Synthesis and reactivity of fluoro complexes: Part 2. Rhodium(I) fluoro complexes with alkene and phosphine ligands. Synthesis of the first isolated rhodium(I) bifluoride complexes. Structure of [Rh-3(mu(3)-OH)(2)(COD)(3)](HF2) by X-ray powder diffraction

The reaction between [Rh(mu-OH)(COD)](2) (COD = 1,5-cyclooctadiene) and 73% HF in THF gives [Rh-3(mu(3)-OH)(2)(COD)(3)](HF2) (1). Its crystal structure, determined by ab initio X-ray powder diffraction methods (from conventional laboratory data), contains complex trimetallic cations linked together in 1 D chains by a mu(3)-OH... F-H-F... HO-mu(3) sequence of strong hydrogen bonds. The complex [Rh(mu-F)(COE)(2)](2) (COE = cyclooctene; 2), prepared by reacting [Rh(u-OH)(COE)(2)](2) with NEt3.3HF (3:2), has been characterized. Complex 1 reacts with PR3 (1:3) to give [RhF(COD)(PR3)] [R = Ph (3), C6H4OMe-4 (4), Pr-i (5), Cy (6)] that can be prepared directly by reacting [Rh(U-OH)(COD)](2) with 73% HF and PR3 (1:2:2). The reactions of 1 with PPh3 or Et3P have been studied by NMR spectroscopy at different molar ratios. Complexes [RhF(PEt3)(3)] (7), [RhF(COD)(PEt3)] (8), and [RhF(PPh3)(3)] (9) have been detected. The complex [Rh(F)(NBD)(Pr3P)] (NBD = norbornadiene; 10) was prepared by the sequential treatment of [Rh(mu-OMe)(NBD)](2) with 1 equiv of NEt3.3HF and Pr3P. The first isolated bifluoride rhodium(I) complexes [Rh(FHF)(COD)(PR3)] [R = Ph (11), Pr-i (12), Cy (13)], obtained by reacting fluoro complexes 3, 5, and 6 with NEt3.3HF (3:1), have been characterized. The crystal structures of 3 and 11 have been determined.