Carbonyls dinitrogen derivatives

With the aim of studying the potential activation of molecular oxygen using (PCP) Rh complexes, Milstein and coworkers synthesized [27] the low-valent p -02 complex (69) from the dinitrogen derivative (68) (Scheme 2.32). Further reaction of complex (69) with excess of carbon monoxide afforded the carbonyl complex (70). These results are in sharp contrast with those observed by Sacco and coworkers [18] (see Scheme 2.23) where the oxygen complex (43) was capable of oxidizing CO to CO2. 

Since these products are, therefore, readily available as starting materials we have studied their further use. The diazido compounds 38 are not very stable. They loose readily dinitrogen (usually on crystallization from alcohol) and give the tetrazolyl derivatives 39. Treatment of 39 with acetic anhydride leads in the usual way (cf. the conversion of 3 via 9-11 to 12) to the oxadiazolyl derivative 40. The carbonyl group in this structure can be reduced with sodium borohydride to the methylene group. Careful hydrolysis of this compound (41) with acid, yields the hydrazide 42, while alkaline hydrolysis of both affords the acid 43 [84JHC1881],... 

The olefin complexes of iron, nickel, rhodium, and iridium described in this chapter have found broad application in the synthesis of phosphine, phosphite, and carbonyl derivatives of these metals. In Chapter Two, the synthesis of another labile olefin complex, (ethylene)bis(tricyclohexylphosphine)nickel, is described as an initial step in synthesis of a complex of dinitrogen. 

At this point, it only remains to report on an alternative synthesis for nitride clusters Equation (3.33), which is based on a different approach as the previously described cleavage of NO. A nucleophilic attack by Nj on coordinated CO followed by the elimination of dinitrogen will generate a coordinated isocyanate ligand. The subsequent step to form the nitride is based on the observation that the preformed [Ru4(CO)i3(NCO)]" isocyanate substituted carbonyl cluster slowly converts into the [Ru4(m4-N)(CO)i2] nitride derivative on standing in solution. [268, 363]... 

In 2003, Morales-Morales and Jensen reported [35] on the reactivity of different (PCP)Ir derivatives with carbon monoxide. Thus, direct reactions of the dihydride species (82) (in the presence of TBE), dinitrogen (83), and hydrido-hydroxy (84) afforded the (PCP)Ir(I) carbonyl complex (85) (Scheme 2.38). Worth noting is the reaction of compound (84) with CO, which besides complex (85) also affords a very small amount of a pale yellow air sensitive (PCP)Ir(I) carboxyl compound (86) (Scheme 2.38). The structure of this compound was unequivocally determined by single-crystal X-ray diffraction analysis. 

Bis(imino)pyridine]bis(dinitrogen)iron complexes such as [( PDI)Fe(N2)]2(p2-N2) are active catalysts for the hydrogenation of a,P-unsaturated esters (Scheme 4-334). The efficiency of the catalyst can be adjusted by the substitution pattern of the aryl moiety. The dimethylaiyl substituent shown is superior to the corresponding ethyl or isopropyl derivatives. Bis(imino)pyridines with phenyl substituents in the imine backbone exhibit a much reduced activity to alkene hydrogenation as they are prone to carbonyl coordination. ... 

---