Tetramethyl-p-phenylenediamine Research Articles

Quantitative vapour concentration measurements in n-dodecane and n-hexadecane sprays

Quantitative vapour concentration measurements in evaporating sprays of n-dodecane and n-hexadecane at high pressure and temperature are presented in this paper. These two liquids have been selected as they represent realistic fuels such as diesel and biodiesel, and exhibit significantly different boiling points. The objective of this study is to understand the effect of boiling point on vapour distribution in evaporating sprays. The experiments are performed in a high pressure spray chamber with optical access filled with nitrogen and heated to reach a pressure of 50-bar and temperature of 900 K. Two injection pressures of 1000 and 1500-bar are considered. Planar laser induced fluorescence (PLIF) of an exciplex tracer system consisting of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) and α-methyl naphthalene has been used for vapour concentration measurements. A calibration point relating the TMPD concentration and PLIF signal is obtained by using a fuel vapour jet at a known temperature. Various corrections to the PLIF signal are performed. The vapour mixture fraction (or vapour mass fraction) obtained from the experimental data is compared for the two liquids. It is observed that the mixture fractions for both liquids are very close to each other. An analytical model is used to explain this trend by estimating the variation of mixture fraction along centerline for the two liquids. The model shows the predominance of the density ratio, which is similar for both liquids leading to similarity in the experimental data of mixture fraction. Also, the measurements provide a comprehensive dataset for assessment of CFD simulations of single component evaporating sprays in terms of predicting vapour-air mixing.

Characterization of Respiration in Paraburkholderia tropica Ppe8T under Static Culture Conditions

Objective: To investigate the respiratory chain of Paraburkholderia tropica under limited oxygen conditions would allow us to better understand their functions in plant tissue. Methods: We first optimized the medium for P. tropica biomass production in static culture. Oxidase and Oxidoreductase activities were determined in absence and presence de inhibitors. Spectroscopic analysis of cytochromes was obtained at room and liquid nitrogen temperature. Findings: Isolated membranes showed respiratory oxidase activities with succinate, glucose, NADH and ascorbate-N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD). Succinate and glucose respiration were inhibited by 2-heptyl-4-hydroxyquinoline-N-oxide, antimycin A and myxothiazol, suggesting the presence of a bc1 complex.KCN inhibition curves in the presence of ascorbate-TMPD, succinate or glucose were biphasic, with KCN-sensitive and -resistant oxidases. Spectral analysis with physiological or artificial substrates revealed the presence of only cytochromes b and c, with remarkable cytochrome reduction by ascorbate alone. The CO difference and photodissociation spectra of glucosereduced membranes revealed one component with the spectral features of a cytochrome o´-like CO complex. Air-oxidation spectra of the cytochromes with KCN showed that cytochrome c is an obligate participant in the KCN-sensitive pathway and revealed the presence of a cyanide-resistant oxidase cytochrome bo. Novelty: The characterization of the electron transport system of P. tropica allowed us to propose the following components: 1. Dehydrogenases for succinate, glucose and NADH, 2. A ubiquinone, 3. A bc complex and 4. Two oxidases, cbb-type cytochrome c oxidase and bo-type quinol oxidase. Keywords: bc1 complex, cbb oxidase, Cytochromes, Paraburkholderia tropica, Quinol Oxidase, Respiration

Effect of artificial redox mediators on the photoinduced oxygen reduction by photosystem I complexes.

The peculiarities of interaction of cyanobacterial photosystem I with redox mediators 2,6-dichlorophenolindophenol (DCPIP) and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) were investigated. The higher donor efficiency of the reduced DCPIP form was demonstrated. The oxidized form of DCPIP was shown to be an efficient electron acceptor for terminal iron-sulfur cluster of photosystem I. Likewise methyl viologen, after one-electron reduction, DCPIP transfers an electron to the molecular oxygen. These results were discussed in terms of influence of these interactions on photosystem I reactions with themolecular oxygen and natural electron acceptors.

