丹参酮ⅡA及丹参酮ⅡA-Cu(Ⅱ)配合物的分子结构和电子吸收光谱研究

用ICCD瞬态光谱探测系统,检测了乙醇溶剂中丹参酮ⅡA及其与Cu(Ⅱ)形成的配合物的紫外-可见吸收光谱。采取密度泛函(DFT)方法优化几何构型,获得了丹参酮ⅡA及丹参酮ⅡA-Cu(Ⅱ)配合物的稳定几何结构。在此基础上,运用含时密度泛函(TD-DFT)方法,计算了丹参酮ⅡA及丹参酮ⅡA-Cu(Ⅱ)配合物的气相和乙醇溶剂(PCM)中的电子吸收光谱。结果表明,乙醇溶剂效应使丹参酮ⅡA的吸收光谱红移,配合物的吸收光谱蓝移。计算得到的溶液相丹参酮ⅡA及丹参酮ⅡA-Cu(Ⅱ)配合物电子吸收光谱与实验测量光谱符合较好。本文首次测量和计算得到了丹参酮ⅡA与Cu(Ⅱ)形成的配合物的电子吸收光谱。     

几种N-取代-3-羟基-2-吡啶硫酮Be配合物的结构与光谱性质

在B3LYP/6-31+G(d)级别水平上对4种Be配合物的几何结构进行了全优化,并探讨了烷基取代基对其分子的几何结构和电子结构等方面的影响.采用TD-B3LYP方法在同样级别水平上研究了各配合物的电子吸收光谱,分析了光谱的变化规律.上述计算结果表明,随烷基取代基团给电子能力的增强,前线分子轨道能级升高、能隙增大、最大吸收波长发生蓝移,且最大吸收波长的跃迁类型为配体内的π→π*跃迁.     

几种N-取代-3-羟基-2-吡啶硫酮Be配合物的结构与光谱性质

在B3LYP/6-31+G(d)级别水平上对4种Be配合物的几何结构进行了全优化,并探讨了烷基取代基对其分子的几何结构和电子结构等方面的影响。采用TD-B3LYP方法在同样级别水平上研究了各配合物的电子吸收光谱,分析了光谱的变化规律。上述计算结果表明,随烷基取代基团给电子能力的增强,前线分子轨道能级升高、能隙增大、最大吸收波长发生蓝移,且最大吸收波长的跃迁类型为配体内的π→π*跃迁.     

Spectroscopic and computational studies on self‐assembly complexes of bis(pyrrol‐2‐ ylmethyleneamine) ligands linked by alkyl spacers with Cu(II)

Bis(pyrrol‐2‐ylmethyleneamine) ligands and their mononuclear monomeric and dinuclear dimeric self‐assembly complexes with Cu(II) were investigated by means of IR and Raman spectroscopies and density functional theory. The ground‐state geometries were calculated by using the Becke Lee Yang Parr composite exchange‐correlation functional (B3LYP) and a combined basis set (LanL2DZ for Cu; 6–31G(d) for C, H, N), and they were compared with the single‐crystal X‐ray diffraction (XRD) structures. The DFT‐calculated Cu N bond lengths are generally higher by 0.001–0.040 Å than those determined through XRD. The vibrational spectra were also calculated at the same level of theory for the optimized geometries. The calculated wavenumbers were scaled by a uniform scaling factor and compared with the experimental fundamentals. The predicted spectra are in good agreement with the experimental ones with the deviations generally less than 30 cm⁻¹. In comparison with the spectra of the ligands, the coordination effect shifts the υ(CN) wavenumber by about 50 cm⁻¹ toward a lower value. Because of the weak intermolecular C H···Cu hydrogen bond, the Cu N stretching mode is shifted toward a lower wavenumber. Copyright © 2006 John Wiley & Sons, Ltd.     

DFT studies on the vibrational and electronic spectra of acetylsalicylic acid

The following is a theoretical and experimental study on the vibrational and electronic properties of acetylsalicylic acid (ASA). Vibrational information was obtained by FT-IR and Raman spectroscopy which agree well with harmonic vibrational frequency calculations. The calculations were carried out using density functional theory B3LYP methods with 6-311G** and LANL2DZ basis sets. The vibrational assignments were calculated by Gaussview. Absorption UV-Vis experiments of ASA reveal three maximum peaks at 203, 224 and 277 nm, which are in agreement with calculated electronic transitions using TD-B3LYP/6-311G**.     

