The preparation and substitution chemistry of the cationic bis(hydrazido(2−))rhenium(VII) complex [ReCl 2(NNMePh) 2(PPh 3)][BPh 4]. The crystal and molecular structures of [Re(NNMePh) 2(S 2CNMe 2) 2][BPh 4] and [ReOCl(NNMePh)(PPh 3) 2][PF 6] 2

Abstract

Reaction of [ReOCl 3(PPh 3) 2] with MePhNNH 2 in boiling methanol gives the orange five-coordinate bis(hydrazido) cation [ReCl 2(NNMePh) 2(PPh 3)][BPh 4] ( 1). Attempted recrystallization of 1 as its [PF 6] − salt led unexpectedly to the brown crystalline oxo-hydrazido dication [ReOCl(NNMePh)(PPh 3) 2][PF 6] 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 (NaS 2CNR 2, R = Me and Et) to give the red-crystalline bis(hydrazido)-bis-(dithio-carbamato) cations [Re(NNMePh) 2(S 2CNR 2) 2][BPh 4] [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(PPh 3)][BPh 4] ( 5). Reaction of the imido precursor [ReCl 3(NPh)(PPh 3) 2] with excess MePhNNH 2 gives the yellow imido-hydrazido cation [ReCl 2(NPh)(NNMePh)(PPh 3)][BPh 4] ( 6). Complexes 1, 2 and 6 contain the formally isoelectronic cores [Re(NNR 2) 2] 3+, [ReO(NNR 2)] 3+ and [Re(NPh)(NNR 2)] 3+.