Estrogen and mitochondrial function in cerebral arteries and endothelium in rats and mice

Estrogen has numerous direct and indirect effects on mitochondrial and cerebral vascular function but the mechanisms are not fully understood. We and others have found enhanced mitochondrial respiration in female compared with male rats and mice, and in young rats exposed to ovariectomy (OVX) prior to sexual maturity followed by 3 wk of estradiol/placebo treatment. However, the effects of delayed hormone replacement therapy after OVX are unclear in more mature rats. The aims of this study were 1) to determine the effects of estrogen on mitochondrial functioning of Sprague Dawley rats undergoing OVX after reaching sexual maturity (6 wk), then exposed to a delayed treatment administered between weeks 11 and 14 of 0.5 mg of 17 β‐estradiol (E) or placebo (P); 2) to determine the activity of citrate synthase, a key mitochondrial protein involved in ATP production, of isolated cerebral arteries of male and female C57BL/6J mice; and 3) to elucidate the mechanisms of estrogen on isolated primary mouse brain microvascular endothelial cells (MBMEC). There were no differences in body weights of 6 wk old rats immediately after OVX (P: 167.3 ± 3 g; E: 163.2 ± 3.4 g), whereas estrogen treatment resulted in a significantly lower body weights by the end of 14 wk in E (287.5 ± 6.4 g) compared with the P treated group (347.2 ± 8.3 g). There was significantly greater uterus weight/tibia length ratio in E group (0.119 ± 0.011) compared with P (0.025 ± 0.002). Basal respiration and proton leak measured with the Seahorse Bioscience Analyzer were significantly increased in E compared with P group (E: 341 ± 45.52; P: 154 ± 52; E: 250.9 ± 36.9; and P: 101.7 ± 42.2, respectively, pmol/min/mg protein), as well as the respiratory control ratio in the presence of 0.5 mM N,N,N′,N′‐tetramethyl‐p‐phenylenediamine (TMPD) + 2mM ascorbate + 1 mM ADP. In addition, we found a greater citrate synthase activity in arteries isolated from female mice (1.7e‐004 ± 4.7e‐005) compared with males (8e‐005 ± 2.5e‐005). Estradiol treatment (100 nM) resulted in an increase in the extracellular acidification rate (ECAR) vs. oxygen consumption rate (OCR) values (70.3 ± 16.7 and 157 ± 46.6) of isolated MBMEC, indicative of the energy phenotype for these cells, compared with vehicle treatment (11.4 ± 5.5 and 132.4 ± 22.7), which was further increased in the presence of TMPD + ascorbate + ADP (vehicle: 201.3 ± 55.7 and 383.8 ± 77; estradiol: 216.5 ± 47 and 517.1 ± 85.3). Our results indicate that estrogen enhances mitochondrial respiration upon a delayed administration protocol in rats, increases citrate synthase activity in female mice, and energizes MBMEC under baseline conditions and in the presence of the electron donor TMPD. Thus, promotes enhanced mitochondrial function in cerebral vascular cells of mice and rats.Support or Funding InformationThis work was supported by National Institutes of Health grants [HL‐077731; HL093554 (DWB), and NS094834 (PVK)], Louisiana Board of Regents Endowed Chairs for Eminent Scholars program (DWB), American Heart Association grants [15POST23040005; 17SDG33410366 (IR), and 14SDG20490359 (PVK)].This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Plasma 2-hydroxyglutarate, a promising prognostic biomarker candidate for skeletal muscle injury in Fischer 344 rats.

Previously, we have demonstrated the potential of plasma 2-hydroxyglutarate (2HG) as an easily detectable biomarker for skeletal muscle injury in rats. Here, we examined whether plasma 2HG was superior to conventional skeletal muscle damage biomarkers, including aspartate aminotransferase (AST), creatine kinase (CK), and skeletal muscle-type CK isoenzyme (CK-MM) levels, in rats. Skeletal muscle injury was induced in 4- or 9-week-old male Fischer 344 rats by cerivastatin (CER) or tetramethyl-p-phenylenediamine (TMPD) administration. Plasma 2HG levels were measured on days 4, 8, and 11 (CER group) and at 6 and 24 hr post-administration (TMPD group). Plasma AST, CK, and CK-MM activities and histopathological changes in the rectus femoris muscle were evaluated at the study endpoints. In the CER group, AST, CK, and CK-MM increased in 4- and 9-week-old rats, whereas increases in CK (4- and 9-week-old rats) and CK-MM (4-week-old rats) were not obvious in the TMPD group. In both 4- and 9-week-old rats, plasma 2HG increased on day 8 and at 24 hr post-administration in the CER and TMPD groups, respectively. Histopathological analysis revealed myofiber vacuolation and necrosis in both groups. The histopathological damage to the rectus femoris muscle was more severe in the CER than in the TMPD group. Increased plasma 2HG was associated with CER- and TMPD-induced skeletal muscle injuries in rats and was not affected by age differences or repeated blood collection. The results suggest that plasma 2HG is superior to CK and CK-MM as a biomarker for mild skeletal muscle injury.

