Subject terpyridine

Like mthenium, amines coordinated to osmium in higher oxidation states such as Os(IV) ate readily deprotonated, as in [Os(en) (NHCH2CH2NH2)] [111614-75-6], This complex is subject to oxidative dehydrogenation to form an imine complex (105). An unusual Os(IV) hydride, [OsH2(en)2] [57345-94-5] has been isolated and characterized. The complexes of aromatic heterocycHc amines such as pyridine, bipytidine, phenanthroline, and terpyridine ate similar to those of mthenium. Examples include [Os(bipy )3 [23648-06-8], [Os(bipy)2acac] [47691-08-7],... 

Nomenclature is always a vexing subject the ligand (Fig. 1) has been known variously as 2,2, 2"-tripyridyl, 2,2, 2"-tripyridine, 2,6 -bis(2-pyridyl)-pyridine, and 2,2 6, 2"-terpyridine. The latter is the systematic name (262) and will be used throughout this article. All other compounds will be named systematically, according to lUPAC recommendation A-54. In this article, the abbreviations terpy, quaterpy, quinquepy, bipy, and phen will be used for the ligands in Figs. 1-5, respectively. Substituted derivatives will not be similarly described thus 4,4"-diethyl-4 -phenyl-2,2 6, 2"-terpyridine (Fig. 6) will be denoted 4,4"-Et2-4 -Phterpy. 

Although there are many examples of diimine ligands tethered to organic chromophores, most compounds are based upon 2,2 -bipyridine and 2,2, 2"-terpyridine structures, the subject of other reviews in this series. Historically, (1) and its derivatives have been largely unexplored for... 

One more class of thallium(III) compounds has been subjected to structural investigations, namely the compounds of the type TKpoly-dentate ligandlX, where the polydentate ligands were EDTA (ethylene-diaminetetraacetate), DTPA (diethylenetriaminepentaacetate), TPEN (tetrakis-(2-pyridylmethyl)-ethylenediamine), NTA (nitrilotriacetate), bipy (bipyridine), terpy (2,2" 6, 2 terpyridine), pent-en (N,N,N, N -tet-rakis-(2-aminoethyl)-ethylenediamine), andX = OH, H2O, CN", N03 (106, 109, 94). In these compounds, thallium(III) is usually hepta- or even octa-coordinated, in contrast to monodentate ligands, where the... 

---