Low-temperature Heat Capacities and Thermodynamic Properties of Hydrated Sodium Cupric Arsenate [ NaCuAsO4·1.5H2O(s)]

Low-temperature heat capacities of the solid compound NaCuAsO4 · 1.5H2O(s) were measured using a precision automated adiabatic calorimeter over a temperature range of T = 78 K to T = 390 K. A dehydration process occurred in the temperature range of T = 368-374 K. The peak temperature of the dehydration was observed to be TD = (371.828±0.146) K by means of the heat-capacity measurement. The molar enthalpy and entropy of the dehyperimental values of heat capacities for the solid(Ⅰ) and the solid-liquid mixture(Ⅱ) were respectively fitted to two polynomial equations by the least square method. The smoothed values of the molar heat capacities and the fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were tabulated at an interval of 5 K.     

Synthesis,Characterization and Thermodynamic Study of the Solid State Coordination Compound Ni(Nic)2·H2O(s)(Nic=Nicotinate)

A novel compound‐monohydrated nickel nicotinate was synthesized by the method of room temperature solid phase synthesis and ball grinder. FTIR, chemical and elemental analysis, TG/DTG, and X‐ray powder diffraction technique were applied to characterize the structure and composition of the coordination compound. Low‐temperature heat capacities of the solid coordination compound have been measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 386 K. A solid‐solid phase transition occurred in the temperature range of 328–358 K in the heat capacity curve, and the peak temperature, the molar enthalpy and molar entropy of the phase transition were determined to be T_trs=(356.759±0.697) K, Δ_trsH_m=(13.650±0.408) kJ· mol^?1, and Δ_trsS_m= (38.279±0.086) J·K^?1·mol^?1, respectively. The experimental values of the molar heat capacities in the temperature ranges of 78–328 K and 358–386 K were fitted to two polynomials, respectively. The polynomial fitted values of the molar heat capacities and fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were calculated and tabulated at the intervals of 5 K.     

Low-temperature Heat Capacities and Thermodynamic Properties of Hydrated Sodium Cupric Arsenate [NaCuAsO4·1.5H2O（s）]

Low-temperature heat capacities of the solid compound NaCuAsO4·1.5H2O(s)were measured using a precision automated adiabatic calorimeter over a temperature range of T=78 K to T=390 K.A dehydration process occurred in the temperature range of T=368-374 K.The peak temperature of the dehydration was observed to be TD=(371.828±0.146)K by means of the heat-capacity measurement.The molar enthalpy and entropy of the dehydration were ΔDHm=(18.571±0.142)kJ/mol and ΔDSm=(49.946±0.415)J/(K·mol),respectively.The experimental values of heat capacities for the solid(Ⅰ)and the solid-liquid mixture(Ⅱ)were respectively fitted to two polynomial equations by the least square method.The smoothed values of the molar heat capacities and the fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were tabulated at an interval of 5 K.     

Low-Temperature Heat Capacities and Thermodynamic Properties of Octahydrated Barium Dihydroxide,Ba（OH）2·8H2O（s）

Low-temperature heat capacities of octahydrated barium dihydroxide, Ba（OH）2·8H2O（s）, were measured by a precision automated adiabatic calorimeter in the temperature range from T=78 to 370 K. An obvious endothermic process took place in the temperature range of 345-356 K. The peak in the heat capacity curve was correspondent to the sum of both the fusion and the first thermal decomposition or dehydration. The experimental molar heat capacifies in the temperature ranges of 78-345 K and 356-369 K were fitted to two polynomials. The peak temperature, molar enthalpy and entropy of the phase change have been determined to be （355.007±0.076） K, （73.506±0.011） kJ·ol^-1 and （207.140±0.074） J·K^-1·mol^-1, respectively, by three series of repeated heat capacity measurements in the temperature region of 298-370 K. The thermodynamic functions, （Hr-H298.15 k ）and （Sr-S298.15k）, of the compound have been calculated by the numerical integral of the two heat-eapacity polynomials. In addition, DSC and TG-DTG techniques were used for the further study of thermal behavior of the compound. The latent heat of the phase change became into a value larger than that of the normal compound because the melfing process of the compound must be accompanied by the thermal decomposition or dehydration of 71-120.     

