Preparation of dinuclear rhodium and iridium complexes with two bridging hydroselenido ligands and their conversion into tri- and tetranuclear selenido clusters

Reactions of [(Cp*MCl)(2)(mu-Cl)(2)] (M = Rh (4), Ir (5); Cp* = eta(5)-C5Me 5) with H2Se generated in situ from NaSeH and HCl(aq) in CH2Cl2 afforded th e dirhodium and diiridium complexes containing bridging hydroselenido ligan ds [(Cp*MCl)(2)(mu-SeH)(2)] (M = Rh (6), Ir (7)). Complexes 6 and 7 reacted further with 0.5 equiv of 4 and 5, respectively, to form the selenido-brid ged trinuclear M(III) clusters [(Cp*M)(3)Cu-3-Se)(2)][PF6](2) (M = Rh (8[PF 6](2)), Ir (9[PF6](2)) after anion metathesis using K[PF6], while treatment of 6 with [(Rh(CO)(2))(2)(mu-Cl)(2)] or [RhCl(PPh3)(3)]/KPF6 produced the trinuclear Rh(III)(2)Rh(I) clusters [(Cp*Rh)(2){Rh(CO)(2)}(mu(3)-Se)(2)][Rh Cl2(CO)(2)] (10) or [(Cp*Rh)(2){Rh(PPh3)(2)}(mu(3)-Se)(2)][PF6]. On the oth er hand, the reactions of 6 and 7 with NEt3 gave the tetranuclear selenido clusters with a cubane-type core [(CP*M)(4)(mu(3)-Se)(4)] (M = Rh, Ir). Rea ctivities of 4 and 5 toward other H2Se or SeH- sources were also investigat ed, which revealed that treatment with Al2Se3 and H2O in CH2Cl2, followed b y the anion metathesis using K[PF6], gave 8[PF6](2) and 9[PF6](2), respecti vely, as the final products, while the reactions with NaSeH in THF produced a mixture either of a cubane-type cluster [(Cp*Rh)(4)(mu(3)-Se)(3)(mu(3)-C l)][HCl2] (14), 8Cl(2), and 6 or of [(CP*Ir)(4)(mu(3)-Se)(3)(mu(2)-Cl)][HCl 2] (15) and 9Cl(2). The X-ray analyses have disclosed the detailed structur es for 6, 8[PF6](2), 9[PF6](2), 10, 14, and 15 . CH2Cl2.