Effect of iron on the growth of Phaeodactylum tricornutum via photosynthesis.

Iron is a limiting factor that controls the phytoplankton biomass in the modern ocean, and iron fertilization of the ocean could lead to blooms dominated by diatoms. Thus, iron plays an important role in controlling the distribution of diatoms. In this study, we measured the growth rate and photosynthetic activity of the model diatom Phaeodactylum tricornutum cultured under different iron concentrations and found that it grew more rapidly and had a much higher photosynthetic efficiency under higher iron concentrations. In order to explore the unique mechanism of the response of diatoms to iron, a proteomic analysis was carried out, and the results indicated that iron promotes the Calvin cycle of P.tricornutum. Diatoms can tolerate the pressure of iron limitation by replacing iron-rich proteins with flavodoxin, and so on. Moreover, we found that the photosystem I (PSI) activity of iron-limited algae that were treated by N',N',N',N'-tetramethyl-p-phenylenediamine (TMPD) was increased significantly. As TMPD plays the role of a cytochrome b6 /f complex that transfers electrons from photosystem II to PSI, the cytochrome b6 /f complex is the key to photosynthesis regulation. Iron could influence the growth of P.tricornutum by regulating its biosynthesis. All of the results suggest that iron might affect the growth of diatoms through the Calvin cycle and the cytochrome b6 /f complex.

Triplet-State Dissolved Organic Matter Quantum Yields and Lifetimes from Direct Observation of Aromatic Amine Oxidation.

Excited triplet state chromophoric dissolved organic matter (3CDOM*) is a short-lived mixture of excited-state species that plays important roles in aquatic photochemical processes. Unlike the study of the triplet states of well-defined molecules, which are amenable to transient absorbance spectroscopy, the study of 3CDOM* is hampered by it being a complex mixture and its low average intersystem crossing quantum yield (ΦISC). This study is an alternative approach to investigating 3CDOM* using transient absorption laser spectroscopy. The radical cation of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), formed through oxidation by 3CDOM*, was directly observable by transient absorption spectroscopy and was used to probe basic photophysical properties of 3CDOM*. Quenching and control experiments verified that TMPD•+ was formed from 3CDOM* under anoxic conditions. Model triplet sensitizers with a wide range of excited triplet state reduction potentials and CDOM oxidized TMPD at near diffusion-controlled rates. This gives support to the idea that a large cross-section of 3CDOM* moieties are able to oxidize TMPD and that the complex mixture of 3CDOM* can be simplified to a single signal. Using the TMPD•+ transient, the natural triplet lifetime and ΦISC for different DOM isolates and natural waters were quantified; values ranged from 12 to 26 μs and 4.1-7.8%, respectively.

Graphene oxide electrochemistry: the electrochemistry of graphene oxide modified electrodes reveals coverage dependent beneficial electrocatalysis.

