The chemistry of cyclopentadienyl nitrosyl compounds of molybdenum. Part 13. Hydrazine, hydrazido(1–)-, and hydrazido(2–)-complexes

Abstract

Reaction of [{Mo(η-C₅H₅)(NO)X₂}₂](X = Cl, Br, or I), [Mo(η-C₅H₅)I(NO)(O₂CMe)], or [Mo(C₅H₅)₂I(NO)] with alkyl- or aryl-hydrazines, NHRNR′R″(R = R′= H, R″= Me, Ph, C₆H₄NO₂-p, C₆H₄Me-p, or C₆F₅; R = H, R′= R″= Me or Et or R′= Me, R″= Ph; R = R′= R″= Me), affords (i) simple hydrazine adducts. [Mo(η-C₅H₅)(NHRNR′R″)(NO)X₂](1), (ii) hydrazido(1–)-complexes, [Mo(η-C₅H₅)(NRNR′R″)l(NO)](2), and (iii) hydrazido(2–) complexes, [{Mo(η-C₅H₅)(NO)X}₂NNR′R″](4). Protonation of (2) or (4) with HBF₄ gives the hydrazine adducts [Mo(η-C₅H₅)I(NHRNR′R″)(NO)][BF₄](3). The species (1), on the basis of spectral data, may contain either a unidentate or a chelating hydrazine, the latter forming a three- membered ring with the metal. Species (2) may also contain a three-membered MoNN chelate ring which on protonation affords (3), whose structure is known to involve a bidentate hydrazine bound to only one metal atom. The binuclear species (4) contain the hydrazido(2–)-ligand asymmetrically bridging the two Mo atoms, one N atom being bound to one Mo atom by a σ- and a (p_π→d_π)-donor bond, and the other Mo atom being attached to both N atoms viaσ bonds in a three-membered ring. The chemical and structural relationships between (1), (2), (3), and (4) are discussed.