Purification and structural determination of hematopoietic stem cell-stimulating monoacetyldiglycerides from Cervus nippon (deer antler)

A mixture of monoacetyldiglycerides was newly isolated from the chloroform extract of antlers of Cervus nippon, guided by the hematopoietic stimulation of stem cells. The structures of monoacetyldiglycerides were determined by various spectroscopic methods: FAB MS, CID tandem MS, and 1D and 2D NMR. A mixture of at least nine inseparable sn-3-monoacetyldiglycerides was identified: 1 [C(39)H(72)O(6) (C16 : 0/C18 : 1)], 2 [C(39)H(72)O(6) (C18 : 1/C16 : 0)], 3 [C(39)H(70)O(6) (C16 : 0/C18 : 2)], 4 [C(39)H(70)O(6) (C18 : 2/C16 : 0)], 5 [C(41)H(74)O(6) (C18 : 0/C18 : 2), 6 [C(41)H(74)O(6) (C18 : 2/C18 : 0)], 7 [C(41)H(74)O(6) (C18 : 1/C18 : 1)], 8 [C(43)H(74)O(6) (C18 : 0/C20 : 4)], and 9 [C(43)H(74)O(6) (C20 : 4/C18 : 0)]. Among these nine monoacetyldiglycerides in deer antlers, compound 3 was one of the major compounds and was efficiently synthesized from glycerol. Spectral data of synthetic monoacetyldiglyceride 3 were compared with the corresponding data for the mixture of natural monoacetyldiglycerides. The mixture of natural monoacetyldiglycerides from deer antlers showed potent activity on the hematopoiesis (stimulation index=1.40+/-0.05, p<0.02 at 1 microg/ml), and synthetic monoacetyldiglyceride 3 showed even better activity (stimulation index=1.54+/-0.12, p<0.001, at 1 microg/ml).     

Secondary hypervalent I(III)...O interactions: synthesis and structure of hypervalent complexes of diphenyl-lambda3-iodanes with 18-crown-6

Reported here for the first time are the synthesis and characterization of supramolecular complexes between diaryl-lambda(3)-iodanes and 18-crown-6 (18C6). Slow evaporation of solvents afforded 1:1 and 2:1 complexes between Ph(2)IBF(4) and 18C6 as stable crystals, depending on the conditions. X-ray crystal structures of these complexes indicated that each iodine atom contacts with the three adjacent oxygen atoms of 18C6 through two hypervalent secondary bonding and a weak interaction. (1)H NMR analyses and CSI-MS spectra showed that, in dichloromethane solution, Ph(2)IBF(4) exclusively forms the 1:1 complex with 18C6 (binding constant K(a), 1.02 x 10(3) M(-)(1)). The binding constants decrease with the increased solvent donor ability (Gutmann's DN). Changing the heteroatom ligand from BF(4) to the less nucleophilic PF(6) and AsF(6) increased the binding constant by about six times. Substitution of an electron-withdrawing group onto the para position of Ph(2)IBF(4) tends to increase in the complex stability. A linear Hammett relationship (rho = 0.59) between log K(a) and sigma(p)(+) values of substituents indicates that the diaryl-lambda(3)-iodanes with electropositive iodine(III) interact more efficiently with 18C6. Decreased binding magnitude was measured with 15C5, dibenzo-18C6, dibenzo-21C7, and dibenzo-30C10.     

Synergistic extraction of cobalt(II) from cesium containing aqueous solutions with mixtures of 4-acyl-pyrazol-5-ols and crown ethers

