Ligated tetrapositive metal ions are rare gas-phase species which tend to form complexes with lower charges due to the high 4th ionization energies of metals. We report the observation of tetrapositive Zr(TMPDA)₃⁴⁺ and Zr(TMOGA)₃⁴⁺ complexes in the gas phase by electrospray ionization of Zr(ClO₄)₄/TMPDA and Zr(ClO₄)₄/TMOGA mixtures. The Zr⁴⁺ center in both complexes is coordinated by nine atoms from three neutral diamide ligands forming nine-coordinate twisted tricapped trigonal prismatic geometry on the basis of DFT calculations. Collision-induced dissociation of both complexes resulted in the loss of protonated ligands to form tripositive Zr(TMPDA)(TMPDA-H)³⁺ and Zr(TMOGA)(TMOGA-H)³⁺ products which retain the IV oxidation state of zirconium at the cost of charge reduction from 4+ to 3+ of the whole complexes. The very high 4th ionization energy of zirconium (34.34 eV) makes tetrapositive zirconium complex the most challenging tetracation to be stabilized against charge reduction in the gas phase to date.

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连接的四正金属离子是稀有的气相物质，由于金属的第4高电离能，它们往往以较低的电荷形成络合物。我们报告了通过Zr（ClO ₄）₄ / TMPDA和Zr（ClO ₄）₄ / TMOGA混合物的电喷雾电离在气相中观察到四正Zr（TMPDA）₃ ⁴⁺和Zr（TMOGA）₃ ⁴⁺配合物。Zr ⁴⁺在DFT计算的基础上，两个络合物的中心都由来自三个中性二酰胺配体的九个原子配位，形成了九个坐标的扭曲的三棱柱三角几何形状。两种复合物的碰撞诱导解离导致质子化配体的损失，从而形成Zr（TMPDA）（TMPDA-H）³⁺和Zr（TMOGA）（TMOGA-H）³⁺产品，这些产品保留了锆的IV氧化态。整个复合体的电荷从4+降低到3+的成本。锆的非常高的第四电离能（34.34 eV）使四正性锆配合物成为目前最具挑战性的四阳离子，需要稳定化以防止气相中的电荷减少。

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