Cooperation of metal-organic coordination complex separator and wide-temperature-range electrolyte enables safe and high-performance lithium batteries

With the increase of people’s demand,it is extremely desired for developing high-safety,widetemperature-range and high-energy-density lithium batteries,but huge challenges are remained due to shrinkage and combustion of commonly used polyolefin separators at high temperatures,as well as narrow usable temperature range and high flammability of conventionally commercialized liquid electrolytes.In this work,we report a multifunctional separator mainly consisting of Zn^(2+)-phytate coordination complex nanoparticles and bacterial cellulose nanofibers,named the BZP separator,which possesses high porosity,excellent thermotolerance,good flame retardancy,abilities of anion binding and Ni^(2+)capturing.Through cooperating with the fluoride-free wide-temperature-range electrolyte,Li//LiFePO_(4) cells not only deliver discharge capacities of 110.39 mA h g^(-1)and 113.25 mA h g^(-1)after 2200 cycles (2 C) and1600 cycles (5 C) at 25℃,with capacity retentions of 76.59%and 86.09%,respectively,but also exhibit excellent cycling performance at 80℃ and-40℃.Significantly,the Li//NCM811 cell with a loading of7.8 mg cm^(-2)delivers a discharge capacity of 146.64 mA h g^(-1)after 200 cycles at 0.5 C,with a capacity retention of 89.03%.In addition,pouch cells can work at 120℃ and have low flammability.

Alkylation of naphthalene with n-butene catalyzed by liquid coordination complexes and its lubricating properties

With the development of coal chemical industry,large amounts of naphthalene and n-butene are produced,and converting them into high value-added products through alkylation has gained particular importance and interest.In this work,liquid coordination complexes(LCCs)were used as acid catalysts for the first time in the naphthalene alkylation reaction under mild conditions to obtain multibutylnaphthalenes with high yield.Various reaction conditions were thoroughly investigated.The LCC consisting of urea and AlCl_(3) showed excellent catalytic performance under optimal reaction conditions,giving 100%conversion of naphthalene and 99.66%selectivity towards multi-butylnaphthalenes.Combining the catalyst properties and catalytic results,a plausible reaction mechanism was proposed.The lubricating properties of the synthesized products were investigated for their potential application as lubricating base oils.The synthesized multi-butylnaphthalenes showed comparable physicochemical properties and tribological performances as the commercial cycloalkyl base oil.

Crystal Structure and Luminescent Property of a Coordination Complex Constructed with Pyrazine and 1,4-Phenylenediacetic Acid

A new coordination complex [Cd(pda)(pyz)(H2O)2]n(1, H2 pda = 1,4-phenylenediacetic acid, pyz = pyrazine) have been synthesized and structurally characterized. Crystal data for the title complex are as follows: orthorhombic system, space group Ccmb with a = 11.5245(3) b = 19.5069(5) c = 11.4231(3) A, V = 2568.00(12) A3, Mr = 188.31, Z = 16, F(000) = 1480, Dc = 1.948 g/cm3, μ(Mo Kα) = 1.725 mm-1, R = 0.0195 and w R = 0.0462 for 1357 observed reflections with I 】 2σ(I). In the title complex, the central Cd(II) ion is located in a distorted octahedral coordination environment. Two Cd(II) ions are bridged by two pda2- ligands and one pyz ligand to form a bi-loop structure. Luminescent property of the complex has also been studied.

Two Cobalt(II) Complexes Derived from the Hydrolysis Product of Di-Schiff Base Ligand N,N'-Bis-(1-benzimidazo-2-yl-ethylidene)-ethane-1,2-diamine:Preparation,Characterization and Crystal Structure of the 6-Coordinate Species [CoL_2]X·H_2O (X = ClO_4^-, N