The synergistic extraction of cobalt(II) from aqueous solutions loaded with cesium chloride or nitrate, with mixtures of 1-phenyl-3-methyl-4-acyl-pyrazol-5-ols (HL) [acyl = benzoyl (HPMBP), para-tert.-butyl-benzoyl (HPMB'P), stearoyl (HPMSP)] and crown ethers E = B15C5, 18C6, DC18C6, DB18C6 and DB24C8 (DC = dicyclohexano, B = benzo, DB = dibenzo), in CHCl(3), CH(2)Cl(2) and ClCH(2)CH(2)Cl, has been studied. The experimental data agree with the extracted species E(2)CsCoL(3) (E = B15C5), ECsCoL(3), (E = DB18C6) and CoL(2)E (E = DB24C8). The extraction yields follow the orders: 18C6 DC18C6 > DB18C6 > B15C5 > DB24C8, HPMBP > HPMB'P > HPMSP, and ClCH(2)CH(2)Cl > CH(2)Cl(2) > CHCl(3). In spite of the better complexation of potassium than cesium with "18C6" type crown ethers, the extraction of ECsCo (PMBP)(3) is generally higher than the EKCo(PMBP)(3) one. Except in the case of DB24C8, loading the aqueous phase with Cs(+), K(+), Sr(2+) or Ba(2+) improves the synergistic extraction of cobalt.     

Structure of hydrated clusters of dibenzo-18-crown-6-ether in a supersonic jet--encapsulation of water molecules in the crown cavity

The structure of dibenzo-18-crown-6-ether (DB18C6) and its hydrated clusters has been investigated in a supersonic jet. Two conformers of bare DB18C6 and six hydrated clusters (DB18C6-(H(2)O)(n)) were identified by laser-induced fluorescence, fluorescence-detected UV-UV hole-burning and IR-UV double-resonance spectroscopy. The IR-UV double resonance spectra were compared with the IR spectra obtained by quantum chemical calculations at the B3LYP/6-31+G* level. The two conformers of bare DB18C6 are assigned to "boat" and "chair I" forms, respectively, among which the boat form is dominant. All the six DB18C6-(H(2)O)(n) clusters with n = 1-4 have a boat conformation in the DB18C6 part. The water molecules form a variety of hydration networks in the boat-DB18C6 cavity. In DB18C6-(H(2)O)(1), a water molecule forms the bidentate hydrogen bond with the O atoms adjacent to the benzene rings. In this cluster, the water molecule is preferentially hydrogen bonded from the bottom of boat-DB18C6. In the larger clusters, the hydration networks are developed on the basis of the DB18C6-(H(2)O)(1) cluster.     

Selective extraction of strontium with supercritical fluid carbon dioxide

Strontium (Sr(2+)) can be selectively extracted from aqueous solutions into supercritical fluid CO(2) at 60 °C and 100 atm with dicyclohexano-18-crown-6 (DC18C6) using CF(3)(CF(2))(6)CO(2) (-) (PFOA(-)) or CF(3)(CF(2))(6)CF(2)SO(3) (-) (PFOSA(-)) as a counter anion; at a mole ratio of Sr(2+) : DC18C6 : PFOA(-) = 1:10:50, the extraction of Sr (5.6 × 10(-5) M) from water at pH 3 is near quantitative whereas Ca(2+) and Mg(2+) at equal concentration are only extracted to a level of 7 and 1%, respectively; PFOSA(-) is an effective counter anion for selective extraction of Sr(2+) from 1.3 M HNO(3) with DC18C6 in supercritical CO(2).     

Rapid dioxin assessment in fish products by fatty acid pattern recognition

A novel, cost- and time-effective dioxin screening method relying on fatty acid profile was developed for fish products. The method is based on multivariate covariance between fatty acid composition and dioxin. A dioxin range varying from 1.1 to 47.1 ng TEQ-WHO kg fat(-1) was investigated using 64 fish meal samples. An optimal multivariate dioxin prediction model was developed based on reduction from the original 32 to 13 fatty acids, thus increasing the parsimony and the robustness of the model. The model obtained with three partial least squares regression (PLS) components included the following 13 fatty acids: C14:1 n-5, C16:4 n-1, C18:1 n-9, C18:2 n-6, C18:3 n-6, C18:3 n-3, C20:0, C20:1 n-9, C20:4 n-6, C20:3 n-3, C22:1 n-7, C22:6 n-3, C24:1 n-9. Considering the whole investigated dioxin range, the performance of the PLS model based upon full cross-validation yielded a correlation of 0.90 (r(2)) and a prediction error of 3.31 ng PCDD/F TEQ-WHO kg fat(-1). A submodel of samples in the lower dioxin range 1 to 15 ng PCDD/F TEQ-WHO kg fat(-1) returned a r(2) of 0.88 and an error of 1.85 ng PCDD/F TEQ-WHO kg fat(-1).     

