84175-08-6

Upstream product

• 7275-43-6 [2,2']bipyridinyl 1,1'-dioxide 
• 366-18-7 [2,2]bipyridinyl 
• 51595-55-2 4,4'-dinitro-2,2'-bipyridyl-N,N'-dioxide 

Downstream Products

• 1762-41-0 4,4'-dichloro-2,2'-bipyridine 
• 254450-33-4 4,4'-([2,2'-bipyridine]-4,4'-diyl)diphenol 
• 85698-56-2 N⁴,N⁴,N^4',N^4'-tetramethyl-[2,2'-bipyridine]-4,4'-diamine 
• 17217-57-1 4,4'-Dimethoxy-2,2'-bipyridin 
• 101028-38-0 4,4'-bis(methylthio)-2,2'-bipyridine 

Relevant academic research and scientific papers

Electronic effects on reactivity and anticancer activity by half-sandwich N,N-chelated iridium(iii) complexes

The synthesis and characterization of a series of organometallic half-sandwich N,N-chelated iridium(iii) complexes bearing a range of electron-donating and withdrawing substituents were described. The X-ray crystal structures of complexes 1, 3 and 5 have been determined. This work demonstrated how the aqueous chemistry, catalytic activity in converting coenzyme NADH to NAD+ and anticancer activity can be controlled and fine-tuned by the modification of the ligand electronic perturbations. In general, the introduction of an electron-withdrawing group (-Cl and-NO2) on the bipyridine ring resulted in increased anticancer activity, whereas an electron-donating group (-NH2,-OH and-OCH3) decreased the anticancer activity. Complex 6 bearing a strongly electron-withdrawing NO2 group displayed the highest anticancer activity (7.3 ± 1.2 μM), ca. three times as active as cisplatin in the A549 cell line. Notably, selective cytotoxicity for cancer cells over normal cells was observed for complexes 1 and 6. DNA binding does not seem to be the primary mechanism for cancer fighting. However, the aqueous chemistry, cell apoptosis and cell cycle, which show similar dependence on the ligand electronic perturbations as the anticancer activity, appear to together contribute to the anticancer potency of theses complexes. This work may provide an alternative strategy to enhance anticancer activity for these N,N-chelated organometallic half-sandwich iridium(iii) complexes.

Synthesis and in vitro evaluation of diverse heterocyclic diphenolic compounds as inhibitors of DYRK1A

Dual-specificity tyrosine phosphorylation-related kinase 1A (DYRK1A) is a dual-specificity protein kinase that catalyses phosphorylation and autophosphorylation. Higher DYRK1A expression correlates with cancer, in particular glioblastoma present within the brain. We report here the synthesis and biological evaluation of new heterocyclic diphenolic derivatives designed as novel DYRK1A inhibitors. The generation of these heterocycles such as benzimidazole, imidazole, naphthyridine, pyrazole-pyridines, bipyridine, and triazolopyrazines was made based on the structural modification of the lead DANDY and tested for their ability to inhibit DYRK1A. None of these derivatives showed significant DYRK1A inhibition but provide valuable knowledge around the importance of the 7-azaindole moiety. These data will be of use for developing further structure-activity relationship studies to improve the selective inhibition of DYRK1A.

Ruthenium(II)–Pyridylimidazole Complexes as Photoreductants and PCET Reagents

Complexes of the type [Ru(bpy)2pyimH]2+[bpy = 2,2′-bipyridine; pyimH = 2-(2-pyridyl)imidazole] with various substituents on the bpy ligands can act as photoreductants. Their reducing power in the ground state and in the long-lived3MLCT excited state is increased significantly upon deprotonation, and they can undergo proton-coupled electron transfer (PCET) in the ground and excited state. PCET with both the proton and electron originating from a single donor resembles hydrogen atom transfer (HAT) and can be described thermodynamically by formal bond dissociation free energies (BDFEs). Whereas the class of complexes studied herein has long been known, their N–H BDFEs have not been determined even though this is important in view of assessing their reactivity. Our study demonstrates that the N–H BDFEs in the3MLCT excited states are between 34 and 52 kcal mol–1depending on the chemical substituents at the bpy spectator ligands. Specifically, we report on the electrochemistry and PCET thermochemistry of three heteroleptic complexes in 1:1 (v/v) CH3CN/H2O with CF3, tBu, and NMe2substituents on the bpy ligands.

