Ca(Ⅱ)-NTP-HRB混配物的稳定性和配体堆积作用研究

The stability constants of the ternary mixed-ligand complexes of Ca(NTP)(HRB) n-(n=2 or 3) have been determined by potentiometric pH titration in aqueous solution (I=0.1mol/L,KNO3,25℃),Where NTP refers to adenosine 5′-triphorphat e (ATP) and uridine 5′-triphoophate (UTP);HRB,1,10-phenanthroline (Phen),2,2 ′-bipyridyl (Bpy),and L-tryptophan (Trp).The stability difference between the ternany complexes and the binary complexes has been compared and discussed.The increased stability in ternany mixed-ligand complexes was attributed to the coo perative effect of πA-πB and the intramolcular ligand-ligand aromatic st acking interaction.The extent of the stacking interaction in the ternary calcium compl exes was calculated,which is in accordance with the size of the aromatic rings f orming the stacks.     

Synthesis, molecular structure and intramolecular aromatic-ring stacking interaction of a novel binuclear Cu(Ⅱ) complex with 1, 10-phenanthroline and phenylacetate

The complex [Cu(phen)2(POAc)3]ClO·4H2O has been synthesized and investigated by elemental analysis, IR spec-troscopy and X-ray diffraction methods, where phen = 1,10-phenanthroline, POAc = phenylacetate group). The complex crystallizes in the triclinic space group PI with two molecules in a unit cell of dimensions a = 1.0579(2) nm, b = 1.2423(3) nm, c = 1.9190(4) nm, α = 71.84(1)°, β = 80.50(2)°, γ = 88.60(1)°, V = 2.3625(9) nm3, R = 0.0407 and Rw = 0.0656. The complex results from bridging of two Cu(phen)2 units by three carboxylate groups, and each Cu2 ion is in a distorted square pyramidal geometry with two nitrogen atoms of phen and three carboxylate oxygen atoms of POAc. It has been showed that intramolecular stacking interactions occur between the phenyl moieties of POAc and aromatic rings of phen, leading to a novel molecule structure with two coordinating modes of carboxylate ligands, of which two phenylacetates are μ2-carboxylate-O-bridging ligands, and the other is a μ2-carboxylate-     

Intramolecular stacking interaction in mixed-ligand complexes containing ATP4- and aromatic N-heterocyclic ligands

The stability constants of the binary ML2+ and ternary M(ATP)L2- complexes,where L=Iq (isoquinoline) or BIm (benzimidazole) and M=Zn2+ or Cd2+,have been determined by poten-tiometric pH titration in aqueous solution at I=0.1 mol/L (NaClO4),T=25℃.The stability of the ternary complexes characterized by corresponding to the equilibrium M(ATP)2-+ML2+=M(ATP)L2-+M2+ is higher than what would be expected on statistical grounds.The increase may be related to the stacking interaction between the aromatic ring of the ligands L and the purine moiety of ATP4- 1H NMR studies of Zn2+/ATP4-/L confirm the presence of stacking in the ternary complexes.It is concluded that the strength of the intramolecular stacking interaction is dependent on the structure of the aromatic ring of the ligand L and the formation of a metal ion bridge.Possible implications are discussed briefly.     

锌(Ⅱ)-氨基酸水杨醛席夫碱-α-氨基酸三元配合物的稳定性

The stability constants of binary complexes of Zn(Ⅱ)-α-amino acid and ternary complexes of Zn(Ⅱ)-N-Salicylideneaminio acid (ligand A)-α-amino acid(ligand B) at (25±0.1)℃ and in the presence of 0.1 mol·L^-1 KNO₃ have been determined by pH method. The α-amino acid(Aa) used were Glycine(Gly), L-Serine(Ser), L-Leucine(Leu), L-Proline(Pro) and L-Phenylalanine(Phe). It was found that the linear free energy relationship (LFER) exists nicely between the following parameter pairs logβ₁₀₂ and pK^B₂, logβ₁₁₁ and pK^B₂, and logβ₁₁₁ and pK^A₂. The ΔlgK was used to characterize the stability of ternary complexes related to the stability of parent binary complexes. The hydrophobic interaction between ligands in the ternary complexes was studied.     

