Hydrides rhenium polyhydrides

In this regard a more significant determination should be obtained from a study of the polyhydride complexes [ReH7(PR3)2], in that (i) if the complex is a classical hydride the rhenium atom would be in its maximum oxidation state (+ 7) and, therefore, could not undergo further oxidation processes (ii) if the complex is a non-classical hydride, the rhenium atom would be in a lower oxidation state and, consequently, could display oxidation processes. 

A reversible deprotonation for a 17-electron hydride complex was shown for the stable cationic cobalt(II) hydride complex [CoH CH3C(CH2PPh2)3 (PEtj)]BPh4, yielding a presumed Co(0) neutral species. Although the latter species could not be isolated and fully characterized, it was shown that it can be reprotonated to yield the Co(II) hydrido species back [40]. Polyhydride complexes have also been shown to readily lose protons. Early examples have been provided by Walton on rhenium compounds, e.g. ReH5(PR3)3 derivatives [101], on the basis of electrochemical investigations. 

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