The interaction between the aluminum ion (Al3+) and Inogashira fulvic acid (IFA) at pH 3 was investigated using the calibration curve method for 27Al NMR spectra. The average conditional stability constant (log K) can be calculated to be 2.00–2.04 (M−1) (bidentate–monodentate) from the results of 27Al NMR measurements. In addition, because IFA has various coordination sites, including COOH, phenolic and/or alcoholic OH groups, we attempted to synthesize 2,3-dihydroxyterephthalic acid (DHTPA) as a model compound with the functional groups of IFA for the investigation of the microscopic coordination mechanism between Al3+ and IFA by potentiometric titration and 27Al NMR measurements. The pKai values of DHTPA could be determined successfully (pKa1 = 2.3, pKa2 = 3.4 and pKa3 = 7.2; pKa4 was not determined), and these values indicate that DHTPA can act as a powerful chelating ligand, even at pH 3. DHTPA can interact with Al3+, and it predominantly forms 1:1 and 2:1 Al–DHTPA complexes. The calculated average conditional formation constant (log K1 and K2) of each complex can be determined as 1.09 (1:1) and 4.81 (M−1) (2:1). The results obtained showed that both the 1:1 and 2:1 Al–DHTPA complexes are formed and Al3+ interacts with IFA at pH3.We have attempted to synthesize 2,3-dihydroxyterephthalic acid (DHTPA) as a model compound with the functional groups of Inogashira fulvic acid (IFA) for the investigation of the microscopic coordination mechanism between Al3+ and IFA. The complexation of aluminum ions was investigated by means of potentiometric titration and 27Al NMR, and the estimated structures of the complexes formed with the aluminum ion are discussed.

Macrocyclic N,N′,N″,N″′,N″″,N″″′-hexakis(2-aminoethyl)-1,4,7,10,13,16-hexaazacyclooctadecane (haeh) and its complexes with Ni2+ and Cu2+ were synthesized. The protonation and formation constants with Ni2+, Cu2+, and Zn2+ were determined by pH-metry at 25 °C in a 0.5 mol dm−3 KNO3 aqueous solution. The macrocycle haeh forms stable di- and trinuclear species with Cu2+; log K(Cu2(haeh)) = 38.84 ± 0.04 and log K(Cu3(haeh)) = 49.08 ± 0.05. For Ni2+ and Zn2+, the macrocycle forms only a dinuclear complex; log K(Ni2(haeh)) = 29.00 ± 0.02 and log K(Zn2(haeh)) = 26.38 ± 0.02. These metal complexes show a significant tendency to form protonated and hydroxo species. The formation constants obtained are discussed on the basis of electrostatic repulsion and the flexibility of the macrocycles. The formation constants of the metal complexes were also determined at 15 and 35 °C in a 0.5 mol dm−3 aqueous KNO3 solution to obtain the thermodynamic parameters ΔH and ΔS. The results obtained showed that the stability of the copper complexes is dominated by ΔS.The synthesis and characterization of a new, fully functionalized hexaaza macrocycle ligand are described. The complexation of transition metal ions was investigated by means of potentiometric titration, and the estimated structure of the complexes formed with metal ions is discussed.

X-ray photoelectron spectroscopy (XPS) was applied to a neat ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [EMI+][Tf2N–] and its lithium salt solution at room temperature to clarify the composition and structure of its near-surface region. Core level peaks were recorded for Li 1s, N 1s, C 1s, F 1s, O 1s, S 2s, and S 2p. Valence band XPS spectra (0–40 eV binding energy) were also studied. The XPS spectra were analyzed using DV-Xα calculations. Results show that the planar type isomer of the EMI+ cation is dominant at the near-surface region of EMI-Tf2N. Results of XPS measurements show a spectrum of Li 1s in Li/EMI-Tf2N. The proposed models for the preferred orientation of the ions exhibit good agreement with results obtained from the DV-Xα calculations.