Thermochemical Properties of Palladium(II) Chelates Involving Dialkyldithiocarbamates

The standard molar enthalpies of formation of crystalline dialkyldithiocarbamates chelates, [Pd(S₂CNR₂)₂], with R=C₂H₅, n-C₃H₇, n-C₄H₉ and i-C₄H₉, were determined through reaction-solution calorimetry in acetone, at 298.15 K. From the standard molar enthalpies of formation of the gaseous chelates, the homolytic (172.4±3.8, 182.5±3.2,150.9±3.1 and 162.6±3.1 kJ mol⁻¹) and heterolytic (745.0±3.8, 803.7±3.3,834.3±3.1 and 735.2±3.0 kJ mol⁻¹) mean palladium-sulphur bond-dissociation enthalpies were calculated. This revised version was published online in July 2006 with corrections to the Cover Date.     

The mean enthalpy of the lanthanide-oxygen bond in 2,2,6,6-tetramethyl-3,5-heptanedione chelates of praseodimium and holmium

The general thermochemical reaction LnCl₃·6H₂O(c)+3Hthd(1)+73.92H₂O(1) = Ln(thd)₃(c) +3HCl·26.64H₂O(aq); rHm (Ln = Pr, Ho and thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) was employed to determine through solution-reaction calorimetry at 298.15 K the standard molar enthalpies of formation of crystalline chelates, –2434.3±11.5 (Pr) and –2384.8±11.5 (Ho) kJ mol^–1. These values and the corresponding molar enthalpies of sublimation enabled the determination of the standard molar enthalpies of chelates in the gaseous phase. From these values the mean enthalpies of the lanthanide-oxygen bond, 265±10 (Pr) and 253±10 (Ho) kJ mol^–1 were calculated.     

Thermochemical studies of phthalimide and two N-alkylsubstituted phthalimides (ALKYL=ETHYL AND n-PROPYL)

The standard (p⁰=0.1 MPa) molar enthalpies of formation, Δ_fH_m⁰, for crystalline phthalimides: phthalimide, N-ethylphthalimide and N-propylphthalimide were derived from the standard molar enthalpies of combustion, in oxygen, at the temperature 298.15 K, measured by static bomb-combustion calorimetry, as, respectively, – (318.0±1.7), – (350.1±2.7) and – (377.3±2.2) kJ mol^–1. The standard molar enthalpies of sublimation, Δ_cr^gH_m⁰, at T=298.15 K were derived by the Clausius-Clapeyron equation, from the temperature dependence of the vapour pressures for phthalimide, as (106.9±1.2) kJ mol^–1 and from high temperature Calvet microcalorimetry for phthalimide, N-ethylphthalimide and N-propylphthalimide as, respectively, (106.3±1.3), (91.0±1.2) and (98.2±1.4) kJ mol^–1. The derived standard molar enthalpies of formation, in the gaseous state, are analysed in terms of enthalpic increments and interpreted in terms of molecular structure.     

Standard molar enthalpies of formation of some methylfuran derivatives

The standard (p ^o = 0.1 MPa) molar enthalpies of formation \Updelta_\textf H_\textm^\texto ( \textl), {{\Updelta}}_{\text{f}} H_{\text{m}}^{\text{o}} ( {\text{l),}} of the liquid 2-methylfuran, 5-methyl-2-acetylfuran and 5-methyl-2-furaldehyde were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The Calvet high temperature vacuum sublimation technique was used to measure the enthalpies of vaporization of the three compounds. The standard (p ^o = 0.1 MPa) molar enthalpies of formation of the compounds, in the gaseous phase, at T = 298.15 K have been derived from the corresponding standard molar enthalpies of formation in the liquid phase and the standard molar enthalpies of vaporization. The results obtained were −(76.4 ± 1.2), −(253.9 ± 1.9), and −(196.8 ± 1.8) kJ mol⁻¹, for 2-methylfuran, 5-methyl-2-acetylfuran, and 5-methyl-2-furaldehyde, respectively.     

