Synthesis,X-ray Structure,Spectroscopic Properties and DFT Studies of a Novel Schiff Base

A series of Schiff bases, salicylideneaniline derivatives 1–4, was synthesized under mild conditions and characterized by ¹H NMR, HRMS, UV-Vis and fluorescence spectra, and single-crystal X-ray diffraction. In solid and aprotic solvents 1–4 exist mainly as E conformers that possess an intramolecular six-membered-ring hydrogen bond. A weak intramolecular C–H···F hydrogen bond is also observed in fluoro-functionalized Schiff base 4, which generates another S(6) ring motif. The C–H···F hydrogen bond further stabilizes its structure and leads it to form a planar configuration. Compounds 1–3 exhibit solely a long-wavelength proton-transfer tautomer emission, while dipole-functionalized Schiff base 4 shows remarkable dual emission originated from the excited-state intramolecular charge transfer (ESICT) and excited-state intramolecular proton transfer (ESIPT) states. Furthermore, the geometric structures, frontier molecular orbitals (MOs) and the potential energy curves for 1–4 in the ground and the first singlet excited state were fully rationalized by density functional theory (DFT) and time-dependent DFT calculations.     

A 3D 3d-4f Heterometallic Coordination Polymer: Synthesis,Crystal Structure and Properties

Abstract  A three-dimensional heterometallic coordination polymer formulated as Sm₂Zn₂(BIPA)₅(H₂O)₂ (1) (H₂BIPA = 5-bromoisophthalic acid) was synthesized by hydrothermal reaction of H₂BIPA with Sm₂O₃ and Zn(NO₃)₂. Complex 1 shows an 8-connected (3⁶.4¹⁸.5³.6) topological network. The thermal analysis of complex 1 has been measured and discussed. Additionally, the photoluminescent property of complex 1 was investigated. Graphical Abstract  An intriguing feature of complex 1 is a 3D eight-connected framework of 3⁶.4¹⁸.5³.6 topology.      

Novel bioactive copper and nickel polymeric complexes: Synthesis,characterization, antimicrobial activity,and DFT calculations

Polymeric complexes, especially metal-containing polymers, possess aggregated medical applications, especially as antibacterial and antifungal agents. This work describes a facile procedure for producing a series of novel copper and nickel complexes of poly(2-hydroxyphenyl methacrylamide) and poly(2-carboxyphenyl methacrylamide). The polymeric ligands were synthesized through a multistep procedure. Firstly, 4-formylphenyl methacrylate was constructed by acylating 4-hydroxybenzaldehyde with methacryloyl chloride. Then, polymerization of the as-prepared monomer to obtain poly(4-formylphenyl methacrylate) using benzoyl peroxide as an initiator. Thirdly, the polymeric ligands PL1 and PL2 were achieved via exchange reactions between poly(4-formylphenyl methacrylate) and o-aminophenol and anthranilic acid, respectively. Consequently, the two ligands were reacted with copper and nickel acetates to afford four target complexes (Cu-PL1, Ni-PL1, Cu-PL2, and Ni-PL2). By FT-IR, ¹HNMR, UV-visible, and TGA analyses, the structures of PL1, PL2, and their complexes were investigated. Furthermore, the geometries of PL1, PL2, and their complexes were reported through a molecular modeling to investigate some interesting parameters such as the bond length, bond angle, charge on the atoms, the HOMO and LUMO using the Material Studio program. The calculation results illustrated that octahedral geometries are proposed for the synthesized metal complexes. The reported antimicrobial efficiency showed a strong potency for most synthesized compounds against the selected microbes, especially compounds Cu-PL1 and Cu-PL2 which are more effective than the standard against Candida albicans.     

Towards Novel 3-Aminopyrazinamide-Based Prolyl-tRNA Synthetase Inhibitors: In Silico Modelling,Thermal Shift Assay and Structural Studies