Does the solid-liquid crystal phase transition provoke the spin-state change in spin-crossover metallomesogens?

Three types of interplay/synergy between spin-crossover (SCO) and liquid crystalline (LC) phase transitions can be predicted: (i) systems with coupled phase transitions, where the structural changes associated to the Cr<-->LC phase transition drives the spin-state transition, (ii) systems where both transitions coexist in the same temperature region but are not coupled, and (iii) systems with uncoupled phase transitions. Here we present a new family of Fe(II) metallomesogens based on the ligand tris[3-aza-4-((5-C(n))(6-R)(2-pyridyl))but-3-enyl]amine, with C(n) = hexyloxy, dodecyloxy, hexadecyloxy, octadecyloxy, eicosyloxy, R = hydrogen or methyl (C(n)-trenH or C(n)-trenMe), which affords examples of systems of types i, ii, and iii. Self-assembly of the ligands C(n)-trenH and C(n)-trenMe with Fe(A)2 x xH2O salts have afforded a family of complexes with general formula [Fe(C(n)-trenR)](A)2 x sH2O (s > or = 0), with A = ClO4(-), F-, Cl-, Br- and I-. Single-crystal X-ray diffraction measurements have been performed on two derivatives of this family, named as [Fe(C6-trenH)](ClO4)2 (C(6)-1) and [Fe(C6-trenMe)](ClO4)2 (C(6)-2), at 150 K for C(6)-1 and at 90 and 298 K for C(6)-2. At 150 K, C(6)-1 displays the triclinic space group P, whereas at 90 and at 298 K C(6)-2 adopts the monoclinic P2(1)/c space group. In both compounds the iron atoms adopt a pseudo-octahedral symmetry and are surrounded by six nitrogen atoms belonging to imino groups and pyridines of the ligands C(n)-trenH and C(n)-trenMe. The average Fe(II)-N bonds (1.963(2) A) at 150 K denote that C(6)-1 is in the low-spin (LS) state. For C(6)-2 the average Fe(II)-N bonds (2.007(1) A) at 90 K are characteristic of the LS state, while at 298 K they are typical for the high-spin (HS) state (2.234(3) A). Compound C(6)-1 and [Fe(C18-trenH)](ClO4)2 (C(18)-1) adopts the LS state in the temperature region between 10 and 400 K, while compound C(6)-2 and [Fe(Cn-trenMe)](ClO4)2 (n = 12 (C(12)-2), 18 (C(18)-2)) exhibit spin crossover behavior at T(1/2) centered around 140 K. The thermal spin transition is accompanied by a pronounced change of color from dark red (LS) to orange (HS). The light-induced excited spin state trapping (LIESST) effect has been investigated in compounds C(6)-2, C(12)-2 and C(18)-2. The T(1/2)LIESST is 56 K (C(6)-2), 48 K (C(16)-2), and 56 K (C(18)-2). On the basis of differential scanning calorimetry, optical polarizing microscopy, and X-ray diffraction findings for C(18)-1, C(12)-2, and C(18)-2 at high temperature a smectic mesophase SX has been identified with layered structures similar to C(6)-1 and C(6)-2. The compounds [Fe(C(n)-trenH)](Cl)2 x sH2O (n = 16 (C(16)-3, s = 3.5, C(16)-4, s = 0.5, C(16)-5, s = 0), 18 (C(18)-3, s = 3.5, C(18)-4, s = 0.5, C(18)-5, s = 0), 20 (C(20)-3, s = 3.5, C(20)-4, s = 0.5, C(20)-5, s = 0)) and [Fe(C18-tren)](F)2 x sH2O (C(18)-6, s = 3.5, C(18)-7, s = 0) show a very particular spin-state change, while [Fe(C18-tren)](Br)2 x 3H2O (C(18)-8) together with [Fe(C18-tren)](I)2 (C(18)-9) are in the LS state (10-400 K) and present mesomorphic behavior like that observed for the complexes C(18)-1, C(12)-2, and C(18)-2. In compounds C(n)-3 50% of the Fe(II) ions undergo spin-state change at T(1/2) = 375 K induced by releasing water, and in partially dehydrated compounds (s = 0.5) the Cr-->SA phase transition occurs at 287 K (C(16)-4), 301 K (C(18)-4) and 330 K (C(20)-4). For the fully dehydrated materials C(n)-5 50% of the Fe(II) ions are in the HS state and show paramagnetic behavior between 10 and 400 K. In the partially dehydrated C(n)-4 the spin transition is induced by the change of the aggregate state of matter (solid<-->liquid crystal). For compound C(18)-6 the full dehydration to C(18)-7 provokes the spin-state change of nearly 50% of the Fe(II) ions. The compounds C(n)-3 and C(18)-6 are dark purple in the LS state and become light purple-brown when 50% of the Fe(II) atoms are in the HS state.     

