Polyhydride complexes of rhenium with the chelating ligand 1,2-bis(diphenylphosphinite)ethane

The reaction of [ReOCl3(AsPh3)(2)] with Ph2POCH2CH2OPPh2 (L) in refluxing T HF yielded the complex [ReOCl3L] (1). The new polyhydride [ReH7L] (2) was o btained by treating 1 with NaBH4 in absolute ethanol. The heptahydride 2 is stable in the solid state but in solution dimerises, giving [Re2H8L2] (3). Polyhydrides 2 and 3 were characterised as classical species by variable-t emperature NMR spectroscopy (H-1 and P-31) and T-1 measurements. The proton ation of [ReH7L] and [Re2H8L2] in CH2Cl2-d(2) with HBF4. Et2O gave the hydr ide cations [ReH6(eta -H-2)L](+) and [Re2H9L2](+), which were characterised as non-classical and classical, respectively, on the basis of T-l(min) mea surements. The reaction of 1 with PPhn(OR)(3-n) (L'; n = 1, 2; R = Me, Et) in refluxing THF gave [ReCl3LL'] (4) in excellent yield. The complex [ReCl3 L{PPh(OEt)(2)}] was converted to the pentahydride [ReH5L{PPh(OEt)(2)}] by t reatment with NaBH4 at room temperature. (C) 2001 Elsevier Science B.V. All rights reserved.