Osmium complexes monodentate

Osmium complexes, 519-619 alkaloids, 569 alkoxo, 596 amido, 557 amines, 557 bidentate, 530 monodentate. 530 amino acids, 602... 

In this section we consider the complexes of mono-, di- and poly-carboxylato complexes. There appear to be marked differences from ruthenium carboxylato chemistry particularly in respect of the II/III and III states. A number of osmyl complexes are known with monodentate or bidentate carboxylates (p. 582) but apparently none of ruthenium(VT). On the other hand, the binuclear ruthenium species [Ru30(OCOR)6L3]"+, in which OCOR functions as a bidentate ligand, does not appear to have an osmium counterpart both elements form lantem -like species containing [M2(OCOR)4]"+ cores, but again with marked differences between ruthenium and osmium. This is clearly an interesting and rewarding field for further study. 

Extension beyond the dimetallic stage for complexes constructed using 1 was accomplished with both a ruthenium(II)12 and an osmium(II) core in octahedral coordination.18 The peripheral metal sites in each complex (5 and 6) were occupied by ruthenium(II) species, each peripheral site capped by a pair of 2,2 -bipyridyl ligands. (In all of the preparations noted here, the bridges of the multinuclear complexes were formed by simple displacement of monodentate chloride or pyridine ligands by the bridging species which was bidentate in nature toward each metal center.) In addition to 2,2 -bipyridyl, o-phenanthroline (7) and 2,2 6, 2"-terpyrid-ine (8) were used. 

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