Synthesis and Physicochemical Study of Chitosan-Containing Calcium Hydroxylapatites

The CaCl₂-(NH₄)₂HPO₄-(C₆H₁₁NO₄)_n-NH₃-H₂O system at 25°C was studied by the solubility (Tananaev’s residual concentrations) technique and pH measurements. The parameters providing for the coprecipitation of nanocrystalline (12.5–18.7 nm) calcium and chitosan hydroxylapatites were found. Calcium-deficient chitosan hydroxylapatites Ca_9.8(PO₄)₆(OH)_1.6 · xC₆H₁₁NO₄ · yH₂O, where x = 0.075 or 0.37 and y = 5.8 or 6.2, and stoichiometric calcium hydroxylapatites Ca₁₀(PO₄)₆(OH)₂ · xC₆H₁₁NO₄ · yH₂O, where x = 0.075, 0.1, 0.2, 0.37, 0.5, or 0.75 and y = 5.7–7.5, were synthesized. Solid phases were characterized by chemical analysis, X-ray powder diffraction, thermogravimetric analysis, and IR spectroscopy.     

Synthesis and physicochemical characterization of nanocrystalline chitosan-containing calcium carbonate apatites

The CaCl₂-(NH₄)₂HPO₄-NH₄HCO₃-(C₆H₁₁NO₄) _n -H₂O system at 25°C has been investigated by the solubility (Tananaev’s residual concentration) method and pH measurements. Coprecipitation conditions have been determined for nanocrystalline type A and B calcium carbonate apatites. Type A: Ca₁₀(PO₄)₆(CO₃) _x (OH)_{2 − 2x} · yC₆H₁₁NO₄ · zH₂O (x = 0.2, 0.5, 1.0; y = 0.1, 0.3, 0.5; z = 5.3−6.7); type B: Ca₁₀[(PO₄)_5.7(CO₃)_0.45]CO₃ · 0.3C₆H₁₁NO₄ · 9H₂O, and Ca₁₀[(PO₄)_5.55(CO₃)_0.675]CO₃ · 0.3C₆H₁₁NO₄ · 9.2H₂O. The solid phases have been characterized by chemical analysis, X-ray diffraction, thermogravimetric analysis, and IR spectroscopy.     

Synthesis and physicochemical characterization of carboxymethylcellulose-containing calcium hydroxylapatite

The CaCl₂-(NH₄)₂HPO₄-C₈H₁₁O₇Na-NH₃-H₂O system was studied at 25°C using the solubility method (Tananaev’s residual concentration method) and pH measurements. The solid phases isolated from the system were characterized using chemical analysis, X-ray powder diffraction, IR spectroscopy, and thermogravimetry. Nanocrystalline carboxymethylcellulose-containing calcium hydroxylapatites Ca₁₀(PO₄)₆(OH)₂ · xH₂O · yC₈H₁₁O₇Na with x = 6–12 and y = 0.1–0.5 were found as a result of the characterization.     

Synthesis and physicochemical characteristics of calcium hydroxyapatite/multiwall carbon nanotubes/collagen nanocomposites

Calcium hydroxyapatite/multiwall carbon nanotubes/collagen nanocomposites were synthesized and subjected to physicochemical analysis. The system CaCl₂-(NH₄)₂HPO₄-multiwall carbon nanotubes-NH₃-H₂O-collagen was investigated at 25°C by the solubility method (Tananaev’s residual concentration method) and by pH measurements. Chemical, X-ray powder diffraction, and thermogravimetric analyses and IR spectroscopy showed that, in the system CaCl₂-(NH₄)₂HPO₄-multiwall carbon nanotubes-NH₃-H₂O-collagen under chosen synthesis conditions, nanocomposites comprising nanocrystalline calcium hydroxyapatite (NCHA), multiwall carbon nanotubes (CNT), and collagen form with the composition Ca₁₀(PO₄)₆(OH)₂ · xCNT · yH₂O · z collagen, where x = 1–5; y = 5.5–7.7, and z = 3, 5, and 10 wt %. The obtained nanocomposites are the products of the coprecipitation of CNT, collagen, and NCHA, which forms in the system by the interaction of CaCl₂ and (NH₄)₂HPO₄.     