Synthesis and Crystal Structure of [Zn(FcCOO)_2(2,2'-bipy)(H_2O)]_2·H_2O

A novel complex [Zn(FcCOO)2(2,2'-bipy)(H2O)]2·H2O (Fc = (η5-C5H5)Fe(η5-C5H4), 2,2'-bipy = 2,2'-bipyridine) has been synthesized and characterized by elemental analysis, IR and X-ray diffraction. It crystallizes in monoclinic system, space group P21/c with a = 6.8187(4), b = 21.7155(13), c = 19.7411(12) A, α = 90, β = 97.7420(10), γ = 90o, C64H58Fe4Zn2N4O11, Mr = 1413.28, V = 2896.4(3) A3, Dc = 1.620 g/cm3, Z = 2, F(000) = 1444, μ(MoKα) = 1.857 mm-1, R = 0.0523 and wR = 0.0982 for 3219 observed reflections (I > 2σ(I)). Structural analysis shows that the zinc atom is coordinated with three oxygen atoms from two ferrocenemonocarboxylates and one water molecule together with two nitrogen atoms from 2,2'-bipyridine, giving a distorted square-pyramidal coordination geometry. The complex molecules are linked to form an infinite one-dimensional chain by both intermolecular hydrogen bonds and π-π stacking interactions of the bipyridine rings.     

Synthesis and Structure of a Novel Compound [Cu_2(EDTA)(Py)_2(H_2O)_2]·2H_2O

1 INTRODUCTION Multinuclear coordination compounds have attrac-ted much attention due to their distinctive optical, elec-tric and magnetic properties as well as enzyme ana-logue[1～4]. It is important for carboxylic acid to de-sign this compound[5～8]. EDTA is a useful titrant formetal determination because EDTA molecule is easyto coordinate with a metal atom (1:1). Other types ofEDTA-M compounds are seldom to know except Ln2-M3(EDTA)3(H2O)11?12H2O[5] and (UO2 )2EDTA[9]. …     

Synthesis and Thermodynamic Properties of MgO·B_2O_3·4H_2O

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

Heat Capacities and Thermodynamic Properties of Lanthanum/Holmium Perchlorate Complexes with Glycine

IntroductionSinceAnghilerietal.1reportedin 1975thatthecom plexoflanthanumchloridewithglycinehadanti canceref fect,complexesofrareearthwithaminoacidhavebeenex tensivelystudied .Inthepastdecades,about 2 0 0kindsofcomplexesofrare earthcompoundswithaminoacidshavebeensynthesizedandstudied .2 Theycanbeusedasantisepticandanticancerdrugsinmedicine,additivesofanimalforageandfertilizerinagriculture,andwooldyeintextileindus try .3,4 Complexesofrareearthwithaminoacidwerewidelyusedinmanyfields,however,the…     

Low Temperature Heat Capacities and Thermodynamic Properties of Zinc L-Threonate Zn（C4H7O5）2（s） by Adiabatic Calorimetry

Low-temperature heat capacities of the solid compound Zn（C4H7O5）2（s） were measured in a temperature range from 78 to 374 K, with an automated adiabatic calorimeter. A solid-to-solid phase transition occurred in the temperature range of 295？322 K. The peak temperature, the enthalpy, and entropy of the phase transition were determined to be （316.269±1.039） K, （11.194±0.335） kJ？mol-1, and （35.391±0.654） J？K-1？mol-1, respectively. The experimental values of the molar heat capacities in the temperature regions of 78？295 K and 322？374 K were fitted to two polynomial equations of heat capacities（Cp,m） with reduced temperatures（X） and [X = f（T）], with the help of the least squares method, respectively. The smoothed molar heat capacities and thermodynamic functions of the compound, relative to that of the standard reference temperature 293.15 K, were calculated on the basis of the fitted polynomials and tabulated with an interval of 5 K. In addition, the possible mechanism of thermal decomposition of the compound was inferred by the result of TG-DTG analysis.     

