A gas-phase polymerization reaction in the cluster ion NO+(propylene)n

Gas-phase reactions of NO+ with propylene (C3H6) were studied by using a pulsed electron beam mass spectrometer. An equilibrium between NO+ and NO+(C3H6)1 was established. However, an NO+-initiated polymerization reaction forming [NO(C3H6)n]+ took place after n=2, and the polymerized species NO+(C3H6)n up to n=5 could be observed at the lowest temperature measured (102 K). The structures of [NO(C3H6)n]+ with n⩽5 were investigated by DFT calculations. There are cluster- and polymer-type isomers for n⩾2. The latter has a long classical terminal C–C bonds (≈1.67 Å) in [NO(C3H6)n−1]+⋯C3H6 with a nitroso group at the other terminal.