Structure of 〔Na(DB18C6) (CH_3OH)〕_2W_6O_(19)·(DB18C6)·(CH_3OH)

1INrnODUCTIoNlnthepreviouspapers,wehavereportedthesynthesisandcrystalstructureofseveralcrownetherpolyoxometalates"-",nowwestudythestructureofthetitlecomplexandcompareitwithsomeothercrownetherpolyoxometalatecomplexes.2EXPERmENTALToal5OmLaqueoussolutioncontaining32g(1OOmol)Na,WO#.2H,Opre-justedtopH=3.5withchloricacid,14g(4Ommol)(n-Bu)'NBrwasadded,thenwhitepowderwasformed.ThewhiteprecipitateobtainedwithafiltrationwaskeptasthenewmaterialAinnextstep.AmixtureoflgAandO.3g(O.8mmol)DB18…     

2,4-dithiouracil: the reproducible H-bonded structural motifs in the complexes with 18-membered crown ethers

2,4-dithiouracil (DTU) forms in the crystals the H-bonded monohydrates of a 1:1:1 ratio with 18-crown-6 (18C6) 1, cis,syn,cis-isomer of dicyclohexano-18-crown-6 (DCH6A) 2, and benzo-18-crown-6 (B18C6) 3, while the anhydrous adduct with cis,anti,cis-isomer of dicyclohexano-18-crown-6 (DCH6B) 4 is of a 2:1 ratio. In 1-3 the components reproducibly alternate in the chains, while in 4 the chains are built of the alternative centrosymmetric dimers of 2,4-dithiouracil and the molecules of the cis,anti,cis-isomer of dicyclohexano-18-crown-6.     

冠醚配合物热力学性质的研究(Ⅴ)——碱金属及碱土金属离子与2,3-苯并-11-甲基-18-冠-6的配位反应的量热滴定研究

用自制滴定量热计研究了70%(W/W)甲醇中2,3-苯并-11-甲基-18-冠-6(BC1-18C6)与Na、K、Rb、Cs、Ca、Mg、Sr、Ba8种碱金属与碱土金属氯化物的配位作用,直接计算了配合物稳定常数及配位反应热函,获得了碱金属与碱土金属稳定性及热函大小的相对顺序.     