The modification of electrode surfaces is widely implemented in order to try and improve electron transfer kinetics and surface interactions, most recently using graphene related materials. Currently, the use of ‘as is’ graphene oxide (GO) has been largely overlooked, with the vast majority of researchers choosing to reduce GO to graphene or use it as part of a composite electrode. In this paper, ‘as is’ GO is explored and electrochemically characterized using a range of electrochemical redox probes, namely potassium ferrocyanide(II), N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD), dopamine hydrochloride and epinephrine. Furthermore, the electroanalytical efficacy of GO is explored towards the sensing of dopamine hydrochloride and epinephrine via cyclic voltammetry. The electrochemical response of GO is benchmarked against pristine graphene and edge plane-/basal plane pyrolytic graphite (EPPG and BPPG respectively) alternatives, where the GO shows an enhanced electrochemical/electroanalytical response. When using GO as an electrode material, the electrochemical response of the analytes studied herein deviate from that expected and exhibit altered electrochemical responses. The oxygenated species encompassing GO strongly influence and dominate the observed voltammetry, which is crucially coverage dependent. GO electrocatalysis is observed, which is attributed to the presence of beneficial oxygenated species dictating the response in specific cases, demonstrating potential for advantageous electroanalysis to be realized. Note however, that crucial coverage based regions are observed at GO modified electrodes, owing to the synergy of edge plane sites and oxygenated species. We report the true beneficial electrochemistry of GO, which has enormous potential to be beneficially used in various electrochemical applications ‘as is’ rather than be simply used as a precursor to making graphene and is truly a fascinating member of the graphene family.

Gate-open-type Sorption in a Zigzag Paddlewheel Ru Dimer Chain Compound with a Phenylenediamine Linker Instructed by a Preliminary Structural Change of Desolvation

Two zigzag-type paddlewheel Ru dimer chains with N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPDA) were synthesized in a solvated form (1-DCE; DCE: dichloroethane) and a non-solvated form (2), according to the Ru dimer used. Compound 1-DCE underwent crystal-to-crystal transition to its solvent-free species (1), with a characteristic structural change with respect to the contraction/expansion of solvent-accessible space. Following this transition, only 1 exhibited gate-open-type gas sorption behavior for N2, O2, NO, and CO2. The structures of the 1⊃Gas were determined by the Rietveld method based on their powder X-ray diffraction patterns under gas atmospheres.

A comparative study of corrosion inhibition of steel and stainless steel in hydrochloric acid by N,N,N′,N′-tetramethyl-p-phenylenediamine

The corrosion of mild steel (MS) and AISI type 321 stainless steel (AISI 321) in 1 M HCl solution and the inhibitive mechanism of N,N,N′,N′-Tetramethyl-p-phenylenediamine (TMPPD) were investigated using open circuit potential measurements (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Potential-time measurements showed that the addition of TMPPD to HCl solutions shifts the potential of MS and AISI 321 to more positive values. Polarization curves measurements indicated that TMPPD act as a mixed type inhibitor for the corrosion of MS and AISI 321 in HCl solutions. EIS measurements showed that the dissolution process occurs under activation control. The applied techniques explained that TMPPD is more efficient as a corrosion inhibitor for mild steel than stainless steel in acidic solutions. Theoretical fitting of different isotherms, Langmuir, Kinetic-thermodynamic, Flory–Huggins, and Temkin isotherms were tested to explain the nature of TMPPD adsorption. The associated activation parameters were also calculated and discussed.

Conductivity Modifications of Graphene by Electron Donative Organic Molecules

Graphene has been studied for the application of transparent electrodes in flexible electrical devices with semiconductor organics. Control of the charge carrier density in graphene is crucial to reduce the contact resistance between graphene and the active layer of organic semiconductor. Chemical doping of graphene is an approach to change the carrier density, where the adsorbed organic molecules donate or accept electrons form graphene. While various acceptor organic molecules have been demonstrated so far, investigation about donor molecules is still poor. In this work, we have investigated doping effect in graphene field-effect transistors functionalized by organic donor molecules such as dibenzotetrathiafulvalene (DBTTF), hexamethyltetrathiafulvalene (HMTTF), 1,5-diaminonaphthalene (DAN), and N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD). Based on conductivity measurements of graphene transistors, the former three molecules do not have any significant effect to graphene transistors. However, TMPD shows effective n-type doping. The doping effect has a correlation with the level of highest occupied molecular orbital (HOMO) of each molecule, where TMPD has the highest HOMO level.

