Observation of diazonium ion - crown ether molecular complexes in the gas phase by field desorption and fast atom bombardment mass spectrometry (original) (raw)

Experimental Section Materials. All chemical ionization mass spectrometry experiments were performed on a Finnigan 4600 gas chromatograph-mass spectrometer. Methane was used as the reagent gas for all positive ion spectra. Pulsed positive ion negative ion chemical ionization (PPINICI)g employed a mixture of methane-nitrous oxide (955). A standard direct exposure probe was utilized for all spectra with a program of 0.050-0.650 V at 0.020 V/s. The pressure of the source was 0.35 Torr. The acetylation and ozonolysis reactions were performed in the same manner for all of the 5-alkenylresorcinols studied. These are illustrated here for 1,3-dihydroxy-5-hexadec-cis-8'enylbenzene. Acetylation of 1,3-Dihydroxy-5-heptadec-cis-8'-enylbenzene. A solution containing 1.2 mg (3.5 pmol) of 1,3-dihydroxy-5-heptadec-cis-8'-enylbenzene in 500 pL of dry pyridine under argon was cooled to 0 "C and treated dropwise with 200 pL (216 mg; 2.1 m o l) of acetic anhydride. The combined solution was stirred under argon at 25 "C for 3 h. The reaction mixture was quenched by the addition of an ice chip and extracted with CHCIB. The chloroform extract w& washed with water, dried over MgS04, and concentrated to afford 1,3-diacetoxy-5-heptadeccis-8'-enylbenzene (11) as an oily product: yield-1.5 mg; silica gel HPTLC (9:l CHCl3-CH30H). R f 0.78; CI mass spectrum (positive ion), m / z 431 (M + H)+. Ozonolysis of 1,3-Diacetoxy-5-hexadec-cis-8'-enylbenaene (11). A solution containing 1.6 mg (3.7 pmol) of 1,3-diacetoxy-5-hexadec-cis-8'-enylbenzene in 250 pL of CS2 was cooled to-78 "C and saturated with OB. Excess O3 was removed with a stream of argon, and the reaction mixture was treated with solid triphenylphosphine (1.0 mg; 3.8 pmol). The resulting solution was allowed to warm to room temperature and was employed directly for mass spectrometric analysis.