Crystal Structure, Lattice Energy, and Standard Molar Enthalpy of Formation of the Complex (C11H18NO)2CuCl4(s)

The complex (C₁₁H₁₈NO)₂CuCl₄ (s), which may be a potential effective drug, was synthesized. X‐ray crystallography, elemental analysis, and chemical analysis were used to characterize the structure and composition of the complex. Lattice energy and ionic radius of the anion of the complex were derived from the crystal data of the title compound. In addition, a reasonable thermochemical cycle was designed, and standard molar enthalpies of dissolution for reactants and products of the synthesis reaction of the complex were measured by an isoperibol solution‐reaction calorimeter. The enthalpy change of the reaction was calculated to be Δ_rH^?_m=(2.69±0.02) kJ·mol^?1 from the data of the above standard molar enthalpies of dissolution. Finally, the standard molar enthalpy of formation of the title compound was determined to be Δ_rH^?_m[(C₁₁ H₁₈NO)₂CuCl₄, s]= ? (1822.96±6.80) kJ·mol^?1 in accordance with Hess law.     

Thermochemical study of 2- and 3-alkyl substituted thiophenes

The standard (p ⁰=0.1 MPa) molar enthalpies of formation, in the condensed phase, of nine linear-alkyl substituted thiophenes, six in position 2- and three in position 3-, at T=298.15 K, were derived from the standard massic energies of combustion, in oxygen, to yield CO₂(g) and H₂SO₄·115H₂O(aq), measured by rotating-bomb combustion calorimetry. The standard molar enthalpies of vaporization of these compounds were measured by high temperature Calvet Microcalorimetry, so their standard molar enthalpies of formation, in the gaseous phase, were derived. The results are discussed in terms of structural contributions to the energetics of the alkyl-substituted thiophenes, and empirical correlations are suggested for the estimation of the standard molar enthalpies of formation, at T=298.15 K, for 2- and 3-alkyl-substituted thiophenes, both in the condensed and in the gaseous phases.     

Synthesis, Characterization and Thermochemistry of 2MgO：B2O3：1.5H2O

Introduction　　 2MgO·B2 O3(Mg2 B2 O5)and 2MgO·B2 O3·H2 Omightbepreparedaswhiskermaterials .12MgO·B2 O3·H2 OnamedszaibelyiteisamagnesiumboratemineralwithastructuralformulaofMg2 [B2 O4 (OH) 2 ].2 Itisdifficulttosynthesizethiscompoundinthelaboratory .Recently ,weobtainedasimilarcompound 2MgO·B2 O3·1 5H2 Owhenwetriedtopreparewhiskerof 2MgO·B2 O3·H2 Obythephasetransformationof 2MgO·2B2 O3·MgCl2 ·14H2 OinH3BO3solutionunderhydrothermalcondition .Itishope fultopreparewh…     

Standard molar enthalpy of formation of [(C12H8N2)2Bi(O2NO)3] and its biological activity on Schizosaccharomyces pombe

The title complex [(C₁₂H₈N₂)₂Bi(O₂NO)₃] was synthesized by reaction of 1,10-phenanthroline (phen) and Bi(NO₃)₃·5H₂O. The structure of the complex was characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analysis. An advanced solution-reaction isoperibol microcalorimeter was applied to determine the standard molar enthalpies of formation at 298.15 K of the complex and Bi(NO₃)₃·5H₂O, giving –(798.92 ± 5.99) and –(1986.87 ± 0.20) kJ mol⁻¹, respectively. The biological effect of the complex was evaluated by microcalorimetry on the growth of Schizosaccharomyces pombe (S. pombe). According to thermogenic curves, the corresponding thermokinetics and thermodynamic parameters were derived. The complex had good bioactivity on the growth metabolism of S. pombe, with the value of IC₅₀ being 2.8 × 10⁻⁵ mol L⁻¹.

