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1.
This study describes the non-covalent interactions of the charge transfer complex (CT), which was responsible for the synthesis of Linagliptin (LNG) with 2,3-Dichloro-5,6-Dicyano-1,4-benzoquinone (DDQ), or with Chloranilic acid (CHA) complexes in acetonitrile (MeCN) at temperatures of (25 ± 2 °C). Then, a UV–Vis spectrophotometer was utilized to identify Linagliptin (LNG) from these complexes. For the quantitative measurement of Linagliptin in bulk form, UV–Vis techniques have been developed and validated in accordance with ICH criteria for several aspects, including selectivity, linearity, accuracy, precision, LOD, LOQ, and robustness. The optimization of the complex synthesis was based on solvent polarization; the ratio of molecules in complexes; the association constant; and Gibbs energy (ΔG°). The experimental work is supported by the computational investigation of the complexes utilizing density functional theory as well as (QTAIM); (NCI) index; and (RDG). According to the optimized conditions, Beer’s law was observed between 2.5–100 and 5–100 µM with correlation coefficients of 1.9997 and 1.9998 for LGN-DDQ and LGN-CHA complexes, respectively. For LGN-DDQ and LGN-CHA complexes, the LOD and LOQ were (1.0844 and 1.4406 μM) and (3.2861 and 4.3655 μM), respectively. The approach was successfully used to measure LGN in its bulk form with high precision and accuracy.  相似文献   

2.
The reactions of ketotifen fumarate (KT) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π acceptors to form charge transfer (CT) complexes were evaluated in this study. Experimental and theoretical approaches, including density function theory (DFT), were used to obtain the comprehensive, reliable, and accurate structure elucidation of the developed CT complexes. The CT complexes (KT-DDQ and KT-TCNQ) were monitored at 485 and 843 nm, respectively, and the calibration curve ranged from 10 to 100 ppm for KT-DDQ and 2.5 to 40 ppm for KT-TCNQ. The spectrophotometric methods were validated for the determination of KT, and the stability of the CT complexes was assessed by studying the corresponding spectroscopic physical parameters. The molar ratio of KT:DDQ and KT:TCNQ was estimated at 1:1 using Job’s method, which was compatible with the results obtained using the Benesi–Hildebrand equation. Using these complexes, the quantitative determination of KT in its dosage form was successful.  相似文献   

3.
The reaction of salicylaldehyde‐S‐methylisothiosemicarbazone in the presence of ethylenediamine base and iron (III)chloride generated unforeseen homotopic dinuclear triple‐stranded iron (III)helicate. The synthesized helicate was characterized by elemental analysis, IR, UV–Vis spectroscopy, magnetic moment measurement, and evaluated cytotoxic activities against K562, HL‐60 and THP‐1 leukemia cells. In addition, solid‐state structure has been determined by single‐crystal X‐ray diffraction technique. In the complex, three dinucleating O, N, N, O donor ligands provide three diazine (NN) bridges between the metal ions and facial O3N3 coordination spheres around them. The ligands are folded about the N N single bond and coordinated to the two metal ions in a helical fashion to form the triple helical structure. In the crystal lattice, chains of centrosymmetric rings, which are connected to one another via π─π stacking interactions, are generated by C─H···O intermolecular interactions. The results are also confirmed by the density functional theory (DFT) calculations. The results obtained from the cytotoxicity test showed to be effective in low concentrations on the leukemia cells. An intercalative binding mode of helicate‐DNA complex was confirmed with the high intrinsic binding constant (Kb = 8×106 M?1) and competitive displacement assay of Ethidium bromide with high Ksv value.  相似文献   