Synthesis and physicochemical characterization of nanocomposites of calcium hydroxylapatite-chitosan-multiwall carbon nanotubes

The synthesis and physicochemical characterization of nanocomposites of calcium hydroxylapatite-chitosan-multiwall carbon nanotubes (CNTs) was performed. The CaCl₂-(NH₄)₂HPO₄-(C₆H₁₁NO₄) _n -CNT-NH₃-H₂O system was studied by the solubility (Tananaev’s residual concentration) method and pH measurements at 25°C. Conditions for the joint precipitation of nanocrystalline calcium hydroxylapatite, chitosan, and multiwall CNTs were found. Nanocomposites with the general formula Ca₁₀(PO₄)₆(OH)₂ · x(C₆H₁₁NO₄) · yCNT · zH₂O, where x = 0.1, 0.2, and 0.5; y = 0.5, 2.0, 4.0, and 5.0; and z = 5.9–7.9. The solid phases were characterized by chemical, thermogravimetric, and X-ray diffraction analysis and IR spectroscopy.     

Lysine-containing calcium hydroxylapatite: Synthesis and physicochemical characterization

The CaCl₂-(NH₄)₂HPO₄-NH₂(CH₂)₄NH₂CHCOOH-NH₃-H₂O system at 25°C is studied using Tananaev’s solubility (residual concentrations) method and pH measurements. Lysine-containing calcium hydroxylapatite Ca₁₀(PO₄)₆(OH)_1.9[NH₂(CH₂)₄NH₂CHCOO]_0.1 · 6H₂O is identified using chemical analysis, thermogravimetry, powder X-ray diffraction, and IR spectroscopy.     

ZrONO3)2-H3PO4-KF(HF)-H2O system at molar ratios of PO 43? /Zr = 0.5?1.6 as the basis for phase formation

The system ZrO(NO₃)₂-H₃PO₄-KF(HF)-H₂O was studied at ∼20°C along sections at molar ratios of PO₄³⁻ = 0.5, 1.0, and 1.6; KF: Zr = 1−5; and HF: Zr = 2−6. Phases in precipitates were identified by X-ray powder diffraction; IR spectroscopy; and crystal-optical, chemical, X-ray fluorescence and thermal analyses. The following crystalline phases were isolated: potassium fluorozirconates K₃ZrF₇, K₂ZrF₆, δ-KZrF₅, and KZrF₅ · H₂O; zirconium hydrophosphate Zr(HPO₄)₂ · 0.5H₂O; and potassium fluorophosphate zirconate K₃Zr₃F₃(HPO₄)₃(PO₄)₂. The following amorphous basic oxo(hydroxo)fluorohydrophosphate nitrates were isolated: K₄Zr₄O_2.5F₈(HPO₄)₂(NO₃)₃ · 6H₂O, K₂Zr₃O₃F₂(HPO₄)₂(NO₃)₂ · H₂O, and KZr₃O_1.5F₃(HPO₄)₂(NO₃)₃ · 2H₂O. Fields of solid phases were constructed, and the roles of anions and cations in the phase formation were considered.     

Synthesis and physicochemical properties of calcium hydroxylapatite/multi-walled carbon nanotubes nanocomposites

Calcium hydroxylapatite/carbon nanotubes (HA/CNT) composites with various CNT contents have been synthesized by coprecipitation from aqueous solutions in the CaCl₂-(NH₄)₂HPO₄-NH₃-CNT-H₂O system (25°C) under conditions modeling the interaction between HA (Ca₁₀(PO₄)₆(OH)₂), which is an inorganic component of osseous tissue, and multi-walled CNTs. The empirical formula of the composites is Ca₁₀(PO₄)₆(OH)₂ · nCNT · 6H₂O, where n = 0.2?C5.0. The synthesis products have been identified by the solubility (Tananaev??s residual concentration) method, pH measurements, chemical analysis, X-ray diffraction, IR spectroscopy, electron spectroscopy for chemical analysis, and scanning and transmission electron microscopy. The effect of the CNT concentration in aqueous solution on the composition of the HA/CNT composites and on the crystallographic and morphological characteristics of HA nanocrystals in HA/CNT has been investigated.     