     

RE(C5H8NS2)3(C12H8N2)的标准摩尔生成焓

在无水乙醇中, 使低水合氯化稀土 (RE = Ho, Er, Tm, Yb, Lu) 与吡咯烷二硫代氨基甲酸铵 (APDC)和1,10-菲咯啉 (o–phen•H₂O) 反应, 制得其三元固态配合物. 用化学分析和元素分析确定它的组成为RE(C₅H₈NS₂)₃(C₁₂H₈N₂) (RE = Ho, Er, Tm, Yb, Lu). IR光谱说明RE³⁺ 分别与3个PDC^–的6个硫原子双齿配位, 同时与o–phen的2个氮原子双齿配位, 配位数为8. 用精密转动弹热量计测定了它们的恒容燃烧热△_cU分别为(-16788.46 ± 7.74), (-15434.53 ± 8.28), (-15287.80 ± 7.31), (-15200.50 ± 7.22)和(-15254.34 ± 6.61) kJ•mol^-1; 并计算了它们的标准摩尔燃烧焓△_cH_m^θ和标准摩尔生成焓△_fH_m^θ分别为( -16803.95 ± 7.74), (-15450.02 ± 8.28), (-15303.29 ± 9.28), (-15215.99 ± 7.22), (-15269.83 ± 6.61) kJ • mol^-1和 (-1115.42 ± 8.94), (-2477.80 ± 9.15), (-2619.95 ± 10.44), (-2670.17 ± 8.22), (-2650.06 ± 8.49) kJ•mol^-1.     

Standard molar enthalpies of formation of [RE(Gly)<Subscript>4</Subscript>(Im)(H<Subscript>2</Subscript>O)](ClO<Subscript>4</Subscript>)<Subscript>3</Subscript> (<Emphasis Type="Italic">RE</Emphasis>=Eu,Sm)

The two complexes, [RE(Gly)₄(Im)(H₂O)](ClO₄)₃(s)(RE = Eu, Sm), have been synthesized and characterized. The standard molar enthalpies of reaction for the following reactions, RECl₃·6H₂O(s)+4Gly(s)+Im(s)+3NaClO₄(s) = =[RE(Gly)₄(Im)(H₂O)](ClO₄)₃(s)+3NaCl(s)+5H₂O(l), were determined by solution-reaction colorimetry. The standard molar enthalpies of formation of the two complexes at T = 298.15 K were derived as Δ_f H _m^Θ {Eu(Gly)₄(Im)(H₂O)}(ClO₄)₃(s)} = = −(3396.6±2.3) kJ mol⁻¹ and Δ_f H _m^Θ {Sm(Gly)₄(Im)(H₂O)}(ClO₄)₃(s)} = −(3472.7±2.3) kJ mol⁻¹, respectively.     

Preparation and Thermal Chemical Property of Complexes of Zinc Nitrate with Trytophan

IntroductionZincisanessentialtraceelementtothelife .Manydiseasesarousedfromadeficiencyofzincelementhavere ceivedconsiderableattention .L α Aminoacidsarebasicunitsofproteins .L α Trytophanisoneoftheeightspeciesofaminoacidsindispensableforlife ,whichhastobeab sorbedfromfoodbecauseitcannotbesynthesizedinthehumanbody .InviewofthecomplexesofL α trytophanandessentialelementsasaddictiveswidelyusedinsuchfieldsasfoodstuff,medicineandcosmetic ,1 3theyhaveabroadenprospectforapplications .Briefly ,ab…     

Hydrothermal synthesis and thermodynamic properties of 2CaO·3B<Subscript>2</Subscript>O<Subscript>3</Subscript>·H<Subscript>2</Subscript>O

2CaO·3B₂O₃·H₂O which has non-linear optical (NLO) property was synthesized under hydrothermal condition and identified by XRD, FTIR and TG as well as by chemical analysis. The molar enthalpy of solution of 2CaO·3B₂O₃·H₂O in HCl·54.572H₂O was determined. From a combination of this result with measured enthalpies of solution of H₃BO₃ in HCl·54.501H₂O and of CaO in (HCl+H₃BO₃) solution, together with the standard molar enthalpies of formation of CaO(s), H₃BO₃(s), and H₂O(l), the standard molar enthalpy of formation of −(5733.7±5.2) kJ mol⁻¹ of 2CaO·3B₂O₃·H₂O was obtained. Thermodynamic properties of this compound were also calculated by a group contribution method.     

