THE PREPARATION AND SUBSTITUTION CHEMISTRY OF THE CATIONIC BIS(HYDRAZIDO(2-))RHENIUM(VII) COMPLEX [RECL2(NNMEPH)2(PPH3)][BPH4] - THE CRYSTAL AND MOLECULAR-STRUCTURES OF [RE(NNMEPH)2(S2CNME2)2][BPH4] AND [REOCL(NNMEPH)(PPH3)2][PF6]2

Reaction of [ReOCl3(PPh3)2] with MePhNNH2 in boiling methanol gives the orange five-coordinate bis(hydrazido) cation [ReCl2(NNMePh)2(PPh3)][BPh4] (1). Attempted recrystallization of 1 as its [PF6]- salt led unexpectedly to the brown crystalline oxo-hydrazido dication [ReOCl(NNMePh)(PPh3)2][PF6]2 (2). The structure of 2 was determined as five-coordinate with the oxo- and hydrazido-moieties in the equatorial plane of a trigonal bipyramid, and with the mutually trans-phosphine ligands occupying the axial sites. Complex 1 is a versatile starting material and reacts with the sodium dithiocarbamates (NaS2CNR2, R = Me and Et) to give the red-crystalline bis(hydrazido)-bis-(dithiocarbamato) cations [Re(NNMePh)2(S2CNR2)2][BPh4] [R = Me (3) and R = Et (4)]. The structure of 3 was determined as pseudo-octahedral with linear, mutually cis-NNMePh groups and cis-chelating dithiocarbamato ligands. Reaction of 1 with the sterically hindered thiol 2,6-dichlorobenzene thiol (DCTH) gives the orange cationic bis(hydrazido)-bis(thiolato) complex [Re(NNMePh)2(DCT)2(PPh3)][BPh4] (5). Reaction of the imido precursor [ReCl3(NPh)(PPh3)2] with excess MePhNNH2 gives the yellow imido-hydrazido cation [ReCl2(NPh)(NNMePh)(PPh3)][BPh4] (6). Complexes 1, 2 and 6 contain the formally isoelectronic cores [Re(NNR2)2]3+, [ReO(NNR2)]3+ and [Re(NPh)(NNR2)]3+.