The structural analysis of the inclusion complex of β-cyclodextrin with m-nitrophenoxyacetic acid

The inclusion complex of β-cyclodextrin with m-nitrophenoxyacetic acid was studied by single crystal X-ray diffraction,2D NMR spectroscopy and semi-empirical methods AMI.The crystallographic study shows that two β-cyclodextrins are held together by hydrogen bonds to form head-to-head dimers.The disordered guest molecule adjusts itself to attain the most stable accommodation into the cavity in which the nitro group is located at the dimer interface while the carboxyl group is buried in the primary hydroxyl groups of β-cyclodextrin.The guest inside the cavity is disordered over two sites and exhibits mobility.Moreover,2D NMR spectroscopy and theoretical study show the same inclusion behavior.In comparison to the inclusion complex of β-cyclodextrin with p-nitrophenoxyacetic acid,the host-guest stoichiometries are different,i.e.,2:1 for m-nitrophenoxyacetic acid and 1:1 for p-nitrophenoxyacetic acid,while the inclusion orientation and the packing pattern of the host are similar in both complexes.     

Study on the inclusion interaction of methylated-β-cyclodextrins with albendazole by spectrofluorimetry and its application

The inclusion interaction between three types of methylated-β-cyclodextrins (Me-β-CDs) and albendazole (ABZ) was studied by spectrofluorimetry. The result showed that Me-β-CDs reacted with ABZ to form an inclusion complex, 1:1 stoichiometry for Me-β-CDs-ABZ complex was established and its association constant have been determined from fluorescence data by Benesi-Hildebrand's method (double reciprocal plots). It was noted that 2,6-DM-β-CD exhibited stronger binding ability than other Me-β-CDs. Based on the significant enhancement of fluorescence intensity of inclusion complex, a simple and highly sensitive fluorimetric method is proposed for the determination of ABZ in the presence of 2,6-DM-β-CD. The proposed method was successfully applied to the determination of ABZ in tablets and human urine.     

Study on the inclusion interaction of methylated-β-cyclodextrins with albendazole by spectrofluorimetry and its application

The inclusion interaction between three types of methylated-β-cyclodextrins （Me-β-CDs） and albendazole （ABZ） was studied by spectrofluorimetry. The result showed that Me-β-CDs reacted with ABZ to form an inclusion complex, 1： 1 stoichiometry for Me- β-CDs-ABZ complex was established and its association constant have been determined from fluorescence data by Benesi- Hildebrand＇s method （double reciprocal plots）. It was noted that 2,6-DM-β-CD exhibited stronger binding ability than other Me-β- CDs. Based on the significant enhancement of fluorescence intensity of inclusion complex, a simple and highly sensitive fluorimetric method is proposed for the determination of ABZ in the presence of 2,6-DM-β-CD. The proposed method was successfully applied to the determination of ABZ in tablets and human urine.     

Molecular structure of [(trien)Zn(im)Zn(trien)](ClO_4)_3 complex and ESR spectra of its single-crystal doped with [(trien)Cu(im)Zn(trien)l(ClO_4)_3 complex

The crystal structure of the title complex was measured, in which the two zinc atoms with coordination polyhedron of distorted tetragonal pyramid (TP) are bridged by an imidazolate in the apical position of the TP forming a dimer. The isomorphous [(trien)Cu(im)Zn(trien)](ClO4)3·H2O complex was doped in the title complex and the recorded single-crystal ESR spectra by fitting gave two sets of the principal values of g and A tensors, which were assigned to the physically distinct sites of the two magnetically equivalent molecules in the unit cell. Lattice distortion at the Cu(II) ion sites and the bonding parameters of Cu(II) ions are further calculated, and the bonding nature of Cu(II) ions is discussed.     

Room temperature phosphorescence of α-bromonaphthalene induced by β-cyclodextrin in the presence of cyclohexane

β-Cyclodextrin (β-CD) can induce a-bromonaphthalene (BrN) to emit strong room temperature phosphorescence (RTP) in the presence of micro amounts of cyclohexane (c-hexane). Experiments of luminescence spectra, phosphorescence lifetime and fluorescence polarization prove the formation of c-hexane/β-CD/BrN ternary inclusion complex. The apparent formation constant of the ternary inclusion complex was determined and the effect mechanism of c-hexane on the RTP of BrN induced by β-CD is discussed.     

