16887-79-9Relevant articles and documents
Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) transition metals isonicotinate complexes: Thermal behavior in N2 and air atmospheres and spectroscopic characterization
Nunes, Wilhan Donizete Gon?alves,Teixeira, José Augusto,Ekawa, Bruno,do Nascimento, André Luiz Carneiro Soares,Ionashiro, Massao,Caires, Flávio Junior
, p. 156 - 165 (2018)
Solid-state M(IN)2·nH2O complexes, where M stands for bivalent transition metals (Mn, Fe, Co, Ni, Cu and Zn), IN is isonicotinate and n = 0.5 to 4.0 H2O, were synthesized. Characterization and thermal behavior of the compounds were performed employing elemental analysis (EA), complexometric titration with EDTA, powder X-ray diffraction (PXRD), infrared spectroscopy (FTIR), simultaneous thermogravimetry and differential scanning calorimetry (TG–DSC) in dynamic dry air and nitrogen atmospheres, differential scanning calorimetry (DSC) and TG–DSC coupled to FTIR. The thermal behavior of isonicotinic acid and its sodium salt was also investigated in both atmospheres. The dehydration of these compounds occurs in a single step in both atmospheres. In air atmosphere, the thermal decomposition of the anhydrous compounds also occurs in a single step, except for the copper compound where two steps are observed. In N2 the thermal decomposition of the anhydrous compounds occurs in two consecutive steps, except for iron compound, where three steps are observed. The main gaseous products of thermal decomposition/pyrolysis of the compounds were identified as CO, CO2 and Pyridine. Mn, Co, Cu and Zn compounds show a physical transformation process in DSC curves. The ligand coordinates through the pyridine nitrogen atom to the metal and for the Zn compound, the carboxylate group also participates in the coordination. The IR absorption profile of hydrated and dehydrated compounds suggest that there is a probable change in the coordination mode of the ligand upon dehydration. This change needs to be further investigated, once it is not possible to ensure only with infrared spectroscopy data.
NMR and theoretical study on interactions between diperoxovanadate complex and 4-substituted pyridines
Yu, Xianyong,Zhang, Jun,Zeng, Birong,Yi, Pinggui,Cai, Shuhui,Chen, Zhong
, p. 644 - 649 (2008)
To understand the substituting group effects of organic ligands on the reaction equilibrium, the interactions between diperoxovanadate complex [OV(O2)2(D2O)]-/[OV(O 2)2(HOD)]- and a series of 4-substituted pyridines in solution were explored using multinuclear (1H, 13C, and 51V) magnetic resonance, DOSY, and variable temperature NMR in 0.15 mol/L NaCl ionic medium for mimicking the physiological condition. Some direct NMR data are given for the first time. The reactivity among the 4-substituted pyridines is pyridine > isonicotinate > N-methyl isonicotinamide > methyl isonicotinate. The competitive coordination results in the formation of a series of new six-coordinated peroxovanadate species [OV(O2)2L]n- (L = 4-substituted pyridines, n = 1 or 2). The results of density functional calculations provide a reasonable explanation on the relative reactivity of the 4-substituted pyridines. Solvation effects play an important role in these reactions.
Hydroxide-promoted redox reactions in water of α-phenyl-4-nitrobenzenemethanol, α-(p-nitrophenyl)-4-pyridinemethanol, and α-(p-Nitrophenyl)-4-pyridinemethanol N-oxide steric inhibition of resonance
Muth, Chester W.,Yang, Kaipeen E.
, p. 249 - 254 (2007/10/03)
α-Phenyl-4-nitrobenzenemethanol (3) reacted with 1 M sodium hydroxide to yield 4,4′-dibenzoylazoybenzene (5) (51%), 4-hydroxy-4′-benzoylazobenzene (6) and benzoic acid (12% each), and smaller amounts of 4-aminobenzophenone and 4-nitrobenzophenone. Both α-phenyl-2-nitrobenzenemethanol (9) and 3,5-dimethyl-4-nitrobenzenemethanol (10a) did not react with 1 M sodium hydroxide, presumably due to steric hindrance. α-(p-Nitrophenyl)-4-pyridinemethanol (14) and its N-oxide 11 with 1 M sodium hydroxide yielded 4,4′-diaroylazoxybenzenes 15a and 12a, respectively, 4,4′-diaroylazobenzenes 15b and 12b, respectively, as well as 4-hydroxy-4′-aroylazobenzenes 16 and 13, respectively. The relative reaction rates were 11 > 14 > 3. Studies with 11 showed that the nitro group is involved in the redox reaction in preference to the N-oxide group.
