Scavenging Effect of Perylenequinone Hydroxyls on Free Radicals: A Theoretical Study

Perylenequinonoidderivatives(PoD),includinghypocrellins,cercosporinandhypericin,etc.,arewidespreadnaturalphotosensitizers.Owingtoexcellentphotodynandcproperties,PoDhaveattractedmoreandmoreattention14.NowthemechanismsofthephotosensitizationofPoDhavebeenstudiedthoroughly,andclassicaltype1andtype11reactionsarefoundtobeinvolvedintheprocess'-':TherearemanyproblemstobesolvedbeforeusingPoDasaphotodynandcmedicine.Forexample,ithasnotbeensufficientlyunderstoodwhethertheactiveoxygens(O2,'O,)generated…     

Theoretical Study on the Structures and Electronic Spectra of the Derivatives of C_(60)-P-2,4,6-Triphenyl Borazinc

1 INTRODUCTION The electron-transfer reaction of C60 derivatives, especially light-induced electron-transfer reaction, has been an active research field for a long time. Many researches are focused on the long-live charge- separated state caused by electron-transfer[1]. And several electron-transfers between electron donor and C60 or intramolecular electron-transfer have been confirmed. As an example, TTF-C60 is proved to be a short-live charge-separated compound[2].Due to the excelle…     

Theoretical Study on Two C_(16)H_(12)O_4 Isomers of Derivatives of Pagodane

1 NTRODUCTION Pagodane ([1.1.1.1]-pagodane) is the trivial name assigned to the D2h-symmetry undecacyclic poly- quinane undecacyclo-[9.9.0.01,5.02,12.02,18.03,7.06,10. 08,12.011,15.013,17.316,20]-eicosane (Fig. 1). It has been synthesized[1] and subsequently studied by Prinzbach and co-workers for more than twenty years[2, 3]. Des- cribed as a waxy solid melting without decomposi-tion and stable to at least 600 ℃ in gas phase, pa- godane is interesting for its exotic structure and as an…     

Theoretical Study on the Pyrolysis Mechanism and Kinetics of 3-Hydroxy-3-Methyl-2-Butanone

Thethermolysisofpyruvicacid2Ieadstotheeliminationofcarbondioxideandacetaldehydeisformedasanotherproduct.Hong'hasstudiedthemechanismofthereactionintheMINDO/3molecularorbitaltheory.Al-AwadiandEL-Dusouqui'havestudiedthepyrolysisofthe3-hydroxy-3-methyl-2-butanoneinordertoexaminetheinfluenceofthehydrogenatominvolvedintheTransitionStateoftheeliminationprocessandtoassessitscontributiontotherate-controllingstep.TheygaveoutthethermalrateconstantsandhypothesizedthatthereactionmightproceedthroughafO…     

Theoretical Studies on the Third-order Nonlinear Optical Properties and Two-photon Absorption of Stilbene Derivatives

Different types of stilbene derivatives (D-π-D, A-π-A, D-π-A) were investigated with AM1, and specially, equilibrium geometries of symmetrical stilbene derivatives (D-π-D) were studied using of PM3. With the same method INDO/CI, the UV-vis spectra were explored and the position and strength of the two-photon absorption were predicated by Sum-Over-States expression. The relationships of the structures, spectra and nonlinear optical properties have been examined. The influence of various substituents on two photon absorption cross-sections was discussed micromechanically.     

A Thermochemical Study on Complex Nickel(Ⅱ) L-α-Histidine

IntroductionNickel is an essential trace biological element.L-α- Amino acids are the structural units of pro-teins.L- α- Histidine is one of the eight species ofamino acids which have to be absorbed from foodbecause they are not synthesized by organism.Thus,the investigation on the complexation ofnickel and L -α- histidine is of considerable practicaland fundamental importance.For the nickel com-plexes of amino acids,more extensive work hasbeen carried out[1— 3 ] . However,the thermochem…     

Theoretical Chemistry Study of the Hydrogen-bonded Interaction between Acylamine and Chloromethane Compounds

1 INTRODUCTION The mutual interaction of molecules is related with many properties of the material, such as optics, electricity and magnetism. Moreover, chemical re- action and molecule recognition are related to the mutual interaction among molecules too. So, the weak interactions among molecules have attracted many chemists’ attentions. The law of mutual interaction of molecules has been widely used in many research fields, such as, studying the mechanism of organic reaction and de- si…     

A New Synthetic Route to Diastereomerically Pure Cyclopropane-Phosphorus Derivatives Utilizing the Chiron 5-L-Men-thyloxy-3-bromo-2(5H)-furanone and Racemic Dialkyl α-Hydroxyalkanephosphonate