A Large Conformational Change of a Bridged β－Cyciodextrin Dimer in Aqueous Solution

A novel bridged β-CD dimer in which two β-cyclodextrius were linked by a naphthalene at positions 2 and 7 has been synthesized. ^1H and ^13CNMR measurements showed that a large change in the conformation of the dimer occurred in aqueous solution. The dimer interacted with methyl and ethyl orange to form stable inclusion complexes v/a “induced fit“ mechanism.     

Non-Isothermal Decomposion Kinetics of Supermolecule Compound [Eu(C_(10)H_9N_2O_4)(C_(10)H_8N_2O_4)(H_2O)_3]_2·phen·4H_2O

Europium(Ⅲ) compound with 2-oxopropionic acid salicyloyl hydrazone (C_(10)H_(10)N_2O_4,H_3L) and 1,10-phenan-throline (C_(12)H_8N_2,phen) has been prepared.A yellow prismatic crystal of the compound was obtained,and themolecule crystallized in the triclinic space group P-1.There are two 9-coordinated complex molecules in everystructure unit,where every Eu atom is coordinated by three water molecules and two tridentate C_(10)H_(10)N_2O_4 ligands,forming two stable pentacycles.The coordination polyhedron around Eu~(3+) was described as a single cap squareantiprism.In the crystal cell,there are one free 1,10-phenanthroline and four water molecules.The thermaldecomposition of the compound and its kinetics were studied by non-isothermal thermogravimetry.The Kissinger'smethod and Ozawa's method were used to calculate the activation energy value of the first-step decomposition.Thestages of the decompositions were identified by TG-DTG-DSC curve.The non-isothermal kinetic data were ana-lyzed by means of integral and differential methods.The possible reaction mechanism and the kinetic equationswere investigated by comparing the kinetic parameters.     

Using PVP/SDS Complex as a Probe to Study the Inclusion Complex of β-cyclodextrin with SDS in Aqueous Solution

PVP/SDS complex was applied as a probe to study the interaction between β-cyclodextrin （β-CD） and sodium dodecyl sulfate （SDS） in aqueous solution. It has been found that a critical concentration, namely cs, exists in the relative viscosity of solution containing PVP/SDS complex versus β-CD concentration plot. As the β-CD concentration is less than cs, the relative viscosity of solution decreases sharply by adding β-CD into solution successively. On the other hand, as the β-CD concentration is greater than cs, the relative viscosity of solution increases gradually by adding β-CD into solution. The decrease of the relative viscosity of solution containing PVP/SDS in the presence of β-CD is just due to the inclusion complex of β-CD with the guest molecule SDS. And, this inclusion interaction takes down SDS from the PVP chains in solution. The ratio of the host molecule β-CD to the guest molecule SDS can be calculated from Cs. In our experiment the inclusion ratio of β-CD to SDS is 1/1. The further experimental results indicate that cs is associated with SDS but free from PVP in PVP/SDS complex. However, the inclusion ratio of β-CD to SDS has proved to be independent of either SDS or PVP in PVP/SDS complex.     

Spectroscopic Study on Interaction of β-Cyclodextrin with Triprolidine Hydrochloride

The complexation of triprolidine hydrochloride （TRP） and β-cyclodextrin （β-CD） in deuterium oxide was investigated by 400 MHz 1^H NMR spectroscopy. The 800 MHz 2D ROESY data revealed that two 1 ：1 and one 2 ： 1 β-CD-TRP inclusion complexes were formed. Both aromatic moieties （p-tolyl and pyridyl ring） has entered into the β-CD cavity, confirming the existence of two different equilibria for 1 ： 1 inclusion complexes in which p-tolyl ring of the guest is more tightly held by the host cavity. The ROE intermolecular interactions provided the plausible structures of these 1 ： 1 and 2 ： 1 stoichiometric inclusion complexes of β-CD-triprolidine hydrochloride in solu- tion.     