First principles calculations of the structural and electronic properties of(CdSe)n clusters

The structural and electronic properties of (CdSe)n(1≤n≤5) clusters are calculated using density functional theory within the pseudopotential and generalized gradient approximations. The calculated binding energies and highest occupied molecular orbital lowest unoccupied molecular orbital gaps are compared with those obtained within local density approximation.     

TDDFT study on the excited‐state hydrogen bonding of N‐(2‐hydroxyethyl)‐1,8‐naphthalimide and N‐(3‐hydroxyethyl)‐1,8‐naphthalimide in methanol solution

The time‐dependent density functional theory method was performed to investigate the excited‐state hydrogen‐bonding dynamics of N‐(2‐hydroxyethyl)‐1,8‐naphthalimide (2a) and N‐(3‐hydroxyethyl)‐1,8‐naphthalimide (3a) in methanol (meoh) solution. The ground and excited‐state geometry optimizations, electronic excitation energies, and corresponding oscillation strengths of the low‐lying electronically excited states for the complexes 2a + 2meoh and 3a + 2meoh as well as their monomers 2a and 3a were calculated by density functional theory and time‐dependent density functional theory methods, respectively. We demonstrated that the three intermolecular hydrogen bonds of 2a + 2meoh and 3a + 2meoh are strengthened after excitation to the S₁ state, and thus induce electronic spectral redshift. Moreover, the electronic excitation energies of the hydrogen‐bonded complexes in S₁ state are correspondingly decreased compared with those of their corresponding monomer 2a and 3a. In addition, the intramolecular charge transfer of the S₁ state for complexes 2a + 2meoh and 3a + 2meoh were theoretically investigated by analysis of molecular orbital. Copyright © 2014 John Wiley & Sons, Ltd.     

An Infrared Spectroscopic Study of Crystalline Copper (II) Propionate and Butyrate

Abstract

Abstract: The vibrational spectra of crystalline anhydrous copper (II) propionate and butyrate were studied by FT-IR spectroscopy. A detailed assignment of the spectra of both compounds is presented and discussed. It is shown that the presence of two non-equivalent sets of carboxylate ligands within the crystals gives rise to several band splittings, which are particularly evident in those bands ascribable to normal modes involving predominantly the -C_βH₃ or -C_βH₂-fragments. In addition, the vibrational assignments made for the studied molecules are shown to be very useful to help understanding the much more complex spectra of long chain copper carboxylates.     

Crystal structure,spectroscopic properties and density functional theory study of (Z)-1-[(2,4-dimethoxyphenylamino)methylene]naphthalen-2(1H)-one

The Schiff base (Z)-1-[(2,4-dimethoxyphenylamino)methylene]naphthalen-2(1H)-one was synthesized from the reaction of 2-hydroxy-1-naphthaldehyde with 2,4-dimethoxyaniline. The title compound has been characterized by FT-IR, UV-Vis and, X-ray single-crystal techniques. The present X-ray investigation shows that the compound exists in the keto-amine tautomeric form. Molecular geometry and vibrational frequencies of the compound in the ground state have been calculated using the density functional theory (DFT) with 6–311G(d, p) basis set and compared with the experimental data. The calculated results show that the optimized geometry is compatible with the crystal structure and the theoretical vibrational frequencies are in good agreement with the experimental values. Besides, molecular electrostatic potential (MEP), frontier molecular orbital analysis (HOMO-LUMO) and non-linear optical (NLO) properties of the compound were investigated using the same theoretical calculations.     

Experimental (UV,NMR, IR and Raman) and theoretical spectroscopic properties of 2-chloro-6-methylaniline

In this work, the experimental and theoretical UV, NMR and vibrational spectra of 2-chloro-6-methylaniline (2-Cl-6-MA, C₇H₈NCl) were studied. The ultraviolet absorption spectra of compound that dissolved in ethanol were examined in the range of 200–400 nm. The ¹H, ¹³C and DEPT NMR spectra of the compound were recorded. FT-IR and FT-Raman spectra of 2-Cl-6-MA in the liquid phase were recorded in the region 4000–400 cm^?1 and 3500–50 cm^?1, respectively. The structural and spectroscopic data of the molecule in the ground state were calculated using density functional theory (DFT) employing B3LYP exchange correlation and the 6-311++G(d,p) basis set. The vibrational frequencies were calculated and scaled values were compared with experimental FT-IR and FT-Raman spectra. The observed and calculated frequencies were found to be in good agreement. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. Isotropic chemical shifts were calculated using the gauge-invariant atomic orbital (GIAO) method. Comparison of the calculated NMR chemical shifts and absorption wavelengths with the experimental values revealed that DFT method produces good results.     

