Cyclopentadienylnickel Azobenzene Complex

The reaction of di-7r-cyclopentadienylnickel and azobenzene gives a purple-blue crystalline nickel complex, mp 118-119°. Based on the following data, structure [5-50] was assigned to the compound. Elemental analysis 

and 440 mfi with molar extinction coefficients of 8370, 18,500 and 587.) The absorption in the 318 mfi region is attributed to the conjugation of the unsaturated nitrogen with the phenyl rings. 

The participation of the 7c-coordination of the N=N linkage to the metal is not ambiguously proved as yet. (T-Coordination using a nitrogen lone pair as shown in structure [5-51] cannot be excluded as a possibility. 

Transition metal complexes of boron hydrides and carboranes also have been reported recently. The number of papers concerned with this fascinating new area of inorganic chemistry is steadily increasing, and the topic could develop into a distinct research area comparable to coordination and organo- 

The sandwich-type bonding of the dicarbollyl group has been established by a single-crystal x-ray diffraction study for the compound 7i-cyclo-pentadienyl-7r-(3)-l,2-dicarbollyliron(III). This compound, prepared by the reaction of an equimolar mixture of sodium cyclopentadienide and disodium (3)-1,2-dicarbollide with iron(III) chloride, followed by air oxidation, has the structure shown in Fig. 5-10. 

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