Investigation of the Substituent Effects on π-Type Pnicogen Bond Interaction

Intermolecular interactions between PH_2Cl and Ar–R(R = H,OH,NH_2,CH_3,Br,Cl,F,CN,NO_2) were calculated by using MP2/aug-cc-p VDZ quantum chemical method.It has been shown from our calculations that the aromatic rings with electron-withdrawing groups represent much weaker binding affinities than those with electron-donating groups.The charge-transfer interaction between PH_2Cl and Ar–R plays an important role in the formation of pnicogen bond complexes,as revealed by NBO analysis.Nevertheless,AIM analysis shows that the nature of the interactions between PH_2Cl and Ar–R is electrostatic,and the interaction energies of the complexes are correlated positively with the electron densities in the bond critical points(BCPs).RDG/ELF graphical analyses were performed to visualize the positions and strengths of the pnicogen bonding,as well as the spatial change of the electron localization upon the formation of complexes.The π-type halogen bond was also calculated,and it has been revealed that the π-type pnicogen bond systems are more stable than the halogen bond ones.     

Synthesis of New Ruthenium（Ⅱ）Bipyridyl Complexes and Studies on Their Photophysical and Photoelectrochemical Properties

Two new mixed-ligand ruthenium(Ⅱ） complexes,Ru(dcbpy)-(LL)NCS)2[where dcbpy=4,4‘-dicarboxyl-2,2‘‘-bipyridine,LL=4,4‘-bis(N-methyl-anilinomethyl)-2,2‘‘-bipyridine(2)],were synthesized,and the tphotophysical properties of these complexes were studied.The metal-to-ligand charge transfer (MLCT) transitions of these complexes exhibited solvatochromic effect due to the existence of NCS ligands.The MLCT energies also strongly depend on the pH values of the solutions because of protonation and deprotonation of the carboxyl groups.The pKa values of the ground state,4.0 for 1 and 3.8 for 2,were obtained from the titration curves.The photoelectrochemical properties of 1 and 2 as sensitizers in sandwich-type solar cells have been studied.Complex 1 exhibited better photoelectrochemical behavior than complex 2 as expected.It was proved that the design of mixed-ligand complex by introducing electron donating group in one of the ligands should be a promising approach.     

TERNARY COMPLEXES OF Cu(ATP)AND HETEROAROMATIC N BASE-ISOQUINOLINE AND BENZIMIDAZOLE:STABILITY CONSTANT AND STACKING EFFECT

The stability constants of the binary complexes ofCu~(2+) with isoquinoline and benzimidazole as well as the ternarycomplexes of Cu(ATP)with the same ligands have been measuredin aqueous solution spectrophotometrically and a strongstacking interaction between the heteroaromatic ring of theligands and the purine moiety of ATP has been found.The factof this stacking interaction is much stronger than that in thesystems of Cu(ATP)with pyridine and imidazole shows thatthe stacking interaction increases with the size of theheteroaromatic ring of the ligands.     

11-钨过渡金属杂多阴离子为配体的配合物的热稳定性研究

The thermal stability of complexes with 11-tungstometalates heteropolyanion as ligands in air was studied by TG-DTA as well as XPS, IR and solubility of different temperatures. It was found that thermal stability of the synthesized heteropolycomplexes was in connection with heteropolycomplexes’ corresponding Keggin units.     

