Nitride ligand

The use of 5-methyl-2-methyldithiocarbazate H2NN(Me)C(S)SMe (H2mdtc, (257)) as a source of the nitride ligand in [Tc=N] radiopharmaceuticals has been developed. The reaction of fTcOCy in EtOH/CH2Cl2 with (257) produces the dark green complex [TcO(Hmdtc)2] (258). 

The addition of electrophilic agents to terminal nitride ligands can be applied to the synthesis of imido complexes. This has been demonstrated with triphenylcarbonium salts and compounds of the formula [Re NC(C6H5)3 X4] (X = C1, Br, F, NCS) have been studied by EPR spectroscopy and show similar spectroscopic features to their [Re NB(C6F5)3 X4] analogues. " ... 

The trends in the emission energies (origins) are rationalized by AOM calculations that show that the phosphine tunes the transition very little because the change in energy for the dxy to dyz transition contains only terms for halide and nitride ligands. Accordingly, the Eoo deceases by 425-600 cm 1 upon substitution of Br with Cl, because chloride as the better 7r-donor, destabilizes the filled dxy orbital. 

A new class of binuclear nitrido complexes of tetravalent osmium and ruthenium is described in which the metal atoms are symmetrically bridged by a nitride ligand to give a linear M-N—M unit They have the stoichiometries M2NX8(H20)2]3 and [M2N(NH3)8Y2]3+ (M = Os, Ru X = Cl, Br Y = Cl, Br, etc.). Studies are reported on their vibrational spectra, structures, and bonding. Preliminary studies are reported also on trinuclear complexes of osmium and iridium. Finally, the use of vibrational spectroscopy in the study of metal-nitrido and metal-oxo complexes is discussed briefly. 

Enough data on these clusters are now available to make a preliminary comparison of the similarities and differences of carbide and nitride ligands. Advances in understanding of the perturbations caused by the shift from C to N will help draw a clearer picture of the complex bonding of atomic species to clusters. In this light, there are three observations that seem to point to the same conclusion. 

We have studied the reactions of H3(NS3) with vanadium more thoroughly than those with any other metal, starting from the known [V(0)(NS3)]. Figure 3 shows that the V(NS3) site will support imide, hydrazido, hydrazine, ammonia and nitride ligands, forming multiple bonds to nitrogen species that may be involved in the later stages of reduction of N2. Several of these complexes are... 

Bridging nitride ligands have been found in several dinuclear ruthenium(iv) and osmium(rv) complexes,23 e.g.,... 

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