The reactions of Co（C1O4）2·6H2O and Co（NO3）2.6H2O with the di-Schiff base ligand N,N＇-bis-（1-benzimidazo-2-yl-ethylidene）-ethane-1,2-diamine （LA） in ethanol have been investigated. The reactions of LA with excess amount of cobalt salts yield the six-coordinate complexes [CoL2]（ClO4）E·H2O 1 and [CoL2]（NO3）E·H2O 2 as isolatable products （L= N-（1- benzimidazo-2-yl-ethylidene）-ethane-1,2-diamine）, where L is a tri-dentate mono-Schiff base ligand, resulting from the hydrolysis of the precursor di-Schiff base LA. Both complexes were characterized by X-ray crystallography. Crystal data for complex 1： monoclinic, space group P21/c, a = 11.9214（10）, b = 23.5828（17）, c = 14.0387（12）A, β = 135.219（4）°, C22H30Cl2CoN8O9, Mr = 680.37, V = 2780.1（4） A^3 ,Z = 4, Dc = 1.625 g/cm^3,μ（MoKa） = 0.876 mm^-1, F（000） = 1404, the final R = 0.0725 and wR = 0.1530 for 5726 observed reflections （I 〉 2σ（I））. Crystal data for complex 2： monoclinic, space group P21/c, a = 18.2162（16）, b = 10.0610（6）, c = 18.593（2）A, β = 130.099（3）°, C22H30CoN10O7, Mr = 605.49, V = 2606.5（4） A3 Z = 4, Dc = 1.543 g/cm^3,μ（MoKa） = 0.722 mm^-1, F（000） = 1260, the final R = 0.0619 and wR = 0.1429 for 5194 observed reflections （I 〉 2σ（I））. X-ray diffraction analysis reveals that each cobalt atom in the two complexes is chelated by six nitrogen atoms from two tridentate iigands L, exhibiting a slightly distorted octahedral coordination sphere. In both complexes, the strong hydrogen-bonding interactions between the lattice waters and N-H groups of the ligands result in 1D chains which are further connected by ClO4^- （or NO3^-） groups to form a 3D framework. In complex 2, the strong π-π interactions increase the stability of the structure.

Syntheses,Crystal Structures,DFT Calculation and Optical Properties of a Schiff Base and Its Dinuclear Mercury(Ⅱ)Complex

A pyridine-contained Schiff base ligand L（L =（pyridine-2-vinyl）hydrazine） has been synthesized and fully characterized. By self-assembly of the ligand with HgI2, a binuclear complex Hg2I4L（C） was obtained. The structures of L and C were analyzed through single-crystal X-ray diffraction. L crystallizes in monoclinic, space group P21/n with a=11.286（5）, b=3.981（5）, c=23.865（5） , β=100.043（5）°, V=1056（1） 3, Z=4, Dc=1.323 g/m3, F（000）=440, Μr=210.24, μ=0.084 mm（-1）, the final R=0.0928 and w R=0.2867 for 6955 observed reflections with I ＆gt; 2（I）. The complex is of monoclinic system, space group P21/n with a=8.706（5）, b=17.468（5）, c=14.675（5） , β=93.922（5）°, V=2227（2） 3, Z=4, Dc=3.338 g/m3, F（000）=1928, Μr=1119.02, μ=19.321 mm（-1）, the final R=0.0366 and w R=0.1276 for 3920 observed reflections with I ＆gt; 2（I）. The structural analysis revealed that the molecule of L possesses a well planar structure. However, in the complex, the coordinated ligand distorts greatly. The absorption spectra of L and the complex in ethanol were experimentally and theoretically studied. The result indicates that the complex exhibits different absorption spectrum compared with the free ligand.

Thermochemical Study on Coordination Complex of Neodymium Trichloroacetic Acid with 8-Hydroxyquinoline

Two coordinate reactions, NdCl 3·6H 2O(s) +3CCl 3COOH(s)( or TCA) =Nd(TCA) 3·3H 2O(s) +3HCl(g) +3H 2O(l) and Nd(TCA) 3·3H 2O(s) +2C 9H 7NO(s)= Nd(TCA)(C 9H 6NO) 2 (s) +2CCl 3COOH(s) +3H 2O(l), were studied by the classical solution calorimetry at 298.15K. The molar dissolution enthalpies of the reactants and the products in certain solvent (the first reaction in 1 mol·L -1 HCl, the second in a mixed solution consisting of absolute ethyl alcohol, dimethyl sulfoxide and 4 mol·L -1 HCl ) were measured by using an isoperibol calorimeter at 298.15K . From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(TCA) 3·3H 2O,s,298.15K] and [Nd(TCA) (C 9H 6NO) 2 ,s, 298.15K] are determined as Δ fH m °[Nd(TCA) 3·3H 2O,s,298.15K]= -3053.3 kJ·mol -1 and Δ fH m° [Nd(TCA) (C 9H 6NO) 2 ,s, 298.15K] = -1355.6 kJ·mol -1 .

