Radical Salts Research Articles

Synthesis and structures of 11,11,12,12-tetracyano-2,6-diiodo-9,10-anthraquinodimethane and its 2:1 cocrystals with anthracene, pyrene and tetrathiafulvalene.

Radical salts and charge-transfer complexes (CTCs) containing tetracyanoquinodimethane (TCNQ) display electrical conductivity, which has led to the development of many TCNQ derivatives with enhanced electron-accepting properties that are applicable toward organic electronics. To expand the family of TCNQ derivatives, we report the synthesis and structures of 11,11,12,12-tetracyano-2,6-diiodo-9,10-anthraquinodimethane (abbreviated as DITCAQ), C20H6I2N4, and its charge-transfer complexes with various electron donors, namely DITCAQ-anthracene (2/1), C20H6I2N4·0.5C14H10, (I), DITCAQ-pyrene (2/1), C20H6I2N4·0.5C16H10, (II), and DITCAQ-tetrathiafulvalene (2/1), C20H6I2N4·0.5C6H4S4, (III). The molecular structure of DITCAQ consists of a 2,6-diiodo-9,10-dihydroanthracene moiety with two malononitrile substituents. DITCAQ possesses a saddle shape, since the malononitrile groups bend significantly up out of the plane of the central ring and the two benzene rings bend down out of the same plane. π-π interactions between DITCAQ and the electron-donor molecules control the degree of charge transfer in cocrystals (I), (II), and (III), which is reflected in both the dihedral angles between the terminal benzene ring and the central ring on the DITCAQ motifs, and their corresponding IR spectra.

Selection of Superior Sorghum Accession by Assessing Agronomic Characters and Biological Activity

Background: Sorghum is a major cereal food crop used in many parts of the world. It has been grown on a subsistence level by farmers, under various conditions of environmental stresses in the semi-arid tropics of Africa and Asia. This plant has received significant attention because of its ability to reduce cholesterol in the blood, and its anti-dementia, antioxidant, and antimicrobial properties. It is possible to develop a functional and commercially viable sorghum variety by using superior cultivars of sorghum. The objective of this study was to build a database of superior sorghum accession. Methods and Results: We used 250 sorghum accessions collected from different geographical bioregions in Korea. We determined various agronomic characters including germination rate and ear length of these accessions. To determine the antioxidant capacity, we measured the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)- diammonium salt radical scavenging activity, total phenolic contents, and total flavonoid contents. Accession 189 showed higher germination ( 80%) than the other accessions. Higher 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity was observed in 11-SB-078 (RCsub50/sub; 1.89 ± 2.88 ㎍/㎖), and higher 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt radical scavenging activity was recorded in 11-SB-116 (RC50; 35.48 ± 2.42 ㎍/㎖) than in the other accessions. The ear length ranged from 15 ㎝ to 48 ㎝, the total phenolic contents ranged from 3 ㎎• GAE/g to 77 ㎎• GAE/g, and total flavonoid contents ranged from 0.09 ㎎• QE/g to 1.07 ㎎• QE/g. Conclusions: Among 250 sorghum accessions, we selected 10 with both superior agronomic characters and highly functional food quality.

BEDT-TTF Salts Formed with Tetrahedrally Coordinated Zinc(II) Complex Anions

Twelve kinds of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) cation radical salts with tetrahedrally coordinated zinc(II) complex anions were obtained by electrocrystallization; most of them were produced via the additional reaction of Lewis-basic cyano-containing anions [N(CN)2–, C(CN)3–, and Au(CN)2–] with ZnX2 (X = Cl–, Br–, and SCN–) that occurred during electrocrystallization. On the basis of the charge and arrangement of ET molecules, these salts were predominantly categorized into four groups: (A) isolated ET•+ dimers or tetramers, (B) infinite ET•+ ribbon, (C) infinite layers either with a peculiar ET0.5+ arrangement of ET molecules with partial charges other than +0.5, and (D) infinite layers of ET0.5+ molecules. In A, zinc(II) complex anions including a unidentate-coordinated C(CN)3 or Au(CN)2 group spatially interrupt the infinite arrangement of ET molecules. The ET•+ ribbon in B runs parallel to the pseudopolymeric chain of disordered Zn[C(CN)3]2Br22– ions. In C, two salts are semico...