Synthesis and crystal structure of [Na2(μ-H2O)(H2O)CB[5]]Cl2 · 6H2O, [Na3(μ-H2O)4(H2O)4(CNPy@CB[6])]Cl3 · 8H2O, and [Rb2(μ-H2O)2(CNPy@CB[6])]Cl · 8H2O

The chain coordination polymers [Na₂(μ-H₂O)(H₂O)CB[5]]Cl₂ · 6H₂O (I), [Na₃(μ-H₂O)₄(H₂O)₄(CNPy@CB[6])]Cl₃ · 8H₂O (II), and [Rb₂(μ-H₂O)₂(CNPy@CB[6])]Cl₂ · 8H₂O (III) were prepared by heating (110°C) of a mixture of sodium or rubidium chloride, cucurbit[n]uril (CB[n], where n = 5, 6), 4-cyanopyridine, and water. According to X-ray diffraction data, binding of polynuclear cations with CB[n] in I–III occurs through coordination of the oxygen atoms of the cucurbit[n]uril portals to alkali metal atoms. Complexes I–III of the above composition isolated to the solid phase as supramolecular compounds with CB[n] were structurally characterized for the first time.     

A theoretical investigation on the structures of (NH3)·(H2SO4)·(H2O)0-14 clusters

Ternary clusters (NH₃)·(H₂SO₄)·(H₂O)_n have been widely studied. However, the structures and binding energies of relatively larger cluster (n > 6) remain unclear, which hinders the study of other interesting properties. Ternary clusters of (NH₃)·(H₂SO₄)·(H₂O)_n, n = 0-14, were investigated using MD simulations and quantum chemical calculations. For n = 1, a proton was transferred from H₂SO₄ to NH₃. For n = 10, both protons of H₂SO₄ were transferred to NH₃ and H₂O, respectively. The NH₄⁺ and HSO₄⁻ formed a contact ion-pair [NH₄⁺-HSO₄⁻] for n = 1-6 and a solvent separated ion-pair [NH₄⁺-H₂O-HSO₄⁻] for n = 7-9. Therefore, we observed two obvious transitions from neutral to single protonation (from H₂SO₄ to NH₃) to double protonation (from H₂SO₄ to NH₃ and H₂O) with increasing n. In general, the structures with single protonation and solvated ion-pair were higher in entropy than those with double protonation and contact ion-pair of single protonation and were thus preferred at higher temperature. As a result, the inversion between single and double protonated clusters was postponed until n = 12 according to the average binding Gibbs free energy at the normal condition. These results can serve as a good start point for studies of the other properties of these clusters and as a model for the solvation of the [H₂SO₄-NH₃] complex in bulk water.     

Self-assembly of reduced molybdophosphate-based supramolecular architectures and the study of their magnetic properties

