Synthesis of Esters of Dioxane Alcohols and Their Performance as Plasticizers for Polyvinyl Chloride Compounds

A procedure was developed for preparing a plasticizer for polyvinyl chloride compounds from the fraction of dioxane alcohols. The main physicochemical properties of the new plasticizer were determined. Items prepared from formulations containing the new plasticizer were fabricated and tested in laboratory.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 972–976.Original Russian Text Copyright © 2005 by Glazko, Gur’yanova, Levanova, Kozlova, Neiman.     

Ascorbic acid as a potential masking agent in the tanning process. Olated chromium complexes involving ligating ascorbate and bridging sulfate groups

Two polynuclear complexes, a dimer and a tetramer, involving sulfate and hydroxo bridges and ligating ascorbate were isolated from aqueous solutions. Structural formulae are proposed on the basis of microanalytical and thermal analysis results, i.r., ¹³C-n.m.r., mass spectral data and magnetic measurements.     

Two‐Dimensional Holo‐ and Hemidirected Lead(II) Coordination Polymers: Synthetic,Spectroscopic, Thermal,and Structural Studies of [Pb(μ‐SCN)2(μ‐ebp)1.5]n and {[Pb(μ‐OAc)(μ‐ebp)](ClO4)}n (ebp=4,4′‐[(1E)‐Ethane‐1,2‐diyl]bis[pyridine]; OAc=Acetato)

Two new coordination polymers of Pb^II complexes with bridging 4,4′‐[(1E)‐ethane‐1,2‐diyl]bis[pyridine] (ebp), thiocyanato, and acetato ligands, [Pb(μ‐SCN)₂(μ‐ebp)_1.5]_n ( 1 ) and {[Pb(μ‐OAc)(μ‐ebp)](ClO₄)}_n ( 2 ), were synthesized and characterized by elemental analysis, FT‐IR, ¹H‐ and ¹³C‐NMR, thermal analysis, and single‐crystal X‐ray diffraction. In 1 , the Pb²⁺ ions are doubly bridged by both the ebp and the SCN⁻ ligands into a two‐dimensional polymeric network. The seven‐coordinate geometry around the Pb²⁺ ion in 1 is a distorted monocapped trigonal prism, in which the Pb²⁺ ions have a less‐common holodirected geometry. In 2 , the Pb²⁺ ions are bridged by AcO⁻ ligands forming linear chains, which are also further bridged by the neutral ebp ligands into a two‐dimensional polymeric framework. The Pb²⁺ ions have a five‐coordinate geometry with two N‐atoms from two ebp ligands and three O‐atoms of AcO⁻. Although ClO acts as a counter‐ion, it also makes weak interactions with the Pb²⁺ center. The arrangement of the ligands in 2 exhibits hemidirected geometry, and the coordination gap around the Pb²⁺ ion is possibly occupied by a configurationally active lone pair of electrons.     

Λ-Shaped Policies to Schedule Deteriorating Jobs

We study a problem of scheduling deteriorating jobs, i.e. jobs whose processing times are an increasing function of their starting times. We consider the case of a single machine and linear job-independent deterioration. The objective is to minimize the sum of weighted completion times, with weights proportional to the basic processing times. The optimal schedule is shown to be Λ-shaped, i.e. the sequence of the basic processing times has a single local maximum. Moreover, we show that the problem is solved in O(N log N) time. In the last section we test heuristics for the case of general weights.     

Estimation of micropore size distribution in active carbons from adsorption isotherms of water vapor

A possibility of estimation of the micropore size distribution in the carbon adsorbents with the developed micro-and mesoporous structure by analysis of the adsorption isotherms of water vapors was considered. At saturation water condenses in micropores in a form of a weakly compressed liquid. However, water molecules in micropores are packed not so closely as in the liquid because of steric hindrance. Therefore, the real density of water adsorbed in the micropores is lower than that of water adsorbed on an open surface and lower than the density of the normal liquid. An analysis of the adsorption isotherms of water vapors with account for the both opposite effects on the water density gives reliable data on the micropore sizes of the carbon adsorbents. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 40–43, January, 2007.     