Constant-volume combustion energy of the lead salts of 2HDNPPb and 4HDNPPb and their effect on combustion characteristics of RDX–CMDB propellant

The constant-volume combustion energies of the lead salts of 2-hydroxy-3,5-dinitropyridine (2HDNPPb) and 4-hydroxy-3,5-dinitropyridine (4HDNPPb), ΔU _c (2HDNPPb(s) and 4HDNPP(s)), were determined as –4441.92±2.43 and –4515.74±1.92 kJ mol^–1 , respectively, at 298.15 K. Their standard enthalpies of combustion, Δ_c ^m H θ(2HDNPPb(s) and 4HDNPPb(s), 298.15 K), and standard enthalpies of formation, Δ_r ^m H θ(2HDNPPb(s) and 4HDNPPb(s), 298.15 K) were as –4425.81±2.43, –4499.63±1.92 kJ mol^–1 and –870.43±2.76, –796.65±2.32 kJ mol^–1 , respectively. As two combustion catalysts, 2HDNPPb and 4HDNPPb can enhance the burning rate and reduce the pressure exponent of RDX–CMDB propellant.     

Standard Molar Enthalpies of Formation of Ce(TCA)_3·3H_2O(s) and Ce(TCA)(C_9H_6NO)_2(s)

IntroductionBothrareearthions1and 8 hydroxyquinolineareofantibacterialfunction ,2 andtheircomplexeshavemorepowerfuldisinfection .Theirbinarycomplexeswerereport edasearlyasin 196 3.Atthesametime ,theresearchontheirternarycomplexeshavebecomeveryactiveinrecentyears,andtheyarewidelyappliedinmanyfields .3 6Dong6 reportedthesynthesisandcharacterizationofthecomplexesofrareearthtrichloroaceticacidsaltswith 8 hy droxyquinoline.Itsapplicationinleathermouldyproofshowedthatthecomplexeshavepowerfuldisinfe…     

Standard enthalpy of formation of 3,4,5-trimethoxybenzoic acid

The energy of combustion of crystalline 3,4,5-trimethoxybenzoic acid in oxygen at T=298.15 K was determined to be -4795.9±1.3 kJ mol^-1 using combustion calorimetry. The derived standard molar enthalpies of formation of 3,4,5-trimethoxybenzoic acid in crystalline and gaseous states at T=298.15 K, Δ_fH_m ^Θ (cr) and Δ_fH_m ^Θ (g), were -852.9±1.9 and -721.7±2.0 kJ mol^-1, respectively. The reliability of the results obtained was commented upon and compared with literature values. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermochemical properties of trialkylarsenites

The heats of the reaction of sodium with ethyl and methyl alcohol were determined by calorimetry. The difference in the standard heats of the formation of triethylarsenite and arsenic trichloride was obtained by calorimetration of the reaction of arsenic trichloride with sodium ethylate, the value of which was −382.42 ± 3.60 kJ/mol. The standard enthalpies of formation were determined from a critical analysis of all data on thermochemistry of trialkylarsenites for the following compounds: triethylarsenite Δ_f H ₂₉₈^ℴ [(C₂H₅O)₃As(liquid)] = (−704.38 ± 3.85) kJ/mol; trimethylarsenite Δ_f H ₂₉₈^ℴ [(CH₃O)₃As(liquid)] = (−599.36 ± 1.88) kJ/mol. The values of standard enthalpies of formation were not adjusted for the following substances in liquid state: arsenic trichloride (−321.96 ± 3.85 kJ/mol), tris-(diethylamido)arsenic(III) As(NEt₂)₃(liquid) (−129.81 ± 4.41 kJ/mol), tri-n-propylarsenite (−720.61 ± 4.49 kJ/mol), triisopropylarsenite (−756.11 ± 4.65 kJ/mol), tri-n-butylarsenite (−775.11 ± 4.53 kJ/mol), and triisobutylarsenite (−809.71 ± 4.59 kJ/mol). The use of sodium alcoxide solutions for the calorimetration of halogen anhydrides of various acids was demonstrated.     

