Structure solvento complexes

Romeo, R., and Alibrandi, G. (1997), Structure-reactivity correlations for the dissociative uncatalyzed isomerization of monoalkylbis(phosphine)platinum(II) solvento complexes, Inorg. Chem., 36,4822—4830. 

In the earliest authentic halocarbon complex (1982), o-diiodobenzene was found to chelate to cationic Ir(III) as shown in diagram (5)." An earlier proposed example proved to be misidentified when the crystal structure was carried out. To be stable, any such complex must resist oxidative addition, hence the use of an oxidation state, Ir(III), that is only oxidized with difficulty. The normally rather weakly basic halocarbon lone pairs are often reluctant to bind, but chelation and involvement of the least electronegative hahde, iodine, favor binding as does the cationic character of the complex. A series of such complexes was soon found, including complexes of fr(I)" and a series of weakly bound dichloromethane complexes for certain systems." These solvento complexes can be very labile and so find use as precursors for binding of other weakly basic hgands. Even fluorocarbon complexes proved viable." A review of the area is available. It now seems... 

The Y + ion is comparable in size with heavier lanthanides, and its coordination chemistry therefore resembles them. Aqua complexes and simple hydrates have been discussed in Solvento Complexes of the Lanthanide Ions. Fewer solution studies of solvated species with other donors have been made for these metals, but an examination of the Y + ion in Odonor solvents using X-ray absorption fine structure (XAFS) and laige angle X-ray scattering shows that the metal is eight coordinate in dimethylformamide and dimethylsut-foxide, but seven coordinate in N, iV -dimethylpropyleneurea (dmpu), as are other lanthanides. It should be noted that in the solid state, six-coordinate [Ln(dmpu)6]l3 (Ln = La, Pr, Nd, Gd, Tb, Er, Yb, Lu) are isolated. ... 

NMR spectroscopy was used to monitor ethane liberated in the synthesis of [Zr(MeCN)Cp2Me][BPh4] by this method. Oxidation of the methyl ligand apparently proceeds via intermediate formation of AgCH3. The X-ray crystal structure of the acetonitrile solvento-complex, [Zr(NCMe)Cp2(CH2Ph)]+, has been determined. Figure 3.3. 

Reduction reactions that involve titanium(lll) species are common in preparative organic chemistryl 9 but relatively rare in coordination chemistry. However, Floriani and coworkers " have described the reduction of vanadium complexes, [VO(salophen)] and [VO(acacen)], by the titanium(IIl) solvento-complex, [TiCl3(THF)3]. Reaction of these vanadyl complexes in THF results in formation of [VCl(salophen)(THF)] and [VCl(acacen)(THF)]. Both compounds have been structurally characterized and an X-ray diffraction study of [VCl(salophen)(THF)] indicated pseudooctahedral coordination for V(Ill). Further, the CP and THF ligands were found to be trans to each other in the axial positions, while the equatorial plane was defined by the salophen ligand. Figure 9.7.1fl The proposed mechanism 2 for these conversions is shown in Scheme 9.7. 

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