Gs. Hill et al., ELECTROPHILIC METHYLPLATINUM COMPLEXES - FIRST STRUCTURE OF A HYDROXYTRIS(PENTAFLUOROPHENYL)BORATE COMPLEX, Organometallics, 16(4), 1997, pp. 525-530
Treatment of [PtMe(2)(bu(2)bpy)] (bu(2)bpy = 4,4'-di-tert-butyl-2,2'-b
ipyridine) with B(C6F5)(3) in the presence of the ligand L gives, unde
r anhydrous conditions, [PtMeL(bu(2)bpy)][MeB-(C6F5)(3)] {L = CO (1a),
C2H4 (2a), PPh(3) (3a)}. Similar reactions performed in the presence
of H2O afford [PtMeL(bu(2)bpy)][HOB(C6F5)(3)] {L = CO (1b), C2H4 (2b),
PPh(3) (3b)}. In the absence of L, the treatment of [PtMe(2)(bu(2)bpy
)] with B(C6F5)(3) and H2O gives [Pt{HOB(C6F5)(3)}Me(bu(2)bpy)] (4), t
he first published example of a hydroxytris(pentafluorophenyl)borate c
omplex. All of the complexes are fully characterized by NMR and IR spe
ctroscopy and, in the case of complex 4, by an X-ray analysis which co
nfirms the attachment of the [HOB(C6F5)(3)](-) ligand to the square-pl
anar platinum atom via a Pt-O bond of 2.062(2) Angstrom. We propose th
at, in the presence of water, B(C6F5)(3) forms an adduct [H2OB(C6F5)(3
)] (which acts as a strong acid H[HOB(C6F5)(3)]) and this then protona
tes a PtMe bond of [PtMe(2)(bu(2)bpy)] forming CH4 and [PtMe(bu(2)bpy)
](+)[HOB(C6F5)(3)](-). This protonolysis methodology provides an alter
native route to the well-established electrophilic methyl-ligand abstr
action by B(C6F5)(3) for the production of late transition-metal catio
ns.