75554-14-2Relevant articles and documents
Dehydrogenation of the Alkane Chain of 1,3-Bispropane on a Rhodium(I) Centre. Complexes of the Resulting Olefinic Ligand with Rhodium(I), Iridium(I), Rhodium(III) and Nickel(II)
Bennett, Martin A.,Neumann, Horst
, p. 1251 - 1259 (2007/10/02)
The title compound, o-Ph2PC6H4(CH2)3C6H4PPh2-o (5), has been synthesized in three steps, starting with the Fe2(CO)9-promoted conversion of 2-bromobenzyl bromide into 1,3-di(2o-bromophenyl)propan-2-one, o-BrC6H4CH2COCH2C6H4Br-o.Compound (5) undergoes dehydrogenation on reaction with the cycloocta-1,5-diene (cod) complex 2 to give a rhodium(I) complex (9), in which the olefin and mutually trans phosphorus atoms are bound to the metal.The tridentate ligand (E)-o-Ph2PC6H4CH=CHCH2C6H4PPh2-o (4) can be liberated from (9)by treatment with sodium cyanide, the overall yield based on 2-bromobenzyl bromide being about 17percent.On reaction with the chlorides of rhodium(III) or nickel(II), (4) loses a methylene proton to give chelate η3-allylic complexes RhCl2(o-Ph2PC6H4CH=CH=CHC6H4PPh2-o) (11) and NiCl(o-Ph2PC6H4CH=CH=CHC6H4PPh2-o) (13) respectively.The proposed structures for the new complexes are based on i.r. and n.m.r. (1H, 31P) data, and also on a comparison with similar complexes formed by the known tridentate ligand (E)-o-Ph2PC6H4CH=CHCHMeC6H4PPh2-o (2).Conformational isomers of the rhodium(I) complex (9) and its iridium(I) analogue (10) formed from ligand (4) cannot be detected by n.m.r. spectroscopy, in contrast with the corresponding complexes formed by ligand (2).
