Generation of novel cationic metal-alkyl complexes via carbocation reagents

Abstract

reagents in organic chemistry,1 their utilization in inorganic chemistry has been limited. Eaborn and coworkers have observed that CH3S03F reactions with metal complexes lead to alkylation of coordinated cyanide, S03F--C1metathesis, and oxidation.2 More unusual, however, is the possibility of generating new cationic metal-alkyl complexes such as those reported here.An excess of CH3SOsF (25.0 mmol) is stirred with 6.18 X 10-1 mmol of Vaska's compound, IrCl(CO)-(PPh3)2, in dry air-free benzene (60 ml) at room temperature until the color is completely dissipated (1-2 hr). A white solid, IrCl(C0)(PPh3)2(CH3)(S03F),3 is then isolated from benzene-heptane. In DCC13 solution the nmr exhibits a triplet for the methyl group (t 8.93, /p_h = 7 Hz, area 3) and an unresolved phenyl proton resonance (r 2.68, area 33). The high vCo (2064 cm-1, Nujol mull) indicates a simple oxidative addition product;4 indeed Eaborn and coworkers list it as such.2 However, as shown below, the compound is ionic and is therefore quite unlike the usual oxidative addition products of Vaska's compound, such as IrCl(CO)(PPh3)2(CH3)I, which typically are six-coordinate, substitution-inert, molecular species. The molecular weight in HCC13, 884, agrees with a molecular or an ion pair formulation (caled 894). In a more polar solvent, nitromethane, its conductance, 71 ohm-1 cm2 mol-1, is characteristic of a 1:1 electrolyte. The observed vco, 2062 cm-1, confirms that the compound still contains a formal Ir(III) oxidation state in this solvent. High conductivity and high vco, 2062 cm-1, also are observed for a solution in acetonitrile. The unsolvated IrCl(CO)(PPh3)2(CH3)-(

Synthesis of novel methyliridium(III) compounds from substitution-labile chloro(methyl)fluorosulfato(carbonylbis(triphenylphosphine)iridium(III) and chloro(methyl)trifluoromethyl sulfatocarbonylbis(triphenylphosphine)iridium(III)

“…Reactions of the strong carbo cation reagents CH3S03F and CH3S03CF3 with transition metal-organometallic complexes yield interesting new metal-alkyl compounds.1-3 Among the products which we have reported is Ir(Cl)(CO)-( PPh3)2(CH3)(S03F), which is a 1:1 electrolyte in polar organic solvents owing to the ready dissociation of the S03Fion (eq 1). This facile dissociation results in high lability of ch3no2 IrCl(CO)(PPh3) 2 (CH 3 )(SO 3F)(s)---V [IrCl(CO)(PPh3)2CH3]+ + S03F" (1) the methyl ñuorosulfate complex and therefore provides a route to new compounds which cannot be prepared by direct oxidative addition (eq 2). The synthetic utility of this new IrCl(CO)(PPh3)2 + CH3Y -IrCl(CO)(PPh3)2(CH3)(Y) N^so3f /y- (2) X IrCl(C0)(PPh3)2(CH3)(S03F) reaction sequence is illustrated in the present paper and structures of the products are elucidated.…”