Gas-phase ion-molecule reactions in organophosphorus esters

Area of Science:

• Organophosphorus chemistry
• Gas-phase ion chemistry
• Mass spectrometry

Background:

• Ion-molecule reactions are crucial for understanding chemical processes in various environments.
• Organophosphorus compounds have diverse applications, necessitating detailed study of their reactivity.
• Previous studies on self-condensation reactions of these compounds are limited.

Purpose of the Study:

• To investigate the self-condensation ion-molecule reactions of selected organophosphorus compounds.
• To elucidate the reaction pathways and identify the principal ions formed.
• To correlate observed reaction patterns with the structural features of the compounds.

Main Methods:

• Ion trap mass spectrometry (ITMS) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were employed.
• Parent ion selection and controlled reaction times (up to 500 ms) were used to study reaction mechanisms.
• High-resolution mass spectrometry was utilized for precise ion composition determination.

Main Results:

• Trimethyl phosphite and triethyl phosphite predominantly formed [M + H]+ and [M + (RO)2P]+ adduct ions.
• Trimethyl phosphate and dimethyl phosphonate yielded abundant [2M + H]+ ions, formed via [M + H]+ and M.
• 2,2-Dichlorovinyl dimethyl phosphate (dichlorvos) primarily underwent fragmentation processes.

Conclusions:

• The reaction patterns are directly related to the distinct structural characteristics of the investigated organophosphorus compounds.
• Gas-phase basicities of the phosphoryl compounds were determined and re-examined.
• This study provides fundamental insights into the gas-phase reactivity of organophosphorus compounds.