Control of the Electronic Structure of Organic Conductors as Exemplified by [NMP][TCNQ] Charge-Transfer Complexes

Through replacement of cations with neutral molecules of similar shape and polarizability in a highly conducting “metal-like” change-transfer organic conductor, the deliberate control of the electronic structure from a quarter to a half-filled band is possible. This goal has been achieved with the N-methylphenazinium (NMP) salt of the tetracyanoquinodimethane (TCNQ) anion by partial replacement of the cation with phenazine. A detailed study of the optical, electrical, and magnetic properties of these conducting molecular solids has lead to the evolution of a broad understanding of the physics of one-dimensional organic conductors and a reinterpretation of the mechanism of electron transport in such solids. Phenomena such as switching from a low coulomb repulsion two-chain conductor to a high coulomb repulsion one-chain conductor as well as soliton-assisted electron transport are observed.     

Charge transport properties for carbazolyl groups pendant poly(glutamate)

Carbazolyl groups pendant poly(glutamate) (PCLG) was prepared to analyze its charge‐transport properties by employing mobility measurements and thermally‐stimulated current (TSC) measurements. The mobility induced TSC (MITSC) model proposed by I.Chen was employed to evaluate the experimental TSC spectra with mobility results. Simulated MITSC spectra showed good agreement in its peak temperature with experimental TSC spectra for PCLG. This suggests that the carrier transport followed the trap‐limited mechanism estimated by the mobility results. Further, the peaks in experimental TSC spectra appeared over the same temperature range as that in thermally‐stimulated polarization current (TSPC) spectra. Since the TSPC spectra were found to be correlated with the dielectric tan δ spectra for PCLG, the peaks in TSPC spectra are attributed to the side‐chain relaxation for PCLG. Therefore, the similarity between TSPC and TSC spectra indicates that the charge‐transport mechanism for PCLG was considerably affected by side‐chain relaxation for PCLG, which would vary the energy state of trap sites and effectively reduces the energy for the release of the carriers trapped on the illuminated surface. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 61–69, 1999     

Charge transport properties of triphenylamine‐pendant polypeptide

The structurally ordered polymer, triphenylamine‐pendant polypeptide (PATPA: poly[γ‐4‐(N,N‐diphenylamino‐phenyl)‐L ‐glutamine]), was prepared in order to obtain high hole mobility and high thermal stability. The hole mobility obtained for PATPA (ca. 10⁻⁵ cm²/Vsec) at room temperature is higher than that for poly(N‐vinylcarbazole) (PVK) (ca. 10⁻⁷ cm²/Vsec) or that of carbazole‐pendant polypeptide (PCLG) (ca. 10⁻⁸ cm²/Vsec). These results are supported by thermally stimulated current (TSC) measurements because the TSC can be correlated with the mobility. The glass‐transition temperature (T_g) of PATPA was estimated to be about 130° by differential scanning calorimetry (DSC). From these results, PATPA is an alternative candidate as a photoconductive polymer with high thermal stability and high hole mobility. The ordered structure along the main chain is thought to facilitate hole transport. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 362–368, 2000     

Cuboidal basis functions

Summary An evaluation of the coulomb integral for a cuboid with uniform density is presented in analytic form, leading to the development of non-overlapping cube basis functions. The coulomb energy of the hydrogen molecule is determined with these functions fitted to the molecular orbital, and this result is compared with theab initio coulomb energy.     

