Ring-forming reactions chelate

Rhodium(IV) complexes magnetic properties, 273 Ring-forming reactions chelate, 433... 

NON-CHELATE RING-FORMING REACTIONS 7.4.2./ Reactions of Donor Atoms... 

A similar reaction is observed with the Cu+2 complex. No reaction occurs with glycine esters. A similar reaction occurs when cobalt (III) complexes are prepared from solutions of hydroxyethylethylenediamine and similar ligands (24, 25). The chelate ring-forming portion of the complex remains intact however, the products derived from the oxidized hydroxyethyl group appear complicated. 

The family of complexes containing Schiff base ligands derived from a-diketones and /J-mercaptoethylamine [the 2,2 -dialkyl (ethanediylidenedinitrilo) -diethanethiol complexes, structure V, Ni(BE), Ni(PE), and Ni(OE)] are well designed to extend chelate ring-forming ligand reactions to their ultimate by forming complete macrocycles, that completely enclose the metal ion. The objective is shown in Equation 24. 

In 1959, the coordinated mercaptide ion in the gold(III) complex (4) was found to undergo rapid alkylation with methyl iodide and ethyl bromide (e.g. equation 3).9 The reaction has since been used to great effect particularly in nickel(II) (3-mercaptoamine complexes.10,11 It has been demonstrated by kinetic studies that alkylation occurs without dissociation of the sulfur atom from nickel. The binuclear nickel complex (5) underwent stepwise alkylation with methyl iodide, benzyl bromide and substituted benzyl chlorides in second order reactions (equation 4). Bridging sulfur atoms were unreactive, as would be expected. Relative rate data were consistent with SN2 attack of sulfur at the saturated carbon atoms of the alkyl halide. The mononuclear complex (6) yielded octahedral complexes on alkylation (equation 5), but the reaction was complicated by the independent reversible formation of the trinuclear complex (7). Further reactions of this type have been used to form new chelate rings (see Section 7.4.3.1). 

Hexaammineplatinum(IV) salts also undergo imine-forming reactions with acetylacetone (equation 49).172 A cobalt(III) acetylacetone complex can be formed as a result of intramolecular addition of cobalt-bound hydroxide ion to acetylacetone. The cobalt-bound oxygen atoms are retained in the new chelate ring (equation 50).173... 

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