THERMOCHEMISTRY AND PHOTODISSOCIATION STUDIES OF [COL](+) AND [COL2](+), L=PYRROLE, FURAN, THIOPHENE AND SELENOPHENE

[CoL](+) and [CoL2](+) (L = pyrrole, furan, thiophene and selenophene) were generated in a prototype Nicolet-FTMS 1000 Fourier transform mas s spectrometer, where they were irradiated with light from a 25 kW Xe are lamp. Photodissociation thresholds, obtained using energy cut-off filters, yielded the bond energies D-0(Co+-pyrrole) = 59 +/- 3 kcal mo l(-1), D-0(Co+-furan) = 57 +/- 3 kcal mol(-1), D-0(Co+-thiophene)= 61 +/- 3 kcal mol(-1) and D-0(Co+-selenophene) = 64 +/- 3 kcal mol(-1) (1 kcal = 4.184 kJ), as wed as D-0([Co(pyrrole)](+)-pyrrole) less than o r equal to 48 +/- 3 kcal mol(-1), D-0([Co(+)furan)](+)-furan) less tha n or equal to 46 +/- 3 kcal mol(-1), D-0([Co(thiophene)](+)-thiophene) less than or equal to 49 +/- 3 kcal mol(-1) and D-0([Co(selenophene)] (+)-selenophene) less than or equal to 51 +/- 3 kcal mol(-1). The phot oappearance threshold for [CoC3H4](+), the CO loss product ion from [C o(furan)](+), yielded D-0(Co+-C3H4) = either 33 +/- 6 or 32 +/- 6 kcal mol(-1), depending on whether C3H4 was allene or propyne, respectivel y. Where possible, these bond energy measurements were further corrobo rated by ligand displacement reactions and competitive collision-induc ed dissociation experiments.