Tetrakis 2-hydroxypropyl Ethylenediamine Research Articles

Quadrol-Pd(II) complexes: phosphine-free precatalysts for the room-temperature Suzuki-Miyaura synthesis of nucleoside analogues in aqueous media.

Commercially available Quadrol, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine (THPEN), has been used for the first time as a N^N-donor neutral hydrophilic ligand in the synthesis and characterization of new water soluble palladium(II) complexes containing chloride, phthalimidate or saccharinate as co-ligands. [PdCl2(THPEN)] (1) [Pd(phthal)2(THPEN)] (2), [Pd(sacc)2(THPEN)] (3) and the analogous complex with the closely related N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine (THEEN) [Pd(sacc)2(THEEN)] (4) were efficiently prepared in a one-pot reaction from [PdCl2(CH3CN)2] or Pd(OAc)2. Structural characterization of 1 and 3 by single crystal X-ray diffraction produced the first structures reported to date of palladium complexes with Quadrol. The resultant palladium complexes are highly soluble in water and were found to be effective as phosphine-free catalysts for the synthesis of functionalized nucleoside analogues under room-temperature Suzuki-Miyaura cross-coupling conditions between 5-iodo-2'-deoxyuridine (& 5-iodo-2'-deoxycytidine) with different aryl boronic acids in neat water. This is the first report of the coupling process performed on nucleosides in water at room temperature.

Effects of bath composition on the morphology of electroless-plated Cu electrodes for hetero-junctions with intrinsic thin layer solar cell

The morphology of an electroless-plated Cu electrode was investigated as a function of bath composition. To enhance the selectivity of Cu electrode deposition on the surface of an indium tin oxide layer, a Ti/Cu multi-layer was deposited as a Cu electrode seed layer by physical vapor deposition, and then electroless plating was performed using various complexing agents and a surfactant. The degree of selectivity was effectively influenced by the type of complexing agent. The electroless plating solution containing N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine (THPED) as complexing agent showed excellent selective growth of the Cu electrode as compared to the solution containing ethylenediaminetetraacetic acid. Even though THPED led to better selective growth of the electroless-plated Cu electrode, the aspect ratio of electrode lateral growth was about 2.7 times that of vertical growth. By adding a nonionic surfactant, the ratio between vertical growth rate and lateral growth rate was improved about 4.6 times. The Cu–THPED electroless plating with nonionic surfactant provided a drastic decrease in lateral growth rate, compared with the Cu–THPED electroless plating bath excluding nonionic surfactant. The Cu–THPED solution including nonionic surfactant is a promising composition of electroless plating solution for the clear selective plating of Cu electrodes on hetero-junctions with intrinsic thin layer solar cells.

Anode oxidation of HCHO in THPED-containing electroless copper plating solution

The electrochemical mechanism of anode oxidation of HCHO in electroless copper plating solution with N, N, N′, N′-tetrakis(2-hydroxypropyl)ethylenediamine (THPED) was investigated by measuring cyclic voltammetry curves and anodic polarization curves. Three different oxidation peaks occur at the potentials of −0.62 V (Peak 1), −0.40 V (Peak 2) and −0.17 V (Peak 3) in the anode oxidation process of THPED-containing solution. The reaction at Peak 1, a main oxidation reaction, is the irreversible reaction of adsorbed HCHO with hydrogen evolution. The reaction at Peak 2, a secondary oxidation reaction, is the quasi-reversible reaction of adsorbed HCHO without hydrogen evolution. The reaction at Peak 3 is the irreversible oxidation of anode copper. The current density of Peak 1 increases gradually, that of Peak 2 remains constant and that of Peak 3 decreases with the increase of HCHO concentration. The current density of Peak 3 increases with the increase of THPED concentration and the complexation of THPED promotes the dissolution of anode copper.

Electroless copper plating process of N, N, N′, N′-tetrakis (2-hydroxypropyl) ethylenediamine system with high plating rate

Electroless copper plating process of N, N, N′, N′-tetrakis (2-hydroxypropyl) ethylenediamine (THPED) chelating agent was researched comprehensively. The results indicate that plating rate decreases with the increase of concentration for THPED, CuSO4 · 5H2O and HCHO, pH value and bath temperature. The additive of K4[Fe(CN)6] · 3H2O, 2, 2′-dipyridyl and polyethylene glycol(PEG) decrease plating rate and K4[Fe(CN)6] · 3H2O has a bad effect on deposits quality, but 2, 2′-dipyridyl and PEG make deposits quality improve greatly. Low concentration of 2-mercaptobenzothiozole (2-MBT) increases plating rate and improves deposits quality, but decreases plating rate and worsens deposits quality when 2-MBT reaches 5 mg/L. The optimal conditions of this electroless copper plating process are that the concentration of THPED, HCHO, CuSO4 · 5H2O, PEG, 2, 2′-dipyridyl and 2-MBT are 16.8 g/L, 16.0 mL/L, 13.3 g/L, 0.5 g/L, 5.0 mg/L and 2.0 mg/L, respectively, pH value is 12.75, bath temperature is 30 °C. Plating rate reaches 9.54 µm/h plating for 30 min in the bath. The SEM images demonstrate that the surface of copper film is smooth and the crystal is fine.