New low-dimensional molecular conductors based on bis(ethylenedithio)tetrathiafulvalene radical cation salts with octahedral metal complex anion [ReIVCl6]2–

Three new radical cation salts of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with the magnetic metal complex anion [ReIVCl6]2–, viz., β-(BEDT-TTF)2[ReCl6] (1), α´-(BEDT TTF)4[ReCl6]•(DCE)2 (2), and δ-(BEDT-TTF)4[ReCl6]1.33•(CB)0.67 (3) (DCE is dichloroethane, CB is chlorobenzene), were synthesized for the first time. The X-ray diffraction analyses of the obtained crystals at room and low temperatures showed that all of them had the sandwich structure characteristic of alternating anionic and cationic layers, which is characteristic of conducting radical cation salts. The structural phase transition accompanied by unit cell tripling and decreasing the symmetry from monoclinic to triclinic in the low-temperature phase occurs in the crystals of salt 2. The transition is related to modulated displacements of both [ReIVCl6]2– anions and BEDT-TTF radical cations. A specific feature of the crystals of salt 3 is a strong positional disorder in the anionic layer, which is expressed as a random distribution of [ReIVCl6]2– anions and CB solvent molecules in a ratio of 2 : 1 along the channels in the ordered cationic framework.

A Biradical Balancing Act: Redox Amphoterism in a Diindenoanthracene Derivative Results from Quinoidal Acceptor and Aromatic Donor Motifs.

The reduced and oxidized states of an open-shell diindeno[b,i]anthracene (DIAn) derivative have been investigated by experimental and theoretical techniques. As a result of moderate biradical character and the ability of cyclopenta-fused scaffolds to stabilize both positive and negative charges, DIAn exhibits rich redox chemistry with four observable and isolable charged states. Structural and electronic properties of the DIAn system are brought to light by UV-vis-NIR and Raman spectroelectrochemical measurements. Aromatization of the diindeno-fused anthracene core upon successive single-electron injections is revealed through single-crystal X-ray diffraction of radical anion and dianion salts. We present a rare case where the pseudoaromatic/quinoidal ground state of a neutral biradical polycyclic hydrocarbon leads to a stable cascade of five redox states. Our detailed investigation of the transformation of molecular structure along all four redox events provides a clearer understanding of the nature of charge carriers in ambipolar organic field-effect transistors.

Exchange interaction between TCNQ and transition metal ion mediated by hydrogen bonds in [Mn(phen)3](TCNQ)2·H2O and [Co(phen)3](TCNQ)2·H2O

The magnetic properties, specific heat and EPR spectra of anion-radical salts [Mn(phen)3](TCNQ)2·H2O and [Co(phen)3](TCNQ)2·H2O, in which TCNQ molecules and transition metal ions are not connected by covalent bonds and magnetic interactions are mediated via hydrogen bonds, were investigated. Measurements of the magnetic response were performed down to 1.8K in magnetic fields up to 7T. The heat capacity of investigated compounds was measured in temperature range from 0.38K to 35K in magnetic fields up to 9T for [Mn(phen)3](TCNQ)2·H2O and up to 3T for [Co(phen)3](TCNQ)2·H2O. The EPR spectra of studied samples were investigated for both samples in the temperature range from 2K to 300K. Theoretical model of weakly-coupled magnetic units composed of four TCNQ anion radicals and of two transition metal ions was proposed for interpretation of obtained data. The energy of exchange interactions between TCNQ molecules and transition metal ion is important for the description of low-temperature behavior of studied anion-radical salts and was estimated to be in the range of 1.3–1.5K.