A Novel Copper Oxide Nanoparticle Conjugated by Thiosemicarbazone Promote Apoptosis in Human Breast Cancer Cell Line

The current study highlights the apoptotic activity of copper oxide (CuO) nanoparticles functionalized by Glutamic acid and conjugated by thiosemicarbazone (TSC) toward human breast cancer (MCF-7) and normal (HEK293) cell lines. To this aim, the co-precipitation method was used for preparation the CuO nanoparticles. Afterward, the CuO nanoparticles functionalized by glutamic acid. After that the functionalized copper oxide nanoparticles (CuO@Glu) conjugated to thiosemicarbazone. In next step, the final nanoparticle product (CuO@Glu/TSC) was characterized by physico-chemical techniques including Fourier transform infrared (FT-IR) spectroscopy, Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Energy dispersive X-ray analysis (EDX), zeta potential analysis and dynamic light scattering (DLS). The effects of in vitro cell viability in CuO@Glu/TSC nanoparticles showed the anti-proliferative properties with a dose-dependent manner (IC₅₀?=?133.97 µg/ml). The IC₅₀ of CuO@Glu/TSC on normal cell line was 230.2 µg/ml. This IC₅₀ deference shows high cytotoxicity of CuO@Glu/TSC nanoparticles on tumor cells and low cytotoxicity on non-tumorigenic cells (HEK293) and is considered as an important aspect for this nanoparticles. Also, CuO@Glu/TSC nanoparticles had efficient effects in inhibiting the growth of breast cancer cell line (MCF-7). In addition, the CuO@Glu/TSC nanoparticle induced apoptosis symptoms which were assessed by Caspase-3 activation assay, Annexin V/ propidium iodide flow cytometry, and Hoechst 33258 staining. Further, Bax and Bcl-2 genes expression was estimated by real time PCR. The expression of Bax increased 1.69 fold, while the expression of Bcl-2 decreased 0.6 fold. The results of the current study propose that CuO@Glu/TSC nanoparticles reveal effective anti-cancer activity against breast cancer cell line.

     

Mechanism of oxidations in partially aqueous media: Kinetics of oxidation of thiosemicarbazide and thiosemicarbazone by chloramine-T and dichloramine-T in aqueous methanol

Kinetics of oxidation of thiosemicarbazide (TSC) and its hydrazone (Benzaldehyde thiosemicarbazone) by chloramine-T (CAT) and dichloramine-T (DCT) in aqueous methanol medium in the presence of perchloric acid has been studied. Oxidation of TSC by both the oxidants showed first order dependences in [oxidant], fractional order in [TSC] and nearly inverse first order in [H⁺]. The conversion of TSC into its benzaldehyde hydrazone changed the rate dependence in [CAT] from first to second order, while the dependence in [DCT] remained unchanged. The dependence in [TSC] changes from fractional order to zero order in both CAT and DCT oxidations. The rate followed inverse fractional order kinetics in [H⁺] in both the cases. Increase in ionic strength of the medium slightly decreased the rate, while the decrease in dielectric constant of the medium increased the rates of oxidations for both the oxidants. But the addition of reaction products, p-toluenesulphonamide and chloride had no effect on the rate. Oxidation of TSC with both the oxidants has been shown to follow Michaelis-Menten type mechanism. In hydrazone oxidations oxidants have been shown to disproportionate in slow steps to HOCl, which in turn attacks the substrate in fast steps to give the final products. [TSC] was varied at different temperatures and the constants of rate limiting steps were calculated at each temperature. Using the latter constants the activation parameters have been computed from the Arrhenius plots. The rate constants have been predicted from the rate law for the variation of [H⁺] at constant [TSC] and [oxidant]. The predicted values are in reasonable agreement with the experimental rate constants, providing additional support to the suggested mechanisms.     

Binding Models of Copper(II) Thiosemicarbazone Complexes with Human Serum Albumin: A Speciation Study

