The mixed phosphine-arsine ligand Ph(2)PCH(2)CH(2)AsPh(2) (arphos) has
been used to stabilize the rhenium polyhydrides Re2H8(arphos)(2) and
ReH7 (arphos). The heptahydride is the first example of a compound of
the type ReH(7)L(2) which contains a mixed phosphine-arsine donor set.
The spectroscopic and electrochemical properties and stabilities of t
hese complexes are described and compared with data for other complexe
s of the types Re(2)H(8)L(4) and ReH(7)L(2).