Theoretical Studies on the Cu-Cu Interaction and Stability of [Cu_a(Ph_2Ppy)_b(CH_3CN)_c]~(a+) (a=1～2,b=1～3,c=0～2)

To study the Cu-Cu interaction and stability of the title complexes,the structures of complexes [Cu(Ph2Ppy)(CH3CN)]+ 1,[Cu(Ph2Ppy)]+ 2,[Cu2(Ph2Ppy)2(CH3CN)2]2+ 3,[Cu2(Ph2Ppy)2(CH3CN)]2+ 4,[Cu2(Ph2Ppy)2]2+ 5 and [Cu2(Ph2Ppy)3(CH3CN)]2+ 6 were calculated by density functional theory PBE0 method,and the following conclusions can be drawn:(1) There is no orbital overlapping between two Cu atoms,indicating no Cu-Cu orbital interaction exists in complexes 3～6.Due to a breakdown of the closed shell configuration of Cu atoms,the weak Cu-Cu interactions result from the 3dCu → 4sCu' charge-transfer in 4～6.The Cu-Cu interaction strength follows 5 6 4,implying that there are stronger Cu-Cu interactions in the complexes with fewer CH3CN or more Ph2Ppy ligands.(2) The calculated interaction energies suggest that the coordination of Cu to Ph2Ppy is stronger than that to CH3CN.In 3～6,there are weaker interactions between Cu and CH3CN or Ph2Ppy in the complexes with more CH3CN or Ph2Ppy ligands.(3) The P-Cu and N-Cu interactions are much stronger than the Cu-Cu interaction,so we mainly attribute the stabilities of the binuclear complexes to the eight-membered rings Cu2P2N2C2.     

Synthesis,Crystal Structure and Antimicrobial Activity of a New Ternary Copper(Ⅱ) Complex with p-Chlorophenoxyacetic Acid and 2-Amino Benzothiazole

A novel ternary complex of Cu(pcpa)2(aben)2 (pcpa=p-chlorophenoxyacetic acid anion,aben=2-amino benzothiazole) was synthesized by the reaction of copper acetate,2-amino benzothiazole and p-chlorophenoxyacetic acid.Elemental analysis,IR,UV and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure.The crystal crystalli-zes in the monoclinic system,space group C2/c with a=25.795(4),b=7.384(3),c =17.741(6),β=107.47(2)°,C30H24Cl2CuN4O6S2,Mr=735.09,V=3223.2(18) 3,Z=4,Dc=1.515 Mg/m3,λ(MoKα)=0.71073 ,μ=1.022 mm-1,F(000)=1500,the final R=0.0464 and wR=0.1244.A total of 3218 unique reflections were collected,of which 2228 with I 2σ(I) were observed.The Cu(II) atom is four-coordinated with two carboxylate oxygen atoms of the two pcpa ligands and two nitrogen atoms in thiazole rings of two aben ligands.The analysis of crystal structure shows intermolecular and intramolecular hydrogen bonds between amino-nitrogen atoms of the two aben ligands and carboxylate oxygen atoms of the two pcpa ligands.The antimicrobial properties of the title complex and its two free ligands were tested against representative bacterial and fungal strains.Results show that the antibacterial activity of the complex is less than or equal to that of 2-amino benzothiazole,but for yeasts and moulds,it exhibits excellent inhibitory effect better than that of its two free ligands.     

Theoretical Investigation on Interaction between Guanine and Luteolin

The interacting patterns of the luteolin and guanine have been investigated by using the density functional theory B3LYP method with 6-31＋G＊ basis set. Eighteen stable structures for the luteolin-guanine complexes have been found respectively. The results indicate that the complexes are mainly stabilized by the hydrogen bonding interactions. Meanwhile, both the number and strength of hydrogen bond play important roles in determining the stability of the complexes which can form two or more hydrogen bonds. Theories of atoms in molecules and natural bond orbital have also been utilized to investigate the hydrogen bonds involved in all the systems. The interaction energies of all the complexes which were corrected by basis set superposition error are 6.04-56.94 kJ/mol. The calculation results indicate that there are strong hydrogen bonding interactions in the luteolin-guanine complexes. We compared the interaction between luteolin and four bases of DNA, and found luteolin-thymine was the strongest and luteolin-adenine was the weakest. The interaction between luteolin and DNA bases are all stronger than luteolin-water.     

