| Abstract
| - The syntheses of the trans-bis(dinitrogen) [Re(N2)2P4][BPh4] (2), the dinitrogen ReCl(N2)P4 (3), and the methyldiazenido [ReCl(CH3N2)(CH3NHNH2)P3][BPh4] (1) [P = PPh(OEt)2] complexes are reported. The bis(aryldiazenido) complexes [Re(ArN2)2P3][BPh4] (5, 6), and other diazo derivatives, [ReCl(ArN2)(ArNHNH2)P3][BPh4] (4) and [ReCl(ArN2)P4][BPh4] (7) [P = PPh(OEt)2, PPh(OMe)2; Ar = C6H5, 4-CH3C6H4], were also prepared. The complexes were characterized spectroscopically (IR; 1H and 31P NMR), and 1, 2, and 7 were also characterized crystallographically. Oxidation reactions of the hydrazine complexes 1 and 4 with Pb(OAc)4 lead to methyldiazene compound [ReCl(CH3NNH)(CH3N2)P3][BPh4] (8) and the bis(aryldiazenido) derivatives 5, respectively.
- Depending on experimental conditions and the nature of the hydrazine, the reactions of ReCl3P3 [P = PPh(OEt)2]with RNHNH2 (R = H, CH3, tBu) afford the bis(dinitrogen) [Re(N2)2P4]+ (2+), dinitrogen ReClN2P4 (3), andmethyldiazenido [ReCl(CH3N2)(CH3NHNH2)P3]+ (1+) derivatives. In contrast, reactions of ReCl3P3 [P = PPh(OEt)2, PPh2OEt] with arylhydrazines ArNHNH2 (Ar = Ph, p-tolyl) give the aryldiazenido cations [ReCl(ArN2)(ArNHNH2)P3]+ (4+) and [ReCl(ArN2)P4]+ (7+) and the bis(aryldiazenido) cations [Re(ArN2)2P3]+ (5+, 6+). Thesecomplexes were characterized spectroscopically (IR; 1H and 31P NMR), and the BPh4 complexes 1, 2, and 7 werecharacterized crystallographically. The methyldiazenido derivative [ReCl(CH3N2)(CH3NHNH2){PPh(OEt)2}3][BPh4](1) crystallizes in space group P1̄ with a = 15.396(5) Å, b = 16.986(5) Å, c = 11.560(5) Å, α = 93.96(5)°, β= 93.99(5)°, γ = 93.09(5)°, and Z = 2 and contains a singly bent CH3N2, group bonded to an octahedral centralmetal. One methylhydrazine ligand, one Cl- trans to the CH3N2, and three PPh(OEt)2 ligands complete thecoordination. The complex [Re(N2)2{PPh(OEt)2}4][BPh4] (2) crystallizes in space group Pbaa with a = 23.008(5) Å, b = 23.367(5) Å, c = 12.863(3) Å, and Z = 4. The structure displays octahedral coordination with twoend-on N2 ligands in mutually trans positions. [ReCl(PhN2){PPh(OEt)2}4][BPh4] (7) crystallizes in space groupP21/n with a = 19.613(5) Å, b = 20.101(5) Å, c = 19.918(5) Å, β = 115.12(2)°, and Z = 4. The structure showsa singly bent phenyldiazenido group trans to the Cl- ligand in an octahedral environment. The dinitrogen complexReClN2P4 (3) reacts with CF3SO3CH3 to give the unstable methyldiazenido derivative [ReCl(CH3N2)P4][BPh4].Reaction of the methylhydrazine complex [ReCl(CH3N2)(CH3NHNH2)P3][BPh4] (1) with Pb(OAc)4 at −30 °Cresults in selective oxidation of the hydrazine, affording the corresponding methyldiazene derivative [ReCl(CH3NNH)(CH3N2)P3][BPh4] (8). In contrast, treatment with Pb(OAc)4 of the related arylhydrazines [ReCl(ArN2)(ArNHNH2)P3][BPh4] (4) [P = PPh(OEt)2] gives the bis(aryldiazenido) complexes [Re(ArN2)2P3][BPh4] (5).Possible protonation reactions of Brønsted acids HX with all diazenides, 1, 4, 5, 6, and 8, were investigated andfound to proceed only in the cases of the bis(aryldiazenido) complexes 5 and 6, affording, with HCl, the octahedral[ReCl(ArNNH)(ArN2)P3][BPh4] or [ReCl{Ar(H)NN}(ArN2)P3][BPh4] (10) (Ar = Ph; P = PPh2OEt) derivative.
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