A comparative study on the solubility and stability of p -phenylenediamine-based organic redox couples for non-aqueous flow batteries

Abstract A methyl-substituted p-phenylenediamine (PD), N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD), is examined as a positive redox couple with high energy density for non-aqueous Li-flow batteries. Methyl substitution affects the solubility of the redox couple, as the solubility is increased by a factor of ten, to a maximum solubility of 5.0 M in 1.0 M lithium tetrafluoroborate-propylene carbonate supporting electrolyte due to elimination of the hydrogen bonding between the solute molecules. The methyl substitution also enhances the chemical stability of the cation radical and di-cation being generated from PD, as the redox center is shielded by the methyl groups. Furthermore, this organic redox couple demonstrate two-electron redox reactions at 3.2 and 3.8 V (vs. Li/Li+); therefore, the volumetric capacity is twice higher compared to conventional one-electron involved redox couples. In a non-flowing Li/TMPD coin-cell, this organic redox couple demonstrates very stable cycleability as a positive redox couple for non-aqueous flow batteries.

Electron-transfer reactions of halogenated electrophiles: a different look into the nature of halogen bonding.

The rates of oxidation of ferrocene derivatives by brominated molecules R-Br (CBr3CN, CBr4, CBr3NO2, CBr3COCBr3, CBr3CONH2, CBr3F, and CBr3H) were consistent with the predictions of the outer-sphere dissociative electron-transfer theory. The similar redox-reactions of the R-Br electrophiles with the typical halogen-bond acceptors tetramethyl-p-phenylenediamine (TMPD) or iodide were much faster than calculated using the same model. The fast redox-processes in these systems were related to the involvement of the transient halogen-bonded [R-Br, TMPD] or [R-Br, I-] complexes in which barriers for electron transfer were lowered by the strong electronic coupling of reactants. The Mulliken-Hush treatment of the spectral and structural characteristics of the [R-Br, TMPD] or [R-Br, I-] complexes corroborated the values of coupling elements, Hab, of 0.2-0.5 eV implied by the kinetic data. The Natural Bond Orbital analysis of these complexes indicated a noticeable donor/acceptor charge transfer, Δq, of 0.03-0.09 ē. The Hab and Δq values in the [R-Br, TMPD] and [R-Br, I-] complexes (which are similar to those in the traditional charge-transfer associates) indicate significant contribution of charge-transfer (weakly-covalent) interaction to halogen bonding. The decrease of the barrier for electron transfer between the halogen-bonded reactants demonstrated in the current work points out that halogen bonding should be taken into account in the mechanistic analysis of the reactions of halogenated species.

Plasma 2-hydroxyglutarate and hexanoylcarnitine levels are potential biomarkers for skeletal muscle toxicity in male Fischer 344 rats.

To identify new candidate biomarkers for skeletal muscle toxicity, an unbiased metabolomic analysis was performed in rats treated with two distinct myotoxicants, cerivastatin (CER) and tetramethyl-p-phenylenediamine (TMPD). Skeletal muscle toxicity was induced in male Fischer 344 rats by administering CER or TMPD and monitored using established endpoints, such as increased plasma creatine kinase (CK) activity and histopathology, and a metabolomic analysis of skeletal muscle and plasma samples. Plasma CK levels in CER-treated rats were markedly elevated at Day 11; however, those in TMPD-treated rats showed a statistically significant decrease at 24 hr after dosing. Light microscopy revealed that vacuolated or necrotic fibers were evident in all CER-treated rats on Day 11, and slightly vacuolated fibers were observed in TMPD-treated rats at 6 and 24 hr after dosing. Metabolomic analysis of the rectus femoris indicated increases in 2-hydroxyglutarate (2HG) in CER-treated rats and hexanoylcarnitine in CER- and TMPD-treated rats. There were also increases in plasma 2HG in CER-treated rats on Days 8 and 11 and in TMPD-treated rats at 24 hr after dosing and increases in plasma hexanoylcarnitine in CER-treated rats on Day 11 and in TMPD-treated rats at 6 and 24 hr after dosing. These experiments demonstrated the potential of plasma 2HG and hexanoylcarnitine as specific and easily detectable biomarkers for skeletal muscle toxicity in rats and demonstrated the value of metabolomics for biomarker detection and identification in toxicological studies.