Investigations of the electron paramagnetic resonance parameters and the tetragonal local structure for (VCl_6)^(4-) coordination complex in MCl:V^(2+) (M=Na,K,Rb) systems

By simulating the electron paramagnetic resonance （EPR） and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl：V2＋ （M=Na, K, Rb） systems at 77K, 195 K and RT （room temperature 295 K or 302 K）, respectively. The theoretical results indicate that there exists a compressed distortion in MCl：V2＋ systems. Meanwhile, it finds that the structure parameters R1, R2 and ｜△R｜（ = R1 - R2） increase with the rising temperature. Subsequently, from the analysis it concludes that the relation of EPR parameter D vs. △R is approximately linear. Finally, the effects of orbital reduction factor k on the g factors for the three systems have been discussed.

Synthesis and Crystal Structure of Two Coordination Complexes Based on H_(2)dpa and Tmd Ligands

Two new transition metal compounds, [Mn（dpa）2（tmd）2]n （1, H2dpa = 4-hydroxy-phenyl-acetic acid, tmd = 4,4-trimethylenedipyridine） and [Co4（dpa）6（tmd）4（H2O）4]n·nH2O·nCl2 （2）, have been synthesized by hydrothermal synthesis. Compound 1 crystallizes in the monoclinic system, space group P21/n with a = 9.828（3）, b = 17.493（5）, c = 11.616（4）, β = 110.146（6）o, V = 1874.9（10）3, C42H42MnN4O6, Mr = 753.74, Z = 2, Dc = 1.335 g/cm3, μ = 0.406 mm-1, F（000） = 790, the final R = 0.1047 and wR = 0.2021 for 2698 observed reflections （I 〉 2σ（I））. Compound 2 crystallizes in the monoclinic system, space group P21/c with a = 11.7214（13）, b = 17.1582（19）, c = 24.625（3）, β = 103.055（3）o, V = 4824.4（9）3, C100H104Cl2Co4N8O23, Mr = 2094.55, Z = 2, Dc = 1.443 g/cm3, μ = 0.809 mm-1, F（000） = 2180, the final R = 0.0550 and wR = 0.0673 for 4104 observed reflections （I 〉 2σ（I））. These complexes were characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. The structural analyses show that the two compounds are both one-dimensional chain structures. However, compounds 1 and 2 form threedimensional supramolecular structures by hydrogen bonds, respectively.

Syntheses,Structures,and Properties of Two Cobalt(Ⅱ)Coordination Complexes Based on(Fluorene-9,9-diyl)dipropanoic Acid and 1,3-Bis(imidazol-1-yl)butane Ligands

Two new cobalt（II） coordination complexes, namely [Co（HL）2（biim）（H2O）2]n·n H2O（1） and [Co（Et L）2（biim）]n·3 n（H2O）·2 n（Et HL）（2）（H2L =（fluorene-9,9-diyl）dipropanoic acid, biim = 1,3-bis（imidazol-1-yl）butane）, have been synthesized using the same starting reactants but different solvent medium. The two complexes exhibit distinctly different structures. Compound 1 exhibits a one-dimensional linear chain structure. However, complex 2 reveals a one-dimensional zigzag chain structure. Thermogravimetric analyses（TGA） and luminescent properties of these two complexes have been discussed.

Synthesis and Crystal Structure of a 1-D Chain Coordination Complex {[Mn_2(HCAM)_3(H_2bipy)]·5H_2O}_n

The 1-D chain coordination complex of {[Mn2（HCAM）3（H2bipy）]·5H2O}n （H3CAM = 4-hydroxypyridine-2,6-dicarboxylic acid, bipy = 4,4＇-bipyridine） has been synthesized by the reaction of 4-hydroxypyridine-2,6-dicarboxylic acid, 4,4＇-bipyridine and manganese carbonate under hydrothermal conditions, and its crystal structure was determined by X-ray diffraction method The crystal belongs to the monoclinic system, space group P21/n with a = 10.110（2）, b = 20.159（4）, c = 17.861（4）A,β = 99.67（3）°, V = 3.5884（12） nm3, Mr= 901.47, Z = 4, Dc= 1.669 g.cm^-3, μ= 0.798 mm^-1, F（000） = 1840, the final R = 0.0713 and ωR = 0.1853. The complex forms a 1-D chain bridged by HCAM, protonated 4,4-bipyridines link the 1-D chains to construct 2-D networks via N-H...O hydrogen bonds, and networks are further extended via π-π stacking and hydrogen bonds into 3-D supramolecular framework.

