2567-83-1Relevant articles and documents
Synthesis, characterization, and surface studies of conjugated polymers possessing 2,2'-biimidazole moieties
Walker,Douglas,Mac Lean
, p. 729 - 737 (2009)
Two novel 2,2'-biimidazole-thiophene structures, 5,5'-bis(2,2'-bithiophene- 5-yl)-1,1'-dimethyl-2,2'-biimidazole and 5,5'-bis(3,4-ethylenedioxythiophene-2- yl)-1,1'-dimethyl-2,2'-biimidazole, have been synthesized and electrochemically polymerized. These materials underwent facile oxidation on Pt and ITO surfaces in CH2Cl2/Bu4NPF6 to yield conjugated, electroactive polymer films. The films were characterized with cyclic voltammetry, electronic absorption spectroscopy, and atomic force microscopy.
Isolation of a metal-to-ligand charge-transfer (MLCT) state of a tris 1,4-diimine complex of iron in the solid state: X-ray crystal structure and EPR
Shee, Nirmal K.,Drew, Michael G. B.,Datta, Dipankar
, p. 452 - 456 (2017)
Using 5,6-dihydro-5,6-epoxy-1,10-phenanthroline as the ligand L, the X-ray crystal structure of [FeL3](ClO4)2·2H2O is determined. Its EPR and magnetic properties indicate entrapment of an MLCT state of the type Fe(iii)-L-?.
Alternative mechanistic scheme for salt effects on solvolysis reactions of haloalkanes and related compounds in binary DMSO/H2O solvent mixture
Hojo, Masashi,Aoki, Sho
, p. 1023 - 1030,8 (2020/08/24)
In 75% (v/v) DMSO/H2O solvent mixture, salt effects on the solvolysis reaction rates of haloalkanes and related compounds (RX) have been examined. In spite of the decreased water activity in the solvent mixture, the log(k/s-1) values of typical Sn1 substrates, such as 1-bromoadamantane, increase with increasing concentration of added metal perchlorates (the order: Li+ + 2+ 2+), which is attributed to the direct chemical interaction between the leaving-group anion and the metal cation in the "modified" solution. Contrastingly, the log(k/s-1) value of an Sn2 substrate decreases with increasing concentration of the metal perchlorates. When nonmetallic salts containing anions (Y- = Cl- or Br -) different from RX (X- = Cl-, Br-, or TsO-) are present, solvolyses of Sn2, such as 1-bromohexane, are subjected to an anion-exchange reaction. By the detailed examination of Δlog(k/s-1)/Δ[Mg(Cl O4) 2] for typical Sn1, Sn1-Sn2 borderline, and Sn2 substrates, we were able to demonstrate a linearity between the Mg(Cl O4)2 effects in the solvolysis rates and the carbocation stabilities expressed by the Gibbs free energy values (ΔG°) of RX in the gas phase. The salt effects on the solvolyses of Sn1 to Sn2 substrates are accounted for without relying on Winstein's reaction scheme or the arbitrary function of ion pairs of two types.
Conductivity and dissociation constants of quaternary ammonium perchlorates and picrates in 4-methyl-pentan-2-one
Goga, Sergey T.,Lebed, Alexander V.,McHedlov-Petrossyan, Nikolay O.
body text, p. 1887 - 1892 (2011/07/30)
The dissociation of 14 ionophores, namely, seven symmetrical (C1 to C7) and five asymmetrical quaternary ammonium perchlorates and two tetraalkylammonium picrates (all with linear hydrocarbon chains), in 4-methyl-pentan-2-one was studied at 25 °C (εr = 12.92) using the conductance method. The values of the association constants of the quaternary ammonium cation, Ct+, with ClO4- vary from (7.4 ± 0.3) ·103 L·mol-1 for tetramethylammonium to (2.4 ± 0.1) ·103 L·mol-1 for tetrahexyl- and tetraheptylammonium; a distinct dependence on the size of the Ct+, especially for symmetrical cations, is evident. The values of the limiting molar conductivities Λ0/S·mol-1·cm2 vary from 122.8 to 90.0 (± 0.7). The plot of Λ0 versus the reciprocal cube root of the total van der Waals volume of the cations, V Ct-1/3, is close to linear up to tetrapentylammonium and hexadecyltrimethylammonium, while for larger cations (with 21 to 28 carbon atoms) the Λ0 values stay practically constant. At the same time, symmetrical and asymmetrical cations with the same VCt values possess equal mobility.
Models for Copper-Dioxygen Complexes: the Chemistry of Copper(II) with Some Planar Tridentate Nitrogen Ligands
Piguet, Claude,Bocquet, Bernard,Mueller, Edgar,Williams, Alan F.
, p. 323 - 337 (2007/10/02)
The solution chemistry of Cu(II) with a series of five planar tridentate nitrogen ligands, 2,6-bis(benzimidazol-2-yl)pyridine (bzimpy, 1), 2,6-bis(1-methylbenzimidazol-2-yl)pyridine (mbzimpy, 2), 2,6-bis(benzothiazol-2-yl)pyridine (bzthpy, 3), 2,6-bis(benzoxazol-2-yl)pyridine (bzoxpy, 4), and 2,2',6',2"-terpyridyl (terpy, 5) is reported.Electronic and EPR spectra are consistent with the complexes 2+ having essentially tetragonal structure in solution, with the fourth coordination site in the plane of the ligand occupied by solvent. bzthpy and bzoxpy show smaller ligand-field splittings than bzimpy, mbzimpy, and terpy, and are easily decomplexed from the copper.Substitution of the coordinated solvent molecule in the plane of the ligand is observed with Cl- and OH- (provided that the ligand has no acidic protons) for all ligands except terpy.The reaction between 2+ and imidazole has been studied by potentiometric titration in MeCN/H2O 1:1 and shows strong binding of the imidazole in the plane (log K = 4.5 at 25 deg C), and also the formation of an imidazolate-bridged dinuclear species.
