Dinitrogen isoelectronic with

Molecular nitrogen. Ni- is isoelectronic with both carbon monoxide and the nitrosyl ion but, despite the numerous complexes of CO and NO, for many years it proved to be impossible to form complexes of dinitrogen This difference in behavior was usually ascribed to the lack of polarity of N2 and a resultant inability to behave as a 7T acceptor.49... 

Although N2 is isoelectronic with CO and RNC, and isosteric with the former, it is far more inert and the first dinitrogen complex, [Ru(NH3)5(N2)]2+, was discovered only in 1965. Dinitrogen can be bound to metal atoms only in the presence of other ligands there are no homoleptic complexes analogous to those formed by CO or RNC. 

Several diatomic ligands similar to CO are worth brief mention. Two of these, CS (thiocarbonyl) and CSe (selenocarbonyl), are of interest in part for purposes of comparison with CO. Several other common ligands are isoelectronic with CO and, not surprisingly, exhibit structural and chemical parallels with CO. Two examples are CN (cyanide) and N2 (dinitrogen). In addition, the NO (nitrosyl) ligand deserves discussion because of its similarities with CO. NS (thionitrosyl) and other ligands isoelectronic with NO also are considered briefly. 

Diazomethane possesses 16 valence shell electrons. This is also the case for two other molecules of similar structure and reactivity dinitrogen oxide (0 = I = N) and ketene (H2C = C = 0). We have already discussed the similarity to ketene in Section 5.3. Furthermore, diazomethane is also isoelectronic with species that have little in common with its structure and reactivity, namely carbon dioxide, nitryl ion (NO ), hydrogen azide, azide ion (Nb") and, of course, the structural isomers of diazomethane. 

Since the nitrogen molecule is isoelectronic with CO, CN, and NO, all of which form a variety of stable molecules, then N2 should also have some tendency to coordinate with metals. Although coordination chemists had long tried to make N2 complexes, the first successful synthesis (of [Ru(NH3)5(N2)]Br2) was not achieved until 1965. This important discovery was immediately followed by intensive research, and many different dinitrogen-metal (N2-M) complexes were prepared. In several cases, it was found that simple ligand substitution (6) can generate the desired product. 

Dinitrogen Molecular nitrogen. Nj. is isoelectronic with both carbon monoxide and the nitrosyl... 

Dinitrogen (N2) is isoelectronic with carbon monoxide, and as a ligand has many similarities to CO. The complex tran -W(N2)2(dppe)2 luminesces at 564 nm with a quantum yield of 0.08 0.02, and a lifetime of 19 Flash photolysis of... 

The formation of the deltate complex has also been investigated. The key intermediate of this reaction is found to be a bimetallic ketene complex where C2O2 lies between both centers. This intermediate is obtained via a C-C coupling between a side-on bimetallic CO complex and a free CO molecule. The side-on complex has never been identified experimentally, despite being isoelectronic with known dinitrogen-bridged diuranium complexes. A summary of the two pathways is reported in Figure 13.8. 

Dinitrogen is isoelectronic with CO and the bonding mechanism is also synergic, but its a -h 7c)-bonding capacity seems to be weaker than that of CO. Thus, metal complexes of N2 generally carry one or two terminal N2 ligands, in contrast to the prevalence of polycarbonyl complexes. As is seen in Table II, the N—distances observed in complexes of the end-on unidentate N2 are not appreciably different from that of free dinitrogen (1.0976 A). 

The total number of valence electrons in carbon monoxide, dinitrogen, and cyanide ions is 10. Because they have the same number of electrons, these ligands are isoelectronic. The total number of electrons in nitric oxide and dioxygen are 11 and 12, respectively. Therefore NO+ is isoelectronic with CO and N, while NO is isoelectronic with O. ... 

Dinitrogen oxide (nitrous oxide), N20, is a linear unsymmetrical molecule with a structure similar to its isoelectronic analog C02 ... 

Cyanides or nitriles, RC=N, have two regions for electrophilic attack, namely the triple bond TT-electrons and the lone pair on nitrogen. The two possibilities of attack are illustrated by the behaviour of cyanides with respect to transition metal ions. In their gas-phase studies on the interaction between cyanides and transition-metal ions Chen and Millerconcluded that both side-on and end-on interaction is present. In this respect cyanides resemble the isoelectronic dinitrogen. 

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