Copper(II) complexes of thiosemicarbazones (TSCs) often exhibit anticancer properties, and their pharmacokinetic behavior can be affected by their interaction with blood transport proteins. Interaction of copper(II) complexes of an {N,N,S} donor α-N-pyridyl TSC (Triapine) and an {O,N,S} donor 2-hydroxybenzaldehyde TSC (STSC) with human serum albumin (HSA) was investigated by UV–visible and electron paramagnetic resonance spectroscopy at physiological pH. Asp-Ala-His-Lys and the monodentate N-methylimidazole were also applied as binding models. Conditional formation constants were determined for the ternary copper(II)-TSC complexes formed with HSA, DAHK, and N-methylimidazole based on the spectral changes of both charge transfer and d-d bands. The neutral N-methylimidazole displays a similar binding affinity to both TSC complexes. The partially negatively charged tetrapeptide binds stronger to the positively charged Triapine complex in comparison to the neutral STSC complex, while the opposite trend was observed for HSA, which demonstrates the limitations of the use of simple ligands to model the protein binding. The studied TSC complexes are able to bind to HSA in a fast process, and the conditional constants suggest that their binding strength is only weak-to-moderate.     

Studies of Copper(II) Thiosemicarbazide Complexes and their Reactivities. X-Ray Structure of Two Unusual Reaction Products, [Cu(bpy)(H2O)2SO4] and [(bpy)2Cu2(C2O4)Cl2]·H2O

A number of ternary complexes of Cu²⁺ with thiosemicarbazide (TSC) including [Cu(bpy)(TSC)₂]Cl₂, [Cu(o-phen)(TSC)₂]Cl₂ and [Cu(bpy)(TSC)₂][CuCl₄] [Cu(o-phen)(TSC)₂] [CuCl₄] have been synthesised and characterized. Their reactivities in aqueous and DMF solutions were studied. It was observed that while on coordination to Cu²⁺ thiosemicarbazide is converted to thiocyanate in aqueous solution, in DMF solution the thiocyanate is further aerially oxidised to sulfate. In the presence of hydrogen peroxide, oxidation to sulfate is rapid and from the mother liquor we could isolate [(bpy)₂Cu₂(C₂O₄)Cl₂]·H₂O whose structure was determined by X-ray crystallography. X-ray crystal structure of [Cu(bpy)(H₂O)₂SO₄] is also discussed.*     

ION CONDUCTION IN COMPLEX OF ACRYLONITRILE-COPOLYMERIZED COMB POLYETHER WITH LITHIUM PERCHLORATE

Poly (oligoether methacrylate-co-acrylonitrile) s, P (MEOn- AN), with oligoether pendants of different lengths were synthesized and the ion conduction property of their Li-salt complexes was studied as the function of polymer structure. At proper copolymer composition, lithium concentration and pendant length, the ion conductivity reaches 7.0×10~(-5)S/cm at ambient temperature, together with improved mechanical strength. The ion transport in the polymer media is assisted by segmental relaxation, which is confirmed both by the consistency between ion conductivity and T_g and by the study of TSC.     

Thiosemicarbazone Complexes of Ruthenium(II) and Rhodium(I) Containing Triphenylphosphine

Several new hexa-coordinated ruthenium(II) and penta-coordinated rhodium(I) complexes of the types [RuCl(CO)(PPh ₃ ) ₂ (TSC)], [RuH(CO)(PPh ₃ ) ₂ (TSC)], and [Rh(PPh ₃ ) ₃ (TSC)] (where TSC = anion of thiosemicarbazone Schiff bases) have been prepared by the reactions of [RuHCl(CO)(PPh ₃ ) ₃ ], [RuH ₂ (CO)(PPh ₃ ) ₃ )], and [RhH(PPh ₃ ) ₄ ] with thiosemicarbazones of 2-furaldehyde (H-FTSC), thiophene-2-carboxaldehyde (H-TCTSC), p-anisaldehyde (H-ATSC), piperonaldehyde (H-PTSC), and cyclohexanone (H-CTSC). All the new complexes obtained have been characterized on the basis of elemental analysis, IR, ¹ H NMR, ³¹ P NMR, and electronic spectral data.     

