Recent development of aminophosphine chalcogenides and boranes as ligands in s-block metal chemistry

The coordination chemistry of the aminophosphine chalcogenide ligands [Ph₂P(O)NHR], [Ph₂P(S)NHR], and [Ph₂P(Se)NHR] (R = 2,6-Me₂C₆H₃,^tBu, CHPh₂, CPh₃) or corresponding borane derivative [Ph₂P(BH₃)NHR] toward group 1 and 2 metals is reviewed. The structural characterization of a huge number of mono- and bis-aminophosphine chalcogenide/borane complexes with group 1 and 2 metals—in most cases lithium, sodium, potassium, magnesium, calcium, strontium, and barium complexes—reveals a poly-metallacyclic motif in each case. The coordination takes place from adjacent chalcogen/borane and nitrogen as donor atom or group of the ligand confirming the direct bond between metal and chalcogen/borane to develop homoleptic and heteroleptic complexes. The heteroleptic group 2 metal complexes were used as pre-catalysts in hydrophosphination and hydroamination reactions. Similarly, aminophosphine chalcogenide alkaline earth metal complexes were used in the catalytic ring-opening polymerization (ROP) study of ?-caprolactone.     

Crown ether complexes of sodium and potassium 2-(benzotriazol-2-yl)phenolates: Synthesis and catalysis towards the ring-opening polymerization of rac-lactide

Crown ether complexes of sodium and potassium 2-(benzotriazol-2-yl)phenolates were synthesized and characterized. In the presence of BnOH these complexes are highly active catalysts for the controlled ring-opening polymerization of rac-lactide. The polymerizations are iso-selective and the P_m of polylactide reached 0.77 when the polymerization was performed in toluene at ?60°C; whereas heterorich-polylactide was obtained when the polymerization was carried out in CH₂Cl₂ or THF.     

7,8-二氢-6,6-二甲基-7,8-环氧-6氢-吡喃[2,3-f]苯并-2,1,3-噁二唑的合成

本文给出了一条较好的制备7,8-二氢-6,6-二甲基-7,8环氧-6氢-吡喃[2,3-f]苯并-2,1,3-噁二唑的合成路线,即由对乙酰氨基苯酚经酯化、Fries重排、环合、还原、脱水、硝化、脱酰基、氧化、脱氧和催化环氧化等反应制得标题化合物,其结构经元素分析和光谱数据确证。     

Protonation and sodium ion-pairing of the sulfite ion in concentrated aqueous electrolyte solutions

A protocol has been developed for the reliable titration of aqueous sulfite solutions which minimizes photodecomposition effects. This procedure has been used to measure the protonation constants of the sulfite ion in aqueous solution by glass electrode potentiometry at 25.0‡C and ionic strengths (I) from 0.1 to 5.0M in NaCI media and atI = 1.0M in KC1 and Me₄NCl media. These measurements provided evidence of weak but significant ionpairing between SO2/3 -and Na⁺ with a formation constant of logK _Na = 0.431 in 1.0M Me₄NCl. This was in very good agreement with the value logK _Na = 0.410 measured directly by Na⁺ ion-selective electrode potentiometry. Evidence is also presented for an extremely weak association of K⁺ and SO ₂ ³ -with logK _k = 0.22 in 1.0M Me₄NCl.     

Conductance Study of the Binding of K+ by Dibenzo-pyridino-18-crown-6 and 1,10-N,N′-didecyl-diaza-18-crown-6 in Acetonitrile

The binding of K+ by dibenzo-pyridino-18-crown-6 (B2-py-18-C-6) and1,10-N,N-didecyl-diaza-18-crown-6 (22-DD) has been studiedconductometrically at 10, 15, 20 and 25 °C in acetonitrile. Thecomplexes formed were assumed to have 1 : 1 stoichiometry. The complexes ofK+ with 18-crown-6 (18-C-6) and dibenzo-18-crown-6 (B2-18-C-6) were alsostudied for comparison purposes. The stability constant, K, of a givencomplex and its molar conductance, c, were obtained by subjectingthe conductance data to a non-linear least-squares curve fitting procedure.The values of the enthalpy change, H, the entropy change, Sand the Gibbs free energy, G, associated with the formation of the 1: 1 complexes were derived and compared with relevant literature data. Thevalues of G at 25 °C indicate that the binding capacity of thefour macrocycles follows the order 18-C-6 > 22-DD > B2-18-C-6 >B2-py-18-C-6. The difference between the molar ionic conductance of the freeK+ cation and that of the bound cation, KL+, was estimated and the trend insuch differences correlates with the molecular size of the macrocycle, L.     

