Synthesis, characterisation and reactivity of ruthenium bis-bifluoride, ruthenium hydride bifluoride and ruthenium hydride fluoride complexes

Bifluoride complexes, trans-[Ru(depe)(2)H(FHF)] (1), trans-[Ru(dppe)(2)H(FHF)] (2), trans-[Ru(dppp)(2)H(FHF)] (3) and cis-[Ru(PMe3)(4)(FHF)(2)] (4) (depe = Et2PCH2CH2PEt2, dppe = Ph2PCH2CH2PPh2, dppp = Ph2PCH2CH2CH2PPh2) were synthesised from the reactions of the corresponding cis-dihydride complexes with NEt3. 3HF in THF. The characteristic features of the low temperature NMR spectra of the bifluoride complexes include F-19 resonances at ca. delta -300 for the proximal fluorine and ca. delta -165 for the distal fluorine. The acidic protons resonate at ca. delta 13. The value of J(HF) for the distal fluorine lies in the range 300-400 Hz. The bifluoride ligands exhibit characteristic vibrations at ca. 2300 cm(-1) and ca. 2430 cm(-1) in the IR spectrum. All the complexes exhibit dynamic exchange processes, probably due to dissociation of FHF-. In addition, complex 3 undergoes a ring flipping process that is suppressed at low temperature. The X-ray crystal structure of 3 has been obtained. The bifluoride ligand is disordered over two positions about the inversion centre. The Ru-F distance is 2.351(5) Angstrom and the F . . . F distance is 2.290(8) Angstrom, the Ru-F . . . F angle is 149.7 degrees. The X-ray crystal structure for 4 reveals that the Ru-F distances are 2.149(5) Angstrom and 2.150(4) Angstrom, the F . . . F bond lengths are 2.323(8) Angstrom and 2.329(8) Angstrom, with Ru-F . . . F angles of 128.5(3)degrees and 138.4(3)degrees. The two bifluoride ligands are cis to each other. Reaction of 1 and 3 with [NMe4]F yields trans-[Ru(depe)(2)(H)F] 5 and trans-[Ru(dppp)(2)(H)F] 6. Reaction of 2 with Me3SiX (X = N-3, OTf) yields trans-[Ru(dppe)(2)(H)N-3] and [Ru(dppe)(2)(H)]OTf. Reactions with several halo-organic compounds yields trans-[Ru(dppe)(2)(H)X] (X = Cl, Br and I). The organic products from CH3I, CH3COCl and C6H5COCl were identified as CH3F, CH3COF and C6H5COF respectively.