NOVEL PHOSPHONIUM CATIONS .4. PHOSPHONIUM IONS OF ,4,6,8-TETRA-TERT-BUTYL-1,3,5,7-TETRAPHOSPHACUBANE AND 6-TETRAPHOSPHATRICYCLO[4.2.0.0(2,5)]OCTA-3,7-DIENE IN THE GAS-PHASE - HOST-GUEST COMPLEXES, PHOSPHONIUM ION DECOMPOSITION PATHWAYS AND INTERACTION WITH ONIUM IONS (AND CARBOCATIONS) - A FIELD DESORPTION (FD), FAST-ATOM-BOMBARDMENT (FAB) AND TANDEM MASS-SPECTROMETRY (CAD-MS MS) STUDY/

We report a mass spectrometic study (FDMS, FABMS) of a series of phosp honium triflate salts derived from ,4,6,8-tetra-tert-butyl-1,3,5,7-tet raphosphacubane 1 and -tetraphosphatricyclo[4.2.0.0(2,5-)]octa-3,7-die ne 2, namely 3(+)(OTf)(-), 4(+)(OTf)(-), 5(+)(OTf)(-), 6(2+)(OTf . SbC l6)(2-), 7(2+)(OTf . SbCl6)(2-) and 8(+)(OTf)(-). Except for the dicat ions, the intact phosphonium ions were observed in all cases. The host -guest (H-G) chemistry of 3(+) and some of its fragment ions with dicy clohexano-24-crown-8 have been probed. Low energy collisional decompos ition of 3(+) gives m/z 115 and 169 as prominent products for which st ructures 12(+) and 11(+) have been suggested in analogy with the recen tly discovered solution chemistries of phosphaalkynes and phosphirenes . The decomposition pathways of the studied phosphonium cations have b een compared and discussed.