Human cytosolic prolyl-tRNA synthetase (HcProRS) catalyses the formation of the prolyl-tRNA^Pro, playing an important role in protein synthesis. Inhibition of HcProRS activity has been shown to have potential benefits in the treatment of fibrosis, autoimmune diseases and cancer. Recently, potent pyrazinamide-based inhibitors were identified by a high-throughput screening (HTS) method, but no further elaboration was reported. The pyrazinamide core is a bioactive fragment found in numerous clinically validated drugs and has been subjected to various modifications. Therefore, we applied a virtual screening protocol to our in-house library of pyrazinamide-containing small molecules, searching for potential novel HcProRS inhibitors. We identified a series of 3-benzylaminopyrazine-2-carboxamide derivatives as positive hits. Five of them were confirmed by a thermal shift assay (TSA) with the best compounds 3b and 3c showing EC₅₀ values of 3.77 and 7.34 µM, respectively, in the presence of 1 mM of proline (Pro) and 3.45 µM enzyme concentration. Co-crystal structures of HcProRS in complex with these compounds and Pro confirmed the initial docking studies and show how the Pro facilitates binding of the ligands that compete with ATP substrate. Modelling 3b into other human class II aminoacyl-tRNA synthetases (aaRSs) indicated that the subtle differences in the ATP binding site of these enzymes likely contribute to its potential selective binding of HcProRS. Taken together, this study successfully identified novel HcProRS binders from our anti-tuberculosis in-house compound library, displaying opportunities for repurposing old drug candidates for new applications such as therapeutics in HcProRS-related diseases.     

Thermal Decomposition of Energetic Materials 78. Vibrational and Heat of Formation Analysis of Furazans by DFT

Density functional theory (DFT) was used to calculate the heats of formation and infrared active vibrational frequencies of twelve furazan compounds. The absolute values of the heats of formation are unreliable but the trends with systematic variations of the bridge and terminal groups are reasonable. The assignments of the vibrational motions to IR frequencies based on a force field analysis are given to clarify the complex coupling in these molecules.     

Synthesis,Characterization, Physico-Chemical and DFT Studies of Potential Organic NLO Materials: Experimental and Theoretical Combined Study

Silicon - 1-(2,4-difluorobenzyl)-2-(2,4-difluorophenyl)-6-methyl-1H-benzo[d]imidazole(1) and 1-(3-(tri fluoromethyl)benzyl)2-(4-(trifluoromethyl)phenyl)-6-methyl-1H-benzo[d]imidazole (2) were...     

以m-BrPhH_3 IDC为配体构筑的钴配合物的合成、晶体结构和热性能

采用溶剂热法使m-Br Ph H3IDC与Co(Ⅱ)合成了单核配合物:[Co(m-Br Ph H3IDC)2(2H2O)],采用元素分析、红外光谱以及单晶X-ray测试了其分子结构。进一步研究了这个配合物在空气中的热稳定性能。     

新型锰配合物的合成、多维结构及光催化性质研究

近年来,金属配合物的研究已经引起了广大研究者的兴趣,不仅是因为它们在催化、磁性、医学和材料科学等方面具有迷人的性质,而且还因为它们较强的协调能力以及各种协调模式,可以有助于构建有趣的框架。过渡金属配合物通过结合新颖的空间结构和过渡金属的特性,使其在降解处理环境污染物催化方面具有广泛的应用潜力。本课题通过水热合成法合成了一种新型的锰配合物[Mn(L)·H_2O](其中L表示1,4-二(2-甲基咪唑基)对苯甲酸),并通过红外光谱、元素分析和X射线单晶衍射仪进行了表征。从这个配合物的结构可以看到其具有孔洞结构,对其光催化性质具有一定影响。实验研究证明,该配合物在光催化降解处理有机染料方面具有良好活性。     

Synthesis, Crystal Structure, Spectroscopic and Thermal Properties of a Novel Complex of Hydantoin-5-acetic acid with Co(II)

The complex, tetraaqua bis(hydantoin-5-acetato) cobalt(II) was synthesized by the reaction of hydantoin-5-acetic acid and CoCl₂·6H₂O presence of NaHCO₃. The structure of the complex was determined by X-Ray single crystal data the thermal analyses, FT–IR and magnetic susceptibility data are also presented. The monoclinic crystal of the title compound, [Co(C₅H₅N₂O₄)₂(H₂O)₄], lie across centers of inversion in space group P21/c. The complex features a distorted octahedral [CoO₆] coordination with hydantoin-5-acetato and water ligands. The hydantoin-5-acetato anion is bonded to the cobalt(II) ion via its deprotonated carboxylic acid O atom. The complex molecules show three dimensional supramolecular networks by O–H···O and N–H···O interactions.     

