The reactions Of C-2(-), C-4(-), and C-6(-) with D2O and ND3 and Of C-4(-) with CH3OH, CH4, and C2H6 have been investigated using guided ion beam tandem mass spectrometry. Hydrogen (or deuterium) atom transfer is the major product channel for each of the reactions. The reaction threshold energies for collisional activation are reported. Several of the reactions exhibit threshold energies in excess of the reaction endothermicity. Potential energy calculations using density functional theory show energy barriers for some of the reactions. Dynamic restrictions related to multiple wells along the reaction path may also contribute to elevated threshold energies. The results indicate that the reactions with D2O have the smallest excess threshold energies, which may therefore be used to derive lower limits on the C-H bond dissociation energies of the C2nH- and C2nH (n = 1-3) linear species. The experimental lower limits for the bond dissociation energies of the neutral radicals to linear products are D-0(C-2-H) >= 460 +/- 15 U/mol, D-0(C-4-H) >= 427 +/- 12 U/mol, and D-0(C-6-H) >= 405 +/- 11 kJ/mol.