FORMATION OF THERMODYNAMICALLY STABLE DICATIONS IN THE GAS-PHASE BY THERMAL ION MOLECULE REACTIONS - TA-2+ AND ZR-2+ WITH SMALL ALKANES

The reactions of doubly charged tantalum and singly and doubly charged zirconium with small linear alkanes are reported. The rate constants for the reactions of singly and doubly charged Zr and Ta with methane are also reported. Ta2+ reacts with methane formally by carbene and hydride abstraction along with some charge transfer. Reactions of Ta2+ with longer chain alkanes result in complete charge transfer. Zr2+ also reacts with methane formally by carbene and hydride abstraction and undergoes dehydrogenation and demethanation reactions and hydride and methide abstraction in addition to charge transfer with propane and butane. With alkanes larger than butane only charge transfer is observed. Zr+ reacts similarly to other early transition metals to multiply dehydrogenate alkanes and, to a lesser extent, yield C-C cleavage fragments.