Diazenido

The third area is the synthesis and characterization of aryldiazenido complexes of transition metals. In 1964 King and Bisnette isolated the first metal complex with an aryldiazenido ligand. The interest of organometallic chemists was concentrated mainly on the isolation and characterization of stable aryldiazenido complexes and not on potential metastable intermediates involved in metal-catalyzed dediazonia-tions. The situation is different, however, for metal complexes with alkyl-diazenido ligands. Complexes with aryl- and alkyldiazenido ligands are the subject of Chapter 10 in the forthcoming second book (Zollinger, 1995). 

Lehnert and Tuczek further studied end-on terminal coordination by density functional theory (DFT) calculations on the compounds [Mo(N2)2(dppe)2], [MoF(NNH)(dppe)2], and [MoF(NNH2)(dppe)2]+, where dppe= 1,2-bis(diphenyl-phosphino)ethane.50 They proposed a reaction scheme, shown in reaction 6.13, for asymmetric dinitrogen reduction and protonation. The end-on model favored by Lehnert in reference 50, as shown in reaction 6.13, appears to be a less thermodynamically unfavorable pathway, at least to reach the M-NNH3 intermediate. Step 1 produces a metal-attached diazenido ion (NNH-), step 2 produces a hydrazido ion (NNH2 ), and step 3 produces a hydrazidium ion (NNHj). 

Nitrido ligands are often formed from 0x0 precursors by reactions with hydrazine derivatives. More details of the formation of hydrazido and diazenido species will be given in Section 5.3.2.10. Here, only those complexes which still contain 0x0 ligands and, thus may be regarded as intermediates of this conversion are regarded. The dithiocarbamato complex... 

Re-Mn, and Re-Ru-Mn combinations. Related compounds such as the diazene/diazenido species [Re(CO)3 PPh2(OEt) 2(/x-HNArArNNFe(CO)2 P(OPh)3 ] " " have been isolated during this type of reactions. ... 

Diazenido ligand, 27 218-226 alkyl and acyl complexes of, formation, 27 ... 

Diazoalkane complexes, in preparation of diazenido complexes, 27 222 Diazoaminobenzene-copper complex, 2 39 Diazobutadiene compiexes with iron, 12 274, 275... 

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