Acids solvento complexes

Acid-catalyzed elimination of RH has again proven a valuable tool, applied most extensively to Tp Pt(H)2Me (152). Thus, protonation of 152 with [H(OEt2)2]BArf4 affords the anticipated solvento complex... 

The reactions of coordinated linear nitrosyls with azide ions provide a method for the synthesis of a variety of solvento-complexes.52 For example, the ruthenium(ll) compounds, [RuXY(bipy)2], where X and Y are various anionic ligands, can be synthesized through redox and acid-base transformations of the starting material, [Ru(N02)(bipy)2(N0)]2+, Scheme 3.11 ... 

An additional pathway for the formation of solvento-complexes is the decomposition by probe acids of coordinated carbonate or oxalate ligands. There are several examples of such reactions reported in the literature. Thus, the ruthenium(II) bis(aqua)-complex has been prepared by the reaction shown in Eq. 3.20 ... 

Certain low-valent metal carbonyls are oxidized easily with protic adds in non-aqueous media. Thus, [MofCO) ] in diglyme is oxidized by 100% formic acid with the formation of [Mo2(02CH)4). In a related reaction, [Mo(S03CF3)3] is prepared by boiling a [Mo(CO>6) suspension in an excess of HSO3CF3.28 It is reasonable to assume that if a similar reaction was performed in the presence of a strong donor solvent, ttie reaction would lead to the formation of a homoleptic solvento-complex. 

Many metal salts contain water of crystallization or coordinated water molecules. The interaction of such salts with non-aqueous solvents is a complex process involving competition for the metal ion between the solvent molecules, water, and the anion. To prepare homoleptic solvento-complexes, salts of strong acids, whose anions are poor electron donors, e.g, HCIO4, HBF4, HPF6, HSO3CF3, HS03Ar etc., are employed. This essentially eliminates competition from the X- anion for coordination sites at the metal center. 

Hydrated metal halides have been used to prepare solvento-complexes. Toluene complexes of copper(I) have been synthesized from hydrated copper(II) halides by reduction with copper metal in the presence of a suitable Lewis acid,55 Eqs. 4.8 and 4.9 ... 

A technique has been developed (see Table 4.2) for the synthesis of homoleptic solvento-complexes by halide abstraction from metal halides by Lewis acids, i.e. boron(III), aluminum(lll), gallium(III), indium(III), thallium(III), tin(IV), antimony(V), and iron(in) halides.7l-77... 

An additional technique is based on the interaction of metal oxides with acids or acid anhydrides in non-aqueous solvents.78,79 This method is convenient but has not been widely used for the synthesis of homoleptic solvento-complexes in preparative coordination chemistry. 

Acid anhydrides have commonly been neglected as dehydrating agents in the synthesis of homoleptic solvento-compIexes. Applications of acid anhydrides in the synthesis of anhydrous salts or complexes with different ligands 2-44 aj-g more typical. 

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