Investigation of radical pairs produced upon pulse action of elastic waves on the 3,6-di-tert-butylcatechol-3,6-di-tert-butyl-o-benzoquinone-sulfur system

The pulse action of elastic waves on polycrystalline mixtures of 3,6-di-tert-butylcatechol and 3,6-di-tert-butyl-o-benzoquinone produces radical pairs stable at room temperature, and the addition of polycrystalline sulfur considerably increases their yield. The dependences of formation and decay rates of paramagnetic centers on the composition of the mixture were studied. The threshold character of formation of paramagnetic centers at various powers of elastic wave pulse was established.Translated fromIzvestiya Akademii Nauk. Seriva Khimicheskaya, No. 4, pp. 864–868, April, 1996.     

Chemistry of 2-methylene-2,3-dihydro-3-furanones

2-p-Chlorobenzoylmethylene-5-phenyl-2,3-dihydro-3-furanone reacts with arylamines orN-arylideneamines to form the products of ring opening, 1,6-diaryl-1-arylamino-4-hydroxy-1,4-hexadiene-3,6-diones. The reaction of 5-aryl-2-p-chlorobenzoylmethylene-2,3-dihydro-3-furanones witho-aminophenol afforded 3-p-chlorobenzoylmethylene-3,4-dihydro-2H-benzo[b]-1,4-oxazin-2-one. Nucleophilic attack of amines is directed either to electrophilic centers at the C(5) and C(2) atoms or to the carbonyl group of the 2-phenacylidene substituent of the 3-oxofuran ring. For communication 15, see Ref. 1. Translated fromIzestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1340–1345, July, 1997.     

Synthesis,structure and antiproliferative activity of dinuclear ruthenium arene complexes with differently coordinated thiosemicarbazones

A series of di‐nuclear ruthenium arene complexes with TSC ligands ([(η⁶‐p‐cymene)Ru(N¹,S‐TSC)]₂Cl₂, A‐type, 1 and 2 ) and their corresponding analogues ([(η⁶‐p‐cymene)Ru(N²,S‐TSC)]₂Cl₂, B‐type, 3 and 4 ), in which TSCs act as different coordination mode, have been synthesized and structurally characterized by a variety of physical methods. The molecular structures of 1 , 3 and 4 were determined using single‐crystal X‐ray diffraction analysis. The Gibbs free energy of the two examples of the two types of complexes ( 1 and 3 ) and bonding order in their single‐crystals were discussed using density functional theory (DFT) calculations. The compounds were further evaluated for their in vitro antiproliferative activities against several cancerous and HEK‐293 T noncancerous cell lines, and the results indicate that B‐type complexes show stronger cytotoxicity than A‐type complexes. Furthermore, the interactions of the compounds with DNA were investigated by electrophoretic mobility spectrometry studies.     

Beiträge zur Chemie der Pyrrolpigmente, 78. Mitt.: Die Eigenschaften desb-Nor-bilatrien-abc-b-Nor-biladien-ac-Systems

The redox coupleb-nor-biladiene-ac (2)/b-nor-bilatriene-abc (3) exhibits an oxidative half wave potential of 800 mV in acetonitrile solution. It is demonstrated that it can be used as an extremely efficient electron carrier through bulk membranes. Whereas2 is not suitable as a ligand in carrier mediated cation transport,3 is a medium suited carrier for Cu(II) or Zn(II) ions, however, it is the most efficient one found so far for transport of Hg(II) ions. A 1:1 zinc chelate of3 is isolated and characterized. it is deduced to represent a polymer consisting of about 73 monomer units.

     

Bacterial interactions and transport in unsaturated porous media

The convection-dispersion transport model, which can well define solute transport, has been introduced to describe bacterial transport. Due to different interaction natures within the porous media, bacterial transport in the subsurface, especially in the vadose zone is a complex scenario. When transported in the vadose zone, bacteria may be captured on the media surface, at the air–water interface, or at the media–air–water three-phase interface depending upon the predominant interactions of concerned bacteria within the pore system. In this study, transport of Echerichia coli, Pseudomonas fluorescens and Bacillus subtilis in silica sand under water unsaturated conditions was investigated using column experiments. Bacterial interactions within the system were characterized based on bacterial and media surface thermodynamic properties, which were determined independently by means of contact angle measurements. These calculated interactions provided solid evidence of the bacterial retention mechanisms in the pore system, which served as the bases for suitable assumptions of bacterial transport modeling. The micro-scale interaction investigations helped eliminate uncertainties arising with bacterial transport modeling.     

