Abstract
The reaction of [ReCl~2~(OCH~3~)(NO)(PPh~3~)~2~] with phosphane in the presence of NaBH~4~ gives different dihydride [ReH~2~(NO){PPh~2~(OEt)}~3~] (1) and alkoxy‐hydride [ReH(OR^1^)(NO)P~3~] (2, 3) [R^1^ = CH~3~, C~2~H~5~; P = PPh(OEt)~2~, P(OEt)~3~] derivatives depending on the nature of the phosphane and the solvent used. The protonation reactions of the new hydrides with Brønsted acid were performed and led to thermally unstable [Re(OR^1^)(η^2^‐H~2~)(NO)P~3~]^+^ (2*, 3*) dihydrogen cations. Hydrazine complexes [ReH(RNHNH~2~)(NO){PPh~2~(OEt)}~3~]BPh~4~ (4) (R = H, CH~3~,C~6~H~5~) and [Re(OR^1^)(RNHNH~2~)(NO)P~3~]BPh~4~ (5, 6) [R^1^ = CH~3~, C~2~H~5~; R = H, CH~3~,C~6~H~5~; P = PPh(OEt)~2~] were prepared by allowing the hydrides [ReH~2~(NO)P~3~] and [ReH(OR^1^)(NO)P~3~] to react first with triflic acid and then with hydrazine. The complexes were characterized spectroscopically and by the X‐ray crystal structure determination of [Re(OC~2~H~5~)(NH~2~NH~2~)(NO){PPh(OEt)~2~}~3~]BPh~4~ (5a). Oxidation of the hydrazine complexes 4−6 was studied with Pb(OAc)~4~ at −30 °C and, depending on the nature of the hydrazine and the stoichiometry of the complexes, led to aryldiazene [ReH(C~6~H~5~N=NH)(NO){PPh~2~(OEt)}~3~]BPh~4~ (7c), [Re(OC~2~H~5~)(C~6~H~5~N=NH)(NO){PPh(OEt)~2~}~3~]BPh~4~ (8c), methyldiazene [ReH(CH~3~N=NH)(NO){PPh~2~(OEt)}~3~]BPh~4~ (7b) and a mixture of methyldiazene [Re(OCH~3~)(CH~3~N=NH)(NO){PPh~2~(OEt)}~3~]BPh~4~ (9b) and methyleneimine [Re(OCH~3~)(η^1^‐NH=CH~2~)(NO){PPh~2~(OEt)}~3~]BPh~4~ (9*b) derivatives. Mono‐ and binuclear aryldiazene complexes [ReH(ArN=NH)(NO){PPh~2~(OEt)}~3~]BPh~4~ (10), {ReH(NO)[PPh~2~(OEt)]~3~}~2~(µ‐HN=NAr−ArN=NH)~2~ (11), [Re(OR^1^)(ArN=NH)(NO)P~3~]BPh~4~ (12, 14, 16) and {Re(OR^1^)(NO)P~3~}~2~(µ‐HN=NAr−ArN=NH)~2~ (13, 15) [R^1^ = CH~3~, C~2~H~5~; P = PPh(OEt)~2~, P(OEt)~3~; Ar = C~6~H~5~, 4‐CH~3~C~6~H~4~; Ar‐Ar = 4,4′‐C~6~H~4~‐C~6~H~4~] were also prepared by allowing hydrides [ReH~2~(NO)[PPh~2~(OEt)}~3~] and [ReH(OR^1^)(NO)P~3~] to react with mono‐ and bis‐aryldiazonium cations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)