Hallowita Nuwan, Carl Damon R, Armentrout P B, Rodgers M T
Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
J Phys Chem A. 2008 Sep 4;112(35):7996-8008. doi: 10.1021/jp800434v. Epub 2008 Aug 13.
Threshold collision-induced dissociation of M (+)( nMA) x with Xe is studied using guided ion beam mass spectrometry, where nMA = N-methylaniline and N, N-dimethylaniline and x = 1 and 2. M (+) includes the following alkali metal cations: Li (+), Na (+), K (+), Rb (+), and Cs (+). In all cases, the primary dissociation pathway corresponds to the endothermic loss of an intact nMA ligand. The primary cross section thresholds are interpreted to yield 0 and 298 K bond dissociation energies (BDEs) for ( nMA) x-1 M (+)-( nMA) after accounting for the effects of multiple ion-neutral collisions, the internal and kinetic energy distributions of the reactants, and the dissociation lifetimes. Density functional theory calculations at the B3LYP/6-31G* level of theory are used to determine the structures of these complexes, which are also used in single-point calculations at the MP2(full)/6-311+G(2d,2p) level to determine theoretical BDEs. The results of these studies are compared to previous studies of the analogous M (+)(aniline) x complexes to examine the effects of methylation of the amino group on the binding interactions. Comparisons are also made to a wide variety of cation-pi complexes previously studied to elucidate the contributions that ion-dipole, ion-induced-dipole, and ion-quadrupole interactions make to the overall binding.
使用导向离子束质谱法研究了M(+)(nMA)x与Xe的阈碰撞诱导解离，其中nMA = N-甲基苯胺和N,N-二甲基苯胺，x = 1和2。M(+)包括以下碱金属阳离子：Li(+)、Na(+)、K(+)、Rb(+)和Cs(+)。在所有情况下，主要解离途径对应于完整nMA配体的吸热损失。在考虑了多次离子-中性碰撞、反应物的内能和动能分布以及解离寿命的影响后，对主要截面阈值进行解释，以得出(nMA)x-1M(+)-(nMA)在0和298K时的键解离能(BDEs)。在B3LYP/6-31G*理论水平上进行密度泛函理论计算，以确定这些配合物的结构，这些结构也用于MP2(全)/6-311+G(2d,2p)水平的单点计算，以确定理论BDEs。将这些研究结果与之前对类似M(+)(苯胺)x配合物的研究进行比较，以研究氨基甲基化对结合相互作用的影响。还与之前研究的各种阳离子-π配合物进行比较，以阐明离子-偶极、离子诱导偶极和离子-四极相互作用对整体结合的贡献。