丙烯酸酯有机硅共聚物的合成、表征及耐热性研究

以3-甲基丙烯酰氧丙基三甲氧基硅烷(硅烷偶联剂KH-570)为桥梁,用溶液聚合法分三步反应合成了一种新型的丙烯酸酯有机硅共聚物。FT-IR、1H-NMR鉴定了丙烯酸酯有机硅共聚物的分子结构。所得树脂的Mw=43 748,多分散系数为2.32。虽然丙烯酸酯改性的有机硅树脂比有机硅树脂在800℃时的质量保持率有所降低,但起始分解温度均有所提高。当丙烯酸甲酯质量分数为20%和40%时,丙烯酸酯改性的有机硅树脂起始分解温度分别比有机硅树脂提高了13℃和55℃。     

Synthesis,Characterisation and DFT Studies of Stigmasterol Mediated Silver Nanoparticles and Their Anticancer Activity

The present investigation reports the facile, reproducible and eco-friendly biological synthesis of nano silver using Ficus Hispida leaf extract (FHLE) as a reductant. The properties of the synthesized silver nanoparticles (Ag-NP’s) is characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy (TEM), UV–visible spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction studies. The synthesized Ag-NPs are found to have spherical shape with average particle size in the range of 50–100 nm. The XRD studies and selected area electron diffraction pattern of TEM images confirm the face cantered cubic structure of biosynthesised silver nanoparticles. The DFT studies reveal that the stigmasterol present in FHLE is responsible for leaf extract to behave as a reducing agent for reduction of Ag⁺ ions into Ag⁰. The antitumor studies against DLA cell lines of the biosynthesized Ag-NPs is found to have 100% inhibition with concentration of 200 µg/ml of Ag-NP’s.     

Nano-Silica Catalyzed Synthesis,Solvent Effect,NMR Spectral and DFT Studies of Some Imidazole Derivatives

A series of novel imidazole derivatives has been designed and synthesized using nano-SiO₂ as an efficient catalyst. Synthesized compounds have been characterized by ¹H and ¹³C-NMR spectral studies. The significant features of this nanocatalyst are high product yield, short reaction times and a vast range of substrates usage. Proton and ¹³C chemical shifts of the synthesized compounds were calculated. The absorption and emission properties of imidazole derivatives were studied in several solvents. Polar solvents favor the stabilization of excitation of the imidazole derivative. Decrease in the total dipole moment of the solvent molecules (non-polar solvents) results in the change of the molecular charge distributions of the imidazole derivatives. Optimization of 4,5-dimethyl-2-phenyl-1-m-tolyl-1H-imidazole (1) was performed by DFT at B3LYP/6-31G (d, p) using Gaussian-03.     

A Novel Binodal (4,9)-Connected 3D Calcium Coordination Polymer: Synthesis, Characterization, Thermal Stability and Luminescent Properties

A novel coordination polymer, namely, [Ca₃(BIPA)₃(H₂O)₃·H₂O] _n (1) has been prepared by the reaction of 5-bromoisophthalic acid (H₂BIPA) with corresponding Ca(II) ions, and characterized by single-crystal X-ray diffraction, element analysis, infrared spectroscopy, thermogravimetric analysis In compound 1, a trimer unit [Ca₃O₁₉] is bridged the carboxylate oxygen atoms, forming an inorganic layer structure. The inorganic layers are linked by the BIPA^2? ligands, resulting in a three-dimensional (3D) pillared layered structure with a binodal (4,9)-connected 3D net structure with Schläfi symbol of (3⁴·4²)(3⁸·4¹⁰·5¹²·6⁶). In compound 1, the carboxylate groups of the BIPA^2? ligands coordinate to calcium ions using different coordinated modes. In addition, the thermal stability and luminescent properties of 1 were also investigated.     

新型铱配合物磷光材料的合成及性质研究

两个含有载流子β-二酮配体的新型铱配合物被成功合成。分别为Ir(L)2(acac-Ox)和Ir(L)2(acac-Cz)。其中L=3-(2-吡啶)香豆素环金属铱配合物,acac-Ox=3-(4-(5-(4'-叔丁基苯基)-1,3,4-噁二唑)苄基)-戊二酮,acac-Cz=3-((4-(9-咔唑-)苯基)甲基)戊烷-2,4-戊二酮,并且通过了核磁,紫外等数据分析。配合物的光物理性质采用紫外-可见,光致发光光谱分析研究。配合物acac-Cz做成的器件,在9%的参杂浓度下器件的发光效率效果最佳。配合物acac-Ox当参杂浓度为6%时,器件的发光效率最佳。通过对器件发光性能的比较,acac-Cz通过引入咔唑空穴传输基团提高了器件的性能。它们都是很好的绿光发光材料。     