Complex coordinate rotation method based on gradient optimization

In atomic,molecular,and nuclear physics,the method of complex coordinate rotation is a widely used theoretical tool for studying resonant states.Here,we propose a novel implementation of this method based on the gradient optimization(CCR-GO).The main strength of the CCR-GO method is that it does not require manual adjustment of optimization parameters in the wave function;instead,a mathematically well-defined optimization path can be followed.Our method is proven to be very efficient in searching resonant positions and widths over a variety of few-body atomic systems,and can significantly improve the accuracy of the results.As a special case,the CCR-GO method is equally capable of dealing with bound-state problems with high accuracy,which is traditionally achieved through the usual extreme conditions of energy itself.

A Theoretical Study of Tris-(o-benzoquinonediimine)-First-Row Divalent Transition Metal Complexes

The ligand o-phenylenediamine (opda) and its oxidized form, o-benzoquinonediimine (bqdi), act as a fascinating candidate coordinating toward transition metal ions leading to the photochemical hydrogen production in absence of photosensitizers. Herein, we report the systematic study of the interaction between the oxidized form bqdi ligand, tris-(o-benzoquinonediimine) with divalent first-row transition metal series using DFT calculations. The lowest energy structures, bond length, binding energies, frontier molecular orbital analysis, natural bond orbitals, and global reactivity descriptor were calculated using B3LYP/6-311G(d,P) level of theory. The time dependent-DFT at the CAM-B3LYP/6-311+G(d,p) level of theory was applied to determine the electronic structures and the optical spectra. The theoretical binding trend of the divalent first-row transition metal series is decreasing as follows: Cu >Ti > V > Co > Ni > Fe > Cr > Zn >Mn. Among them, the binding potency of iron (II) by the bqdi ligand was not predominantly sturdy as compared to other first-row divalent transition metal ions. The origin of strong coordination with Fe(II) is attributed to its extra capability to induce covalent coordination of bqdi ligands. The complex exhibited two strong peaks at 370 nm and 452 nm, due to the HOMO-3 to LUMO+1 and HOMO-1 to LUMO transitions, respectively. Natural bond orbital analysis showed that the major interaction happens between the N lone pair electrons of the ligand with an anti-bonding orbital of metal ions, in which Ti showed the highest interaction energy than other metal ions. The present systemic DFT study of bqdi ligands with the first-row transition metals strongly encourages the future establishment of photochemical hydrogen production in absence of photosensitizers.

Synthesis and Characterization of a Novel Coordination Complex Based on Fluorescein

A novel coordination complex,{[Cd）2（C（20）H（10）O5）2（H2O）4]·10H2O}n,has been synthesized based on fluorescein（2-（6-hydroxy-3-oxo-3 H-xanthen-9-yl） benzoic acid） and systematically characterized by elemental analysis,infrared（IR） spectrum,thermo gravimetric analysis（TGA）,powder X-ray diffraction（PXRD） and single-crystal X-ray diffraction.Compound 1 crystallizes in monoclinic,space group P2/n with a = 20.428（5）,b = 8.084（2）,c = 21.689（5）A,β = 96.360（5）°,Mr = 993.46,V = 3559.7（15）A^3,Z = 4,Dx = 1.845 g/cm^3,μ = 1.276 mm^-1,F（000） = 1974,GOOF = 1.044,λ（Mo Kα） = 0.71073 ？,the final R = 0.0553 and wR = 0.1720 for 7245 observed reflections with I 〉 2σ（I）.