High Capacity Catholytes for All-Organic Non-Aqueous Redox Flow Batteries

Only about 3% of the electrical energy consumed today is supplied by intermittent energy sources such as solar and wind power. To decrease our reliance on CO2-producing fossil fuels, which currently supply almost 70% of electricity, it is necessary to smooth out the intermittency of renewable energy production. The development of low-cost electrical energy storage (EES) systems could lead to significant integration with the electrical grid. Redox flow batteries (RFBs) are of great interest as a low-cost solution, and systems as large as 20 MWh (check value) have been employed for commercial applications. The commercialization of vanadium-based RFBs has been enabled by the combination of low cost, long lifetime, and high efficiency, and stands out due to the unique ability to scale storage capacity independently of the reactor area. Despite their advantages, current RFBs are limited in charging voltage to ca. 1.5 V due to the electrochemical instability of water above this potential. The replacement of the acidic, aqueous electrolytes with aprotic organic equivalents could allow for higher charging voltages – up to 4-5 V, depending on the identity of the electrolyte solvent.1 Compared to aqueous RFBs, non-aqueous RFBs are still in their infancy due to limited stability and/or solubility of electro-active materials, membrane crossover, and the cost of materials. Recently the performance of organic compounds has been tested in flow systems or stationary mimics. More recently, reports of non-aqueous RFBs containing organic electro-active materials have surfaced. N-oxidanyl amines (e.g. TEMPO), dialkoxybenzenes, and phenothiazines serve as electron-donating electro-active materials, while phthalimide, anthroquinones, quinoxilanes, fluorenone, and viologen act as electron-accepting counterparts. Many of the electron donors have been used as electron-transfer catalysts in other energy storage and collection applications, including redox shuttles for overcharge protection of lithium-ion batteries (LIBs), electron-transfer agents in lithium-air batteries, and redox mediators in dye-sensitized solar cells, among others. Our recent work in protecting LIBs from overcharge has led to the development of several phenothiazine derivatives that exhibit high stability in the neutral and singly oxidized (radical cation) forms,2-6 and some examples exhibit high solubility in organic electrolytes – the combination of which inspired us to evaluate these materials as electron-donating electro-active materials for non-aqueous RFBs.7 Here we will share our recent results in the evaluation of highly soluble phenothiazine derivatives using a variety of electrochemical techniques and – in some cases – in flow batteries. Two highly soluble (miscible) derivatives – one of which is a liquid at room temperature – can be prepared in large scales in one step from commercially available phenothiazine. The persistency of the singly oxidized state has enabled us to synthesize and isolate radical cation salts, which can be used in symmetric flow tests. Additionally, we have found that appropriate identity and positioning of substituents around the periphery of the phenothiazine ring has led to a reversible second oxidation event as measured by cyclic voltammetry. Cycling tests reveal that the dication of these molecules is more stable than versions that do not contain substituents and give an atom economy as low as 150 g/mol e-.