Reduced molybdophosphate-based supramolecular compounds, such as (4,4′-H₂bipy)[Co(H₂O)₂]₂[Co(H₂PO₄)₂(HPO₄)₄(PO₄)₂(MoO₂)₁₂(OH)₆] · 17H₂O (1), [Co(2,2′-bipy)₂(H₂O)]₄[Co(H₂O)₂][Co(HPO₄)₆(PO₄)₂(MoO₂)₁₂(OH)₆] · 2H₂O (2), and [Co(2,2′-bipy)₂(H₂O)]₄[Co(H₂PO₄)(H₂O)₂]₂[Co(HPO₄)₆(PO₄)₂(MoO₂)₁₂(OH)₆] · 8H₂O (3) (4,4′-bipy=4,4′-bipyridine, 2,2′-bipy=2,2′-bipyridine), have been synthesized under hydrothermal conditions and characterized. Compound 1 exhibits a three-dimensional supramolecular twofold interpenetrating architecture built up of one-dimensional [P₄Mo₆]-based infinite covalent chains and free 4,4′-bipy molecules. Compound 2 also shows a three-dimensional supramolecular network constructed from one-dimensional covalent [P₄Mo₆]-based chains. Unlike compounds 1 and 2, compound 3 exhibits an interesting three-dimensional ‘honeycomb-like’ supramolecular network constructed by the stacking of [Co(2,2′-bipy)₂(H₂O)] units with one-dimensional channels, in which the [P₄Mo₆]-based polyoxometalate chains are located. The magnetic properties of compounds 2 and 3 are reported. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

两个三维柱层式单一手性配位化合物:合成、结构和性质（英文）

在溶剂热合成条件下得到2个单一手性配位聚合物,即[Cd3((R)-CIA)2(bipy)2.5(H2O)2]·xGuest(1)和[Zn3((R)-CIA)(bmib)2(H2O)2 Cl]·H2O·xGuest(2)((R)-H3CIA=(R)-5-(1-羧基乙氧基)间苯二甲酸,bipy=4,4′-联吡啶,bmib=1,4-双(2-甲基-1H-咪唑-1-基)苯)。X射线单晶结构分析揭示配合物1和2都是柱层式结构的三维框架。从拓扑分析的角度看,配位物1具有(3,3,3,6,6)-连接的网络,拓扑符号为(4.5^2)2(4.8^2)2(42.6^8.8^3.10^2)(4^2.6^8.8^3.9^2)(5.8.9)2,而配合物2是(3,4,4)-连接的网络,拓扑符号为(6·7^2)2(6·7^5)2(6^2·7^4)。此外,对上述配合物的热稳定性、圆二色谱和荧光性质也做了研究。     

基于半刚性双(噻唑基苯并咪唑)和不同羧酸的五个一维配合物的合成和表征

通过水热或溶剂热合成的方法制备了5个一维配合物{[Zn(btbb)_(0.5)(m-phda)]·0.5H_2O}_n(1),{[Cd_2(btbb)(adtda)_2(H_2O)]·H_2O}_n(2),[Mn_2(btbb)(tbi)_2]_n(3),{[Cd(btbb)_(0.5)(3-Nitro-o-bdc)(H_2O)]·H_2O}_n(4)和[Cd_2(btbb)(tbi)_2]_n(5)(btbb=1,4-双(2-(4-噻唑基)苯并咪唑-1-基甲基)苯,m-H_2phda=间苯二甲酸,H_2adtda=1,3-金刚烷二羧酸,H_2tbi=5-叔丁基间苯二甲酸,3-Nitro-o-H_2bdc=3-硝基-1,2-苯二甲酸)。配合物1是一个包含22元环的一维链。配合物2是一个包含8元环的一维链,并且氮配体在这个一维链中仅仅起到装饰作用。配合物3是一个一维双链结构。配合物4是一个包含14元环的一维链。配合物5是一个阶梯状的一维双链结构。     

Synthesis of continuous substitutional solid solutions M1?xNix(H2PO4)2 · 2H2O with M = Mg, Mn, Co, or Zn

New continuous substitutional solid solutions Mg_1−x Ni _x (H₂PO₄)₂ · 2H₂O, Mn_1−x Ni _x (H₂PO₄)₂ · 2H₂O, Co_1−x Ni _x (H₂PO₄)₂ · 2H₂O, and Zn_1−x Ni _x (H₂PO₄)₂ · 2H₂O (0 ≤ x ≤ 1.00) crystallizing in monoclinic space group P2₁/n have been synthesized. Their end-member is Ni(H₂PO₄)₂ · 2H₂O. Ni(H₂PO₄)₂ · 2H₂O is isostructural to magnesium, manganese, iron, cobalt, zinc, and cadmium dihydrogenphosphates. The chemical composition and the unit cell parameters have been determined for the solid solutions. Their IR spectra have been measured. Original Russian Text ? V.N. Viter, P.G. Nagornyi, 2007, published in Zhurnal Neorganicheskoi Khimii, 2007, Vol. 52, No. 1, pp. 19–25.     