Stability of lyophobic sols

The coagulation of positively charged sol of hydrous ferric oxide of different average sizes for potassium sulphate has been studied in the presence of glucose and urea which stabilise the sol. The degree of stabilisation increases with the fineness of dispersed particles. It has been concluded that the adhesive tendency of the surface of dispersed particles decreases in the presence of said non-electrolytes leading to a decrease in the frequency of collisions resulting in stabilisation. The stability ratioW increases in the presence of glucose and urea for the same amount of the coagulant.

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Zusammenfassung Die Koagulation positiv geladener Sole von wäßrigem Ferrioxid verschiedener mittlerer Partikelgrößen mit Kaliumsulfat wird in Gegenwart von Glykose und Harnstoff, die beide das Sol stabilisieren, untersucht. Der Grad der Stabilisierung hängt von der Teilchengröße ab. Es wird geschlossen, daß die Adhäsionstendenz der Oberflächen der dispergierten Partikel in Gegenwart besagter Nichtelektrolyte abnimmt und so zur Abnahme der Kollisionshäufigkeit und damit zur Stabilisierung führt. Das StabilisierungsverhältnisW wächst in Anwesenheit von Glykose und Harnstoff für gleiche Beträge des Koagulators.

     

Synthesis and structural characterization of a coordination polymer of silver(I) with saccharinate and nicotinamide

A silver(I)-saccharinato (sac) complex with nicotinamide (nia), [Ag(sac)(nia)] _n has been synthesized and characterized by elemental analysis, IR spectroscopy, DTA-TG analyses and single crystal X-ray diffractometry. The complex crystallizes in monoclinic space group P2₁/n with unit cell parameters of a=7.0258(4) Å, b=24.3784(10) Å, c=8.4301(5) Å, β=109.407(5)°, V=1361.85(13) ų and Z=4. [Ag(sac)(nia)] _n contains [Ag(sac)(nia)] units, which are doubly bridged by both nia and sac ligands, leading to a linear one-dimensional polymeric chains running along the a axis. The silver(I) ion has a highly distorted AgN₂O₂ tetrahedral geometry and the coordination polymer exhibits relatively short intra-chain ligand supported Ag···Ag separations of 3.1593(4) Å. The one-dimensional chains are crosslinked by N–H···O hydrogen bonds and aromatic π(sac)···π(nia) stacking interactions to generate a two-dimensional layer structure. IR spectra and thermal analysis data are in agreement with the crystal structure.     

An Aqua‐Bridged Helical‐Chain Copper(II)‐Saccharinato Polymer Linked into a Two‐Dimensional Supramolecular Framework

A new assembly [Cu₂(sac)₂(μ‐dmea)₂(μ‐H₂O)]_n (sac = saccharinate and Hdmea = 2‐dimethylaminoethanol) has been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X‐ray diffraction. The complex crystallizes in the monoclinic space group C2/c and consists of dinuclear modules of [Cu₂(sac)₂(dmea)₂]. The sac ligand is N‐coordinated, while the dmea ligand is in the deprotanated form by losing the ethanol hydrogen atom and acts as a bidentate donor through the alkoxo group and N atom. The alkoxo group also serves as a bridge between two copper(II) ions, leading to an intra‐dimer Cu···Cu separation of 3.0229(7) Å. The dimeric units are bridged by aqua ligands to generate a one‐dimensional water‐bridged helical chain, in which the copper(II) ions exhibit a distorted square‐pyramidal CuN₂O₃ coordination. The Cu–Cu distance in the chain separated by the bridging aqua ligands is 5.297Å. The polymeric chains are further linked by π(sac)···π(sac) and C–H···π(sac) interactions into a two‐dimensional supramolecular network.     

[Hg2(μ‐bpe)(μ‐OAc)2(μ‐SCN)2]n,a New Two‐Dimensional Coordination Polymer Involving Three Simultaneously Bridging Ligands: 1,2‐Bis(4‐pyridyle)ethene,Acetate, and Thiocyanate

A new mercury(II) complex of 1,2‐bis(4‐pyridyle)ethene (bpe) with anionic acetate and thiocyanate ligands has been synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. The single crystal X‐ray analysis shows that the complex is a two‐dimensional polymer with simultaneously bridging 1,2‐bis(4‐pyridyle)ethane, acetate and thiocyanate ligands and basic repeating dimeric [Hg₂(μ‐bpe)(μ‐OAc)₂(μ‐SCN)₂] units. The two‐dimensional system forms a three‐dimensional network by packing via π‐π stacking interactions.