4.
Two ruthenium(II) dithiocarbamates, cis-[Ru(DMP)2L](BF4), where L = 4-(4-methoxy-phenyl)piperazine-1-carbodithioate (1) and 4-(3-methoxyphenyl)piperazine-1-carbodithioate (2) and DMP = 2,9-dimethyl-1,10-phenanthroline, have been synthesized and characterized. The DNA-binding affinity of these metal complexes was investigated by UV–visible spectrophotometry with DNA-binding constants of 6.2 × 104 M?1 (1) and 1.2 × 105 M?1 (2) and electrostatic binding mode was confirmed by viscometric measurements. For insight into the structural differences, both complexes were studied computationally. B3LYP/LANL2DZ level of Density Functional Theory was used for the computational studies in Gaussian 09. The optimized bond lengths are in agreement with the reported values. Comparative computational studies reveal interesting transformations in bond lengths, angles, Natural Bond Orbital charges, molecular orbitals, Molecular Electro Static Potentials, and global chemical reactivity indices. Based on quantum chemical results a structure–activity relationship has been attempted.  相似文献   

5.
The interaction of chlorothiazide (CH) as donor (D) with picric acid (PA) and iodine (I2) as π- and σ-acceptors (A), respectively, gives charge-transfer (CT) complexes as a final products. The reaction of donor and acceptors were studied spectrophotometrically. The complexes are generally of the n-π* and n-σ* types, with the ground state wave function primarily characterized by the non-bonding structure. For the micro determination of chlorothiazide using picric acid and iodine as acceptors, the ideal conditions encouraging the formation of complexes are thoroughly explored. It was discovered that the stoichiometry of the molecular structure is 1:1 (D:A). The equilibrium constant and the molar extinction coefficient were calculated using Benesi-Hildebrand and its modifications. DFT/TD-DFT calculations with B3LYP/LanL2DZ and 6-311G++ level of theory were used to provide comparable theoretical data along with electronic energy gap of HOMO→LUMO. Molecular docking calculations have been performed between CT complexes and Covid-19 protease (6LU7) to study the interaction between them and their inhibitory effect.  相似文献   

6.
The 1:1 proton transfer compound LH2, (creatH)+ (pydcH)?, has been prepared from the reaction of creatinine, creat, and dipicolinic acid, pydcH2, (2, 6‐ pyridinedicarboxylic acid) and characterized using IR, 1H and 13C NMR spectroscopy. The first coordination complex (creatH)[Zn(pydc)(pydcH)]·4H2O, was prepared using LH2 and zinc(II) nitrate, and characterized using IR, 1H and 13C NMR spectroscopy and single crystal X‐ray crystallography. The crystal system is triclinic with space group with two molecules per unit cell. The unit cell dimensions are a = 8.085(2) Å, b = 10.802(4) Å, c = 13.632(4) Å, α = 104.98(2)°, β = 90.31(2)° and γ = 92.55(3)°. The structure has been refined to a final value for the crystallographic R factor of 0.0381 based on 3003 reflections. The zinc atom is six‐coordinated with a distorted octahedral geometry. The (pydc)2? and (pydcH)? units are almost perpendicular to each other. Extensive hydrogen bondings between carboxylate groups, (creatH)+ and water molecules throughout the zinc(II) complex as well as π–π stacking and ion pairing play important roles in stabilizing the corresponding lattices. The protonation constants of the building blocks of the pydcH2‐creat adduct, the equilibrium constants for the reaction of (pydc)2? with creat and the stoichiometry and stability of the ZnII complex with LH2 in aqueous solution were accomplished by potentiometric pH titration. The solution studies support a self‐associated (creatH)+(pydcH)? as the most abundant species at pH = 3.4. The stoichiometry of the crystalline complex (i.e. (creatH) [Zn(pydc)(pydcH)])and that of the most abundant species detected in solution were found the same.  相似文献   