Synthesis,characterization, and DFT Raman study of pure and Mn-doped LiTaO3 nanofibers

Pure and Mn-doped lithium tantalate nanofibers, with Mn concentrations of 1%, 2.5%, and 5%, were synthesized by the electrospinning method. The morphology, microstructure, and crystal structure of as-spun and annealed composite nanofibers were characterized by scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. Raman spectroscopy has shown to be a powerful tool to detect either local variations or changes of the whole structure. Position and width of one Raman line can be used as markers of a structural change. Some vibrational modes are especially associated with the site of Li or Ta ions and so, they can be affected by the introduction of dopant ions. Any damages or local changes in the microstructure can be detected by a line broadening. With the use of Raman spectroscopy, the sites where Mn ions enter the doped structures were established by recording the shift and broadening of peaks in Mn-doped structures with respect to pure lithium tantalate. Thus it was proven that Mn ions enter the Li sites for low Mn concentration and, on the other hand, for higher concentrations, the dopant substitutes Li and Ta sites. First-principles calculations were performed within the density functional theory, including lattice-dynamic calculations of the phonon modes at the zone center (Γ point), for the pure structure, to find the irreducible representation of the modes.     

Synthesis and Thermal Characterization of Novel Fluorene-Based Polysiloxane Derivatives

Three novel poly(tetramethylsilfluorenylenesiloxane) derivatives having different substituent at 9-position of fluorenylene moiety, i.e. dimethyl (P1), spirocyclohexyl (P2), and spirofluorenyl (P3) substituents, were obtained by polycondensation of novel three disilanol monomers, i.e. 2,7-bis(dimethylhydroxysilyl)-9,9-dimethyl- fluorene (M1), 2’,7’-bis(dimethylhydroxysilyl)-spiro(cyclohexane-1,9’-fluorene) (M2), 2,7-bis(dimethylhydroxysilyl)-9,9’-spirobifluorene (M3), respectively. P1–P3 exhibited the good solubility in common organic solvents, such as tetrahydrofuran (THF), chloroform, dichloromethane, and toluene. It was suggested from the differential scanning calorimetry (DSC) and the X-ray diffraction analysis that P1 exhibited the crystallinity whereas P2 and P3 were amorphous polymers. The glass transition temperature (T _g) determined by DSC and the temperature at 5% weight loss (T _d5) determined by thermogravimetry (TG) were dependent on the substituent at 9-position on fluorene; both orders of T _g and T _d5 were P3 > P2 > P1, indicating the bulkiness of substituent at 9-position of fluorene resulted in the good thermal stability. It is noteworthy that amorphous P3 exhibiting very high T _g of 156 °C and T _d5 of 535 °C is a new heat-resistant polysiloxane derivative as well as a promising candidate for blue-light-emitting materials.     

苦味酸铋的合成、分解反应动力学及热安全性(英文)

合成了苦味酸铋配合物(Bi-PA),对其结构进行了表征,并用TG-DTG及DSC技术研究了化合物的热行为和分解反应动力学。结果表明,在TG曲线上出现一个最大的失重阶段,对应于DSC曲线上的最大放热峰。放热分解反应过程可以认为是化学反应,其机理方程的微分式为f(α)=3(1-α)[-ln(1-α)]2/3,动力学方程为dα/dt=1013.51(1-α)[-ln(1-α)]2/3e-1.96×104/T。反应阶段的活化熵(ΔS≠),活化焓(ΔH≠)及活化自由能(ΔG≠)分别为2.25J.mol-1.K-1,159.82kJ.mol-1及158.60kJ.mol-1。     

Synthesis,Structure Investigation,DFT Analysis And Dielectric Characterization of Substituted Pyridinylidenepropanedinitrile (CMHQCPP) Nanostructure: Novel Approach

Journal of Inorganic and Organometallic Polymers and Materials - For the first time, a novel...     

镉苯并咪唑二乙酸配合物的合成、晶体结构和热性能研究

1,3-苯并咪唑二乙酸与镉离子的反应,采用溶液法得到结构新颖的配合物:{[Cd3(η2-L-μ2-η2)2(4,4'-bipy)2(SO4)2(H2O)4]·5H2O}n。通过元素分析、红外光谱、热稳定性对配合物进行了初步表征,且通过单晶X-ray衍射对其晶体结构进行了测定。