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Starting from 1,10-phenanthroline, a series of novel ligands(L), imidazo[f]1,10-phenanthroline (IP), 2-phenylimidazo[f]1,10-phenanthroline (PIP) and the derivatives, and their complexes [Ru(bpy) 2 L] 2+ have been synthesized and characterized. The effects of different electron donor and acceptor groups on the 1 H NMR, electronic absorption and emission spectra were studied. Time-resolved luminescence studies revealed that the addition of calf thymus DNA into the complex solution results in increases for both the emissive intensities and excited state lifetimes, and indicates that the electron group on L has no significant effect on the intercalation binding mode between DNA and the complexes.

Two ruthenium(II) complexes with polypyridyl, Ru(bipy)2(phen)](ClO4)2·H2O (1) and [Ru(bipy)2(Me-phen)](ClO4)2 (2), (phen = 1,10-phenanthroline, bipy = 2,2′-bipyridine, Me-phen = 5-methyl-1,10-phenanthroline), were synthesized and characterized by IR, MS and NMR spectra. Their structures were determined by single crystal X-ray diffraction techniques. The strong steric interaction between the polypyridyl ligands was relieved neither by the elongation of the RuN bonds nor increase of the NRuN bite angles. The coordination sphere was distorted to relieve the ligand interaction by forming specific angles (δ) between the polypyridyl ligand planes and coordination planes (NRuN), and forming larger twisted angles between the two pyridine rings for each bipy. The bond distances of RuN(bipy) and RuN(phen) were virtually identical with experimental error, as expected of π back-bonding interactions which statistically involve each of the ligands present in the coordination sphere.

Two cobalt(III) complexes with phenanthroline, [Co(phen)2(gly)]Cl2 · 4H2O (1) and [Co(phen)2(H2O)2](NO3)3 · 2H2O (2), (phen = phenanthroline and gly = glycine), were synthesized and characterized by IR and NMR spectra. Their structures were determined by single crystal X-ray diffraction techniques. The coordinated cations all contain a six-coordinated cobalt atom chelated by two phen ligands and one gly anion or two aqua ligands in cis arrangement. The CoN bond distances in the cations lie in the range 1.934–1.952 A, the bond distances of CoO = 1.919 A (H2O) are significantly longer than that of CoO = 1.884 A (COO−). The complex 2 contains a crystallographic two-fold axis.