Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama, 35487-0336, USA.
Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA.
Chemistry. 2019 Mar 21;25(17):4245-4254. doi: 10.1002/chem.201803932. Epub 2019 Jan 15.
Gas-phase bimolecular reactions of metal cations with water provide insights into intrinsic characteristics of hydrolysis. For the actinide dioxide cations, actinyl(V) AnO , melding of experiment and computation provides insights into trends for hydrolysis, as well as for oxo-exchange between actinyls and water that proceeds by a hydrolysis pathway. Here this line of inquiry is further extended into the actinide series with CCSD(T) computations of potential energy surfaces, for the reaction pathway for oxo-exchange through hydrolysis of nine actinyl(V) ions, from PaO to EsO . The computed surfaces are in accord with previous experimental results for oxo-exchange, and furthermore predict spontaneous exchange for CmO , BkO , CfO and EsO , but not for AmO . Natural Bond Order analysis of the species involved in both hydrolysis and oxo-exchange reveals an inverse correlation between the barrier to hydrolysis and the charge on the actinide centre, q(An). Based on this correlation, it can be concluded that hydrolysis, and related phenomena such as oxo-exchange, become less favourable as the charge on the metal centre decreases. The new results provide a straightforward rationalization of trends across a wide swathe of the actinide series.
气相双分子反应金属阳离子与水提供了内在特性水解的见解。对于镎二氧化物阳离子，酰基（V）AnO，融合实验和计算提供了水解的趋势的见解，以及之间的酰基和水的氧交换进行水解途径。在这里，这条探究线进一步扩展到镎系列，通过 CCSD（T）计算的势能面，用于通过水解的氧交换反应途径九酰基（V）离子，从 PaO 到 EsO 。计算表面与以前的实验结果相吻合，对于 oxo-exchange，并且还预测了 CmO 、BkO 、CfO 和 EsO 的自发交换，但 AmO 则没有。在水解和 oxo-exchange 中涉及的物种的自然键序分析揭示了水解的势垒与金属中心的电荷之间的反比关系，q（An）。基于这种相关性，可以得出结论，水解以及相关现象，如 oxo-exchange，变得不那么有利，因为金属中心的电荷减小。新的结果提供了对整个镎系列的趋势的直接合理化。
