Group 8 VIII cyclopentadienyl complexes

The Group VIII cyclopentadienyl complexes of formula CpM(NO) (M = Ni, Pd, Pt) have all been synthesized. The nickel complex is best prepared from nickelocene and nitric oxide, and a method for the preparation of the nickelocene m situ without its isolation has been described (56). The palladium complex can be prepared from [Pd(NO)Cl] and sodium cyclopentadienide (23) and the platinum complex from Pt2(CO)2Cl4 and sodium cyclopentadienide and nitric oxide (22). The microwave (13) and infrared spectra (18) of CpNi(NO) have received detailed study, and the electronic structure of the complex is discussed in an early paper (77). 

Compound VIII crystallizes in a monoclinic system the space group is C2/c with eight molecules per unit (Fig. 6.4). The distance between Ti(l) and Ct(l) measures 2.0340 A, which is considerably longer than the Ti-Ct distance in the analogue cyclopentadienyl titanium complex CpTiCl2(THF) (2.014 A) (Table 6.2), which, to our best knowledge, is the only other example of a monomeric Cp-type titanium(III) chloride compound that could be isolated [32,33]. Bis THF adducts, as described for CpTiCl2(THF)2, are not found in the case of VIII [32],... 

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