Gas-Phase Syntheses of Three Isomeric C↓(5)H↓(2) Radical Anions and Their Elusive Neutrals. A Joint Experimental and Theoretical Study

摘要

Three different radical anions of the empirical formula C↓(5)H↓(2) have been generated by negative ion chemical ionization mass spectrometry in the gas phase. The isomers C↓(4)CH↓(2)↑(·-), C↓(2)CHC↓(2)H↓(·-), and HC↓(5)H↓(·-) have been synthesized by unequivocal routes and their connectivities confirmed by deuterium labeling, charge reversal, and neutralization reionization experiments. The results also provide evidence for the existence of neutrals C↓(4)CH↓(2), C↓(2)CHC↓(2)H, and HC↓(5)H as stable species; this is the first reported observation of C↓(2)CHC↓(2)H. Ab initio calculations confirm these structures to be minima on the anion and neutral potential energy surfaces.