Synthesis,Crystal Structure and PTPs Inhibition of a Zinc(Ⅱ) Complex with N-(4-hydroxybenzyl)-L-serine

The reaction of the reduced Schiff base HL（N-（4-hydroxybenzyl）-L-serine） with Zn（CH3COO）2·2H2O in aqueous solution afforded [Zn（L）2]·3H2O（I）. The complex has been characterized by elemental analysis, FT-IR, powder X-ray diffraction, electrospray ionization mass spectrometry and single-crystal X-ray diffraction. Complex I crystallizes in the orthorhombic system, space group P212121, with a=9.197（2）, b=10.445（2）, c=24.149（5） , V=2319.8（8） 3, Z=4, C（20）H（30）N2O11 Zn, Mr=539.83, Dc=1.546 g·cm3, μ=1.122 mm（-1）, F（000）=1128, GOOF=0.971, the final R=0.0206 and w R=0.0506 for 4346 observed reflections（I ＆gt; 2σ（I））. In complex I, each Zn（II） ion coordinates with three carboxyl oxygen atoms and two amine nitrogen atoms from three L-anions, forming a distorted five-coordinated trigonal bipyramidal geometry. Complex I exhibits a 1D wavy chain structure that is extended by hydrogen-bonding interactions to form a supramolecular network. The bioactivity of the complex as a potential PTPs inhibitor in vitro was investigated, displaying potent inhibition against PTP1B（IC（50）, 0.24 μM） and TCPTP（IC（50）, 0.53 μM） with a moderate selectivity.

The Effects of Oxidation States and Spin States of Chromium Interaction with <i>Sargassum Sp</i>.: A Spectroscopic and Density Functional Theoretical Study

The study of various oxidation states of chromium with Sargassum sp. is of particular interest since hexavalent chromium is reduced to trivalent chromium in an aqueous solution. In this study, a systematic density functional theory (DFT) calculations were performed to study the interactions of transition metal chromium ion with different oxidation states and spin states with the Sargassum sp. decorated with carboxylate (acetate) at the wB97XD/6-311++ G(d,p) level of theory. The structures and binding energies of chromium metal-carboxylate complexes at various oxidation states and spin states in gas phase were examined. The coordination strength of Cr(VI) with the acetate ligand was predominantly the strongest compared to the other oxidation states. Vibrational frequency analysis, for the homoleptic monomers of tris [CrIII(AC)3]0 and [CrVI(AC)3]3+ complexes, illustrate good harmony with the experimental and theoretical calculated frequencies. Using the time-dependent DFT (TD-DFT) at the level of CAM-B3LYP/6-311++G(d,p), the vertical excitation energies were obtained. The stabilization energies derived using the second order perturbation theory, Eij(2), of NBO analysis confirmed the greater charge transfer for the observed trends in the metal binding. The calculated binding energies (ΔE) and interactions energies SEij(2) favor the formation of [CrVI(AC)3]3+ complexes. The findings of this study identify efficient electronic factors as major contributors to the metal binding affinities, with promising possibilities for the design of metal-ligand complexes and sensing of the metal ions.

Hydrothermal Synthesis,Crystal Structure and Spectral Characterization of a New Copper Isopolytungstate: [Cu(phen)_3][W_6O_(19)]

An unusual inorganic-organic hybrid hexatungstate complex [Cu（phen）3][W6O19] 1 （C36H24 CuN6O19W6, Mr= 2011.20） was hydrothermally synthesized and characterized by singlecrystal X-ray diffraction, IR spectrum, UV-VIS spectrum and elemental analyses. This compound crystallizes in the monoclinic system, space group C2/c with a = 19.1005（11）, b = 11.2585（11）, c = 20.2867（15） A, β= 102.177（2）°, V= 4264.4 A^ 3, μ（MoKa） = 16.691 mm^-1, Dc = 3.133 g/cm^3, Z = 4, F（000） = 3628, the final R = 0.0338 and wR = 0.0798 for 4090 observed reflections with I 〉 2σ（I）. The result of structure determination shows that the crystal structure is constructed from [W6O19]^2- cluster anions and [Cu（phen）3]^2＋ complex fragments, which are held together into a three-dimensional network through hydrogen-bonding interactions.

Synthesis,Crystal Structure and Luminescent Property of a New Indium(Ⅲ)Coordination Polymer

A new coordination complex [In（pda）1.5（bpy）]n （1, H2pda = 1,4-phenylenediacetic acid, bpy = 2,2＇-bipyridine） has been synthesized under hydrothermal conditions and characterized by IR spectrum, elemental analysis, PXRD and single-crystal X-ray diffraction analysis. Crystal data for the title complex are as follows： monoclinic system, space group P21/n with a = 11.8015（7）, b = 15.9551（10）, c = 11.8858（8）A^°, β = 94.844（6）°, V = 2230.0（2） A^°3, Mr = 559.25, Z = 4, F（000） = 1124, Dc = 1.666 g/cm^3, μ（MoKα） = 1.106 mm^-1, R = 0.0269 and wR = 0.0569 for 4534 observed reflections with I 〉 2σ（I）. Complex 1 displays a 3D supermolecular structure based on the 1D zizag chains. Fluorescence spectrum measurement indicates that complex 1 shows strong fluorescence emission with a maximum peak at 447 nm in the solid state at room temperature.

