Polydentate nitrogen ligands

Figure 1.26 Cold(I) derivatives with polydentate nitrogen ligands...

Table 57 Complexes of Ethylenediamine and other Polydentate Nitrogen Ligands with Dioxouranium(VI) Compounds...

Synthetically useful phosphorane-derived phenyliodonium triflates have been synthesized from the highly electrophilic pyridinium complex 20 <2002TL2359>. Similarly, benziodoxole 21 reacts with trimethylsilyl trifluoro-methanesulfonate (TMSOTf) and pyridine to form a precipitate of complex 22 (Equation 6) <2002TL5735>. The first example of a pentavalent iodine complex with a chelating polydentate nitrogen ligand 24 was obtained from diacetate 23 under similar conditions (Equation 7) <2002TL5735>. 

Polydentate nitrogen ligands are very suited to stabilize mono(cyclooctatetraene) lanthanide(III) complexes. These include silylated benzamidinates [RC6H4C(NSiMe3)2]Ln-(COT)(THF) (Ln = Y, Ce, Pr, Nd, Sm, Tm, Lu R = H, MeO, CF3) (Figure 82a) and diiminophosphinates... 

Table 32 Complexes of ethylenediamine and other polydentate nitrogen ligands with dioxouranium(VI) ...

Substrates 1-4, containing Rp substituents (Cf. eqs. 1-3) have been prepared according to literature procedures [13]. Their electrochemical behaviour and in particular, the CO2 fixation under mild conditions have been examined in the presence of several nickel(II) complexes used as catalyst precursors. Ni(II) derivatives associated to polydentate nitrogen ligands have been reported as efficient catalysts in the electrochemical carboxylation of atkynes [14] and diynes... 

Some polydentate nitrogen ligands prepared during 1980-1990 decade... 

Complexes of rhodium(III) with polydentate nitrogen ligands can also be prepared. Tridentate diethylenetriamine (22) forms [Rh(dien)2]l3 when allowed to react with rhodium trichloride in the presence of Nal. The trichloride salt can be obtained by metathesis with AgCl. The reactions of 1,4,7-triazacyclononane inorganic complexes are of current interest (Scheme 15). ... 

In coordination chemistry, architectures containing the triazole heterocycle have been developed as monodentate and polydentate nitrogen ligands. Special attention has been given to (2-pyridyl)- and more flexible (2-picolyl)-l,2,3-triazoles. Thus, a hbrary of selected 1,4-disubstituted 1,2,3-triazoles differently functionahzed with pyridine, pyrimidine, and pyrazine have been synthesized by the reaction of aryl, heteroaryl, and heteroarylmethyl azides with alkynes. Three different copper(l) sources, that is, CuSO /sodium ascorbate, CuBrlPPhglg, and (CuOTf)2 CgHg, were used to promote the reactions [89]. 

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