Physicochemical modeling of precipitating and dissolving of gypsum in chloride solutions

Physicochemical modeling is used to study the isolation of sulfate ions as α (β)-CaSO₄ · 2H₂O from aqueous solutions. The equilibrium compositions of liquid, solid, and gas phases of the NA₂SO₄-CaCl₂-CO₂-H₂O system are calculated at 25°C, CO₂ partial pressures of 10^−1.53 kPa, CaCl₂/Na₂SO₄ molar ratios of 0.2–3.0, and CaCl₂ concentrations from 0.01 to 0.15 mol/kgH₂O. The Gibbs energies of formation for α(β)-gypsum were determined from experimental solubility data on the α(β)-gypsum-air-water system by solving the inverse problem of physicochemical modeling. The data obtained are ΔG° _f298 (α-CaSO₄ · 2H₂O) = −1796.446 kJ/mol and G° _f298 (β-CaSO₄ · 2H₂)) = −1797.317 kJ/mol. Published in Russian in Zhurnal Neorganicheskoi Khimii, 2006, Vol. 51, No. 5, pp. 889–894. This article was translated by the authors.     

Thermal decomposition of lighter lanthanide selenate hydrates and their solid solutions

The thermal dehydration-decomposition of Ln₂(SeO₄)₃·nH₂O (wheren=12 forLn=Pr, Nd andn=8 forLn=Sm) and Pr_xLn_2−x(SeO₄)₃·nH₂O (wheren=12 forx=1.0 andLn=Nd;n=8 forx=0.2 and 1.0 in case ofLn=Sm) have been reported.

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Zusammenfassung Die thermische Dehydratation-Zersetzung von Ln₂(SeO₄)₃·nH₂O (mitn=12 fürLn=Pr, Nd undn=8 fürLn=Sm) und Pr_xLn_2−x(SeO₄)₃·nH₂O (mitn=12 fürx=1.0 undLn=Nd;n=8 fürx=0.2 und 1.0 in Falle vonLn=Sm) wurde beschrieben.

     

Syntheses and characterization of four coordination compounds derived from 10,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene and benzene-dicarboxylic acids

[Co₂(TTBT)₄(1,2-BDC)₂] _n ?·?4nH₂O (1), [Pb₂(TTBT)₂(1,3-BDC)₂] _n ?·?nTTBT?·?2nH₂O (2), [Fe(TTBT)(1,4-BDC)(H₂O)] _n (3), and [Zn(TTBT)(1,4-BDC)(H₂O)] _n (4) have been hydrothermally synthesized by self-assembly of TTBT (TTBT?=?10,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene), benzene-dicarboxylic acid ligands 1,2-H₂BDC, 1,3-H₂BDC or 1,4-H₂BDC (1,2-H₂BDC?=?1,2-benzenedicarboxylic acid, 1,3-H₂BDC?=?1,3-benzenedicarboxylic acid, 1,4-H₂BDC?=?1,4-benzenedicarboxylic acid), and various metal salts. Compound 1 has dinuclear cluster units, four dimeric Co₂ units connected to form a 32-membered ring via weak offset π–π interactions, which are further stacked via strong π–π interactions to form a 3-D supramolecular framework. Complex 2 contains 2-D layers with rhombohedral grids, which are connected to a 3-D structure by π–π interactions. 3 and 4 feature 1-D infinite chains, which are further extended by strong π–π interactions and O–H···O hydrogen bonds resulting in 3-D supramolecular architectures. The photoluminescent properties of 2 and 4 have also been investigated.     

