Complexes with oxygen-coordinating ligands

Rhodium complexes with oxygen ligands, not nearly as numerous as those with amine and phosphine complexes, do, however, exist. A variety of compounds are known, iucluding [Rh(ox)3] [18307-26-1], [Rh(acac)3] [14284-92-5], the hexaaqua ion [Rh(OH2)3] [16920-31 -3], and Schiff base complexes. Soluble rhodium sulfate, Rh2(804 )3-a H2 0, exists iu a yellow form [15274-75-6], which probably coutaius [Rh(H20)3], and a red form [15274-78-9], which contains coordinated sulfate (125). The stmcture of the soluble nitrate [Rh(N03)3 2H20 [10139-58-9] is also complex (126). Another... 

Coordination Complexes. The abiUty of the various oxidation states of Pu to form complex ions with simple hard ligands, such as oxygen, is, in order of decreasing stabiUty, Pu + > PuO " > Pu + > PuO Thus, Pu(Ill) forms relatively weak complexes with fluoride, chloride, nitrate, and sulfate (105), and stronger complexes with oxygen ligands (Lewis-base donors) such as carbonate, oxalate, and polycarboxylates, eg, citrate, and ethylenediaminetetraacetic acid (106). The complexation behavior of Pu(Ill) is quite similar to that of the light lanthanide(Ill) ions, particularly to Nd(Ill)... 

In diorganotin dihalide complexes with sulphoxide-containing ligands, the coordination number at tin is increased to six and the sulphoxide oxygen-tin distances are significantly shortened as compared with 142-145. In poly[c/ s-dichloro-tra .s-dimethyUin-/r-meso-... 

The complexes are similar to complexes cited with carbonyl ligands. The similarities are particularly the anion coordination possibility and the different coordination numbers for complexes with a given ligand depending upon the anion. All the complexes have the group L-O, where L = P, As, N, S and the coordination to the metal is through oxygen, Ln-O-L where L = N, S, P, As. The evidence for this is based on infrared spectra for most of the complexes and the X-ray diffraction method of determination of some structures. 

An increase in R resulted in the band shift towards the short-wave region. Further, a linear correlation between the bond distance R of Ln-O bond and the wave numbers of some f-f transitions in the absorption spectra of Pr(III) and Nd(III) complexes with different coordination numbers and symmetry was noted [51,52]. The complexes had oxygen donor ligands and R (Ln-O) is the mean lanthanide-oxygen distance. This correlation has been examined in the light of the atomic overlap model. 

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