The interaction between ketamine and some crown ethers in common organic solvents studied by NMR: the effect of donating atoms and ligand structure

1H NMR spectroscopy was used to investigate the stoichiometry and stability of the drug ketamine cation complexes with some crown ethers, such as 15-crown-5 (15C5), aza-15-crown-5 (A15C5), 18-crown-6 (18C6), aza-18-crown-6 (A18C6), diaza-18-crown-6 (DA18C6), dibenzyl-diaza-18-crown-6 (DBzDA18C6) and cryptant [2,2,2] (C222) in acetonitrile (AN), dimethylsulfoxide (DMSO) and methanol (MeOH) at 27 degrees C. In order to evaluate the formation constants of the ketamine cation complexes, the CH3 protons chemical shift (on the nitrogen atom of ketamine) was measured as function of ligand/ketamine mole ratio. The formation constant of resulting complexes were calculated by the computer fitting of chemical shift versus mole ratio data to appropriate equations. A significant chemical shift variation was not observed for 15C5 and 18C6. The stoichiometry of the mono aza and diaza ligands are 1:1 and 1:2 (ligand/ketamine), respectively. In all of the solvents studied, DA18C6 formed more stable complexes than other ligands. The solvent effect on the stability of these complexes is discussed.     

Synthesis and Crystal Structure of ［Na（DB18C6）（CH_3OH）］_2Mo_6O_（19）·（DB18C6）·（CH_3OH）

ＳｙｎｔｈｅｓｉｓａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ［Ｎａ（ＤＢ１８Ｃ６）（ＣＨ_３ＯＨ）］_２Ｍｏ_６Ｏ_（１９）·（ＤＢ１８Ｃ６）·（ＣＨ_３ＯＨ）￥ＺｈｏｕＹｉｎ－Ｚｈｕａｎｇ；ＴｕＳｈｕ－Ｊｉｅ；ＪｉｎＸｉａｎｇ－Ｌｉｎ；ＬｉｕＳｈｕｎ－...     

Novel zinc phosphate topologies defined by organic ligands

Six new zinc phosphates [C18H20N4][Zn4(HPO4)4(H2PO4)2(C18H18N4)3].2H2O (1), [Zn4(HPO4)4(C18H18N4)3].4H2O (2), [Zn3(HPO4)3(H2PO4)(C22H22N8)0.5(C22H24N8)0.5] (3), [Zn2(HPO4)2(C18H16N4)] (4), [Zn(HPO4)(C18H14N2)] (5), and [Zn2(HPO4)2(C12H10N4)] (6) have been synthesized under mild hydrothermal conditions in the presence of 1,4-bis(N-benzimidazolyl)butane (L1), 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene (L2), 1,4-bis(imidazol-1-ylmethyl)naphthalene (L3), 9-(imidazol-1-ylmethyl)anthracene (L4), and 1,4-bis(1-imidazolyl)benzene (L5), respectively, and their structures were determined by X-ray crystallography. Compound 1 exhibits a unique inorganic motif of isolated 8-rings interconnected by L1. Compound 2, also formed from L1, contains a previously unobserved chain structure composed of edge-sharing 4-rings and 8-rings. Compound 3, prepared from L2, possesses an unusual one-dimensional framework, which is composed of vertex-sharing 4-rings and triple fused 4-rings. The inorganic portions of 4, 5, and 6 each adopt a layer structure. The sheets in 4 and 5 have a 4.8(2) topology, and in 6, a 6(3) topology is observed. The zinc atoms in compounds 1-6 are all tetrahedrally coordinated by a combination of phosphate groups and organic ligands. Potential relationships between the inorganic motifs reported in the present study are identified. These are indicative of a possible pattern of self-assembly of zinc and phosphorus tetrahedra and indicative of the role of the organic ligands in the formation of hybrid structures.     

阳离子- π相互作用————————[K(DI18C6)]2[M(SCN)4] (M=Pd,Pt)的合成与结构 研究

合成了二苯并18冠6与Pd,Pt生成的新颖配合物：[K(DI18C6)]2[Pd(SCN)4](1),(K(DB18C6)]2[Pt(SCN)4](2),并通过元素分析、红外光谱、单晶X射线衍射进行了表征,两个配合物均为三斜晶系,空间群P-1.1的晶体学数据：a=087375(17)nm,b=1.1990(2)nm,C=1.3180(3)nm,α=73.56(3)°,β=99.90(3)°,γ=82.34(3)°,V=1.2986(4)nm^3,Z=1,F(000)=584,R1=0.0752ωR2=0.1660.2的晶体学数据：a=0.8553(5)nm,b=1.3127(3)nm,c=1.1819(3)nm,α=106.21(2)°,β=82.77(3)°,γ=99.72(3)°V=1.2516(8)nm^3,Z=1,F(000)=818,R1=0.0254,ωR2=0.0682.1,2均由两个[K(DB18C6)^+配离子和一个[M(SCN)4]^2+配阴离子组成。在固态、配合物两个分子的[K(DB18C6)]^+和[M(SCN)4]^2-通过K^+-π相互作用形成假一维无限链状结构。     