7.
Five new Cu (II), Zn (II), Pd (II), Ru (III) and Ag(I) complexes, derived from the 3-acetylcoumarin-2-hydrazinobenzothiazole Schiff base (Hachbt), have been synthesized and characterized. The structures were established with the aid of elemental analyses (C, H, N), FT-IR, 1H-NMR, ESR, UV–visible and ESI-mass spectra. The complexes were also investigated by magnetic susceptibility, thermal gravimetric analysis (TG-DTA) and cyclic voltammetry measurements. The results suggest that the Schiff base ligand behaves in two different ways: neutral mono/bidentate or mono-negative bi/tridentate. The calf thymus DNA (CT DNA) binding affinities of Hachbt and its complexes have been examined by UV–visible spectroscopy. The antifungal activity of the compounds was also screened against two fungal species of wood-decay basidiomycetes using the agar dilution method. Different complexes caused a reduction in the fungal colony diameters at a media concentration of 100 μg/ml. The best antifungal activity was observed for the Pd (II) and Ag(I) complexes with a 60% and 79% reduction, respectively. The effect of the complexes on the ability of the same fungi to decolorize poly-R dye on agar plates was also tested. All of the complexes showed an enhanced effect on the decolorization ability and the Cu (II) and Ru (III) complexes exhibited the strongest effect at a media concentration of 5 μg/ml. Theoretical studies were performed for all the complexes using the DFT/B3LYP/6–31 + g(d) basis set for calculations on the ligand atoms and LAN2DZ for the Pd (II) complex. The optimized geometries were found to be in a good agreement with the proposed structures. The molecular docking calculations show that the binding affinity of the Pd (II) complex is −309.170-309.2 kcal/mol, which suggests complexation with the DNA minor groove.  相似文献   

8.
A novel 1:2 proton transfer self‐associated compound LH2 , (GH+)2(pydc2—), was synthesized from the reaction of dipicolinic acid, pydcH2, (2, 6‐pyridinedicarboxylic acid), and guanidine hydrochloride, (GH+)(Cl). The characterization was performed using IR, 1H and 13C NMR spectroscopy and single‐crystal X‐ray diffraction. LH2 · H2O crystallizes in the space group C2/c of the monoclinic system and contains eight molecules per unit cell. The unit cell dimensions are: a = 26.480(5)Å, b = 8.055(2)Å, c = 14.068(3)Å. The first coordination complex (GH)2[Cd(pydc)2] · 2H2O, was prepared using LH2 and cadmium(II) iodide, and characterized by 1H and 13C NMR spectroscopy and X‐ray crystallography. The crystal system is triclinic with space group P1¯ with one molecule per unit cell. The unit cell dimensions are: a = 8.5125(7)Å, b = 11.0731(8)Å, c = 13.2404(10)Å. The cadmium(II) atom is six‐coordinated with a distorted octahedral geometry. The two pydc2— units are almost perpendicular to each other. The protonation constants of the building blocks of the pydc‐guanidine adduct, the equilibrium constants for the reaction of pydc2— with guanidine and the stoichiometry and stability of the Cd2+ complex with LH2 in aqueous solution were accomplished by potentiometric pH titration. The solution studies strongly support a self‐association between pydc2— and GH+ with a stoichiometry for the CdII complex similar to that observed for the isolated crystalline complex. In fact, the [Cd(pydc)2]2— complex was found as the most abundant species in solution (> 90 %) at a pH >5.  相似文献   

9.
The dinuclear copper(II) complex, [Cu2(phen)2(4-aminobenzoate)2(H2O)2](NO3)2·2(4-aminobenzoic acid)·3H2O (phen = 1,10-phenanthroline), has been synthesized and structurally characterized by elemental analyses, IR, EPR, UV-visible and single-crystal X-ray crystallography. The complex crystallized in a monoclinic system with space group C2/c, a?=?26.0022(10) Å, b?=?10.2524(4) Å, c?=?20.9983(7) Å, α?=?90°, β?=?106.9550(10)° and γ?=?90°. The Cu(II) ion adopts a distorted square-pyramidal geometry formed by two N atoms from the phen ligand and two O atoms of the two 4-aminobenzoic acid ligands and one water O atom. The Cu…Cu separation is 3.0570(5) Å. A twofold axis passes through the midpoint of the Cu-Cu vector. The complex has intraligand (π–π*) fluorescence properties. The binding of this dinuclear copper(II) complex with calf thymus DNA (CT-DNA) was investigated by UV-vis absorption, fluorescence spectroscopic, cyclic voltammetric and viscosity techniques. Also, the cleavage of pBR322 DNA with dinuclear copper(II) complex was studied using gel electrophoresis method. The exhibited potent cytotoxic effects against human cell line (HepG2) and it was found to have good antimicrobial activities. The primary coordination sphere of dinuclear copper(II) complex is optimized, structural parameters are calculated and energy gaps of frontier orbital (HOMO-LUMO) have been calculated with B3LYP/6-31G/LANL2DZ level of theory in the gaseous phase. The calculated geometric and spectral results reproduced the experimental data with well agreement. Theoretical calculated molecular orbitals (HOMO-LUMO) and their energies have been calculated that suggest charge transfer occurs within the complex.  相似文献   