Comparative Study on the Inclusion Interaction between meso-Tetrakis（4-N-ethylpyridiniurmyl） porphyrin and β-Cyclodextrin Derivatives

The interaction of β-cyclodextrin (β-CD) and the modified cyclodextrins, hydroxy propyl-β-cyclodextrin (HP-β-CD), sulfobutylether-β-cyclodextrin (SBE-β-CD) and synthesized meso-tetrakis(4-N-ethylpyridiniurmyl)porphyrin (TEPyP) in aqueous solution has been studied by spectroscopic methods systematically. A significant change in fluorescence and absorption properties has been observed in the presence of β-CD, HP-β-CD and SBE-β-CD. The stoichiometry and formation constants have been determined by the steady-state fluorescence technique. The results showed that the β-CD derivatives were prior to the native β-CD and the hydrogen bonding and static electric forces played important roles in the formation of the inclusion complexes. The conformation was further confirmed by NMR spectroscopy.     

Hydrothermal Synthesis and Crystal Structure of a Novel Dinuclear Co(Ⅱ) Complex:[Co2(2,2'-bpy)_2(μ-L)_2(L)_2(μ-H_2O)](HL=4-Chlorobenzoic Acid)

A new 4-chlorobenzoic acid bridge Co(Ⅱ) complex [Co2(2,2'-bpy)2(μ-L)2(L)2(μ-H2O)] (HL=4-chlorobenzoic acid) has been obtained by hydrothermal synthesis,and X-ray single-crystal diffraction analysis shows that it crystallizes in the monoclinic system,space group C2/c with a=22.537(5),b=16.212(3),c=15.306(3) ,β=124.37(3)°,V=4616.1(16) 3,Mr=1070.45,Dc=1.540 g/cm3,Z=4,μ=1.012 mm-1,F(000)=2176,the final R=0.0338 and wR=0.0810. The title complex is composed of dinuclear [Co2(2,2'-bpy)2(μ-L)2(L)2(μ-H2O)] molecules. Each Co(Ⅱ) atom is coordinated by two nitrogen atoms from one 2,2'-bipyridine ligand,three oxygen atoms from three 4-chlorobenzoic ions and another oxygen atom from one water molecule. The two Co(Ⅱ) atoms are connected by two 4-chlorobenzoic ions and one bridged water molecule. The dinuclear molecules are interlinked by hydrogen bond and π-π stacking interactions into a three-dimensional supramolecular network.     

Study on the Supramolecular Interaction of β-Cyclodextrin with Gemfibrozil by Spectrofluorimetry and Its Analytical Application

The supramolecular interaction of gemfibrozil with β-cyclodextrin （β-CD） was studied by spectrofluorimetry. The mechanism of the inclusion was discussed by spectrofluoremetry, infrared spectrum and ^1H NMR spectrum. The results showed that a 1 ： 1 （β-CD ： gemfibrozil） complex was formed with an apparent association constant of 3.844 × 10^3 L·mol^-1. Based on the enhancement of the fluorescent intensity of gemfibrozil, a spectrofluorimetric method for the determination of gemfibrozil in bulk aqueous solution in the presence of β-CD was developed. The linear range was 3.30 ng·mL^- 1 -6.00 ug·mL^-1 with the detection limit of 0.980 ng·mL^-1. There was no interference from the excipients normally used in tablet composition and the serum main compositions. The proposed method was then successfully applied to the determination of gemfibrozil in capsules and serum.     

rac-11-t-Butoxy-1,4-dihydro-1,4-methanoanthracene:A two-dimensional framework structure built from C-H…O and C-H…πhydrogen bonds

The title compound rac-11-t-butoxy-l,4-dihydro-l,4-methanoanthracene(C₁₉H₂₀O,M_r = 264.35) has been synthesized and characterized by FT-IR,’H NMR,HRMS spectra and single-crystal X-ray diffraction.The crystal belongs to monoclinic,space group P2₁/n,with a = 13.5240（10）,b = 8.3453（6）,c = 13.9604（9） ,β= 100.0190（10）°.The structure of the title compound comprises a norbomene unit with a t-butoxy group,having a naphthalene ring fused on one side.The naphthalene is essentially planar with a maximum deviation of 0.032（2） for atom C（3）.In the crystal,inversion-related molecules are linked by pairs of C-H…O hydrogen bonds,forming a cyclic dimer with R₂²（16） graph-set motif.The C-H…πinteractions are also observed,linking the molecules into a continuous two-dimensional framework structure.     