포도주 부산물의 총 플라보노이드와 총 페놀 함량 및 항산화 효과

포도주 가공 중에 발생하는 포도주 부산물의 항산화 활성 검토를 위해 포도주 부산물을 유기용매로 추출 및 분획하여 총 플라보노이드 및 총 페놀 함량을 측정하고 포도주 부산물의 항산화 효과를 분석하였다. 포도주 부산물의 분획 및 추출물의 총 플라보노이드의 양을 측정한 결과 MeOH 추출물은 A+M 추출물보다 높은 함량의 총 플라보노이드를 함유하는 것으로 나타났고 분획물들 중에서는 85% aq. MeOH 분획물이 105.1±0.93 mg/g으로 가장 높았으며 총 페놀 함량은 MeOH 추출물과 n-BuOH 분획물에서 높은 함량을 나타내었다. DPPH를 통한 라디칼 소거활성능을 측정한 결과, 0.5 mg/ml 첨가농도에서 MeOH 추출물은 74%의 소거율을 나타내었으며 분획물들 중에서는 n-BuOH 분획물이 72%의 소거활성을 나타내었다. 또한 ABTS+를 통한 라디칼 소거활성능을 측정한 결과, 0.5 mg/ml 첨가농도에서 85% aq. MeOH 및 n-BuOH 분획물들은 각각 90% 및 92% 소거활성을 나타내어 동일한 BHT 농도에서 92%인 것과 비교해 보았을 경우 합성항산화제만큼 높은 항산화능을 나타내었다. 세포내 활성 산소종 소거 효과를 나타내는 ROS 실험을 통해 0.1 mg/ml 첨가농도에서 MeOH 추출물과 n-BuOH 분획물은 각각 64%와 60%의 소거 활성을 나타었다. 이상의 결과를 종합해 보면 포도 및 포도씨와 비교했을 때 포도주 부산물의 경우 총 플라보노이드 및 총 페놀 함유량은 다소 낮았지만 항산화 효과도 지속되는 것으로 여겨지므로 향후 포도주 부산물의 응용이 기대되어진다. We investigated the flavonoid and phenol contents and antioxidant effect of wine by-product extract. Antioxidant effects were measured with 1,1-diphenyl-2-picryhydrazyl (DPPH) and 2.2'-azino-bis(3-ethylbenothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS+) assays. Cellular reactive oxygen species (ROS) were measured with the dichlorofluorescein-diacetate (DCFH-DA) assay. The flavonoid and phenol contents of the methanol (MeOH) extract were greater than those of the acetone+methylene chloride (A+M) extract. Among fractions, the 85% aqueous methanol (85% aq. MeOH) fraction contained the highest flavonoid contents, while the n-BuOH fraction had more phenol contents. In the DPPH and ABTS assays, the MeOH extract showed a scavenging effect greater than that of the A+M extract (p<0.05). The n-BuOH fraction (0.5 mg/ml concentrations) showed scavenging effects of 72% and 92%, respectively, in the DPPH and ABTS assays (p<0.05). However, the 85% aq. MeOH fraction showed a 90% scavenging effect in the DPPH assay only. In 120 min ROS production assay, all tested fractions dose-dependently decreased cellular ROS production induced by H₂O₂ in comparison with that produced by exposure to the extract-free control. The MeOH extract showed a higher sinhibitory effect on cellular ROS producing than that of the A+M extract at all concentrations tested. Treatment with the n-BuOH fraction (0.1 mg/ml concentrations) inhibited cellular ROS production by 60%. These results indicate that the n-BuOH fraction of wine by-product extract inhibited cellular oxidation and may contain valuable bioactive compounds such as flavonoids and phenols.

The Conducting Spin-Crossover Compound Combining Fe(II) Cation Complex with TCNQ in a Fractional Reduction State.

The radical anion salt [Fe{HC(pz)3}2](TCNQ)3 demonstrates conductivity and spin-crossover (SCO) transition associated with Fe(II) complex cation subsystem. It was synthesized and structurally characterized at temperatures 100, 300, 400, and 450 K. The compound demonstrates unusual for 7,7,8,8,-tetracyanoquinodimethane (TCNQ)-based salts quasi-two-dimensional conductivity. Pronounced changes of the in-plane direct-current resistivity and intensity of the electron paramagnetic resonance (EPR) signal, originated from TCNQ subsystem, precede the SCO transition at the midpoint T* = 445 K. The boltzmannian growth of the total magnetic response and structural changes in the vicinity of T* uniquely show that half [Fe{HC(pz)3}2] cations exist in high-spin state. Robust broadening of the EPR signal triggered by the SCO transition is interpreted in terms of cross relaxation between the TCNQ and Fe(II) spin subsystems.

Spin Frustration in an Organic Radical Ion Salt Based on a Kagome-Coupled Chain Structure.

Electro-oxidation of the quinoidal bisdithiazole BT in dichloroethane in the presence of [Bu4N][GaBr4] affords the 1:1 radical ion salt [BT][GaBr4], crystals of which belong to the trigonal space group P3. The packing pattern of the radical cations provides a rare example of an organic kagome basket structure, with S = 1/2 radical ion chains located at the triangular corners of a trihexagonal lattice. Magnetic measurements over a wide temperature range from 30 mK to 300 K suggest strongly frustrated AFM interactions on the scale of J/kb ∼ 30 K, but reveal no anomalies that would be associated with magnetic order. These observations are discussed in terms of the symmetry allowed magnetic interactions within and between the frustrated layers.

