Abstract：
Manganese complexes exhibit a rich redox chemistry, usually accompanied by structural reorganization during the redox processes often followed by ligand dissociation or association. The push-pull ligand 2,6-diguanidylpyridine (dgpy) stabilizes manganese in the oxidation states +II, +III, and + IV in the complexes [Mn(dgpy)2]n+ (n = 2-4) without change in the coordination sphere in the condensed phase [Heinze et al., Inorganic Chemistry, 2022, 61, 14616]. In the condensed phase, the manganese(IV) complex is a very strong oxidant. In the present work, we investigate the stability and redox activity of the MnIV complex and its counterion (PF6-) adducts in the gas phase, using two modified 3D Paul ion trap mass spectrometers. Six different cationic species of the type [Mnx(dgpy)2(PF6)y]n+ (x = II, III, IV, y = 0-3, n = 1-3) could be observed for the three oxidation states MnIV, MnIII, and MnII, of which one observed complex also contains a reduced dgpy ligand. MnII species showed the highest relative stability in collision induced dissociation and UV/vis photo dissociation experiments. The lowest stability is observed in the presence of one or more counterions, which correlates to a lower total charge n+. Gas phase UV/vis spectra show similar features as the condensed phase spectra only differing in relative band intensities. The strongly oxidizing MnIV complex reacts with triethylamine (NEt3) in the gas phase to give MnIII, while MnIII species show little reactivity toward NEt3.
摘要：
锰配合物表现出丰富的氧化还原化学，通常伴随着氧化还原过程中的结构重组，通常伴随着配体解离或缔合。推拉配体2,6-二胍基吡啶（dgpy）将锰稳定在氧化态II，+III,和配合物[Mn（dgpy）2]n（n=2-4）中的IV，凝聚相中的配位球没有变化[Heinze等人。,无机化学,2022，61，14616]。在凝聚阶段,锰(IV)络合物是非常强的氧化剂。在目前的工作中,我们研究了MnIV络合物及其反离子（PF6-）加合物在气相中的稳定性和氧化还原活性，使用两个改进的3DPaul离子阱质谱仪。[Mnx（dgpy）2（PF6）y]n（x=II，III,IV,对于三种氧化态MnIV，可以观察到y=0-3，n=1-3），MnIII,和MnII,其中一个观察到的络合物还含有还原的dgpy配体。MnII物种在碰撞诱导解离和UV/vis光解离实验中显示出最高的相对稳定性。在一种或多种抗衡离子的存在下观察到最低的稳定性，这与较低的总电荷n+相关。气相UV/vis光谱显示出与凝聚相光谱相似的特征，仅在相对谱带强度上有所不同。强氧化性MnIV络合物在气相中与三乙胺（NEt3）反应生成MnIII，而MnIII物种对NEt3几乎没有反应性。
