Alkyne complexes metal hydroxides

One of the many important differences between phosphorus and nitrogen chemistry is the relative strengths of their bonds to hydrogen. The relatively weak P—H bond means that this functionality can be added across a wide variety of unsaturated molecules (alkenes, alkynes, carbonyls) and hence this represents an excellent method for preparing tertiary phosphines. The addition of P 11 compounds to C=0 and C=N has been described in detail by Gilheany and Mitchell.2 The reaction can be catalyzed by base (potassium hydroxide, butyllithium), acid (HC1, carboxylic acids, sulfonic acids, boron trifluoride), free radical (uv, organic peroxides, AIBN) or metal (simple metal salts, late transition-metal complexes). In some circumstances no catalyst is required at all for P 11 additions to proceed.60... 

Tollen s reagent /tol-Sn/ A solution of the complex ion Ag(NH3>2 produced by precipitation of silver oxide from silver nitrate with a few drops of sodium hydroxide solution, and subsequent dissolution of the silver oxide in aqueous ammonia. Tollen s reagent is used in the SILVER-MIRROR TEST for aldehydes, where the Ag ion is reduced to silver metal. It is also a test for alkynes with a triple bond in the Tposi-tion. A yellow precipitate of silver carbide is formed in this case. 

In place of the commonly used metal halides as the metal precursors, transition metal complexes with labile leaving groups have also been used for the preparations of metal alkynyls (Scheme 10.8). The presence of good leaving groups, for example, N2, MeCN or H2O ligands, would provide potential sites for ligand substitutions. These kinds of reactions are usually carried out in the presence of sodium hydroxide or trialkylamine which act as a base to deprotonate the terminal alkynes. 

The strong cr-donating ability of the alkynyl unit that is capable of raising the energy of the LF excited states, together with the interest in metal alkynyl systems, has led to the synthesis of the first series of luminescent alkynyl complexes of platinum]ii) terpyridine, [Pt]trpy)C=C-R], which was reported by Yam and coworkers [156]. The complexes were prepared in reasonable yields by reacting the platinum]ii) terpyridyl complex, [Pt]trpy)]NCMe)]]OTf)2, with various aryl-alkynes in the presence of sodium hydroxide or triethylamine in methanol [Scheme 10.20). 

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