Hexametallic complexes

Star-shaped molecules containing cationic arene complexes of iron and ruthenium have been reported by Astruc and co-workers.298 Utilizing the activating nature of the cyclopentadienyliron moiety on the complexed arene, 260 was converted into 262 via bromobenzylation. The photolysis of 262 gave 263, which was subsequently reacted with 264 to give the hexametallic complex 265. Further nucleophilic aromatic substitution reactions with phenol 266 gave the allyl-substituted complex 267 (Scheme 2.70). 

The hexametallic complex [Ir2Cu4(C=CR)8(PPh3)2] 493 has been synthesized and characterized by X-ray diffractometry. The network of relatively short intermetallic It -Cu distances suggests that this compound may be better represented as a hexanuclear cluster rather than two separated [Ir(C=CR)4(PPh3)2] anions held together by four Cu monocations. 

Dimeric hexametallic complex 88 with a rhodium dppa macrocyclic core has been prepared by COD displacement from [W((//-S)2Rh(COD))2] by dppa (Fig. 2.31) [93]. In contrast, reaction of [Rh(CO)2(Cl)2] with an equimolar amount of dppa gave exclusively the linear polymeric compound [Rh(CO)Cl()U-dppa)] [94]. 

Cationic star-shaped molecules containing cyclopentadienyliron complexes, where the organo-metallic cations are evenly distributed throughout the molecule branches, 250, have been reported (Scheme 2.67).295 296 291 Electrochemical studies of these materials indicated that the iron centers underwent reversible reductions. For the hexametallic star-shaped molecule (n = 1), two redox potentials were observed at KU2 = I -20 and —1.30 V. 

Figure 20 Cyclic vollammogram of hexametallic star complex 32 in DMF.

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