The ternary metal mixed ligand complexes formed by benzimidazole and N, N-bis(2-hydroxyethyl) glycine

The stability constants of the ternary M(Bic)(Bzim)~ complexes, where M~(2 )=Cu~(2 ), Ni~(2 ) or Zn~(2 ), Bic~-=the anion of N, N-bis(2-hydroxyethyl) glycine and Bzim = benzimidazole, were determined by potentiometric pH titration in aqueous solution. One of them (M~(2 ) = Cu~(2 )) was also separately determined by spectrophotometry. The results show that these ternary complexes are stabler than expected on statistical grounds. The enhanced stability of the ternary M(Bic) (Bzim)~ complexes is attributed to the π_A-π_B cooperative effect between Bic~- and benzimidazole. Besides, compared with Cu(Bic) (Bzim)~ and Ni(Bic) (Bzim)~ , the ternary Zn(Bic)(Bzim)~ complex has relatively high stability. The crystal structure of [Cu(Bic)(Bzim)]ClO_4 was determined by single crystal X-ray diffraction techniques. The copper atom has a trigonal-bipyramidal geometry, the basal plane is formed by an oxygen atom of the carboxylato group and two hydroxyl oxygen atoms, the apical position is occupied by a nitrogen a     

Hydrothermal Synthesis and Crystal Structure of [Mn（phen）-（m-phth）]n （phen=1 ,10-phenanthroline, m-phth=isophthalate）

Introduction Recently, many novel polymers with a variety of metal ions have been prepared and structurally characterized owing to the versatility of carboxylate ligands.1-5 Much attention has been devoted to this field partly because polymers of carboxylate ligands are good candidates for the investigation of exchange-coupling interactions between adjacent metal ions. A successful strategy to synthesize these complexes is the reaction of metal salts with properly selected multi-dentate carbox…     

Crystal Structure,Thermal Behavior and Luminescence of a One-dimensional Coordination Polymer [Zn（4-CPOA）（Phen）（H2O）]n

A novel coordination polymer of [Zn（4-CPOA）（Phen）（H2O）]n （C21H16N2O6Zn,1,4-CPOA = 4-carboxylato-phenoxyacetate dianion and Phen = 1,10-phenanthroline） has been synthesized and characterized by elemental analysis,IR,TG,PL and single-crystal X-ray diffraction. The crystal crystallizes in the triclinic system,space group of P1 with a = 9.622（3）,b = 9.631（3）,c = 11.526（4）A,α = 67.719（5）,β = 71.203（5）,γ = 83.552（6）o,V = 935.5（5） A^3,Z = 2,Dc = 1.625 g/cm^3,μ = 1.357 mm^-1 and F（000） = 468. The Zn（II） ion is surrounded by three carboxylate O atoms from two different 4-CPOA groups,two N atoms from the Phen ligand and one water molecule,forming a distorted octahedral coordination configuration. The Zn（II） ions were alternately interlinked by carboxylate groups of 4-CPOA with chelating bisbidentate and monodentate modes into a one-dimensional zigzag chain having an intrachain distance of ca. 9.631（1） . Under the direction of supramolecular recognition and attraction,the adjacent chains yield a double-stranded chain through π-π stacking between the phen ligands,which was further expanded into a 2-D framework via strong C–H–π interaction （ca. 2.95（1） ） between the 4-CPOA ligands and into a 3-D supramolecular network by strong hydrogen bond between terminal water molecule and carboxyl group. TG/DTG shows that its chain skeleton is thermally stable up to 419 oC and the blue fluorescent emission of the complex was determined at 471 nm in a solid state with its long decay lifetime of 1.83 ns.     

