Dissociation of CuH+center dot and ZnH+ complexes of ethylenediamine and their N- methylated homologues: Family and neighbours, but not the same

作者：Jobst Karl J; Terlouw Johan K; Ruttink Paul J A; Burgers Peter C^*

来源：International Journal of Mass Spectrometry, 2013, 354: 144-151.

DOI：10.1016/j.ijms.2013.06.010

• Metal hydride
• Transition metal
• Metal complex ion
• Collision induced dissociation
• Model chemistry calculations
• Isotope effect

Upon collisional activation, complexes of CuH+center dot and ZnH+ with H2NCH2CH2NH2 eliminate Cu(O)(center dot) and Zn(O) to produce protonated ethylenediamine H2NCH2CH2NH3+ via a proton transfer. Variable collision energy experiments and model chemistry calculations (CBS-QB3 method) indicate that (i) the energy requirement for this process is significantly larger for the zinc complex than for the copper complex; and (ii) the transition-state for the proton transfer is rate-determining for dissociation of the zinc complex, whereas the same process in the copper complex is essentially barrierless. The large activation energy for the zinc complex opens up a competing fragmentation process, viz, loss of NH3, which does not occur in the copper complex. %26lt;br%26gt;N-methyl substitution has no effect for the Cuff** complex ions: Cu(O)(+) is lost from the complex (CH3)(2)NCH2CH2N(CH3)(2)...CuH+center dot. However, a different situation obtains for the complex with Znir, which predominantly loses ZnH2. Experiment and theory indicate that loss of ZnH2 is more energy demanding than loss of Zn(O), but that ZnH2 loss prevails at elevated collision energies.

• 出版日期2013-11-15