Facile synthesis of an isolable and ambient stable bay-substituted perylene diimide radical anion salt and its optical response to base–acid and metal ions

An isolable and ambient stable bay-substituted perylene diimide adical anion salt was straightforwardly synthesized by base catalysis reduction of N,N-diethylhexyl-1,7-di(pentafluoro-phenoxyl) perylene diimide (DFPDI) in polar solvents, such as acetone, DMF, DMSO, NMP in yields of 48.7 %. Elemental analysis and 1H NMR, 13C NMR and EPR were carried out to confirm the formation of the compounds. Solvent-dependent cyclic voltammetries revealed the only condition for generating DFPDI radical anion in polar solvents—the reduction potential (DFPDI/DFPDI−) is more positive than −0.36 V (vs. Ag/AgCl). Redox studies revealed that DFPDI radical anion was not only ambient stable to moderate oxidants air (O2) and moisture for prolonged existence but also sensitive to strong oxidants-acid H+ and strong oxidization metal ions with low limit value.

DBTTF derivative with bis(propylenedioxy) (BPDO) groups: Synthesis, electrochemical properties, conductivity, and crystal and band structures of salts

A new bis(propylenedioxy)-dibenzotetrathiafulvalene (BPDO-DBTTF) with expanded functional propylenedioxy (PDO) groups was synthesized as an electron donor and its redox potentials were investigated by cyclic voltammetry. The electronic state of the charge-transfer (CT) complexes was characterized by the difference of the first potentials of donor and acceptor (ΔE(DA)), UV-vis-NIR, and IR spectra. BPDO-DBTTF CT complexes have mixed-valence state in the 3:2 Me2TCNQ and the 4:3 MeTCNQ complexes with high σRT values of 2.0 and 0.53Scm−1, respectively. X-ray crystal structures of the semiconductive Au(CN)4, GaCl4·PhCN, and SbF6·TCE radical salts were determined to have columnar structures with D:A=3:1 compositions and many intermolecular short contacts. The introduction of PDO groups produced many intermolecular intrastack CH⋯O short contacts; however, these existed within a triad in the 3:1 salts. Overlap between a triad and a neighboring triad was largely shifted. The band structure for the SbF6·TCE salt with σRT value of 0.13Scm−1 was calculated by the extended Hückel method, which provided a two-dimensional electronic structure.

Charge Carrier Doping into the Peierls Insulator of the TCNQ Anion Radical Salt (TCNQ = 7,7,8,8-Tetracyanoquinodimethane)

Hole-doping into K–TCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane) crystals with segregated TCNQ anion radical columns with dimeric deformation (Peierls state) has been performed by a contact doping method using F4TCNQ (F4TCNQ = 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) crystals or powder. The sheet resistance of the K–TCNQ surface has been found to decrease by the F4TCNQ contact. Formation of K–F4TCNQ nanocrystals at the contact interface has been observed, but conductive AFM images indicate that current paths form along the hole-doped K–TCNQ surface. Interestingly, hole-doping into K–TCNQ suppresses the phase transition to the high-temperature phase (Mott insulator). This is considered to result from the energy gain by the delocalization of the doped carriers.

Facile synthesis of graphene oxide sheet-immobilized perylene diimide radical anion salt and its optical response to different solvents and pH values

Graphene oxide/reduced perylene diimide radical anion hybrid (GO/rSFPDI) with high dispersibility in polar organic solvents has been flexibly developed using N,N′-diethylhexyl-1-bromo-7-pentafluorophenox-perylene diimide (SFPDI). The interaction of the GO with the SFPDI suggested the catalysis of perylene diimide (SFPDI) to reduced perylene diimide radical anion (rSFPDI). The successful preparation of GO/rSFPDI was confirmed via FT-IR, Raman, UV–Vis absorption spectrum, XRD, and SEM. Compared to the two neutral SFPDI and GO, GO/rSFPDI exhibited a novel lower energy electronic transition (max. at 700 nm) in addition to the solvatochromism and characteristics of spectral response to pH. Moreover, the fluorescence emission spectrum of GO/rSFPDI shows strong fluorescence quenching in dilute solution.

