Aryldiazene, Aryldiazenido, and Hydrazine Complexes of Manganese. Preparation, Characterization, and X-ray Crystal Structures of [Mn(CO)₃(4-CH₃C₆H₄NNH){PPh(OEt)₂}₂]BF₄ and [Mn(CO)₃(NH₂NH₂){PPh(OEt)₂}₂]BPh₄ Derivatives

Aryldiazene complexes [Mn(CO)3(ArNNH)P2]BF4 (1, 2) and [{Mn(CO)3P2}2(μ-HNNArArNNH)](BF4)2 (3, 4) [P = PPh(OEt)2, PPh2OEt; Ar = C6H5, 2-CH3C6H4, 4-CH3C6H4, 4-CH3OC6H4; ArAr = 4,4‘-C6H4C6H4, 4,4‘-(2-CH3)C6H3C6H3(2-CH3), 4,4‘-C6H4CH2C6H4] were prepared by reacting hydride species MnH(CO)3P2 with the appropriate aryldiazonium cations in CH2Cl2 or acetone solutions at −80 °C. The compounds were characterized by IR, 1H and 31P NMR spectra (with 15N isotopic substitution), and a single-crystal X-ray structure determination. The complex [Mn(CO)3(4-CH3C6H4NNH){PPh(OEt)2}2]BF4 (1c) crystallizes in the space group C2/c with a = 31.857(5) Å, b = 11.119(2) Å, c = 22.414(3) Å, β = 97.82(1)°, and Z = 8. Treatment of aryldiazene compounds 1−4 with NEt3 gave the pentacoordinate aryldiazenido [Mn(CO)2(ArN2)P2] (5, 6) and [{Mn(CO)2P2}2(μ-N2ArArN2)] (7, 8) [P = PPh(OEt)2, PPh2OEt; Ar = C6H5, 4-CH3C6H4; ArAr = 4,4‘-C6H4C6H4, 4,4‘-(2-CH3)C6H3C6H3(2-CH3)] derivatives. Protonation reactions of these aryldiazenido complexes 5−8 with HCl afforded the aryldiazene [MnCl(CO)2(ArNNH)P2] (9) and [{MnCl(CO)2P2}2(μ-HNNArArNNH)] (10) derivatives. Hydrazine complexes [Mn(CO)3(RNHNH2)P2]BPh4 (11, 12) [P = PPh(OEt)2, PPh2OEt; R = H, CH3, C6H5, 4-NO2C6H4] were prepared by allowing hydride species MnH(CO)3P2 to react first with triflic acid and then with the appropriate hydrazine. Their characterization by IR, 1H and 31P NMR spectra, and an X-ray crystal structure determination is reported. The compound [Mn(CO)3(NH2NH2){PPh(OEt)2}2]BPh4 (11a) crystallizes in the space group P1̄ with a = 13.772(3) Å, b = 14.951(4) Å, c = 13.319(3) Å, α = 104.47(1)°, β = 100.32(1)°, γ = 111.08(1)°, and Z = 2. Oxidation reactions of hydrazine compounds 11 and 12 with Pb(OAc)4 at −40 °C gave stable aryldiazene [Mn(CO)3(RNNH)P2]BPh4 and thermally unstable (upon reaching −40 °C) diazene [Mn(CO)3(HNNH)P2]BPh4 derivatives.