Zhou Wenjing, Liu Jianbo, Chambreau Steven D, Vaghjiani Ghanshyam L
Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, USA.
PhD Program in Chemistry, the Graduate Center of the City University of New York, 365 5th Ave., New York, New York 10016, USA.
Phys Chem Chem Phys. 2024 Aug 14;26(32):21697-21711. doi: 10.1039/d4cp02329c.
The formation and fragmentation of negatively charged 2-hydroxyethylhydrazinium nitrate ([HOCHCHNHNH]NO, HEHN) ionic liquid clusters were examined using a guided-ion beam tandem mass spectrometer furnished with collision-induced dissociation of selected ions with Xe atoms. Measurements included the compositions of cluster ions formed in the ionization source, and the dissociation products, cross sections, and 0 K threshold energies for individually selected cluster ions. To identify the structures of the main cluster ion series [(HEHN)(HNO)NO] formed, molecular dynamics simulations were employed to create initial geometry guesses, followed by optimization at the ωB97XD/6-31+G(d,p) level of theory, from which global minimum structures were identified for reaction thermodynamics analyses. A comparison was made between the cluster formation and fragmentation in the negatively charged 2-hydroxyethylhydrazinium nitrate with those in the positive mode (reported by W. Zhou , , 2023, , 17370). In both modes, the cluster ions were predominantly composed of / below 350; loss of a neutral 2-hydroxyethylhydrazinium nitrate ion pair represents the most important cluster fragmentation pathway, followed by intra-ion pair proton transfer-mediated 2-hydroxyethylhydrazine and HNO elimination; and all clusters started to dissociate at threshold energies less than 1.5 eV. The overwhelming similarities in the formation and fragmentation chemistry of positively negatively charged 2-hydroxyethylhydrazinium nitrate clusters may be attributed to their inherent ionic nature and high electric conductivities.
使用配备了对选定离子与Xe原子进行碰撞诱导解离功能的导向离子束串联质谱仪，研究了带负电荷的硝酸2-羟乙基肼鎓（[HOCH₂CH₂NHNH₃]NO₃，HEHN）离子液体团簇的形成和碎片化过程。测量内容包括在电离源中形成的团簇离子的组成，以及单个选定团簇离子的解离产物、截面和0K阈值能量。为了确定所形成的主要团簇离子系列[(HEHN)ₙ(HNO₃)NO₃]的结构，采用分子动力学模拟来创建初始几何结构猜想，随后在ωB97XD/6-31+G(d,p)理论水平上进行优化，从中确定全局最小结构以进行反应热力学分析。对带负电荷的硝酸2-羟乙基肼鎓中的团簇形成和碎片化与正模式下的情况（由W. Zhou等人于2023年报道，17370）进行了比较。在两种模式下，团簇离子主要由350以下的离子组成；中性的硝酸2-羟乙基肼鎓离子对的损失是最重要的团簇碎片化途径，其次是离子对内质子转移介导的2-羟乙基肼和HNO₃消除；并且所有团簇在阈值能量小于1.5eV时开始解离。带正电荷和负电荷的硝酸2-羟乙基肼鎓团簇在形成和碎片化化学方面的压倒性相似性可能归因于它们固有的离子性质和高电导率。