Anti-oxidant activities of mung bean starch and starch gels prepared from whole and hulled seeds.

Anti-oxidant activities of ethanol extracts from whole and hulled mung bean starches (WMS and HMS) isolated using distilled water, and gels (WMSG and HMSG) were investigated. Total chlorophyll contents of WMS and WMSG were 4.61 and 2.14 μg/mL, respectively. WMS at 0.29 mg of gallic acid/g of MS and 0.54 mg of quercetin/g of MS had higher total phenolic compounds and flavonoid contents than HMS at 0.11 mg of gallic acid/g of MS and 0.28 mg of quercetin/g of MS. Total phenolic contents of WMSG and HMSG increased by 2.14x and 1.64x, respectively. Total flavonoid contents decreased by 0.98x and 0.57x. The 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis(3-ethyl-benzothiazoline-6-sulfonic acid) diammonium salt radical scavenging activities and reducing powers of WMS and WMSG were higher than for HMS and HMSG. Cheongpomuk made using WMS exhibits increased anti-oxidant activities of gels and is a good food for improvement in health functionality.

In vitro antioxidant activity on roots of Limnophila heterophylla

Objective: The present study was investigating the antioxidant activity of methanol extract of roots of Limnophila heterophylla (Plantaginaceae). Methods: Roots of methanol extract of Limnophila heterophylla were tested for in vitro free radical scavenging assays, such as hydroxyl radical, antioxidant assay by thiocyanate method, inhibition of superoxide anion radical, 2, 2-diphenyl-1-picryl hydrazyl radical (DPPH), lipid peroxidation as- say, scavenging of 2, 2'- azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt radical cation assay (ABTS), total antioxidant activity (phosphomolybdic acid method) and reducing ability. Results: Limnophila heterophylla roots extract effectively scavenged free radicals at all different concentrations and showed its potent antioxidant activity. Further, these effects were in a dose dependent manner. Results were compared to standard antioxidants such as vitamin E, α-tocopherol, curcumin, querce- tin, rutin, butylated hydroxytoluene (BHT), and ascorbic acid. Conclusion: Limnophila heterophylla enclose strong antioxidant potential. Further the study validates the therapeutic benefits of the Indian system of medicine.

Analysis and characterization of anthocyanins and carotenoids in Japanese blue tomato.

Tomato (Solanum lycopersicum) is rich in anthocyanins, which are polyphenolic pigments. This study aimed to analyze and characterize the anthocyanin composition in cultivated blue tomato in Japan. The extracts of peel, seed, and pulp of tomatoes were purified following which anthocyanins and lycopene contents were analyzed using high-performance liquid chromatography and electrospray ionization mass spectrometry. Eleven types of anthocyanins were identified, including delphinidin, petunidin, and malvidin. Further, the antioxidant activity of anthocyanins was evaluated using 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt radical quenching assays and electron spin resonance. "Blue tomato" extracts exert antioxidant activity. Thus, we showed that petunidin was present in the "blue tomato" peel while lycopene was present in the peel and pulp. Additionally, the blue tomato peel extract was found to significantly inhibit H2O2-induced cell death in vitro. This is the first study on cell protective effects of Japanese blue tomato extract and petunidin in murine photoreceptor cells.

