FAST-ATOM-BOMBARDMENT (FAB) MASS-SPECTRA OF COORDINATION-COMPLEXES - AGGREGATION PROCESSES IN THE MASS-SPECTRA OF GROUP-11 ALKYNYL COMPLEXES

The FAB mass spectra of m(C2Ph)(PPh3) (m = Cu, Ag, Au) and C2{Au(PR3)}2 (R = Ph, m-tolyl) have been studied and the fragmentation routes determined by a combination of MIKES and B2/E techniques. A particular feature in the spectra of both types of complex is the presence of aggregate ions containing up to twelve metal atoms. For m(C2Ph)(PPh3), these ions have the compositions [m(a)(C2Ph)b(PPh3)c]+ (a greater-than-or-equal-to b greater-than-or-equal-to c; for Cu, a = 1-4; Ag, 1-3; Au, 1-4), although [Cu5(C2Ph)3(PPh3)3]+ was detected in the B2/E scan. Fragmentation involves loss of PPh3. Ph or C2Ph groups. For C2{Au(PR3)}2, loss of PR3 is the predominant fragmentation mode. In general, the ions are derived from several, rather than one, higher nuclearity ions. In both series, many ions can be considered to be formed by addition of [m(PR3)]+ cations to neutral oligometric M(n) species; these ions are isolobal with protonated M(n) ions.