Synthesis of Pt and Pt-Fe nanoparticles supported on MWCNTs used as electrocatalysts in the methanol oxidation reaction

This work reports a feasible synthesis of highly-dispersed Pt and Pt-Fe nanoparticles supported on multiwall carbon nanotubes （MWCNTs） without Fe and multiwall carbon nanotubes with iron （MWCNTs-Fe） which applied as electrocatalysts for methanol electrooxidation. A Pt coordination complex salt was synthesized in an aqueous solution and it was used as precursor to prepare Pt/MWCNTs, Pt/MWCNTs-Fe, and Pt-Fe/MWCNTs using FeC12.4H20 as iron source which were named S 1, S2 and S3, respectively. The coordination complex of platinum （TOA）2PtC16 was obtained by the chemical reaction between （NH4）2PtC16 with tetraoctylammonium bromide （TOAB） and it was characterized by FT-IR and TGA. The materials were characterized by Raman spectroscopy, SEM, EDS, XRD, TEM and TGA. The electrocatalytic activity of Pt-based supported on MWCNTs in the methanol oxidation was investigated by cyclic voltammetry （CV） and chronoamperometry （CA）. Pt-Fe/MWCNTs electrocatalysts showed the highest electrocatalytic activity and stability among the tested electrocatalysts due to that the addition of ＂Fe＂ promotes the OH species adsorption on the electrocatalyst surface at low potentials, thus, enhancing the activity toward the methanol oxidation reaction （MOR）.

Two Cobalt(Ⅱ)Coordination Polymers Based on Tetrazylphosphonate and Tetrazylphosphonic Acid Ligands

Two cobalt coordination polymers with the same 2D structure have been hydrothermally synthesized based on two bifunctional ligands with tetrazole and phosphonate（phosphonic acid） groups,namely,diethyl 4-（2H-1,2,3,4-tetrazol-5-yl） benzylphosphonate（C_2H_5-L1） and 4-（2H-1,2,3,4-tetrazol-5-yl）benzylphosphonic acid（H_2L2）. The structures of the two complexes are characterized by elemental analysis,IR,TGA and X-ray single-crystal/powder diffraction. The pink block crystals of complex [Co（L1）（H_2O）]·H_2O（1） belong to the monoclinic system,space group C2/m with a = 20.8390（11）,b = 7.2695（3）,c = 10.0156（6） A,β = 109.773（7）°,V = 1427.80（13） A^3,Z = 4,D_c = 1.680 mg/cm^-3,M_r = 361.16,F（000） = 740,R = 0.0316 and wR = 0.0826 for 1702 observed reflections（I 〉 2σ（I））. The purple block crystals of complex [Co（L2）（H_2O）]·2H_2O（2） also belong to the monoclinic system,space group C2/c with a = 25.5382（16）,b = 7.3844（3）,c = 15.1925（11） A,β = 124.238（9）°,V = 2368.6（2） A^3,Z = 8,D_c = 1.969 mg/cm^-3,M_r = 351.12,F（000） = 1432,R = 0.0475,wR = 0.1617 for 2088 observed reflections（I 〉 2σ（I））. Both the nitrogen atoms of tetrazole group and oxygen atoms of phosphonate（phosphonic acid） groups in the ligands coordinated with the metal cobalt. The magnetic property of complex 1 is also investigated.

Synthesis,Characterization and Calorimetry of Ni(C_4H_8N_2O_3)_2Cl_2

A coordination complex was synthesized from NiCl2 and dipeptide glycylglycine（GG）. It was characterized by element analysis, NMR and TG methods, and then was determined to be Ni（C4HsN2O3）2Cl2. Using an isoperibolic reaction calorimeter, the standard molar enthalpy of formation of Ni（GG）2Cl2（solid） has been determined to be -（1 674.66±2.02） kJ · mol^-1 at 298.15 K.