We present gas-phase structures of dimers of Mn^III and Fe^III meso-tetra(4-sulfonatophenyl)porphyrin multianions with various amounts of sodium and hydrogen counterions. The structural assignments are achieved by combining mass spectrometry, ion mobility measurements, quantum chemical calculations, and trajectory method collision cross section calculations. For a common charge state, we observe significant topological variations in the dimer structures of [(MTPPS)₂+nX]^(6-n)- (M=Mn^III, Fe^III; X=H, Na; n = 1–3) induced by replacing hydrogen counterions by sodium. For sodium, the dimer structures are much more compact, a finding that can be rationalized by the stronger interactions of the sodium cations with the anionic sulfonic acid groups of the porphyrins as compared to hydrogen.

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我们提出了具有不同数量的钠和氢抗衡离子的Mn ^III和Fe ^III内消旋四（4-磺酰胺基苯基）卟啉多阴离子二聚体的气相结构。通过结合质谱，离子迁移率测量，量子化学计算和轨迹法碰撞截面计算来实现结构分配。对于常见的电荷状态，我们观察到[（MTPPS）₂ + nX] ^（6-n）-（M = Mn ^III，Fe ^III ; X = H，Na; n = 1–3）通过用钠代替氢抗衡离子而诱发。对于钠而言，二聚体结构要紧凑得多，与氢相比，钠阳离子与卟啉的阴离子磺酸基团之间更强的相互作用可以合理化这一发现。

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