Synthesis, Crystal Structure and Spectral Properties of [Ce(NO_3)_5(H_2O)_2]·2(Hphen)·(H_2O)

1 INTRODUCTION Recently, the ternary or quaternary mixed anion complexes of cerium(III) containing 1,10-phenanthroline (phen) have attracted considerable attention due to their rich structural chemistry and appealing magnetic properties[1]. Panagiotopou…     

Synthesis and Structure of the First Protonated Zincoborophosphate: (H_3O)Zn(H_2O)_2BP_2O_8·H_2O

IntroductionInthelastfewyearsthesearchfornewmaterialswithmicroporousandzeolite analogoussystemshasprimarilyfocusedonaluminumphosphatesandaluminosilicatecom poundssubstitutedwithavarietyofatoms .1 3 Cobalt sub stitutedaluminophosphatesaresystematicallystudiedmainlyduetotheirpotentialuseassolid acidcatalysts .Insuchmaterials ,theBr nstedacidsiteisgeneratedbyeachsubstitutionofAl(III)byCo(II)inwhichaprotonisneededtobalancethecharge .4 7Tofindnewtypeofze oliticmaterials ,theborophosphatemateri…     

Preparation and Properties of(BEDT-TTF)_2Br3H_2O Salt

Chargetransfersaltsoforganicdonormoleculehis(ethylenedithio)tetrathiafulvalene(BEDT--TTF)havebeenofgreatinterestduringthelastdecades,becauseofthewiderangeofphysicalpropertieswhichtheyexhibitl'2'3.Recently,ourgrouppreparedandstudiedorganicconductorsonthebaseofNi(dmit)2anions(dmit=l,3-dithiol-2-thione4,5-dithiolate)withEDA4(2-diethylamino-l,3-dithiolanylium),andfoundedthatthereweremanySScontactswhichareshorterthanthesumofvanderWaalsradii(3.70A)betweencanonsandanions.Theresultspromptedustoi…     

Low-temperature heat capacities and thermodynamic properties of rare-earth triisothiocyanate hydrates (Ⅲ)——Sm(NCS)_3·6H_2O,Gd(NCS)_3·6H_2O,Yb(NCS)_3·6H_2O and Y(NCS)_3·6H_2O

The heat capacities of four RE isothiocyanate hydrates,Sm( NCS)3 6H2O,Gd( NCS)3 6H2O,Yb(NCS)3 6H2O and Y( NCS)3 6H2O,have been measured from 13 to 300 K with a fully-automated adiabatic calorimeter No obvious thermal anomaly was observed for the above-mentioned compounds in the experimental tem-peiatnre ranges.The polynomial equations for calculating the heat capacities of the four compounds in the range of 13-300K were obtained by the least-squares fitting based on the experimental Cp data.The Cp values below 13 K were estimated by using the Debye-Einstem heat capacity functions.The standard molar thermodynamic functions were calculated from 0 to 300 K.Gibbs energies of formation were also calculated.     

Structure of Coordination Polymer, 〔Zn(bipy)(H_2O)_3SO_4〕·2H_2O (bipy=4,4'-bipyridine)

1　INTRODUCTION4,4' bipyridine( bipy) is a good candidate for building open framework struc ture because of their rodlike rigidity and length.Framework structures formed bytransition metalsbridged by bipy vary with metaland anion.The structures of Zn bipy system include interpenetrating square grid sheets〔 Zn( bipy) 2 ( H2 O) 2 〕Si F6〔1〕,two dimensionallayer〔 Zn( bipy) ( H2 O) 4 〕( NO3) 2 · bipy〔2〕,〔 Zn( bipy) ( H2 O) 4 〕 ( NO3) 2 · 2 bipy· 3 H2 O〔2〕 and〔 Zn( bipy)…     

Synthesis, Crystal Structure and Luminescent Properties of [Zn（bipy）_2（H_2O）_4]·L·3H_2O

A novel coordination complex [Zn(bipy)2(H2O)4]·L·3H2O (1, bipy = 4,4'-bipyridine, LHNa = aniline-2,5-disulfonic acid monosodium salt) has been synthesized from LHNa by using hydrothermal method and structurally characterized. The result indicates that complex 1 belongs to the monoclinic system, space group P21/c with a = 20.392(3), b = 7.4052(12), c = 23.843(3) , β = 116.253(10)°, V = 3.2291(8) 3, Z = 4, Dc = 1.553 g·cm-3, μ = 0.962 mm-1, F(000) = 1568, and the final R = 0.0497 and wR = 0.1290. The complex 1 has a 0-D discrete structure, and generates an infinite 3-D network with the aid of O–H…O hydrogen bonds and π-π interactions.     