Comparative Phytochemical Analyses and in-vitro Antioxidant Activity of Aqueous and Ethanol Extracts of Simarouba glauca (Paradise Tree)

Aims: The study was conducted to evaluate the phytochemical and antioxidant potentials of ethanol and aqueous leaf extracts of Simarouba glauca vis-a-vis standard antioxidants. Study Design: True experimental study. Place and Duration of Study: Department of Biochemistry, University of Benin, Benin City. Nigeria, between August and October 2015. Methodology: Samples were harvested, air dried, pulverized and extracted with aqueous and absolute ethanol; freeze dried at the National energy commission centre, University of Benin. Total phenol content was determined by Folin-ciocalteau method, tannin determined according to Folin and Denis methods while flavonoids content was determined according to the methods described by Ebrahimzadeh et al. DPPH radical scavenging activity was conducted based on the ability of 1,1-diphenyl-2-picrylhydrazyl (DPPH), a stable free radical, to decolorize in the presence of antioxidants. Reducing power activity of extracts was conducted based on test samples extract’ Original Research Article Osagie-Eweka et al.; EJMP, 13(3): 1-11, 2016; Article no.EJMP.24736 2 ability to reduce ferricyanide to ferrocyanide indicated in the colour change. Total antioxidant activity of ethanol and aqueous leaf extracts was determined based on the ability of the sample to reduce the ferric-tripyridyltriazine (Fe (III)-TPTZ) complex to ferrous tripyridyltriazine (Fe(II)-TPTZ) at low pH. Hydroxyl radical activity of extracts was conducted on the principle based on the ability of test samples to reduce H2O2 in the presence of 1,10-phenanthroline. Trolox equivalent antioxidant activity of extracts was conducted based on the ability of test sample to scavenge 2,2’azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical generated based on the principle of decolourization. Nitric oxide (NO.) radical scavenging activity of S, glauca leaf extracts was estimated based on the ability of test samples to scavenge radicals generated by the reaction of naphthylethylenediamine dihydrochloride. Butylated hydroxytuolene (BHT), Ascorbate, Quercetin and Trolox were standard antioxidant. Results: DPPH radical scavenging activity yielded aqueous and ethanol extracts IC50 values of 3.2144 and 4.9100 μg/ml respectively. Reducing power activity yielded (aqueous and ethanol extracts) EC50 of values 60.3233 and 60.1000 μg/ml respectively. Total antioxidant activity yielded (ethanol and aqueous extracts) IC50 values of 52.4320 and 68.8201 μg/ml respectively. Hydroxyl radical activity yielded (ethanol and aqueous extracts) IC50 values of 49.3130 and 50.2341 μg/ml respectively. Trolox equivalent antioxidant activity yielded (ethanol and aqueous extracts) IC50 values of 45.2015 and 52.0721 μg/ml respectively. Nitric oxide scavenging activity yielded aqueous IC50 value of 14.2102 μg/ml but ethanol extract yielded no inhibition concentration at 50 percent. Conclusion: The study showed that aqueous and ethanol leaf extracts of S. glauca demonstrated substantial amount of biochemically valuable phytochemicals and antioxidant potential capable of scavenging reactive oxygen species.

Ambient-Pressure Organic Superconductor κ-(ET)2Ag(CN)[N(CN)2] Formed with Polymeric Silver(I) Complex Anion

We obtained a new cation radical salt of bis(ethylenedithio)tetrathiafulvalene (ET) with a κ-type packing motif, κ-(ET)2Ag(CN)[N(CN)2], by electrooxidation. In the salt, each ET layer is separated by polymeric {Ag(CN)[N(CN)2]−}∞ layers, which are composed of Ag(I) ions trigonally coordinated to form an infinite zigzag chain of –NC–Ag–NC–Ag– with pendant dicyanamides. The salt undergoes a superconducting transition with a midpoint critical temperature (Tc) of 6.6 K and an onset Tc of 7.2 K, thereby indicating the highest Tc among ET superconductors formed with a polymeric Ag(I) complex anion.

Interaction of Azobenzene and Benzalaniline with Strong Amido Bases.

The interaction of azobenzene with lithium dicyclohexylamide (Cy2NLi) in THF or Et2O afforded the ion-radical salt of azobenzene (1) structurally characterized for the first time and dicyclohexylaminyl radical, which begins a novel chain of transformations leading eventually to the imino-enamido lithium complex (3). Benzalaniline, being a relative of azobenzene, reacted with Cy2NLi without electron transfer by a proton-abstraction mechanism to form the dilithium salt of N(1),N(2),1,2-tetraphenylethene-1,2-diamine quantitatively.