Structural and nonlinear optical properties of cross‐conjugated system benzophenone thiosemicarbazone: a vibrational spectroscopic study

The nonlinear optical (NLO) compound of interest benzophenone thiosemicarbazone (BTSC) was grown and the molecular structure generated with the aid of density functional theory (DFT). FT‐Raman and IR spectra were recorded and analyzed. The harmonic wavenumbers and IR and Raman intensities were computed with the B3LYP method. The observed vibrational wavenumbers were compared with the calculated results. The assignments of the experimental spectra were made with the help of normal coordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The electronic structure of the most important molecular fragments is described in terms of natural bond orbital (NBO) analysis. Copyright © 2010 John Wiley & Sons, Ltd.     

A cobalt (II) complex with 6-methylpicolinate: Synthesis,characterization, second- and third-order nonlinear optical properties,and DFT calculations

A cobalt(II) complex of 6-methylpicolinic acid, [Co(6-Mepic)₂(H₂O)₂]·2H₂O, was prepared and fully determined by single crystal X-ray crystal structure analysis as well as FT-IR, FT-Raman. UV–vis spectra were recorded within different solvents, to illustrate electronic transitions and molecular charge transfer within complex 1. The coordination sphere of complex 1 is a distorted octahedron according to single crystal X-ray results. Moreover, DFT (density functional theory) calculations with HSEH1PBE/6-311 G(d,p) level were carried out to back up the experimental results, and form base for future work in advanced level. Hyperconjugative interactions, intramolecular charge transfer (ICT), molecular stability and bond strength were researched by the using natural bond orbital (NBO) analysis. X-ray and NBO analysis results demonsrate that O−H···O hydrogen bonds between the water molecules and carboxylate oxygen atoms form a 2D supramolecular network, and also adjacent 2D networks connected by C−H···π and π···π interactions to form a 3D supramolecular network. Additionally, the second− and third−order nonlinear optical parameters of complex 1 were computed at DFT/HSEH1PBE/6-311 G(d,p) level. The refractive index (n) was calculated by using the Lorentz−Lorenz equation in order to investigate polarization behavior of complex 1 in different solvent polarities. The first−order static hyperpolarizability (β) value is found to be lower than pNA value because of the inversion symmetry around Co (II). But the second−order static hyperpolarizability (γ) value is 2.45 times greater than pNA value (15×10⁻³⁰ esu). According to these results, Co(II) complex can be considered as a candidate to NLO material. Lastly molecular electrostatic potential (MEP), frontier molecular orbital energies and related molecular parameters for complex 1 were evaluated.     

The Low Temperature Polarised Electronic Spectra of Some Tetragonal Nickel(II) Haloacetate Complexes

We have recently reported the single crystal electronic spectra of some substituted ethylenediamine complexes of nickel(II), discussing both cis (1) and trans (2) examples. We have also reported data for their cobalt(II) analogs (3). These were analysed using the Normalised Spherical Harmonic Hamiltonian (NSH) (4) and the Orbital Angular Overlap Model (OAM) (5) approaches. We have     

NH_3在Ir(211)和Ir(221)表面吸附的第一性原理计算

采用密度泛函理论,结合周期性平板模型,研究了NH_3在Ir(211)和Ir(221)表面上的吸附行为.计算结果显示,在Ir(211)、(221)两个面上,NH_3的优势吸附位皆为脊上的top位,吸附能均达到1.0 eV以上,都为化学吸附.电子结构计算结果表明,NH_3通过其N原子的2p_z轨道与底物金属Ir的5d_z~2轨道混合吸附于表面.     

基于密度泛函理论的菲分子结构与光谱研究

选用密度泛函理论(DET)中的B3LYP方法,在6-311++G(d,p)下对菲分子结构进行优化,计算了其振动频率、极化率及热力学参数,对比了菲分子实测光谱图,首次对其振动频率进行了完全归属。此外,分析并讨论了其前线分子轨道、分子静电势和密立根布局,获得了HOMO-LUMO能隙、分子静电势分布、原子电荷分布等与分子性质密切相关的重要数据,为后续其他多环芳烃分子的光谱检测技术及其光谱和电子结构的分析提供了理论基础。     

Spectral and luminescent investigations of ammonia cyclometalated Pt(II) complexes

A method of synthesis of ammonia cyclometalated Pt(II) complexes [Pt(NH₃)₂C∧N]ClO₄, where C∧N is 2-phenylpyridinate or 2-phenylbenzothiazole ion, is developed. The electronic absorption and emission properties of the complexes are studied. It is found that the state responsible for intense long-lived luminescence is the excited charge-transfer state of the ³(d-π*) type, the π* orbital being localized at the corresponding cyclometalating ligand. Formation of platinum blue is observed in air-saturated aqueous solutions of ammonia cyclometalated complexes.     

