Halocarbon chelation in 2-o-HalC6H4PPh2)>SbF6 (Hal = Br, Cl): structural and chemical studies

Article abstract of DOI:10.1016/0022-328X(88)89103-4

The bromo- and chloro-arene groups of Ph2P(o-HalC6H4) (L^Cl, X = Cl; L^Br, X = Br) are nonchelating in (1) but chelate to the metal in SbF6 (2), as shown by 1H and 31P NMR and X-ray structural studies of both the L^Cl and L^Br species.The Ir-Hal distances of 2.381(4) and 2.473(4) Angstroem, respectively, are normal covalent distances.The L^F analog of 1 is formed but an analog of 2 could not be made. 2 reacts with Cl^- to open the chelate ring to give 1 back again.MeCN adds to give a 5-coordinate species at -80 deg C but this opens to the substitution product 1-L^Br)>SbF6 at room temperature.H2 adds to give a dihydride, which is an alkene hydrogenation catalyst, even though 2 does not oxidatively add a C-Hal bond of the L ligand.C-Hal oxidative addition is presumed to be involved in the conversion of 2 to by LiBEt3H or NaOCHO.LiMe give 1-L^Br)>.Selected crystal data (the data for the L^Br analogue is given first) are: a 13.127(1), 13.094(6); b 10.293(4), 10.184(4); c 12.007(8), 11.933(7) Angstroem; α 68.12(4) deg, 68.47(4) deg; β 77.07(4) deg, 76.75(4) deg; γ 104.16(2) deg, 103.59(3) deg, R = 9.6, 6.7percent.There is disorder in the SbF6 and cod groups.Both species crystallize in the P1 space group with Z = 2.