Intervalence charge transfer in mixed valence compound modified by the formation of a supramolecular complex

The electrochemical and spectroelectrochemical properties of N,N-diphenyl-1,4-phenylenediamine (PDA) were investigated in the absence and in the presence of 18-crown-6-ether (18C6) or dibenzo 24-crown-8-ether (DB24C8), in a solution of tetrabutylammonium hexafluorophosphate (TBAPF6) in acetonitrile and in the presence of trifluoroacetic acid (TFA) only for 18C6. In neutral acetonitrile, PDA undergoes two reversible oxidation processes, which lead first to the formation of the cation-radical considered as mixed valence (MV) compound, and then to the dicationic species. When 18C6 is added in the medium and depending on 18C6 concentration, cyclic voltammetry shows a marked shift to more cathodic potentials of the current waves of the second redox process only. This is attributed to a strong interaction between the PDA(+2) dication and two 18C6 molecules, leading to the formation of a supramolecular complex with an association constant value K(a) = 7.0 × 10(7) M(-2). The interaction of 18C6 with PDA(+2) dication has a direct effect on the PDA(+.) cation-radical corresponding to a decrease in the lifetime of the MV compound and of the intramolecular electron transfer rate when 18C6 is present. Indeed, it results in a large decrease in the intervalence charge transfer (IV-CT) between the two amine centers in the MV compound (k(th) = 1.35 × 10(10) s(-1) in 18C6-free neutral solution containing 5.0 × 10(-4) M PDA, and k(th) = 3.6 × 10(9) s(-1) in the same medium at [18C6]/[PDA] = 20/1). And the comproportionation constant K(co) falls from 6.0 × 10(6) in 18C6-free solution to 1.6 × 10(3) at [18C6]/[PDA] = 20/1. In acidified acetonitrile and when TFA concentration is increased, PDA still shows the two successive and reversible oxidation processes, but both are shifted to more anodic potentials. However, when 18C6 is added, the two oxidation waves shift to more cathodic potentials, indicating an interaction of all protonated PDA redox states with 18C6, resulting in the formation of supramolecular complexes. In the presence of TFA, the value of K(co) is decreased to 4.3 × 10(4), but it remains unchanged when 18C6 is added, indicating no change in the lifetime of the MV compound. In this medium, IV-CT in the MV compound is greater with 18C6 (k(th) = 2.3 × 10(10) s(-1) for [18C6]/[PDA] = 20/1) than without (k(th) = 1.4 × 10(9) s(-1)), which indicates a more important IV-CT rate when 18C6 is present. The results show for the first time that is it possible to control the IV-CT rate, through the lifetime and the potential range where the MV compound is the most important. This control is not obtained as usual by chemical modification of the structure of the starting molecule, but by varying either the acidity or the 18C6 concentration as external stimuli, which lead to reversible formation/dissociation of a supramolecular complex species. Moreover, we also studied the electrochemical properties of PDA in the presence of wider crown ether such as DB24C8. We showed that PDA undergoes the same electrochemical behavior with DB24C8 than with 18C6 in neutral organic medium (K(a) = 2.9 × 10(3) M(-1)). This result suggests that the complexation between the electrogenerated PDA(+2) dication and the crown ethers may occur through face-to-face mode rather than rotaxane mode even with DB24C8 which is supposed to form inclusion complexes.     