ＩｎｔｒｏｄｕｃｔｉｏｎＣｙｃｌｏｐｒｏｐａｎｅ ｃｏｎｔａｉｎｉｎｇｎａｔｕｒａｌａｎｄｎｏｎｎａｔｕｒａｌｐｒｏｄｕｃｔｓｈａｖｅｒｅｃｅｉｖｅｄｃｏｎｓｉｄｅｒａｂｌｅａｔｔｅｎｔｉｏｎａｓｓｙｎｔｈｅｔｉｃｔａｒｇｅｔｓａｓｔｈｅｉｎｃｏｒｐｏｒａｔｉｏｎｏｆｔｈｅｒｉｇｉｄｉｆｉｅｄｃｙｃｌｏｐｒｏｐｙｌｍｏｔｉｆｉｎｔｏｂｉｏａｃｔｉｖｅａｎａｌｏｇｕｅｓｌｅａｄｔｏｃｏｎｆｏｒｍａｂｌｙｃｏｎ ｓｔｒａｉｎｅｄｍｏｌｅｃｕｌｅｓ .1,2 Ｓｕｃｈｍｏｄｉｆｉｃａｔｉｏｎｓａｒｅｅｘｐｅｃ…     

Design and Synthesis of Novel Aryloxyalkyl-arylpiperazine Derivatives as α_(1A)-Adrenoceptor Antagonists

Benign prostatic hyperplasia (BPH) is the non-malignant enlargement of the prostate andclinically occurs predominantly in men aged over 60 years1. α1-Adrenoceptor (α1-AR)antagonists such as terazosin and doxazosin relax the smooth muscle in the prostate andlower urinary tract and are currently being used as treatment for BPH2,3. These clinicalagents, while effective, have been associated with side effects such as orthostatichypotension, dizziness, asthenia, and nasal congestion4. …     

CIDNP Study of Photoinduced [2+2] Cycloadditions (the Paterno- Bühi Coupling) of Arylacetylenes and Quinone

Thephotoinduced[2+2]cycloadditionofanolefintoacarbonylcenter,alsoknownasthePaterno-B點hireaction,isaconvenientwaytoprepareoxetanewithhighregio-andstereoselectivities.Mostimportantly,therangeofcarbonylcompoundshasbeenextendedtoenones,quinones,dionesetc.,andthealkenes,dienes,andacetylenesastheolefiniccounterparts.TheprocesscanbeviewedasavariantofthePaterno-B點hireaction1.Itisbelievedthatinallpostulatedmechanisms,theformationofa1,4-biradicalisacrucialintermediatepriortocyclization.Photoinducedr…     

Synthesis,Crystal Structure,Theoretical Calculation,and Photophysical Property of a New Cd(Ⅱ) Complex Based on N-heterocyclic Ligand and Isophthalic Acid

A new metal-organic coordination complex[Cd(imp)(m-bdc)]_n (1,ipm=5-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)-2-methoxyphenol,m-bdc=isophthalic acid) has been synthesized by hydrothermal reaction and characterized by elemental analysis,thermogravimetric (TG) analysis,infrared spectrum (IR) and single-crystal X-ray diffraction.Complex 1 crystallizes in monoclinic,space group C2/c with a=15.373(5),b=16.719(5),c=19.406(6)A,β=106.995(5)°,V=4770(2)A³,C₂₈H₁₈Cd N₄O₆,M_r=618.86,D_c=1.724 g/cm³,μ(Mo Kα)=0.971 mm^–1,F(000)=2480,Z=8,the final R=0.0391 and w R=0.1044 for 4701 observed reflections (I>2σ(I)).Single-crystal X-ray diffraction reveals that 1 exhibits a one-dimensional (1D) double-chain architecture,and the H-bond intersections link the 1D double-chain architecture into a 2D layer structure.TG analysis shows clear courses of weight loss,which corresponds to the decomposition of different ligands.We also study the luminescent properties of complex 1.In addition,to elucidate the essential electronic characters of this complex,theoretical calculation analysis was performed by the PBE0/LANL2DZ method in Gaussian 03 Program.     

Synthesis,Crystal Structure and Fluorescence Property of a Zinc(Ⅱ) Coordination Polymer with a Theoretical Calculatio

We have designed and synthesized a new luminescent coordination polymer[Zn₂(NO₃)(NCP)₃(H2O)₃]n·2 nH₂O(1,HNCP=2-(2-carboxyphenyl)imidazo-[4,5-f]-1,10-phenanthroline)under hydrothermal conditions,which has been structurally characterized by single-crystal X-ray diffraction analyses.1 crystallizes in monoclinic,space group P2₁/n,with a=13.7748(3),b=19.2651(4),c=19.9543(4)?,β=95.339(2)o,V=5272.35(19)?³,C₆₀ H_39.73 N₁₃ O_13.33 Zn₂,M_r=1286.80,D_c=1.621 g/cm³,Z=4,μ(Mo Ka)=2.118,F(000)=2629,the final R=0.0598 and w R=0.1483.In 1,the organic ligand NCP-displays two different bridging modes to connect adjacent Zn(II)ions into a 1 D chain along the c-direction.Photoluminescent analyses reveal that 1 exhibits a strong green emission with a fluorescent lifetime of 5.57 ns.The first-principle calculation results show that the luminescence mainly originates from ligand-centered charge transition.     