Hydrothermal Synthesis and Crystal Structure of a Novel Dinuclear Co（ Ⅱ ） Complex： [Co2（2,2＇-bpy）2（μ-L）e（L）2（μ-H2O）] （HL = 4-Chlorobenzoic Acid）

ABSTRACT A new 4-chlorobenzoic acid bridge Co（Ⅱ ） complex [[Co2（2,2＇-bpy）2（μ-L）e（L）2（μ-H2O）] （HL = 4-chlorobenzoic acid） has been obtained by hydrothermal synthesis, and X-ray single-crystal diffraction analysis shows that it crystallizes in the monoclinic system, space group C2/c with a = 22.537（5）, b = 16.212（3）, c = 15.306（3） A, β= 124.37（3）°, V= 4616.1（16）A3, Mr = 1070.45, Dc = 1.540 g/cm3, Z = 4, p = 1.012 mm-1, F（000） = 2176, the final R = 0.0338 and wR= 0.0810. The title complex is composed of dinuclear [Co2（2,2＇-bpy）2（μ-L）2（L）2（μ-HaO）] molecules. Each Co（Ⅱ ） atom is coordinated by two nitrogen atoms from one 2,2’-bipyridine ligand, three oxygen atoms from three 4-chlorobenzoic ions and another oxygen atom from one water molecule. The two Co（Ⅱ） atoms are connected by two 4-chlorobenzoic ions and one bridged water molecule. The dinuclear molecules are interlinked by hydrogen bond and π-π stacking interactions into a three-dimensional supramolecular network.     

CRYSTAL AND MOLECULAR STRUCTURE OF MOLYBDENUM COM-PLEX MoO_2Cl_2(C_4H_3OCOOH)_2

<正> The crystal and molecular structure of the title compound was determined by single crystal X-ray diffraction method. The complex crystallizes in the mono-clinic space group P21/n with a = 10. 306 ( 3) , b = 10. 161 (2), c = 14. 798 ( 4) A . β= 108. 52(2)°, V= 1469. 4(6)A3,Z= 4. The structure was solved by direct methods. Least-squares refinement converged to a final value of R = 0. 043 and Rw= 0. 040 for 1237 reflections. The molybdenum (Ⅵ) ion is bonded to two chlorine atoms, two oxo atoms and two oxygen atoms from two monodentately and weakly coordinated carboxyl groups of molecules C4H3OCOOH, forming a octahedron. The Mo-O distances are in the range 1. 66 - 2. 39A ,the Mo-Cl distances fall in the range 2. 33-2. 34A.     

羟丙基-β-环糊精对双苯氟嗪包合作用的热力学研究

The inclusion complexes formation of dipfluzine(DF)with hydroxpropy -β-cyclodextrin(HP-β-CD)in aqueous solution was investigated by the phase-solubility method.With the increase of HP-β-CD concentration in aqueous sloutions,the solubility of DF increased linearly,which showed typical AL-type phase solubility diagram.The molar ratio of the DF-HP-β-CD complex was 1: 1.The effect of temperature on the reaction was studied through thermodynamics.The apparent stability constants of inclusion reation were determined.Thermodynamic parameters during the inclusion process were as follows: △_rH=30.58 kJ·mol~(-1),△_rS=158.8 J·mol~(-1)·K~(-1),△_rG＜0.The complex process was endothermic and spontaneous.With the increase of temperature,the tendency of spontaneous reaction increased.     

Synthesis, Crystal Structure and Properties of a Dinuclear Cobalt（II） Complex [Co2（a-furacrylato）4（Phen）2（H2O）]·C2H5OH

A dinuclear cobalt(Ⅱ) complex [Co2(α-furacrylato)4(Phen)2(H2O)]·C2H5OH has been synthesized with α-furacrylic acid and 1,10-phenanthroline as the ligands, and its crystal structure was determined. The crystal is of monoclinic system, space group C2/c with a=1.07388(8), b=2.4300(2), c=1.86708(14)nm, β=104.3830(10)o, V=4.719.4(7) nm3 , Dc=1.503 g/cm3 , Z=2, F(000)=2196, GOOF=1.053, the final R=0.0343 and wR=0.0883. The crystal structure shows that two neighboring cobalt(Ⅱ) ions are linked by the bridging coordination of two α-furacrylic acid anions and one water molecule, and their end positions are respectively coordinated with two 1,10-phenanthroline molecules and two α-furacrylic acid anions, forming a dinuclear structure. Both cobalt(Ⅱ) ions adopt hexa-coordinated distorted octahedral geometry. The electrochemical and fluorescence properties of the title complex are also discussed.     