Alkali Cation Ligating Chains and Sheets of the Macrocycle 1, 7‐Dithia‐18‐Crown‐6 with Bridging Iodo‐ and Thiocyanatocuprate(I) Units

Treatment of an acetonitrile solution of CuI with 1, 7‐dithia‐18‐crown‐6 (1, 7‐DT18C6) at 100°C affords the coordination polymer ¹[(CuI)₂(1, 7‐DT18C6)₂] ( 1 ) in which 1, 7‐DT18C6 ligands bridge (CuI)₂ rings into double chains. 1D polymers of the type ¹[M{(Cu₃I₄)(1, 7‐DT18C6)}] (M = K, 2 ; M = Cs, 3 ) can be isolated under similar conditions in the presence of respectively KI and CsI. Both contain bridging heptacyclic [Cu₆I₈]^2— units but crystallise in different space groups, namely P1 and C2/m. The cesium cation of 3 is markedly displaced from the best plane through the thiacrown ether donor atoms. Reaction of 1, 7‐DT18C6 with CuSCN in the presence of NaSCN yields ²[{Na(CH₃CN)₂} {(CuSCN)₂(1, 7‐DT18C6)}][Cu(SCN)₂] ( 4 ), in which ¹[(CuSCN)₂] double chains are linked through macrocycles into sheets. Infinite ¹[{Cu(SCN)₂}^—] chains compensate the charge of the Na⁺ cations. Complex 1 can imbibe 0.90 mol CsNO₃ per mol of 1, 7‐DT18C6 pairs.     

Profiling of esterified fatty acids as biomarkers in the blood of dengue fever patients using a microliter‐scale extraction followed by gas chromatography and mass spectrometry

An improved gas chromatography with mass spectrometry procedure was developed to highlight the esterified fatty acids in 100 μL blood of dengue fever patients in the early febrile phase versus healthy volunteers. 24 adult patients and 24 healthy volunteers were included in this study. The recoveries of targeted esterified fatty acids content were in the range of 92.10–101.00% using methanol/dichloromethane (2:1, v/v) as the extraction solvent. An efficient chromatographic separation of targeted 17 esterified fatty acid methyl esters was obtained. The limits of detection and quantification were within the range of 16–131 and 53–430 ng/mL, respectively. The relative standard deviation of intraday and interday precision values ranged from 0.4 to 5.0%. The statistical data treatment showed a significant decrease of the content of four saturated fatty acids, C14:0, C15:0, C16:0, and C18:0 (P value < 0.05), and also showed a decrease of the content of eight unsaturated fatty acids, C16:1, C18:3n6, C18:2n6, C18:1n9, C20:3n3, C20:4n6, C20:2, and C22:6n3 (P value < 0.05) in dengue fever patients. Moreover, the amount of three omega‐6 fatty acids including C18:3n6, C18:2n6, and C20:4n6 was dramatically decreased in the blood of dengue fever patients to a limit of 50 ± 10%.     

Solvent effects on extraction of potassium picrate with benzo-18-crown-6. A new equation for the determination of ion-pair formation of crown ether-metal salt complexes in water

In order to determine the ion-pair formation constant of a crown ether-metal salt 1:1:1 complex in water, an equation is derived from regular solution theory and its predictions are verified experimentally by the solvent extraction method using benzo-18-crown-6 (B18C6), potassium picrate (KA), and various diluents of low dielectric constant. The distribution constants of B18C6 itself and the overall extraction constants of KA with B18C6 were determined at 25±0.2°C. The distribution constants of the neutral K(B18C6)A complex were calculated from these data. The literature value for the complex-formation constant of K(B18C6)⁺ in water and the ion-pair formation constant (K _K(B18C6)A ) for K(B18C6)A in water determined in this study were log K _K(B18C6)A =3.12±0.23 at 25°C). The distribution behavior of B18C6 and K(B18C6)A is explained in terms of regular solution theory. The molar volumes V (cm³·mol^–1) and solubility parameters (cal^1/2-cm^–3/2) are as follows: V _B18C6 =249±36; V _K(B18C6)A =407±56; _B18C6 = 11.5 ± 0.5; and _K(B18C6)A = 11.5 ± 0.5.     

