Health & Environmental Research Online (HERO)


Print Feedback Export to File
8328596 
Journal Article 
Diazene-N- (di-imide) and hydrazido-(2-)N- (aminoimido) complexes: The addition of acids to dinitrogen complexes 
Chatt, J; Heath, GA; Richards, RL 
1974 
1 
Journal of the Chemical Society. Dalton Transactions
ISSN: 1472-7773
EISSN: 1364-5447 
19 
2074-2082 
English 
The protonation and reduction of dinitrogen in a mononuclear complex are described. The diazene compounds [MX2(N2H2)(dpe)2] (I; M = W, X = Cl or Br; M = Mo, X = Br; dpe = Ph2PCH2CH2PPh2), and hydrazido- (2-)N complex salts, [Mo(N2H2)(depe)2]X (X = Cl or Br; depe = Et2PCH2CH2PEt2) and trans-[WCl(N2H2)(PMe2Ph)4]Cl were prepared by the reaction of trans-[M(N2)2(diphos)2] (M = Mo or W; diphos = dpe or depe) or cis-[W(N2)2 (PMe2Ph)4] with an excess of the appropriate hydrogen halide. Compounds (I) contain labile halogen and are converted into the hydrazido-(2-)N complex salts [MX(N2H2)(dpe)2]Y (Y = BPh4, ClO4, or PF6, M = W; Y = BF4, M = Mo) by treatment with NaBPh4, LiClO4, NaPF6, or [NEt4]BF4 as appropriate. The structural implications of the i.r., 1H and 31P n.m.r. spectroscopic properties of the N2H2 compounds and of their 15N analogues are discussed. With only 2 mol equiv. of HCl, trans-[W(N2)2(dpe)2] gives the hydride [WH(N2)2(dpe)2]HCl2 and trans-[Mo(N2)2(dpe)2] gives the dihydride [MoH2Cl2(dpe)2]. [WH(N2)2(dpe)2]HCl2 is converted into [WH2Cl2(dpe)2] in refluxing methanol and [WCl2(N2H2)(dpe)2] gives [WCl2{N2H(COCH3)}(dpe)2] with acetyl chloride or acetic anhydride. This work provides the first chemical evidence that dinitrogen is as likely to be reduced at a mono- as at a bi-metal site in nitrogenase.