物在有机合成、催化过程和小分子活化中常常表现出卓越的性能，并且它们通常在反应活性方面呈现出一些有价值的差异，这些差异会受到金属中心及其氧化态的影响。金属羧酸盐前体的脱羧反应是获得众多有机金属配合物的有效方法，这些配合物非常适合通过将电喷雾电离质谱（ESI-MS）实验与密度泛函理论（DFT）计算相结合的方式进行气相研究。
通过在甲醇中对LnCl和CHCONa混合物进行电喷雾电离，在气相中产生(CHCO)LnCl和(CHCO)LnCl（Ln = Sm、Eu和Yb）前体阴离子。采用碰撞诱导解离（CID）技术，通过镧系元素乙酰氯阴离子的碎片化反应获得(CH)LnCl和(CH)LnCl。通过离子-分子反应（IMR）实验研究(CH)LnCl或(CH)LnCl通过CH或H释放对水分子的活化作用。在DFT计算的支持下，还探讨了镧系元素中心及其氧化态的影响。
(CHCO)LnCl（Ln = Sm、Eu和Yb）在CID作用下通过脱羧反应生成(CH)LnCl，而(CHCO)LnCl经历连续两步的CO/CH损失或一步的CHCO·和CO损失，生成(CH)LnCl。所有三种(CH)LnCl阴离子都能与HO自发反应，形成Ln(OH)Cl并伴有甲烷释放，反应程度一般为(CH)SmCl ＞(CH)EuCl ＞(CH)YbCl。对于(CH)EuCl与HO的反应，还会通过氢损失反应生成少量的(CHO)EuCl。三种(CH)LnCl阴离子通过CH损失与HO反应的速度比(CH)LnCl快得多，反应活性增强程度为Yb＞Eu＞Sm，这与从(CH)LnCl到(CH)LnCl的Ln-C键伸长趋势非常吻合。此外，(CH)SmCl和(CH)YbCl而不是(CH)EuCl会与HO发生H损失反应，这与(CH)LnCl的情况相反。
甲基镧系氯化物配合物对水的反应活性受到镧系元素中心及其氧化态的显著影响。一般来说，甲基镧系（II）氯化物配合物(CH)LnCl的反应活性比甲基镧系（III）氯化物配合物(CH)LnCl高得多。此外(CH)LnCl的反应活性顺序为Sm＞Eu＞Yb，而(CH)LnCl的反应活性顺序为Eu＞Sm≈Yb。
