1.10- Phenanthroline ligand structure

The versatility of the structural types possible for 1,10-phenanthroline ligands is exemplified in a review article on metal-to-ligand charge-transfer (MLCT) excited states of copper(ll) bis-phenanthroline coordination compounds, where 14 different 1,10-phenanthroline-based ligands were discussed (Figure 2) <2000CCR243>. 

Examples of redox indicators are Indigo Carmine (C.I. 73015 [ 860-22-0] 8), which is frequently employed, and ferroin, an iron(n) complex with three 1,10-phenanthroline ligands (14), which is widely used in water and wastewater analysis in the determination of chemical oxygen demand (COD) in an internationally standardized procedure. For the structure of the organic ligand, see p. 539. 

For [Cr(CO)4(phen)] and [W(CO)4(phen)], the crystal structures are known (85CJSC66, 85CJSC69, 90MK129). The ability of 1,10-phenanthroline to substitute 2,2 -bipyridine from [Mo(CO)4(bpy)] is ascribed to the more expressed ji-acceptor function and rigidity of the 1,10-phenanthroline ligand (88IC81). 

Fig. 13 Structure of the first trefoil knot as it exists in its crystals, with the copper(I) ions shown as clear spheres in the tetrahedral coordination sphere of two phenanthroline ligands...

Figure 2.31 Molecular structure of Eu(F )3 (dmphen)(EtOH)dmphen. (Displacement ellipsoids for non-FI atoms are shown at the 50% probability level and H atoms are represented by circles of arbitrary size) [26b]. (Reprinted from Inorganica Chimica Acta, 360, C.R. De Silva, J.R. Maeyer, R. Wang, GS. Nichol, Z. Zheng, Adducts of europium -diketonates with nitrogen p,p -disubstituted bipyridine and phenanthroline ligands Synthesis, structural characterization, and luminescence studies, 3543-3552, 2007, with permission from Elsevier.)...

The Lehn group synthesised the trinuclear copper(I) complex of the substituted 2,2 -bipyridyl/ether derivative 29 and confirmed its helical structure by X-ray diffraction (Figure 6.15). A dinuclear copper(I) complex of 30 (Figure 6.15) was also synthesised and subsequently the corresponding dimeric ethane-bridged bipyridine and phenanthroline ligands were also demonstrated to yield similar di-helicate copper(I) species. These results thus indicate that helicate formation is tolerant towards minor modification of ligand structure. ... 

No attempt has been made to include coverage of the structurally related 1,10-phenanthroline ligand nor of substituted derivatives of bpy once again, this was in an attempt to keep the literature to manageable proportions. We hope that this review will be of use to those working in the area of metal-bpy complexes. Complexes of the related ligand 2,2 6, 2 -terpyridine have been reviewed previously 158). 

Hara K., Horiuchi H., Katoh R., Singh L. P., Sugihara H., Sayama K., Murata S., Tachiya M. and Arakawa H. (2002), Effect of the ligand structure on the efficiency of electron injection from excited Ru-phenanthroline complexes to nanocrystalline Ti02 films , J. Phys. Chem. B. 106, 374-379. 

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