Iridium derivatives of fluorinated aromatics by C-H activation: isolation of classical and non-classical hydrides.
A reaction of trans-[Ir(H)(5)(PiPr(3))(2)] (1) with 2,3,5,6-tetrafluoropyridine, pentafluorobenzene or 1,3-difluorobenzene in the presence of neohexene affords the square-pyramidal C-H activation products cis-trans-[Ir(4-C(5)NF(4))(H)(2)(PiPr(3))(2)] (2), cis-trans-[Ir(C(6)F(5))(H)(2)(PiPr(3))(2)] (4) and cis-trans-[Ir(2-C(6)H(3)F(2))(H)(2)(PiPr(3))(2)] (6). Irradiation of complex 1 with 2,3,5,6-tetrafluoropyridine or pentafluorobenzene gave the hydrides cis-trans-[Ir(4-C(5)NF(4))(H)(2)(H(2))(PiPr(3))(2)] (3) or cis-trans-[Ir(C(6)F(5))(H)(2)(H(2))(PiPr(3))(2)] (5). The presence of non-classical bound H(2) moieties has been demonstrated by the measurement of T(1) times at different temperatures. For 3 the H-H distance in the H(2) ligand can be estimated to be 0.82 A. The dihydride compounds 2, 4 and 6 react with CO to yield the complexes cis-trans-[Ir(Ar)(H)(2)(CO)(PiPr(3))(2)] (7: Ar = 4-C(5)NF(4), 8: Ar = C(6)F(5), 9: Ar = 2-C(6)H(3)F(2)). A reaction of 2 or 3 with an excess of ethylene leads to the formation of ethane and the Ir(i) ethylene complex trans-[Ir(4-C(5)NF(4))(eta(2)-C(2)H(4))(PiPr(3))(2)] (10). Treatment of 10 with CO furnishes the Ir(i) complex trans-[Ir(4-C(5)NF(4))(CO)(PiPr(3))(2)] (11).
Salomon
Marcel Ahijado
MA
Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Strasse 2, Berlin, Germany.
Braun
Thomas
T
Krossing
Ingo
I
D003198:Computer Simulation; D006841:Hydrocarbons, Aromatic / Q000138:chemical synthesis; D006859:Hydrogen / Q000737:chemistry; D007202:Indicators and Reagents; D007495:Iridium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D010777:Photochemistry; D014961:X-Ray Diffraction
D006841:Hydrocarbons, Aromatic; D007202:Indicators and Reagents; D009942:Organometallic Compounds; D007495:Iridium; D006859:Hydrogen