Cyclometallation reactions in complexes of the type Rh(oq)(CO)(P( o-BrC 6F 4)Ph 2) : III. Synthesis of the compounds cis-Rh(oq)Br(P( o-C 6F 4)Ph 2)L. The Molecular structure of cis-Rh(oq)Br(P( o-C 6F 4)Ph 2)(PPh 3) (oq = 8-oxyquinolinate)

Abstract

The reaction of Rh(oq)(CO)(PCBr) (PCBr = P( o-BrC 6F 4)Ph 2; oq = 8-oxyquinolinte)_ in refluxing toluene in the presence of Et 4NBr (1/4 molar ratio) gives Rh(oq)Br(PC) (H 2O), PC = P ( o-C 6F 4)Ph 2, in practically quantitative yield. The water molecule is readily displaced by various P-donor ligands to give complexes of general formula Rh(oq)Br(PC) PR 3 (PR 3 = PPh 3, P( p-MeC 6H 4) 3, P( p-MeOC 6H 4) 3, P( p-FC 6H 4) 3, P(PMe) 3 and P(OPh 3). The molecular structure of the compound Rh(oq)Br(PC) (PPh 3) has been determined by X-ray methods. Crystals of the title compound are monoclinic, space group P2 1/ n with unit cell dimensions a 11.273(4), b 20.087(8), c 17.471(7) Å and β 102.15(8)°. The final R for 2304 diffractometer data refined by least-squared is 0.0468. The compound has a distorted octahedral coordination with the phosphorus atoms in a cis disposition. The RhP bond lengths are significantly different. The P atom of the metallated phosphine, which is trans to N, has a RhP distance of 2.308(4) Å, while the PPh 3, which is trans to C, has a RhP distance of 2.422(4) Å. The most distorted angles around the rhodium atom are P(1)Rh-P(2) 104.7(1)° and P(1)RhC(1) 69.2(3)°.