Electrophilic Methylplatinum Complexes:  First Structure of a Hydroxytris(pentafluorophenyl)borate Complex

Abstract

Treatment of [PtMe2(bu2bpy)] (bu2bpy = 4,4‘-di-tert-butyl-2,2‘-bipyridine) with B(C6F5)3 in the presence of the ligand L gives, under anhydrous conditions, [PtMeL(bu2bpy)][MeB(C6F5)3] {L = CO (1a), C2H4 (2a), PPh3 (3a)}. Similar reactions performed in the presence of H2O afford [PtMeL(bu2bpy)][HOB(C6F5)3] {L = CO (1b), C2H4 (2b), PPh3 (3b)}. In the absence of L, the treatment of [PtMe2(bu2bpy)] with B(C6F5)3 and H2O gives [Pt{HOB(C6F5)3}Me(bu2bpy)] (4), the first published example of a hydroxytris(pentafluorophenyl)borate complex. All of the complexes are fully characterized by NMR and IR spectroscopy and, in the case of complex 4, by an X-ray analysis which confirms the attachment of the [HOB(C6F5)3]- ligand to the square-planar platinum atom via a Pt−O bond of 2.062(2) Å. We propose that, 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 protonates a Pt−Me bond of [PtMe2(bu2bpy)] forming CH4 and [PtMe(bu2bpy)]+[HOB(C6F5)3]-. This protonolysis methodology provides an alternative route to the well-established electrophilic methyl-ligand abstraction by B(C6F5)3 for the production of late transition-metal cations.

The Synthesis, Structure and Reactivity of B(C6F5)3‐Stabilised Amide (MNH2) Complexes of the Group 4 Metals

“…Solvents were dried over Na (toluene), Na/K alloy (light petroleum), Na/benzophenone (THF) and CaH 2 (dichloromethane) and distilled under nitrogen prior to use. 1 H, 13 C, 19 4 ] was prepared according to the literature procedure. [3] The cyclopentadienyl compounds [MCpA C H T U N G T R E N N U N G (NR 2 ) 3 ] (M= Ti, Zr; R = Me, Et) were produced by treating the corresponding tetra-A C H T U N G T R E N N U N G (amide) complexes with one equivalent of cyclopentadiene.…”

“…2À ligands [19] or to derive weakly coordinating anions. [20,21] We recently reported preliminary results demonstrating that the ammonia adduct H 3 N·BA C H T U N G T R E N N U N G (C 6 F 5 ) 3 reacts as a Brønsted acid with tetrakis(dimethylamido)metal complexes,…”

Dimethyl(2-methylphenyl)ammonium hydroxotris(pentafluorophenyl)borate

“…et al, 1993). Others have taken this report to refer to the¯uorinated compound [Et 3 NH]-[(C 6 F 5 ) 3 BOH] (Hill et al, 1997). Regardless, to the authors knowledge, a full crystal structure report has never been published or deposited.…”

Isobutene polymerization initiated by [CP*TiMe2]+ in the presence of a series of novel, weakly coordinating counteranions

“…The development of weakly coordinating anions has been an important theme in the context of metallocene‐induced Ziegler–Natta polymerizations,22–38 and on the premise that the delocalization of negative charge over as many atoms as possible in a large anion should be advantageous, there have been reported several very bulky anions in which the perfluorophenyl groups of [BMe(C 6 F 5 ) 3 ] − have been substituted by more complex perfluoroaryl groups 28–37. Alternatively, synthetically less challenging procedures involve the interaction of B(C 6 F 5 ) 3 with various anions X − (X − = OH − ,22, 39–48 CN − ,27, 49, 50 N,50 OR − ,40–42, 48 SR − ,40–42 or imidazolate51) to form the complex anions [XB(C 6 F 5 ) 3 ] − and [(μ‐X){B(C 6 F 5 ) 3 } 2 ] − . We described elsewhere the solution chemistry of the Brønsted acidic 1:1 adducts ( n ‐C 18 H 37 EH)B(C 6 F 5 ) 3 (E = O or S) and the corresponding [C 10 H 6 (NMe 2 ) 2 H] + (protonated proton sponge) salts of the presumed weakly coordinating anions [( n ‐C 18 H 37 E)B(C 6 F 5 ) 3 ] − 52.…”