Dinuclear complexes, quadruply bridged

Quadruply Bridged Dinuclear Complexes of Platinum, PEdladium, and Nickel Keisuke Umakoshi and Yoichi Sasaki... 

QUADRUPLY BRIDGED DINUCLEAR COMPLEXES OF PLATINUM. PALLADIUM, AND NICKEL... 

Quadruply bridged dinuclear complexes (so-called lantern-type complexes) (Fig. 1) are known for a wide variety of transition metal ions such as Cu, Cr, Mo, W, Tc, Re, Ru, Os, Rh, Ir, Ni, Pd, and Pt, and they appear to be one of the most important common basic structures of transition metal complexes (2-3). Most bridging ligands form five-membered rings on bridging between two metal ions. Platinum corn-... 

Fig. 1. Basic structure of quadruply bridged dinuclear complexes.

Fig. 3. Basic structures of quadruply bridged dinuclear complexes for the oxidation states of +2, + 3, and + 2.5.

Similar structural characteristics of the quadruply bridged dinuclear complexes of Pt(II), Pd(II), and Ni(II) indicate that the mixed-metal dinuclear complexes of these metal ions should be stable. However, probably because of the synthetic difficulties, only a few mixed-metal complexes of group 10 elements with such a structure have been prepared so far, although there are a number of examples having a doubly bridged structure (98, 99). For other metals, quadruply bridged mixed-metal complexes are known with the group 6 metal ions Cr, Mo, and W (1, 100, 101). 

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