Photochemical reactions of Re(CO)5Br with Ph2P(CH2) n PPh2 (n = 1, dppm; 2, dppe; 3, dppp)

The new complexes fac-Re(CO)₃Br{Ph₂P(CH₂) _n PPh₂}] (1a–3a) (1a), n = 1; (2a), n = 2; (3a), n = 3] and Re₂(CO)₈Br₂{-Ph₂P(CH₂) _n PPh₂}] (1b–3b) (1b), n = 1; (2b), n = 2; (3b), n = 3] have been prepared by the photochemical reaction of Re(CO)₅Br with Ph₂P(CH₂) _n PPh₂ (n = 1, dppm; 2, dppe; 3, dppp). The complexes have been characterized by elemental analysis, mass spectroscopy, f.t.-i.r. and ³¹P-¹H]-n.m.r. spectrometry. The spectroscopic studies suggest cis-chelate bidentate coordination of the ligand in fac-Re(CO)₃Br{Ph₂P(CH₂) _n PPh₂}] (1a–3a) and cis-bridging bidentate coordination of the ligand between two metals in Re₂(CO)₈Br₂{cis--Ph₂P(CH₂) _n PPh₂}] (1a–3a).