The iridium(III) dimethyl derivatives Ir(Me)
2Cp*(L) (Cp*=η
5-C
5Me
5; L=PPh
3 (
1a), PMePh
2 (
1b), PMe
2Ph (
1c), PMe
3 (
1d)) react with NOBF
4 in CH
2Cl
2 to give the iridium(III) cationic ...alkylnitrosyl derivatives Ir(Me)
2Cp*(NO)BF
4 (
2), and Ir(Me)Cp*(NO)(L)(BF
4)
2 (L=PMePh
2
4b, PMe
2Ph
4c, PMe
3
4d). EPR spectroscopy shows that the reaction proceeds through the iridium(IV) intermediates
1a
+
–
1d
+. Treatment of
1d with NOBF
4 in acetonitrile gives, in addition to
4d, the acetonitrile substitution products Ir(Me)Cp*(CH
3CN)(PMe
3)BF
4 (
5d) and IrCp*(CH
3CN)
2(PMe
3)(BF
4)
2 (
6d). Electrochemical and chemical reduction of
4b–
4d afford the corresponding Ir(Me)Cp*(NO)(L)(BF
4)
7b–
7d, which have been studied by EPR spectroscopy. Reaction of
2 with PPh
3 gives Ir(Me)
2Cp*(PPh
3); treatment of
4b and
4c with the appropriate phosphine gives Ir(Me)Cp*(L)
2(BF
4) (L=PMePh
2, PMe
2Ph), respectively.
Ruthenium(II) dimethyl complexes. Ru(Me)
2(
η
6-C
6Me
6)(PR
3) (R = Ph 1a, R
3 = MePh
2 1b, R
3 = Me
2Ph 1c, R = Me 1d, R = Et 1e), react with CH bonds of benzene or toluene under severe conditions ...(85–105°C depending on the phosphine ligand) to give methane and the new methyl aryl derivatives Ru(Me)(Ar)(
η
6-C
6Me
6)(PR
3). The methyl tolyl complexes are formed as
2
1
mixture of meta and para isomers. In contrast the reaction of 1a-1e with arenes, in the presence of FeCp
2PF
6, proceeds rapidly at room temperature: the corresponding methyl aryl derivatives Ru(Me)(Ar)(
η
6-C
6Me
6)(PR
3) (Ar = Ph, Tol) and/or the intramolecular reaction products are formed depending on the steric hindrance of the phosphine. The fact that electrochemistry and ESR spectroscopy show that on oxidation that ruthenium(II) complexes give stable ruthenium(III) congeners suggests that the catalytic reaction triggered by ferrocenium ions proceeds through a different redox pathway.
Reaction of Ir(Me)
2Cp*(L) complexes (Cp*=
η
5-C
5Me
5; L=PPh
3, PMePh
2, PMe
2Ph, PMe
3) with equimolar amounts of Fe Cp
2
+ in pyridine gives methane and the corresponding cationic derivatives ...Ir(Me)Cp*(L) (pyridine)
+. Reaction with an excess of NOBF
4 yields methane and Ir(Me)Cp*(L)(NO)
2+ (L=PMe
3, PMe
2Ph, PMePh
2) or Ir(Me)
2Cp*(NO)
+ and Ir(Me)Cp*(L)
2
+ (L=PPh
3) via the formation of the primary oxidation products Ir(Me)
2Cp*(L)
+, which have been detected by EPR spectroscopy.
N,N-Diethylaniline is formed under mild conditions either by the direct amination of benzene with diethylamine in the presence of Ir(
η
5-C
5Me
5)(
CO)
2
1 and HgSO
4, or by reacting (C
6H
5)
2Hg or ...C
6H
5HgCl/Ag
2SO
4 with diethylamine in the presence of
1. A preliminary investigation about the chemistry underlying these reactions is also reported.