Development of comprehensive descriptors for multiple linear regression and artificial neural network modeling of retention behaviors of a variety of compounds on different stationary phases

A new series of six comprehensive descriptors that represent different features of the gas–liquid partition coefficient, K L, for commonly used stationary phases is developed. These descriptors can be considered as counterparts of the parameters in the Abraham solvatochromic model of solution. A separate multiple linear regression (MLR) model was developed by using the six descriptors for each stationary phase of poly(ethylene glycol adipate) (EGAD), N, N, N′, N′-tetrakis(2-hydroxypropyl) ethylenediamine (THPED), poly(ethylene glycol) (Ucon 50 HB 660) (U50HB), di(2-ethylhexyl)phosphoric acid (DEHPA) and tetra- n-butylammonium N, N-(bis-2-hydroxylethyl)-2-aminoethanesulfonate (QBES). The results obtained using these models are in good agreement with the experiment and with the results of the empirical model based on the solvatochromic theory. A 6-6-5 neural network was developed using the descriptors appearing in the MLR models as inputs. Comparison of the mean square errors (MSEs) shows the superiority of the artificial neural network (ANN) over that of the MLR. This indicates that the retention behavior of the molecules on different columns show some nonlinear characteristics. The experimental solvatochromic parameters proposed by Abraham can be replaced by the calculated descriptors in this work.

The neutral oxygen donor in complexes of lead and cadmium: A differential pulse polarographic, potentiometric and calorimetric study

Differential pulse polarography has been used to determine the formation constants of Pb II with ethylenediamine (en) at ionic strength 0.1 M and 5, 25 and 50°C. The equilibria between Pb 2+ and the ligands en and OH − are established rapidly on the polarographic time scale for all complexes studied, so that one peak is observed, that for the metal ion and its labile complexes. At 5°C the following complexes were found: M(HL), ML, ML 2 and ML 2(OH), for which the stability constants (logβ) were found to be 12.97, 5.62, 9.70 and 13.45, respectively. At 25 and 50°C, the complexes ML, ML 2, ML 2(OH) and ML 2(OH) 2 were found and their stability constants were found to be 5.05 and 4.43, 8.67 and 7.37, 12.6 and 11.75, 15.29 and 14.8, respectively. The Lingane equation was modified to allow calculation of formation constants for labile complexes of lead with the two ligands, en and OH −. The two stepwise protonation constants of en at an ionic strength of 0.1 M and temperatures of 5 and 50°C are reported and their values were found to be log K 1 = 10.44 and 8.98 and log K 2 = 7.39 and 6.53, respectively. From the polarographic data, thermodynamic quantities were derived for the overall complex formation reactions of Pb II with en and the values of ΔH° (kJ mol −1) for ML, ML 2, ML 2(OH) and ML 2(OH) 2 were found to be −44.7, −90.6, −65.7 and −39.1, respectively. The stepwise protonation constants of N, N, N′, N′-tetrakis(2-hydroxypropyl)ethylenediamine (THPED) at an ionic strength of 0.5 M and 25°C are reported and their values (log K) wer found to be 8.85 and 4.38. At 25°C and an ionic strength of 0.5 M, the complexes ML, M(HL) and ML(OH) of Cd II and Pb II with THPED were found and their cumulative stability constants (log β) were found to be 7.98 and 7.51, 11.75 and 11.3, 11.14 and 13.00, respectively. The values of ΔH° (kJ mol −1) for ML complexes of Cd II and Pb II with THPED were found to be −48.0. Values of ΔG°, ΔH° and ΔS° for the ligand displacement reaction in which en is displaced by THPED in ML complexes of Pb II and Cd II are also reported and discussed. It is suggested that the coordination numbers of Pb IIin the complexes Pb(en) 2+ and Pb(THPED) 2+ in solution probably differ.

Metal binding properties of poly[N,N,N?,N?-tetrakis(2-hydroxypropyl)ethylenediamine methacrylate

When incorporated into a polymer hydrogel, the metal chelator, N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine (THPED), retains its metal binding properties. The resultant poly(THPED methacrylate) homopolymer is a polybase with displacement binding constants for copper (II) and zinc(II) of-3.11 and-6.55, respectively, as compared to values for THPED of-3.83 and-7.44. The chelating capacity of the polymer for various divalent metal ions at pH 5.5 follows the order Cu>Cd>Co>Zn>Mn, while calcium and magnesium do not bind. Metal ion release curves indicate that after 30 hours, Cd(II), Co(II), Zn(II), and Mn(II) are released at a slow, steady rate, while Cu(II) is not released under experimental conditions.

The Affinity of Gallium(III) and Indium(III) for Nitrogen Donor Ligands

Abstract Dedicated to Professor Arthur Martell on the occasion of his seventy fifth birthday. The complexes of In(III) and Ga(III) with a variety of nitrogen donor ligands were studied in aqueous solution by glass electrode potentiometry at 25°C in 0.1 M NaNO3. The ligands were 2-aminomethylpyri-dine (AMPY), ethylenediamine (EN), N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine (THPED), and N,N-bis(2-hydroxyethyl)glycine (BICIN). A variety of mixed ligand complexes of the MLOH type were detected with many of the above ligands as L. The logK1 values obtained were with Ga(III) 8.40 (AMPY), 7.94 (THPED) 12.72 (EN), and In(III) 7.6 (AMPY), 8.20 (THPED), and 7.06 (BICIN). These formation constants are discussed in relation to previous predictions that In(III) and Ga(III) would have a substantial chemistry with nitrogen donor ligands. Of particular interest is the Ga(III) system with EN, where a very stable Ga(EN)3+ complex is formed, but no higher complexes except for hydrolyzed species such as Ga(EN)OH2+ an...