Studies on the Structure-Activity Relationship of p-Substituted Thiobenzanilides as Extractant for Pd( Ⅱ )

Introduction The metal extraction is a process of complex formation by organic ligands with metal ions or corresponding ionic groups, that is to say, it is a multicomponent coordination process in the heterogeneous phase system. The property of extraction is chiefly dependent on the stability of metal complexes, which is closely related to both the structure of ligands and the nature of metal ions. Therefore, the physicochemical behaviour of the substituent in the ligand will influence the extractive ability of the extractant for a certain     

TERNARY Cu(Ⅱ)(ATP)AND HETEROAROMATIC N BASE COMPLEXES IN SOLUTION:STABILITY CONSTANTS AND ANTITUMOR MECHANISM EXPLORATION

The stability of the complexes of four pyridine-like ligandswith Cu(ATP)~(2-) was studied and by comparing the stability constants of theternary complexes[Cu(ATP)L]~(2-) with those of the binary complexes[CuL]~(2+),astacking interaction between the pyridine ring and the purine ring of ATP isindicated.It is possible to interpret the antitumor mechanism of[Pt(NH_3)_8(N-het)Cl]Cl in terms of this stacking interaction.     

Molecular Dynamics Simulations of the Interactions between Konjac Glucomannan and Carrageenan

The interactions between konjac glucomannan and carrageenan were studied with the method of molecular dynamics simulation. Part representative structure segments of KGM and two unit structures of κ-carrageenan （Fig. 2） were used as mode, and the force-field was AMBER2. The stability and sites of konjac glucomannan/carrageenan interactions in water were researched at 373 K with the following results： the potential energy （EPOT） of the mixed gel was dropped, while those of single-konjac glucomannan gel and single carrageenan were increased. The surface area （SA） of KGM in the mixed system was decreased to 1002.2A^°^2, and that of carrageenan to 800.9 A^°^2. The variations of two parameters showed that the stability of compound gel konjac glucomannan/carrageenan was improved, which is consistent with the previous studies. The sites of interactions in the mixed gel were the -OH groups on C（2）, C（4） and C（6）, the acetyl group in KGM mannose, and the -OH group on C（6） in carrageenan. The hydrogen bond was formed directly or indirectly by the bridge of waters.     

Improved biocompatibility of poly(vinylpyrrolidone)-graft-poly(2-dimethylaminoethyl methacrylate)/DNA complexes by coating with bovine serum albumin

Bovine serum albumin(BSA) was utilized to assemble with the binary complexes of poly(vinylpyrrolidone)-graft-poly(2- dimethylaminoethyl methacrylate)(PVP-g-PDMAEMA)/DNA formed by layer-by-layer electrostatic interactions to screen the residual surface positive charges of complexes.The coating of BSA was able to decrease the zeta potential of binary complexes nearly to electroneutrality without interfering with DNA condensation ability.The ternary complexes of BSA/PVP-g-PDMAEMA/ DNA demonstrated lower cytotoxicity compared with the binary complexes and also maintained high gene transfection efficiency in HepG2 cells.     

SYNTHESIS AND CHARACTERIZATION OF DVE-CO-MA DERIVATIVES OF CIS- PLATINUM COMPLEXES

Copolymer of divinyl ether and maleic anhydride (DVE-co-MA) derivatives of cis-platinum complexes were synthesized and characterized by elementary analysis, IR and XPS ( X-ray photoelectron spectroscopy). The behavior of the products in biological environment was also studied. UV-visible and fluorescence spectra show that these polymer derivatives are able to exchange ligands with selected nucleophilic groups in biological environment.     

Synthesis, Characterization, Crystal Structure and Stability of a Ternary Cu（Ⅱ） complex with 1, 10-Phenanthroline and L-Valinate

It is important to research the mixed-ligand copper complexes containing bioligands, such as amino acids, nucleic acids and proteins, in exploring the functional mechanism of microelement copper in organism because the reaction of any micronutrient with two or more bioligands in the concentrated bioligands background gives mixed-ligand ternary complexes, which are more stable and related with storage of substance and transportationof metal ions in the life process.