Pseudohalides carboxylates

Covalent Organotin Halide, Pseudohalide, Carboxylate, and Nitrate Complexes... 

Iron porphyrins, the prosthetic group of the heme proteins are of course of great interest. Tetraphenylporphine, (TPPH2) (Fig. 2) is not a naturally occurring porphyrin. But because of its ease of preparation and close similarity to other porphyrins, tetraphenylporphinatoiron (TFPFe) derivatives have been extensively studied. Hemes are Fe(II) compounds such as TPPFe(II), and hemins are rive coordinate Fe(III) derivatives such as TFPFe(III) X (X = halide, pseudohalide, carboxylate, alkoxide, etc.)16). Six coordinate Fe(III) prophyrins are known as hemichromes, such as [TPPFe(III) L2] X (L = pyridine, piperidine, imidazole, etc.)16). Hemichromes are usually low spin, S = 1/2, systems 0 eff 1-9 B.M.) and hemins are of the high spin,... 

The trivalent [P04] and [As04] ions react similarly. Examples of anions that give insoluble Hg(I) compounds in this way include halides, pseudohalides, halates, carboxylates and sulfate. A trace of HNO3 or HCIO4 is often added to the solution of the Hg(I) nitrate or perchlorate to prevent disproportionation induced by alkali. Table 1 lists common Hg(I) derivatives prepared in this way and includes values of the solubility products of the sparingly soluble Hg(I) compounds where these are measured. A similar reaction is used to prepare HgjCO, from a soluble bicarbonate ... 

The palladium-catalyzed Heck carbonylation reaction is a powerful means of generating amides, esters, and carboxylic acids from aryl halides or pseudohalides [28]. The development of rapid, reliable, and convenient procedures for the introduction of carbonyl groups is important for the development of high throughput chemistry in general and high-speed microwave-mediated chemistry in particular. Unfortunately, the traditional method of introducing carbon monoxide into a reaction mixture via a balloon or gas tube is not practical because of the special requirements of microwave synthesis. 

The complex Cp3Ce(IV)Cl has been synthesized by reacting NaCp and bis(pyridinium) hexachlorocerate in THF. It may also be obtained [56] by the reaction of bis(pyridinium) hexachlorocerate and Cp4Ce. These compounds, Cp3CeCl may be used to prepare other compounds [57] like Cp3CeX, where X = alkyl, aryl, pseudohalide, mercaptide, carboxylate. 

Diorganyl tellurides are starting materials for the preparation of diorganyltellurium dihahdes, pseudohalides, and carboxylates, of telluroxides, and of teUuronium salts, and are used as ligands for the synthesis of transition metal complexes. 

We see that only complexes with formation constants of the order of 106 M-1 or more will lead to titration curves with a sufficiently steep change in pL near the equivalence point (at CM VM / CL VL = 1) to be useful for volumetric analysis. None of the common monodentate ligands, such as the halide anions (Cl-, Br , I-) or the pseudohalides (CN , SCN-, N3 ), form such strong complexes, nor do the carboxylic acid anions (such as acetate) or ammonia (NH3). However, in section 5.2 we will encounter special ligands, the chelates, that do form sufficiently strong 1 1 complexes. 

The greater reactivity of the P-X bond compared with the P-F bond is also evident from metathetical reactions with silver pseudohalides 105, 274) and silver salts of perfluorinated carboxylic acids 105), e.g.,... 

Bivalent tin species in acid solutions are frequently of the pyramidal [SnXs]" type, (e.g. X = halide, pseudohalide, or carboxylate group). Increases in the coordination number beyond three are not normally realized. The [SnFa] ion is the stable and dominant ion in solutions containing excess F however, when insufficient F is present, species such as [F2Sn(/r-F)SnF2] result. 

The iridium(III) complex [Ir(H)3(AsPh3)2(p-MeC6H4NC)] (99) is known to react with HX (or pseudohalides) to yield substitution products [lr(H)2(X)(AsPh3)(p-MeC6H4NC)i (X = Cl, Br, I, Nj). With carboxylic acids or pentane-2,4-dione, complex (99) yields the chelated complexes [Ir(L2)(AsPh3)(p-MeC6H4NC)] (L2 = carboxylate or pentane-2,4-dionate) in which Ir is reportedly reduced to 11. Reactions (52>-(60) reveal the utility of complex (99) in synthesizing complexes with iridium in various oxidation states. ... 

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