Generation and characterization of ionic and neutral chloro(hydroxy) phosphanyl [Cl–P–OH]+/ and chloro(thiohydroxy) phosphanyl [Cl–P–SH]+/ in the gas phase by tandem mass spectrometry and computational chemistry

Dissociative electron ionization (70 eV) of diethyl chlorothiophosphate (I) and ethylphosphonodichloridate (II) generates moderately abundant m/z 83 ions of composition [P, Cl, O, H]+. From tandem mass spectrometry experiments and theoretical calculations at the B3LYP/6-31G(d, p), G2, and G2(MP2) levels it is concluded that the majority of the ions have the structure of ClPOH+ (1a+) and it is separated by high-energy barriers from its isomers HP(O)Cl+ (1b+), HPOCl+ (1c+), and OP–ClH (1d+). Neutralization–reionization experiments confirm the theoretical prediction that radical 1a is a stable species in the gas phase. The 70 eV electron ionization of ethylphosphonothioic dichloride (III) yields m/z 99 ions, predominantly of the structure ClPSH+ (2a+). This conclusion follows from tandem mass spectrometry experiments and theoretical calculations. The calculations predict that (2a+) is separated by high-energy barriers from its isomers HP(S)Cl+ (2b+), HPSCl+ (2c+), and SP–ClH (2d+). Neutralization–reionization experiments confirmed that 2a radical is a stable species in the rarefied gas phase, which is in agreement with theoretical calculations.