168646-53-5

The complex 2+ (tpphz = tetrapyridophenazine), is obtained by reaction of 2+ with 5,6-diamino-1,10-phenanthroline; upon reaction with 2+, the fully conjugated dimer 4+ is obtained.

A pair of symmetrical furyl based ruthenium(II) complexes ([Ru(phen) 2dpq-df]2 + (1) and [Ru(bpy)2dpq-df] 2 + (2) (phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine, dpq-df = dipyrido (3,2-a:2′,3′-c) quinoxaline-difuran) have been prepared and characterized. The binding properties of both complexes toward G-quadruplex DNA have been investigated by fluorescence spectroscopy, UV-Vis spectroscopy, circular dichroism (CD), fluorescence resonance energy transfer (FRET) melting assays and molecular docking studies. The experimental results indicated that both Ru-complexes exhibited a remarkable "light switch" effect in the presence of hybrid G-quadruplex DNA. Interestingly, the "light switch" can be repeated off and on through the successive addition of Cu2 + ions and EDTA, and all these behaviors can be observed even by the naked eyes. Moreover, FRET melting assay revealed that both complexes could be potential stabilizers for G-quadruplex architectures. The computational studies not only confirmed that the two complex molecules bound to one G-quadruplex DNA molecule, but also explained the "light switch" effect.

Photoinduced electron-transfer reactions of [(tpy)RuII(tpy-tpy) CoIII(tpy)]5+ (tpy = 2,2′:6′,2″-terpyridine and tpy-tpy = 6′,6″-bis(2-pyridyl)-2,2′:4′,4″: 2″,2″′-quarterpyridyne), [(tpy)RuII(tpy-ph-tpy) CoIII(tpy)]5+ (tpy-ptitpy = 1,4-bis[2,2′:6′,2″- terpyridine-4′-yl]benzene), and [(bpy)2RuII(tpphz) CoIII(bpy)2]5+ (bpy = 2,2′-bipyridine, and tpphz = tetrapyrido[3,2-a:2′,3′-c:3″,2″-h:: 2″′,3″′-j]phenazine) were studied in the range 140-298 K by means of subpicosecond transient absorption spectroscopy. 3MLCT(Ru) of [(tpy)RuII(L-L)CoIII(tpy)] 5+ (L-L: tpy-tpy and tpy-ph-tpy) underwent intramolecular electron-transfer (EET) reaction to form [2RuIII(tpy)(L-L) 2CoII(tpy)]5+ in a shorter time than 10 ps. Low quantum yields of the EET products (0.53 for tpy-tpy and 0.41 for tpy-ph-tpy in butyronitrile at 298 K) measured before the fast return electron-transfer were found as in the intermolecular electron-transfer quenching of 3MLCT(Ru) by [Co(tpy)2]3+. The quantum yield of [(tpy)-RuIII(tpy-tpy)CoII(tpy)]5+ (Φ) decreases to 0.38 in a slowly reorganizing solvent of propylene carbonate and that of [(tpy)RuII(tpy-ph-tpy)CoIII(tpy)]5+ to 0.21 at 180 K. The reductions in the EET yields, 1 - Φ, can be ascribed to a fast transition of the nonrelaxed EET product to the lowest triplet d-d* state of [CoIII(tpy)2] moiety during the solvent reorganization. A tunneling transition of the nonrelaxed EET products to the lowest lying d-d excited-state of [CoIII(tpy)2] moiety takes place as a hole transfer, HT, from the dπ-orbital of Ru(III) to that of Co(II) with a configuration of dπ6da*. An electronic coupling of dπ(Ru)-dπ(Co) estimated from the intensity of inter-valence transition of [(tpy)RuIII(L-L)RuII(tpy)]5+ (Collin, J.-P.; Laine, P.; Launay, J.-P.; Sauvage, J.-P.; Sour, A. J. Chem. Soc., Chem. Commun. 1993, 434) is large enough to carry out the HT. The weak coupling of dπ(Ru)-dπ(Co) in the case of [(bpy)2Ru(tpphz) Co(bpy)2]5+ attenuates the HT rate to bring about a high yield of EET (0.8). The possibility that energy-transfer of 3MLCT(Ru) to the Co(III) moiety via an intermediate super-exchange coupling between dπ(Ru) and dπ(Co) occurs in competition with the EET of [(tpy)Ru III(tpy-ph-tpy)CoII(tpy)]5+ is also pursued.

The synthesis of both 5-amino-6-nitro-1,10-phenanthroline and 5,6-diamino-1,10-phenanthroline (starting from 5-nitro-1,10-phenanthroline) are described in detail.

Intramolecular charge transfer processes in simple molecules can be exploited to implement combinational digital operation.

The single crystal X-ray structure of the newly synthesized ruthenium (II)-polypyridyl complex, [(bpy)2Ru(L)](PF6)2 (1) (bpy is 2,2′-bipyridyl and L is 2-methyl-2H-1,3,7,8-tetraaza- cyclopenta[l]phenanthren-2-ol revealed a near planar conformation for the fused imidazole moiety, suggesting the complex may be capable of binding to duplex DNA. Binding-induced changes in spectral properties, along with thermal denaturation and viscosity measurement studies confirmed that the complex binds to CT-DNA with a moderately high binding constant value (4.1 × 10 5 M-1) through intercalation. Photocleavage studies with the pBR322 plasmid DNA were performed following excitation of this complex into the Ru(dπ) → bpy/L(π*)-based MLCT band and have shown that this complex cleaves the circular pBR322 DNA into linear DNA. Inhibitor studies revealed that the hydroxyl radicals were mainly responsible for the DNA photocleavage reaction. Preliminary studies indicate that the -OH functionality in 1 was also found to hydrolyse the phosphodiester linkage of pBR322 in the dark.

A series of new RuII Schiff base complexes built on the salphen moiety has been prepared. This includes four flexible monometallic RuII compounds and six rigid bimetallic analogues that contain NiII, PdII or PtII cations into the salphen complexation site. Steady state luminescence titrations illustrated the capacity of the compounds to photoprobe G-quadruplex (G4) DNA. Moreover, the vast array of the Schiff base structural changes allowed to extensively assess the influence of the ligand surface, flexibility and charge on the interaction of the compounds with G4 DNA. This was achieved thanks to circular dichroism melting assays and bio-layer interferometry studies that pointed up high affinities along with good selectivities of RuII Schiff base complexes for G4 DNA. In cellulo studies were carried out with the most promising compounds. Cellular uptake with location of the compounds in the nucleus as well as in the nucleolus was observed. Cell viability experiments were performed with U2OS osteosarcoma cells in the dark and under light irradiation which allowed the measurements of IC50 values and photoindexes. They showed the substantial role played by light irradiation in the activity of the drugs in addition to the low cytotoxicity of the molecules in the dark. Altogether, the reported results emphasize the promising properties of RuII Schiff base complexes as a new class of candidates for developing potential G4 DNA targeting diagnostic or therapeutic compounds.

The present invention relates to a 5-nitro-1,10-phenanthroline derivative, an isomer thereof or a pharmaceutically acceptable salt thereof, and a pharmaceutical composition for preventing or treating tuberculosis containing the same as an active ingredient. The 5-nitro-1,10-phenanthroline derivative, and the isomer thereof or the pharmaceutically acceptable salt thereof shows excellent inhibitory effects against active and inactive tubercular bacillus, and thus can be useful for treating tuberculosis.COPYRIGHT KIPO 2017