Terpy

The unstable pale blue-green bis(2,276, 2 -terpyridine)iron(3+) ion [47779-99-7], [Fe(terpy)2], has been obtained by oxidation of [Fe(terpy)2]. It is very unstable with respect to reduction by solvent and ligand dissociation. The perchlorate salt [2153642-5] has been reported. 

The steric crowding introduced in the latter by the four ethyl substituents inhibits nucleophilic attack at platinum, so that complexes of this type tend to undergo substitution by a dissociative mechanism [89]. The complex of the more rigid ligand, 2,2, 2"-terpyridyl, Pt(terpy)Cl+, is found to be about 103 to 104 times more reactive to substitution than the dien analogue this is ascribed to steric strain [90], which is reflected in the short Pt—N bond to the central nitrogen (Pt-N some 0.03 A shorter than the other two Pt-N bonds) and N—Pt—N bond angles of 80-82°). 

With a tridentate ligand Au(terpy)Cl3.H20 has, in fact, AuCl(terpy)2"1" with weakly coordinated chloride and water while Au(terpy)Br(CN)2 has square pyramidal gold(III) the terpyridyl ligand is bidentate, occupying the axial and one basal position [124]. Macrocyclic complexes include the porphyrin complex Au(TPP)Cl (section 4.12.5) cyclam-type macrocyclic ligands have a very high affinity for gold(III) [125],... 

The preference of gold(III) for planar 4-coordination is such that ligands sometimes adopt unusual denticities. Therefore, Au(N03)J has four mono-dentate nitrates Au(terpy)Cl3.H20 contains Au(terpy)Cl2+ Aupy2Cl3 is Aupy2Cl2 CP Au(S2CNBu2)2Br is Au(S2CNBu2)2 Br- Au(S2CNBu2)3 has one bidentate and two monodentate dithiocarbamates and Au(NH3)4(N03)3 has only ionic nitrates, to quote compounds already mentioned. 

Au(diars)2I2 I has 6-coordinate gold with rather long Au-I distances (3.35 A) [139], AuBr(CN)2(terpy) (Figure 4.28), made as follows,... 

Figure 4.28 Square pyramidal 5-coordination in AuBr(CN)2(terpy) made possible by terpyridyl...

MnMe2(Me2PCH2CH2PMe2)2. 4, 34,103 MnCisHuC NsOs MnCl2(terpy trioxide), 4, 52 MnC1 H11F3N202... 

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