Novel di- and tetra(pyrazolyl)bipyridine ligands and their Co (II)-complexes for electrochemical applications

Novel di- and tetra(pyrazolyl)bipyridine ligands have been prepared from available bipyridine N-oxide and N,N′-dioxide nitro derivatives via nucleophilic substitution reactions. The ligands were converted to the corresponding homoleptic octahedral cobalt

Exchange of pyridine and bipyridine ligands in trimethylplatinum(iv) iodide complexes: Substituent and solvent effects

A series of mononuclear trimethylplatinum(iv) complexes of bipyridine ligands, [PtMe3(L-L)I] (L-L = bipy, 4-Mebipy, 4-MeObipy and 4-Me2Nbipy) has been synthesized by the reaction of trimethylplatinum(iv) iodide with bipyridine ligands L-L in an equimolar ratio. Also, treatment of mononuclear trimethylplatinum(iv) iodide complexes of pyridine ligands, [PtMe3L2I] (L = py, 4-Mepy, 4-MeOpy and 4-Me2Npy) with the corresponding bipyridine ligands leads to the exchange of the pyridines by the bipyridine ligands, thereby resulting in the formation of the more stable chelate bipyridine complexes. The ligand-exchange reactions have been studied by 1H NMR spectroscopy. The 1H NMR spectra of a 1: 1 mixture of mononuclear pyridine complexes [PtMe3L2I] and corresponding bipyridine ligands L-L reveal the formation of two chelate bipyridine complexes, [PtMe3(L-L)I] and [PtMe3(L-L)L]I, in solution. Speciation of the pyridine and bipyridine complexes in solution was found to be dependent on the substituent as well as on the nature of the solvent. Furthermore, crystal structures of three bipyridine complexes [PtMe3(L-L)I] (L-L = 4-Mebipy, 4-MeObipy and 4-Me2Nbipy) have also been investigated here.

Strongly blue luminescent cationic iridium(III) complexes with an electron-rich ancillary ligand: Evaluation of their optoelectronic and electrochemiluminescence properties

Two strongly blue luminescent cationic heteroleptic iridium complexes 1b and 2b bearing a 4,4′-bis(dimethylamino)-2,2′-bipyridine (dmabpy) ancillary ligand and either 1-benzyl-4-(2,4-difluorophenyl)-1H-1,2,3-triazole (dFphtl) or 2-(2,4-difluorophenyl)-5-methylpyridine (dFMeppyH), respectively, have been synthesized and fully characterized. In comparison with other analogues, the interplay of the triazole unit with the dmabpy unit and methylation of the pyridine ring are discussed with respect to the photophysical, electrochemical, and electrochemiluminescent (ECL) properties of the complexes. The two complexes, 1b and 2b, are blue emitters with λmax = 495 and 494 nm, respectively. The nature of the excited states was established by various photophysical and photochemical experiments as well as DFT calculations. Both complexes emit from a ligand-centered state, however, the emission of 1b possesses significant charge-transfer character, which is absent in 2b. The presence of the methyl group on the cyclometalating ligand leads only to a modest increase in the radiative rate constant, k r, but otherwise does not appreciably influence the optoelectronic properties of the complex compared with the non-methylated analogue. In contrast, the efficacy of the ECL emission when scanning to 2.50 V is strongly influenced by the presence of the methyl group. ECL emission is also enhanced in complexes bearing dmabpy ancillary ligands compared with those containing dtBubpy ligands. The two complexes exhibit similar electrochemical behavior. Incorporation of the dmabpy ligand shifts both the oxidation and reduction cathodically. The combination of the dmabpy and dFphtl groups increases the redox potential difference and thus the HOMO-LUMO gap but the emission is not further blueshifted. Thus, the structural modification of the cyclometalating ligand, although only modestly tuning the emission energy, modulates the nature of the excited state and the efficiency of the ECL process. The synthesis, photophysical, electrochemical, and electrochemiluminescent properties of two highly emissive cationic blue-emitting Ir complexes are reported. Variation of the ligand results in a change in the nature of the emission. The decoration on both the cyclometalating and ancillary ligands strongly influences the ECL efficiencies. A detailed DFT/TDDFT study corroborates experiment. Copyright

Conversion of solar energy to chemical energy

The rate of evolution of hydrogen from water by photochemical process using solar energy has been investigated employing fourteen metal complexes as catalysts, ten electron relays, three electron donors and two co-catalysts in different permutation and combinations. The effect of varying reaction conditions like temperature, concentration and pH have also been investigated for the optimum production of hydrogen by the photochemical cleavage of water molecules.

Syntheses, characterizations, and properties of electronically perturbed 1,1′-dimethyl-2,2′-bipyridinium tetrafluoroborates

The syntheses of three new 2,2′-bipyridinium tetrafluoroborate sensitizers are reported. Their preliminary electrochemical and photophysical properties are compared to the properties of the more widely used pyrylium cation sensitizers. In addition, the first examples of triplet-triplet absorption spectra of 2,2′-bipyridinium ions are presented.

Catalytic Conversions in Water. Part 22: Electronic Effects in the (Diimine)palladium(II)-Catalysed Aerobic Oxidation of Alcohols

The electronic effects in the (diimine)Pd-(II)-catalysed aerobic oxidation of alcohols were investigated from the viewpoint of both the catalyst and the alcohol. A 'push-pull' mechanism is operative, where both electron-donating substituents on the benzyl alcohol (ρ = -0.58) and electron-withdrawing groups on the 4,4′-disubstituted-2,2′-bipyridine ligand (ρ = +0.18) increase the reaction rate. The results indicate partial reduction of the palladium centre in the transition state of the rate-limiting step.