Structure and formation of gaseous [C4H6O]+˙ ions: 1—The enolic ions [CH2C(OH)CHCH2]+˙ and [CH2CHCHCH(OH)]+˙ and their relationship with their keto counterparts

Abstract The [C 4 H 6 O] +˙ ion of structure [CH 2 CHCHCHOH] +˙ ( a ) is generated by loss of C 4 H 8 from ionized 6,6‐dimethyl‐2‐cyclohexen‐1‐ol. The heat of formation Δ H f of [CH 2 CHCHCHOH] +˙ was estimated to be 736 kJ mol −1 . The isomeric ion [CH 2 C(OH)CHCH 2 ] +˙ ( b ) was shown to have Δ H f ,  761 kJ mol −1 , 54 kJ mol −1 less than that of its keto analogue [CH 3 COCHCH 2 ] +˙ . Ion [CH 2 C(OH)CHCH 2 ] +˙ may be …