苯并18－冠－6与M2[Pt(SCN)6](M=Na,K)配合物的合成、结构

合成了苯并18－冠－6(B18C6)与M2[Pt(SCN)6](M=Na,K)的配合物：{[Na (B18C6)]6[Pt(SCN)6]}[Pt(SCN)6](SCN)2(1),[K(B18C6)]2[Pt(SCN)6]·4H2O(2). 通过元素分析、红外光谱、单晶X射线衍射进行了表征.1为单斜晶系、空间群R3^-, a=b=1.9933(3)nm,c=2.9760(6)nm,α=β=90°,γ=120°,V=10.240(3)nm^3,Z=3, Dcalcd=1.564g/cm^3,F(000)=4908,R1=0.0535,wR2=0.1030.2为三斜晶纱、空间群 P1^-,a=1.1692(3)nm,b=1.1853(4)nm,c=1.2381(5)nm,α=61.419(5)°,β=80.757 (8)°,γ=89.003(5)°,V=1.4836(9)nm^3,Z=1,Dcalcd=1.476g/cm^3,F(000)=666, R1=0.0696,wR2=0.1346.1由{[Na(B18C6)]6[Pt(SCN)6]}^4+配阳离子、[Pt(SCN)6] ^2-配阴离子和SCN^-阴离子组成。相邻{[Na(B18C6)]6[Pt(SCN)6]}^4+通过Na-O键 形成三维网状结构。[Pt(SCN)6]^2-和SCN^-仅起平衡电荷的作用.2由两个[K (B18C6)]^+配阳离子和一个[Pt(SCN)6]^2-配阴离子组成。相邻[K(B18C6)]2[Pt (SCN)6]离子对通过K－O键形成一维链状结构。     

Isolation of (CO)1- and (CO2)1- radical complexes of rare earths via Ln(NR2)3/K reduction and [K2(18-crown-6)2]2+ oligomerization

Deep-blue solutions of Y(2+) formed from Y(NR(2))(3) (R = SiMe(3)) and excess potassium in the presence of 18-crown-6 at -45 °C under vacuum in diethyl ether react with CO at -78 °C to form colorless crystals of the (CO)(1-) radical complex, {[(R(2)N)(3)Y(μ-CO)(2)][K(2)(18-crown-6)(2)]}(n), 1. The polymeric structure contains trigonal bipyramidal [(R(2)N)(3)Y(μ-CO)(2)](2-) units with axial (CO)(1-) ligands linked by [K(2)(18-crown-6)(2)](2+) dications. Byproducts such as the ynediolate, [(R(2)N)(3)Y](2)(μ-OC≡CO){[K(18-crown-6)](2)(18-crown-6)}, 2, in which two (CO)(1-) anions are coupled to form (OC≡CO)(2-), and the insertion/rearrangement product, {(R(2)N)(2)Y[OC(═CH(2))Si(Me(2))NSiMe(3)]}[K(18-crown-6)], 3, are common in these reactions that give variable results depending on the specific reaction conditions. The CO reduction in the presence of THF forms a solvated variant of 2, the ynediolate [(R(2)N)(3)Y](2)(μ-OC≡CO)[K(18-crown-6)(THF)(2)](2), 2a. CO(2) reacts analogously with Y(2+) to form the (CO(2))(1-) radical complex, {[(R(2)N)(3)Y(μ-CO(2))(2)][K(2)(18-crown-6)(2)]}(n), 4, that has a structure similar to that of 1. Analogous (CO)(1-) and (OC≡CO)(2-) complexes of lutetium were isolated using Lu(NR(2))(3)/K/18-crown-6: {[(R(2)N)(3)Lu(μ-CO)(2)][K(2)(18-crown-6)(2)]}(n), 5, [(R(2)N)(3)Lu](2)(μ-OC≡CO){[K(18-crown-6)](2)(18-crown-6)}, 6, and [(R(2)N)(3)Lu](2)(μ-OC≡CO)[K(18-crown-6)(Et(2)O)(2)](2), 6a.