Hydrothermal Synthesis and Crystal Structure of a Novel Dinuclear Co(Ⅱ) Complex: [Co2(2,2(')-bpy)2((-L)2(L)2(μ-H2O)] (HL = 4-Chlorobenzoic Acid)

A new 4-chlorobenzoic acid bridge Co(Ⅱ) complex [Co2(2,2(')-bpy)2(μ-L)2(L)2(μ- H2O)] (HL = 4-chlorobenzoic acid) has been obtained by hydrothermal synthesis, and X-ray single-crystal diffraction analysis shows that it crystallizes in the monoclinic system, space group C2/c with a = 22.537(5), b = 16.212(3),c = 15.306(3)(A), β= 124.37(3)°, V = 4616.1(16) (A)3, Mr = 1070.45, Dc = 1.540 g/cm3, Z = 4, μ = 1.012 mm-1, F(000) = 2176, the final R = 0.0338 and Wr = 0.0810. The title complex is composed of dinuclear [Co2(2,2(')-bpy)2(μ-L)2(L)2(μ-H2O)] molecules. Each Co(Ⅱ) atom is coordinated by two nitrogen atoms from one 2,2'-bipyridine ligand, three oxygen atoms from three 4-chlorobenzoic ions and another oxygen atom from one water molecule. The two Co(Ⅱ) atoms are connected by two 4-chlorobenzoic ions and one bridged water molecule. The dinuclear molecules are interlinked by hydrogen bond and π-π stacking interactions into a three-dimensional supramolecular network.     

SYNTHESIS AND CRYSTAL STRUCTURE OF [(η~5-C_5H_5)_2NdCl·OC_4H_8]_2

All attempts to prepare light lanthanide dicyclopeutadienyt chloride failed,due to the disproportionation reaction. The crystal complex of [(η~5-C_5H_5)_2NdCl.OC_4H_8]_2 was successfully prepared by the reaction of NdCl_3·2C_4H_8O with cyclopentadienyl sodium (molar ratio 1:1.8)in tetrahydrofuran at room temperatureThe composition of the title compound was determined by the methods of elemental analysis, infrared spectroscopy and photoelectron spectroscopy. The crystal structure of [(η~5-C_5H_5)_2NdCl·OC_4H_8]_2 was determined from single crystal X-ray diffraction. Data were collected at-60℃ under dry nitrogen atmosphere.The complex crystallizes in the monoclinic space group P2_1/c,with Z=2. Lattice parameters are: a=8.201(3), b=21.589(6),c=8.596(3),β=109.10(3)°.The structure was solved by Patterson and Fourier techniques and refined by least-squares to a final conventional R=0.0636 for 1680 reflections. There are two Nd atoms in the dimeric unit which are bridged asymmetrically by the two chlori     

Spectroscopic Studies of a Three-dimensional,Five-coordinated Copper(Ⅱ） Complex via Hydrogen Bonds:[Cu(PPD)(H2O)2](H2PDA=Pyridine-2,6-dicarboxylic Acid)

A new copper(Ⅱ） complex[Cu(PDA)(H2O)2] was synthesized and its structure was determined.Cu(Ⅱ）is five-coordinated in a tetragonal pyramid geometry.The two coordinating water molecules are different and the two Cu-O bond lengths differ by nearly 0.02nm.The whole crystal is linked to form a three-dimensional network by means of hydrogen bonds.The X-band ESR spectrum shows three different g tensors with a well-resolved hyperfine structure in the gz signal,giving the ESR parameters gx=2.05,gy=2.065 and gz=2.29.The covalency of the coordinate bonds and the deviation from tetragonal pyramid geometry for the complex are discussed based on the ESR spectra.