Synthesis and Thermodynamic Properties of MgO·B_2O_3·4H_2O

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｒｅａｒｅｍａｎｙｋｉｎｄｓｏｆｍａｇｎｅｓｉｕｍｂｏｒａｔｅｓ ,ｂｏｔｈｎａｔｕｒａｌａｎｄｓｙｎｔｈｅｔｉｃ .Ａｂｏｒａｔｅｄｏｕｂｌｅｓａｌｔ (2ＭｇＯ·2Ｂ2 Ｏ3 ·ＭｇＣｌ2 · 14Ｈ2 Ｏ)ｎａｍｅｄｃｈｌｏｒｏｐｉｎｎｏｉｔｅｗａｓｏｂ ｔａｉｎｅｄｆｒｏｍｔｈｅｎａｔｕｒａｌｃｏｎｃｅｎｔｒａｔｅｄｓａｌｔｌａｋｅｂｒｉｎｅ .1Ｉｎｏｒｄｅｒｔｏｆｉｎｄｔｈｅｆｏｒｍｉｎｇｒｅｌａｔｉｏｎｂｅｔｗｅｅｎｔｈｅｄｏｕｂｌｅｓａｌｔａｎｄｍａｇｎｅｓｉｕｍ ｂｏｒａ…     

白硼钙石的合成新方法及其热化学研究(英)

0IntroductionTherearemanykindsofhydratedcalciumbo-rates,bothnaturalandsynthetic.Someofthemarematerialsusedinglass,potteryandporcelainenamelindustry,especiallyinunalkaliglassindustry.4CaO·5B2O3·7H2O,calledpriceite,isacalciumboratemin-eral,notfoundinCaO-B…     

MZn2HPO4PO4 (M=Na+, K+)的合成、表征和标准摩尔生成焓

采用低温固相法和水热法制备MZn2HPO4PO4 (M=Na+, K+) 并用XRD, FT-IR, TG and SEM对其进行表征,用等温量热计测定热化学性质。按照Hess’s定律,设计一新的热化学循环。结果表明,所合成的物质是等结构三斜晶系的目标产物,具有片层结构,分解温度分别为： 415 ℃和430 ℃。从测定的溶解焓和其他的标准热化学数据,计算出MZn2HPO4PO4 (M=Na+, K+) 的标准摩尔生成焓分别为：ΔfHm [NaZn2HPO4PO4, s]=-3042.38±0.31 kJ·mol-1; ΔfHm [KZn2HPO4PO4,s]=-3093.46 ±0.27 kJ·mol-1。     

The structure and thermochemistry of 3:4,5:6-dibenzo-2-hydroxymethylene-cyclohepta-3,5-dienenone (1) and some related compounds

Condensed and gas phase enthalpies of formation of 3:4,5:6-dibenzo-2-hydroxymethylene-cyclohepta-3,5-dienenone (1, (−199.1 ± 16.4), (−70.5 ± 20.5) kJ mol⁻¹, respectively) and 3,4,6,7-dibenzobicyclo[3.2.1]nona-3,6-dien-2-one (2, (−79.7 ± 22.9), (20.1 ± 23.1) kJ mol⁻¹) are reported. Sublimation enthalpies at T=298.15 K for these compounds were evaluated by combining the fusion enthalpies at T = 298.15 K (1, (12.5 ± 1.8); 2, (5.3 ± 1.7) kJ mol⁻¹) adjusted from DSC measurements at the melting temperature (1, (T _fus, 357.7 K, 16.9 ± 1.3 kJ mol⁻¹)); 2, (T _fus, 383.3 K, 10.9 ± 0.1) kJ mol⁻¹) with the vaporization enthalpies at T = 298.15 K (1, (116.1 ± 12.1); 2, (94.5 ± 2.2) kJ mol⁻¹) measured by correlation-gas chromatography. The vaporization enthalpies of benzoin ((98.5 ± 12.5) kJ mol⁻¹) and 7-heptadecanone ((94.5 ± 1.8) kJ mol⁻¹) at T = 298.15 K and the fusion enthalpy of phenyl salicylate (T _fus, 312.7 K, 18.4 ± 0.5) kJ mol⁻¹) were also determined for the correlations. The crystal structure of 1 was determined by X-ray crystallography. Compound 1 exists entirely in the enol form and resembles the crystal structure found for benzoylacetone.