Synthesis,Crystal Structure and Thermal Stability Properties of a Binuclear Copper(Ⅱ) Coordination Polymer {[Cu_2(4,4'-bipy)_2(o-ABA)_4(H_2O)_2][(H_2O)_2]}_n

One-dimensional chain copper(Ⅱ) coordination polymer has been synthesized and characterized in the solvent mixture of water and alcohol with o-acetamidobenzoic acid,4,4'-bipyridine and copper perchlorate.It is of tetragonal,space group P41212 with a=1.57756(10),b= 1.57756(10),c=2.1438(3)nm,V=5.3352(8) nm3,Dc=1.524 g/cm3,Z=4,F(000)=2536,R= 0.0479 and wR=0.0979.The crystal structure shows two coordination modes.The copper(1) is coordinated with two nitrogen atoms of one 4,4'-bipyridine molecule and two oxygen atoms from two o-acetamidobenzoic acid molecules,forming a distorted tetrahedral coordination geometry;the copper(2) is coordinated with two nitrogen atoms of one 4,4'-bipyridine molecule,four oxygen atoms from two o-acetamidobenzoic acid molecules and two water molecules,generating a distorted octahedral coordination geometry.The result of TG analysis shows that the title complex is stable below 180.0 ℃.     

Thermochromic and Magnetic Properties of a Copper(Ⅱ) Coordination Compound

Copper complexes that can experience reversible heat-induced dehydration and rehydration in the solid state were rarely reported although thermochromic copper complexes have been widely reported, and their heat-induced magnetic properties have not been studied. We firstly observed the reversible thermochromic phenomena of the known copper(II) complex [Cu(bpy)(OOCCH_3)_2]n·xn H_2O(x = 2.5 or 3; bpy = 4,4?-bipyridine) in the solid state, which is associated with the dehydration and rehydration processes, and found that heat-induced coloration clearly enhanced the magnetic susceptibility.     

Preparation and Study of Thermal Decomposition Mechanism of Zn(Thr)(AcO)_2·2H_2O

Introduction -Amino acids as additive have a wide application in medicines, foodstuff and cosmetics.1-3 The synthetic methods of amino acid have been reviewed.4,5 The solu-bility property of Zn(AcO)2-Thr-H2O (Thr=Threonine) system at 298.15 K has been investigated by the semimicro-phase equilibrium method, in which the phase region of the complex did not exist.6 The prepara-tion of Zn(Thr)SO4H2O was reported in Ref. 7∶3 times volume of acetone relative to that of water was added into t…     

Crystal Structure and Magnetic Properties of a Two-dimensional Compound{(Me_2NH_2)_4[Co(SIP)_2]·2(DMF)·3(H_2O)}_n

A new cobalt(II) compound, {(Me2NH2)4[Co(SIP)2]·2(DMF)·3(H2O)}n(1, H3 SIP =5-sulfoisophthalic acid), has been synthesized under solvothermal condition and structurally characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the tetragonal system,space group P 4 21 m, with a = 14.3080(7), b = 14.3080(7), c = 12.1837(9) ?, V = 2494.2(3) ?~3, Z =2, C_(330)H_(58)N_6O_(19)S_2Co, Mr = 929.87, Dc = 1.238 g/cm, μ = 0.496 mm~(-1), F(000) = 982, flack parameter of 0.007(9), the final R = 0.0767 and wR = 0.2110 for 2391 observed reflections with I 2σ(I). The tetrahedral Co(II) ions are linked by carboxylate groups of the 5-sulfoisophthalate ligands to form an anionic two-dimensional(2D) layer displaying a(4,4) square network, which was charge-balanced by the [Me_2NH_2] + cations occupying the spaces between the 2D layers. Magnetic properties of 1 have been investigated in detail using direct-current and alternating-current susceptibility measurements.