10.
The dinuclear Cu(II) complexes [Cu2(L1)2(mb)]?ClO4 ( 1 ) and [Cu2(L2)2(mb)]?ClO4 ( 2 ) (HL1 = 2‐[(2‐diethylaminoethylimino)methyl]phenol; HL2 = 2‐[1‐(2‐diethylaminoethylimino)propyl]phenol; mb = 4‐methylbenzoate) were synthesized and characterized using X‐ray crystal structure analysis and spectroscopic methods. Complexes 1 and 2 are dinuclear with distorted square pyramidal Cu (II) geometries, where Schiff base coordinates with tridentate (N,N,O) chelating mode and mb bridges two metal centres. Optimized structures and photophysical properties of ligands and complexes were calculated using density functional theory and time‐dependent density functional theory methods using B3LYP functional with 6‐31G (d,p) and LanL2MB basis sets. Interactions of the complexes with bovine serum albumin (BSA) and human serum albumin (HSA) were studied using UV–visible absorption and fluorescence spectroscopies and the calculated values of association constants (M?1) are 1.7 × 105 ( 1 –BSA), 5.7 × 105 ( 2 –BSA), 1.6 × 105 ( 1 –HSA) and 6.9 × 105 ( 2 –HSA). Interactions of the complexes with calf thymus DNA were also investigated and the binding affinities are 1.4 × 105 and 1.6 × 105 M?1 for 1 and 2 , respectively. Both complexes catalytically oxidize 3,5‐di‐tert‐butylcatechol to 3,5‐di‐tert‐butylbenzoquinone in the presence of molecular oxygen.  相似文献   

11.
An investigation into the effect of the flexibility of substituents on the disorder of the Cl-Rh-CO moiety in Vaska-type trans-[Rh(CO)Cl(PR3)2] complexes is presented. The influence of the packing of the complexes with PR3 = P(CH2C6H5)3, P(OC6H5)3, P(O-2-MeC6H4)3 and P(O-2,6-Me2C6H3)3 was evaluated by comparing the X-ray structures with the results of DFT calculations on these complexes. Reasonable agreement between the calculated and molecular structures was found. A good agreement, however, was found between the calculated and crystallographic structures when comparing the coordination polyhedron around the Rh atom. The main difference between the calculated and solid state structures appeared to be in the orientation of the phenyl groups of the P-donor ligands.  相似文献   

12.
A new six-coordinate organotin(IV)-phosphoric triamide complex of OP[NC5H10]3 = OP was synthesized ([Cl2Sn(CH3)2(OP)2], 1) and characterized by X-ray crystallography and spectroscopic methods (FT-IR, UV–Vis, and 1H/13C/31P-NMR). The crystal structures of 1 and the analogous previously reported five-coordinate complex [Cl2Sn(CH3)2(OP)] (IZOVIE) were compared on a structural level and by computational means using Hirshfeld surface analysis, density functional theory calculations and the atom in molecule method. The investigation of intermolecular interactions in the crystal structures of the two complexes by the Hirshfeld surface method indicates that in the absence of normal hydrogen bonds, the chlorine-based interactions H?Cl/Cl?H (for 1 and IZOVIE) and Cl?Sn/Sn?Cl (for IZOVIE) play a determinant role in the molecular assemblies. However, the prominent contacts are of H?H type. From calculated electronic parameters such as bond order, Mulliken charge and electron delocalization energy, it was found that the Sn-OP contact has a lower strength in IZOVIE than in 1, suggesting more ionic character of the metal-oxygen contact in five-coordinate complex IZOVIE. Furthermore, we discuss the similarities and differences of the two complexes 1 and IZOVIE derived from the same ligand OP by density functional theory calculations to present an insight into the organotin(IV)-phosphoric triamide coordination chemistry affected by different geometries and coordination numbers.  相似文献   