Synthesis,spectroscopic properties and DFT study of (E)-1-[(3-(trifluoromethyl)phenylimino)methyl]naphthalen-2-olate

The Schiff base (E)-1-[(3-(trifluoromethyl)phenylimino)methyl]naphthalen-2-olate was synthesized from the reaction of 2-hydroxy-1-naphthaldehyde with 3-trifluoromethylaniline. The title compound has been characterized by FT-IR, UV-vis and X-ray single-crystal techniques. The present X-ray investigation shows that the compound exists in the zwitterionic form. Molecular geometry of the compound in the ground state have been calculated using the density functional method (DFT) with 6-31G(d,p) basis set and compared with the experimental data. The calculated results show that the optimized geometry can well reproduce the crystal structural parameters. By using TD-DFT method electronic absorption spectra of the compound have been predicted and a good agreement with the TD-DFT method and experimental one is determined. In addition DFT calculations of the compound, molecular electrostatic potential (MEP), frontier molecular orbital analysis (HOMO-LUMO) and non-linear optical (NLO) properties were performed at B3LYP/6-31G(d,p).     

二亚胺混配镍(Ⅱ),铜(Ⅱ),锌(Ⅱ)配合物的电子光谱与感光氧化特性

报道了新近合成的马来腈二硫纶·5-硝基-邻菲咯啉混配镍(Ⅱ)、铜(Ⅱ)、锌(Ⅱ)配合物MLL’(L=mnt~(2-),1,2-二氰基乙烯-1,2-二硫醇离子,L’-5-NO_2-Phen,5-硝基-1,10-邻菲咯啉)在二甲基亚砜(DMSO),二甲基甲酰胺(DMF),乙二醇二甲醚(DME),乙醇(C_2H_5OH),四氢呋喃(THF),乙腈(CH_3CN)和二氯甲烷(CH_2Cl_2)中的电子吸收光谱,研究了电子光谱吸收带在相关分子轨道能级图中的对应跃迁关系,讨论了标题配合物有价值的配体间荷移跃迁(LL’CT)吸收带的本质特征及其影响因素,探讨了它们在DMSO中的感光氧化特性。     

Density functional theory calculation and vibrational spectral analysis of 4‐hydroxy‐3‐(3‐oxo‐1‐phenylbutyl)‐2H‐1‐benzopyran‐2‐one

The Fourier transform infrared (4000–400 cm⁻¹) and Fourier transform Raman (3500–500 cm⁻¹) spectra of 4‐hydroxy‐3‐(3‐oxo‐1‐phenylbutyl)‐2H‐1‐benzopyran‐2‐one (Warfarin) have been measured and calculated. The structure optimization has been made using density functional theory (DFT) calculations. Complete vibrational assignments of the observed spectra have been compared with theoretical wavenumbers. The wavenumber increasing in the methyl group shows the electronic hyperconjugation effect. The natural bond orbital (NBO) analysis reveals the hyperconjugation interaction and the intramolecular hydrogen bonding. The first‐order hyperpolarizability has been calculated. Copyright © 2009 John Wiley & Sons, Ltd.     

Fe（II）-NH(a1Δ)N4S2自旋翻转单分子磁体的电子输运性质

Spin-crossover (SCO) magnets can act as one of the most possible building blocks in molecular spintronics due to their magnetic bistability between the high-spin (HS) and low-spin (LS) states. Here, the electronic structures and transport properties through SCO magnet Fe(II)-N₄S₂ complexes sandwiched between gold electrodes are explored by performing extensive density functional theory calculations combined with non-equilibrium Green''s function formalism. The optimized Fe-N and Fe-S distances and predicted magnetic moment of the SCO magnet Fe(II)-N₄S₂ complexes agree well with the experimental results. The reversed spin transition between the HS and LS states can be realized by visible light irradiation according to the estimated SCO energy barriers. Based on the obtained transport results, we observe nearly perfect spin- filtering effect in this SCO magnet Fe(II)-N₄S₂ junction with the HS state, and the corresponding current under small bias voltage is mainly contributed by the spin-down electrons, which is obviously larger than that of the LS case. Clearly, these theoretical findings suggest that SCO magnet Fe(II)-N₄S₂ complexes hold potential applications in molecular spintronics.