Osmium complexes nitrido

No nitrido complexes of ruthenium(VIII) have been isolated. For osmium, the only well-established osmium(VIII) nitrido species is [0s(0)3(N)] , which has been well documented in CCC (1987). A number of heterometallic complexes formed by the interaction of [0s(0)3(N)] with a second metal center have been reported. In these complexes, the [0s(0)3(N)] ion acts as a... 

There is a rich chemistry of alkyl nitrido complexes of ruthenium(VI) and osmium(VI), which has been well documented. " ... 

Table 3 Photophysical data of selected osmium(VI) 0x0 and nitrido complexes in acetonitrile at room...

A trinuclear nitrido-bridged osmium complex, [Os3(N)2(CN)io(OH2)4]", has been reported. 

Osmium(IV) cyanoimido complexes can be prepared by the interaction of osmium(VI) nitrido complexes with CN (Equations (62b) and (62e) see also Scheme 6 and Seetion 5.6.4.2.2(ii)). 

Some nitrido complexes of ruthenium, osmium, and rhenium react with phosphines to give phosphineiminato complexes, as shown in Eq. (70). 

Photophysical Data of Selected Osmium(VI) Oxo and Nitrido Complexes in Acetonitrile at Room Temperature... 

An osmium(VI) nitrido complex with tetraanionic chelating amide ligand was prepared by the reaction of [Os(T 4-HBA-B)(PPh3)2] with phenyl azide in benzene at room temperature. The X-ray structure of [Osvi(N)(t)4-HBA-B)]- revealed a square-pyramidal structure with a measured Os=N distance of 1.64(1) A (282). 

A related process has been reported for the synthesis of osmium nitrido complexes with 1,2-benzenedithiolate ligands. Thus, the synthesis of 173 was effected by treatment of (Bu4N)[OsNC14] with deprotonated 1,2-benzenedithiol (Eq. (70)). Interestingly, when 173 is treated with Me3OBF4 alkylation is observed to occur on the sulfur this contrasts the reaction of 173 with Ph3CPF6, for which reaction at the terminal nitride is observed [93]. 

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. 

Table III. Binuclear Osmium and Ruthenium Nitrido Complexes...

There are now a substantial number of nitrido complexes of osmium(VI) and osmium(IV) as well as the osmiamate ion [OsVII 03N]. In addition to the ammine and ethylenediamine complexes, much recent work has been carried out on the bipy, phen and terpy complexes, often in connection with research into the photodissociation of water. The nitrosyl chemistry of the element, though seemingly not as extensive as that of ruthenium, has received much attention, and there has been considerable work on the phosphine, arsine and stibine complexes. 

Preparative routes involve sulfur abstraction by osmium(VI) nitrido complexes from S2C12 or SCN , though the mechanisms of these reactions are not clear reaction of halides with (NSC1)3 has also been used. 

Another example of sulfur abstraction by an osmium nitrido complex occurs in the reaction of [OsNC14]- with (PPh4)NCS to give (Ph4P)2[Os(NS)(NCS)3], in which the thiocyanate groups are thought to be bonded to the metal via nitrogen.265 For reactions of the complex see Scheme 10, p. 563. 

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