13.
[Cr(III)(SSA)(en)2]•2H2O配合物的合成、表征及性质研究   总被引:1,自引:0,他引:1  
刘斌  李英奇  杨斌盛 《化学学报》2006,64(9):917-922
有机铬(III)配合物具有较高的生物利用率. 本文合成了一种新型磺基水杨酸铬(III)混配配合物[Cr(SSA)(en)2]•2H2O (SSA=5-磺基水杨酸, en=乙二胺), 通过红外、紫外、荧光光谱以及元素分析、电导率测定和X晶体衍射等方法对其结构进行了表征. 在pH 7.4, 0.05 mol•L-1 Tris-HCl缓冲液中, 利用荧光光谱研究了配合物与人血清白蛋白的结合. 结果表明配合物可与人血清白蛋白以较强的分子间作用力结合, 条件结合常数为(2.7±0.1)×104 mol•L-1, 结合位点数为3.87. 在pH 7.4, 0.05 mol•L-1 Tris-HCl缓冲液中, 观察了不同温度下EDTA和脱铁伴清蛋白为竞争剂的配体取代反应动力学行为, 其中37 ℃时反应速率常数分别为0.0142和0.0225 h-1.  相似文献   

14.
常温下,溶液法合成了一个单核结构的锌配合物Zn (phen)(H2O)(3-mba)2(phen:邻菲咯啉;3-Hmba∶3-甲基苯甲酸),并用红外光谱、元素分析、热重分析以及X射线单晶衍射表征了其结构.结果表明,配合物属于三斜晶系,空间群P1,晶胞参数:a=10.893(2)(A),b=11.461(2)(A),c=11.505(2)(A),α=95.54(3)°,β=115.80(3)°,γ =100.25(3)°,V=1247.9(4) (A)3,C28H24N2O5Zn,Mr=533.86,Z =2,Dc=1.421 g·cm-3,F(000) =552,最终偏离因子[I≥2σ(I)]R1=0.0471,wR2 =0.0954.在配位物分子中,中心锌离子是五配位模式,双分子间先通过O—H…O氢键形成二聚体,继而二聚体间通过相邻分子中的邻菲咯啉芳环的π-π堆积作用沿着a方向形成了一维超分子链.对配合物的荧光性能进行了测试.CCDC 1023439.  相似文献   

15.
The Schiff base organotin(IV) complex {[4-Et2NC6H3(O)C=NC6H3(O)-5-NO2](nBu2Sn)}2 has been synthesized via the reaction between 4-(diethylamino) salicylaldehyde-2-amino-4-nitrophenol Schiff base(H2L) and dibutyltin oxide. Complex C1 has been characterized by IR, 1H NMR, 13 C NMR spectra, and elemental analysis, and its crystal structure was determined by X-ray diffraction. It crystallizes in the monoclinic system, space group P21/n with a = 15.6559(8), b = 9.1657(5), c = 18.8351(10) , β = 107.3440(10)°, Z = 4, V = 2579.9(2) 3, Dc = 1.442 Mg·m-3, μ(MoKα) = 1.025 mm-1, F(000) = 1152, R = 0.0250 and wR = 0.0633. The central Sn atom is coordinated in a hexadentate manner to assume a distorted octahedral configuration. Complex C1 was studied by TGA analysis in air atmosphere. The interaction between complex C1 and the herring sperm DNA was realized through the intercalation of the complex based on the studies by EB fluorescent probe.  相似文献   