Synthesis of new building blocks based on the <Emphasis Type="Italic">closo</Emphasis>-dodecaborate anion

The reactions of the dioxonium derivative of closo-dodecaborate(12) with aromatic aldehydes and esters containing O- and N-nucleophilic centers were studied. These reactions were used to synthesize new closo-dodecaborate-based building blocks containing aldehyde and acidic groups. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1961–1963, September, 2008.     

Thermally stimulated current studies of thermotropic polyesters with polymethylene spacers (I): The glass transition and relaxation behavior of anisotropic and isotropic glasses

Thermally stimulated current (TSC) and relaxation map analysis (RMA) were used to study the glass transitions and relaxation phenomena of the anisotropic and isotropic glasses for the semiflexible polyesters with various polymethylene spacers (n = 7 ˜ 10). TSC analysis indicated that the glass transition temperatures (T_g) of polymers at around 40 ˜ 50°C exhibited an apparent even-odd behavior not only for the anisotropic glasses but also for the isotropic glasses. The T_g of the isotropic glass for the polymer with even n value was observed to be higher than those for the two neighboring polymers with odd n values. The anisotropic glass for the polymer with even n value had a lower T_g than those for the two neighboring polymers with odd n values. The lower value was attributed to the configuration and orientation effects on the behavior of polarization. RMA revealed that the relaxation modes of the investigated polymers were also influenced by the configuration and orientation effects. The dipolar relaxation of the anisotropic glass for the polymer with odd n value occurred at a higher temperature and had a lower entropy (enthalpy) of activation than that of the isotropic glass for the same polymer due to the orientation effect. However, an inverse relation was found to occur for the polymer with even n value, which came from the trans configuration of the even polymethylene spacers. Finally, the thermokinetic properties evaluated by RMA (e.g., the final state after depolarization) correlated quite well with the results obtained by TSC. © 1995 John Wiley & Sons, Inc.     

Phytochemical Studies of Berberis vulgaris

This study presents a phytochemical investigation of the fruits of Berberis vulgaris Linn. The isolation and structure elucidation of four compounds are discussed. The terpenoids lupeol (1) and oleanolic acid (2) and the steroids stigmasterol (3) and stigmasterol glucoside (4) are isolated for the first time from this plant. The structure and stereochemistry at various asymmetric centers were established by different spectroscopic techniques.     

TSC STUDIES ON SUB-Tg STORAGE OF POLYETHYLENE TEREPHTHALATE

The Thermally Stimulated Current (TSC) spectra of a series of Sub-T_θannealed polyethylene terephthalate (PET) specimens have been measured. It is found that there is only one peak at 80℃above room temperature, which related to the thermo-relaxation of frozen-in dipoles. The activation energy of such dipole motion has been calculated. The relation between the maximum current and the storage time can be explained by the free volume theory and agrees with the results from the excess thermodynamic properties. Compared with Differential Scanning Calorimeter (DSC) and tensile stress-strain method, TSC is a simpler and more sensitive method in studying Sub-T_θannealed polymers.     

Effect of Spectrum of Acidity of Zeolites of Various Structural Types on Their Catalytic Characteristics in the Synthesis of Ethyl tert-Butyl Ether

The catalytic properties of zeolites of various structural types in the liquid phase synthesis of ethyl tert-butyl ether from isobutylene and ethanol have been studied. The activity and selectivity of the catalysts depend on the concentration and strength of the acid centers. A possible mechanism for the synthesis of ethyl tert-butyl ether is proposed, suggesting that isobutylene and ethanol are activated on the weak and strong acid centers respectively.