Molar conductance of aqueous solutions of sodium, potassium, and nickel trifluoromethanesulfonate at 25‡C

The electrical conductivities of aqueous solutions of NaCF₃SO₃, KCF₃SO₃, and Ni(CF₃SO₃)₂ have been measured at 25‡C in the concentration range 1 to 25X 10^-3 mol-dm^-3 The data approach the Onsager limiting law at low concentrations, leading to a limiting molar ion conductivity for the CF₃SO ₃ ⁻ ion of 44.5±0.2 S-cm²-mol^-1, based on standard values for the cations. Using a simple size parameter for unsymmetrical polyatomic ions, based on the ion geometry, it is shown that the well known empirical relation between the molar conductivities of symmetrical ions and their radii can be extended to include certain polyatomic anions including CF₃SO ₃ ⁻ . The results suggest that the CF₃SO ₃ ⁻ ion is either a weak structure breaker in aqueous solution or neutral in this respect.     

Environmental Effect of Macrocyclic Molecules on the Oxidation of Triethylamine by Ferricyanide Ion in Aqueous Solution

The effect of 18-crown-6 and kryptofix (2,2,1) on the oxidation of triethylamine byaqueous ferricyanide ion has been studied at pH 4, 7, and 9.The macrocycle retarded the normal oxidation process at all pH values,the effect depending on the macrocyclic ligand concentration Kryptofix (2,2,1) had a greater effect than 18-crown-6 at all pHvalues in this study. For 18-crown-6, retardation decreases in the order pH 9 > 4 > 7 while forkryptofix it follows the order pH 9 > 7 > 4.     

对位取代酚钾与10′10′-二烃基-9,9′-联二吖啶盐电荷转移光谱的研究

10,10′-二烃基-9, 9′-联二吖啶盐有很强的荧光, 在光学材料^[1]和重金属离子的分析^[2]中有重要的应用价值。     

Preparation of dibenzofuran-type amorphous polyetherketone by novel etherification reaction

4-Fluorobenzophenone reacted with potassium carbonate in the presence of silica catalyst in diphenyl sulfone solvent to yield 4,4′-dibenzoyldiphenyl ether. This new etherification reaction was extended to three difluoro aromatic ketones. 4,4′-Bis(4-fluorobenzoyl)diphenyl ether ( I ) reacted with potassium carbonate to yield a crystalline poly(oxy-1,4-phenylene-carbonyl-1,4-phenylene) (PEK) and 4,4′-bis{4-[4-(4-fluorobenzoyl)phenoxy]benzoyl}benzene ( II ) gave a crystalline poly(oxy-1,4-phenylene-carbonyl-1,4-phenylene-oxy-1,4-phenylene-carbonyl-1,4-phenylene-oxy-1,4-phenylene-carbonyl-1,4-phenylene-carbonyl-1,4-phenylene)(PEKEKEKK). 2,8-Bis(4-fluorobenzoyl)dibenzofuran ( III ) or 2,8-bis(4-chlorobenzoyl)dibenzofuran ( IV ) reacted with potassium carbonate to yield a poly(oxy-1,4-phenylene-carbonyl-2,8-dibenzofuran-carbonyl-1,4-phenylene) (PEKBK). The PEKBK was a noval amorphous polymer with the glass transition temperature of 222°C and it showed excellent thermal stability [T. Tanabe and I. Fukawa, Jpn. Pat., Kokai 64–74223 (1989)]. Several amorphous dibenzofuran type polyetherketone copolymers were prepared by coplycondensation of III with 4,4′-difluorobenzophenone ( V ) or 1,4-bis(4-fluorobenzoyl)benzene ( VI ) [T. Tanabe and I. Fukawa, Jpn. Pat., Kokai 1153722 (1989)]. © 1992 John Wiley & Sons, Inc.     

Osmotic and activity coefficients of sodium chloride-sorbitol and potassium chloride-sorbitol solutions at 25°C

Osmotic and activity coefficients are reported for sorbitol over the range 1.8–11.1m with NaCl as the reference and 1.8–7.6m with KCl as the reference electrolyte. The osmotic coefficients over the range 0–3.7m are identical with those reported earlier by Robinson. It was found that the activity coefficients of sorbitol are uniformly about four percent lower than those of dextrose. Activity coefficients of trace quantities of NaCl in concentrated sorbitol solutions are about one-half of their value in pure NaCl solutions while the activity coefficients of trace quantities of sorbitol in concentrated NaCl solutions are about one-third of their value in pure sorbitol solutions. Potassium chloride lowers the activity coefficient of sorbitol less than does sodium chloride in solutions of similar water activity. Sorbitol lowers the activity coefficients of potassium chloride in concentrated solution but actually elevates them in dilute solutions.