16.
A novel hydrazone ligand derived from condensation reaction of 3‐hydroxy‐2‐naphthoic hydrazide with dehydroacetic acid, and its Ni(II), Cu(II) and Co(II) complexes were synthesized, characterized by spectroscopic, elemental analyses, magnetic susceptibility and conductivity methods, and screened for antimicrobial, DNA binding and cleavage properties. Spectroscopic analysis and elemental analyses indicated the formula, [MLCl2], for the complexes; square planar geometry for the nickel, and tetrahedral geometry for copper and cobalt complexes. The non‐electrolytic natures of the complexes in Dimethyl Sulphoxide (DMSO) were confirmed by their molar conductance values in the range of 6.11–14.01 Ω?1cm2mol?1. The copper complex had the best antibacterial activity against Staphylococcus aureus (ATCC 29213). DNA cleavage activities of the compounds, evaluated on pBR322 DNA, by agarose gel electrophoresis, in the presence and absence of oxidant (H2O2) and free radical scavenger (DMSO), indicated no activity for the ligand, and moderate activity for the complexes, with the copper complex cleaving pBR322 DNA more efficiently in the presence of H2O2. When the complexes were evaluated for antibacterial and A‐DNA activity using Molecular docking technique, the copper complex was found to be most effective against Gram‐positive (S. aureus) bacteria. [CuLCl2] showed good hydrogen bonding interaction with the major‐groove (C2.G13 base pair) of A‐DNA. Density functional theory (DFT) calculations of the structural and electronic properties of the complexes revealed that [CuLCl2] had a smaller HOMO‐LUMO gap, suggesting a higher tendency to donate electrons to electron‐accepting species of biological targets.  相似文献   

17.
1INTRODUCTION There has been great interest in supramolecular tran-sition metal chemistry since self-assembly through coor-dinate bond formation has proven to be powerful tool for constructing rings,polymers and networks.Some of these compounds have potential uses in the context of molecular recognition,catalysis,size-selective guest transportation,optical materials,molecular magne-tism,semiconductors and conductors[1~4].Organic ami-des have proved to be useful in self-assembly through int…  相似文献   

18.
Here, we report a facile route to the synthesizing of a new donor–acceptor complex, L3, using 4-{[(anthracen-9-yl)meth-yl] amino}-benzoic acid, L2, as donor moiety with anthraquinone as an acceptor moiety. The formation of donor–acceptor complex L3 was facilitated via H-bonding and characterized by single-crystal X-ray diffraction. The X-ray diffraction results confirmed the synthesized donor–acceptor complex L3 crystal belongs to the triclinic system possessing the P-1 space group. The complex L3 was also characterized by other spectral techniques, viz., FTIR and UV absorption spectroscopy, which confirmed the formation of new bonds between donor L2 moiety and acceptor anthraquinone molecule. The crystallinity and thermal stability of the newly synthesized complex L3 was confirmed by powdered XRD and TGA analysis and theoretical studies; Hirshfeld surface analysis was performed to define the type of interactions occurring in the complex L3. Interestingly, theoretical results were successfully corroborated with experimental results of FTIR and UV absorption. The density functional theory (DFT) calculations were employed for HOMO to LUMO; the energy gap (∆E) was calculated to be 3.6463 eV. The complex L3 was employed as a photocatalyst for the degradation of MB dye and was found to be quite efficient. The results showed MB dye degraded about 90% in 200 min and followed the pseudo-first-order kinetic with rate constant k = 0.0111 min−1 and R2 = 0.9596. Additionally, molecular docking reveals that the lowest binding energy was −10.8 Kcal/mol which indicates that the L3 complex may be further studied for its biological applications.  相似文献   

19.
A dinuclear copper(Ⅱ) complex[Cu2(TATP)2(L-Leu)2(CIO4)2]2·2H2Owas synthesized and characterized, where, TATP=1,4,8,9-tetraazatriphenylene, and L-Leu=L-leucinate. The complex was crystallized in the triclinic space group P1, with two independent molecules in a unit cell. Two Cu(Ⅱ) ions in each complex [Cu2(TATP)2(L-Leu)2(CIO4)2] molecule were found to be in different coordination geometries, i.e., Cu2 or Cu4 of a distorted square-pyramidal geometry coordinated with two nitrogens of TATP, the amino nitrogen and one carboxylate oxygen of L-Leu and one oxygen of perchlorate, and Cul or Cu3 with an octahedral geometry coordinated with the above stated similar coordinated atoms, and another carboxylate oxygen of L-Leu coordinating to Cu2 or Cu4. The complex can interact with CT-DNA by an intercalative mode and cleave pBR322 DNA in the presence of ascorbate.  相似文献   

20.
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