Theoretical study on the reaction mechanism of (CH_3)_3CO~· radical with NO

Alkoxy radicals RO? form an important class of hydrocarbon oxidation intermediates in combustion processes, interstellar and atmospheric chemistry[1—8]. The number of NO to NO2 conversions can take place during the oxidation of the parent hydrocarbon in the atmosphere and hence affecting tropospheric ozone production. The experimental and theoretical investi-gations of the reactions of alkoxy radicals will be ad-vantageous for safeguarding the environment. Despite the importance of alkoxy r…     

Synthesis and Crystal Structure of α-(N-Protected amino) β-lactam Derivative of 1,5-Benzothiazepine

The crystal of the title compound C, C30H30N2O3S has been prepared by reaction of 1,5-benzothiazepine with N-protected glycine and determined by X-ray single crystal diffraction. Crystal data: Mr=498.62, triclinic with P space group, a=10.880(2), b=13.955(3), c=9.537(2)(A), α=99.34(3)°, β=110.43(3)°, γ=88.56(3)°, V=1338.2(5)(A)3, F(000)=528, λ(MoKα)=0.71073(A), Z=2, Dc=1.237g/cm3, μ=0.154mm-1. Final R=0.0453, wR=0.1256 for 3491 observed reflections [I>2σ(I)]. Structure analysis reveals that the substituents at C(23) and C(7) in four-membered ring are located on the same side. The conformation of seven-membered ring is chair-like.     

Immobilized nickel(Ⅱ) on organic-inorganic hybrid materials: The effective and reusable catalysts for Biginelli reaction

The immobilized nickel(II) on the organic-inorganic hybrid material was prepared and used as an effective catalyst for the Biginelli reaction.In the presence of the immobilized nickel catalyst,aromatic aldehydes reacted with ethyl acetoacetate and urea (or thiourea) smoothly to generate the corresponding Biginelli products in good to excellent yields without using any additive.The work-up procedure is very simple and practical.Furthermore,the silica-supported nickel(II) could be recovered and recycled for s...     

A Density Functional Study on the Geometries of Compounds Fe(HCN)n+(n = 1～6)

The possible geometries of Fe(HCN)n+ (n = 1～6) compounds were studied by using DFT/UB3LYP/6-31G(2df) method. The structure and ground state of each fragmental ion are C∞v (4∑+ or 6∑+), D∞h(4∑g+), D3h (4A1'), C2v or Td or C3v (4A1), and D3h (4A1') or C4v( (2A1') sequentially with n = 1～5. For the compound Fe(HCN)6+, the possible geometry was not obtained. The sequential incremental interaction energy (-△(△E)), dissociation energy (△D0), enthalpy (-△(△H)) and Gibbs free energy (-△(△G)), and frequencies for HCN-Fe(HCN)n-1+ were also calculated, and the results are all in good agreement with the experiments. The bond length of Fe-N is lengthened with the increase of cluster size, and the strength of Fe+-N coordination bond varies nonmon- tonically as increasing the number of ligands. The Fe+-N bond of Fe(HCN)2+ is the strongest in all compounds.     

Study on the Phosphenium Cation (Ⅰ)——Synthesis and Characterization of 5-Methylthio-3-N-Phenyl-2,3-2(H)-1,3,4,2-Thiadiazaphosphenium Cation and the Others

Ten years after the first synthesis of neutral two-coordinated phosphorus in 1962, the first phosphenium cations were synthesized by Fleming, Lupton and Jekot in 1972. Up to now, though 30 years have passed, the members of these phosphenium cations are still very few. the research of phosphenium cations is only limited in France, America and other countries. In our laboratory work was done on a new unique cation: the 5-methylthio-3-N-phenyl-2,3-2(H)-1,3,4,2-thiadiazaphosphenium cation which was found and characterized by 261.9 ppm conclusively of ~(31)p NMR. It also has an electric conductivity in nucleophilic and electrophilic reactions. We are interested in noticing that these phospbenium cations are stabilized by one sulfur atom besides nitrogen atoms.     

TD-DFT Study on the Electronic Spectrum Properties of 2,7′-(Ethylene)-bis-8-hydroxyquinoline and Its Derivatives

The structures of 2,7′-(ethylene)-bis-8-hydroxyquinoline and its derivatives were optimized at the ground states using ab initio HF and B3LYP methods. At the same time, the molecular structures of the first singlet excited state for 2,7′-(ethylene)-bis-8-hydroxyquinoline and its derivatives were optimized by CIS/6-31G(d). The absorption and emission spectra based on the above structures were obtained by the time-dependent density functional theory (TD-DFT) by the B3LYP method with the 6-31G(d) basis set. The calculated results of luminescence originate from the electronic transition from the hydroxphenol ring of 8-hydroxyquinoline A to the pyridine ring of 8-hydroxyquinoline B. Their luminescence wave bands can be tuned by different substituents on the ligand of 8-hydroxyquinoline.