Syntheses and structures of silver(I) complexes of 4-amino-3,5-dimethyl-4<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazole and 4-amino-3,5-diethyl-4<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazole: role of the substituents

Five silver(I) adducts of 4-amino-3,5-diethyl-4H-1,2,4-triazole (4-NH₂-3,5-Et₂-tz) or 4-amino-3,5-dimethyl-4H-1,2,4-triazole (4-NH₂-3,5-Me₂-tz), namely [Ag₄(4-NH₂-3,5-Et₂-tz)₆](ClO₄)₄ (1), [Ag(4-NH₂-3,5-Et₂-tz)₂] _n ·n(ClO₄) (2), [Ag₄(4-NH₂-3,5-Et₂-tz)₆](CF₃SO₃)₄ (3), [Ag₄(4-NH₂-3,5-Me₂-tz)₆](ClO₄)₄·4H₂O (4) and [Ag₄(4-NH₂-3,5-Me₂-tz)₆](CF₃SO₃)₄·2H₂O (5), have been prepared and structurally characterised by X-ray single crystal diffraction. Two types of Ag₄tz₆ cluster have been observed in the structures of compound 1, 3, 4 and 5, which is rationalised based on the minimisation of the steric repulsions between the substituents on the 3,5-positions of triazole ring. Compound 2 displays an infinite chain structure and may be an intermediate or a minor product in the preparation.     

Complex formation in Nb6O 198? -WO 42? -H+-H2O system where cNb: cW = 4 : 2

Processes occurring in Nb₆O₁₉⁸⁻-WO₄²⁻-H⁺-H₂O system where c _Nb: c _W = 4: 2, c _Nb+W⁰ = 5 × 10⁻³, 2.5 × 10⁻³, or 10⁻³ mol/L, and ionic strengths I = 0.01–0.14 are created by NaCl background electrolyte were studied by pH titration and mathematical modeling. Solute ion species distribution diagrams were obtained for $ Z = \frac{{c_{H^ + }^0 }} {{c_{Nb + W}^0 }} = 0 - 1.5 $ Z = \frac{{c_{H^ + }^0 }} {{c_{Nb + W}^0 }} = 0 - 1.5 . The concentration constants and thermodynamic constants of formation were calculated for isopolyniobotungstate anions (IPNTAs). H _x Nb₄W₂O₁₉^(6−x)−, (x = 1–5), ions were shown to appear in solution only after Nb₆O₁₉⁸⁻ was protonated and aquapolytungstate anions were formed. The results of modeling were supported by the synthesis of Tl₃H₃Nb₄W₂O₁₉ · 16.5H₂O, Tl₂H₄Nb₄W₂O₁₉ · 11H₂O, and NaTl₃(H₄Nb₄W₂O₁₉)₂ · 22H₂O salts, which were identified by chemical analysis and IR spectroscopy.     

大环超分子二(三环己基锡)吡啶-二甲酸酯的合成、结构和抗癌活性

在微波溶剂热中,三环己基氢氧化锡分别与2,6-H_2pydc和3,5-H_2pydc(H_2pydc=吡啶二甲酸)反应,合成了4个二(三环己基锡)吡啶-二甲酸酯:{[(2,6-Hpydc)SnCy_3]·MeOH}_n(1)、[(2,6-pydc)Sn_2Cy_6(H_2O)]·PhH(2)、[(3,5-pydc)Sn_2Cy_6(MeOH)]·MeOH(3)和[(3,5-pydc)Sn_2Cy_6(H_2O)]·EtOH(4)。对它们的组成和结构进行了元素分析、IR、(1H,13C和119Sn)NMR和单晶X射线衍射表征。化合物中心锡与配基原子构成畸形四、六面体构型,由于氢键作用,化合物形成二维大环网状超分子结构。初步探索了1、3对人结肠癌(HT-29)、肝癌细胞(HepG2)、乳腺癌(MCF-7)、鼻咽癌(KB)和肺癌细胞(A549)的增殖抑制活性,结果表明化合物具有广谱和较强的抗癌作用。