Overlapping Role of Respiratory Supercomplex Factor Rcf2 and Its N-terminal Homolog Rcf3 in Saccharomyces cerevisiae

The mitochondrial electron transport chain consists of individual protein complexes arranged into large macromolecular structures, termed respiratory chain supercomplexes or respirasomes. In the yeast Saccharomyces cerevisiae, respiratory chain supercomplexes form by association of the bc1 complex with the cytochrome c oxidase. Formation and maintenance of these assemblies are promoted by specific respiratory supercomplex factors, the Rcf proteins. For these proteins a regulatory function in bridging the electron transfer within supercomplexes has been proposed. Here we report on the maturation of Rcf2 into an N- and C-terminal peptide. We show that the previously uncharacterized Rcf3 (YBR255c-A) is a homolog of the N-terminal Rcf2 peptide, whereas Rcf1 is homologous to the C-terminal portion. Both Rcf3 and the C-terminal fragment of Rcf2 associate with monomeric cytochrome c oxidase and respiratory chain supercomplexes. A lack of Rcf2 and Rcf3 increases oxygen flux through the respiratory chain by up-regulation of the cytochrome c oxidase activity. A double gene deletion of RCF2 and RCF3 affects cellular survival under non-fermentable growth conditions, suggesting an overlapping role for both proteins in the regulation of the OXPHOS activity. Furthermore, our data suggest an association of all three Rcf proteins with the bc1 complex in the absence of a functional cytochrome c oxidase and identify a supercomplex independent interaction network of the Rcf proteins.

Janus Reversal and Coulomb Blockade in Ferrocene-Perylenebisimide and N,N,N',N'-Tetramethyl-para-phenylenediamine-Perylenebisimide D-σ-A Rectifiers.

Sandwiches "EGaIn|Ga2O3|LB monolayer of 2|Au" and "EGaIn|Ga2O3|LB monolayer of 3|Au" rectify. They are formed from a Langmuir-Blodgett (LB) monolayer of 2 or 3 transferred onto thermally evaporated gold. Molecules 2 and 3 are of the donor-sigma-acceptor (D-σ-A) type and have the same perylenebisimide (PBI) acceptor as previously studied molecule 1. Molecule 1 has the weak donor pyrene, 2 has the good donor ferrocene, and 3 has the very strong donor N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD). All three molecules have a long swallowtail ending in a thioacetyl group, which ensures slow chemisorption onto the Au electrode. These molecules were contacted directly by a gallium indium eutectic (EGaIn) drop, covered by a defective oxide Ga2O3 layer. As before for 1, the direction of rectification for 2 is bias-dependent. In the ±1.0 V range, the rectification is at positive V, with a rectification ratio (RR) that is initially greater than 5 and then decreases on successive scans to 2, while the currents decrease by as much as 2 orders of magnitude. In the ±2.5 V range, the rectification direction for 2 reverses, while upon repeated scanning the rectification ratio (in the negative direction) increases and the currents decrease. For molecule 3, both directions have a charge-trapped state (Coulomb blockade) leading to Voffset in both biases, but at high potentials rectification set is, with large RR (up to 2,800) at ±2.5 V.

Charge transfer adducts of rare earth 3,5-dinitrobenzoates with N,N,N′,N′-tetramethyl-p-phenylenediamine

Crystallization of products of an exchange reaction between LnCl3·6H2O and potassium 3,5-dinitrobenzoate from acetonitrile in the presence of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) and DMSO results in two types of charge transfer adducts: [Ln2(O2CC6H3(NO2)2)6(DMSO)4]·TMPD·2MeCN (type A) and [Ln2(O2CC6H3(NO2)2)6(DMSO)4]·3TMPD (type B). Type A adducts were isolated in pure form for Tb(1), Dy(2a), Ho(3a), Er(4a) and Y(5a), whereas type B adduct was isolated for Er (4b). Crystallization in the absence of TMPD gives coordination polymers, [Ln(O2CC6H3(NO2)2)3(DMSO)2]n (Ln=Tb (8), Dy (9)) and [Ln(O2CC6H3(NO2)2)3(DMSO)]n·nMeCN (Ln=Ho (10), Er (11), Y (12)). In the case of Sm and Gd, the [Ln(O2CC6H3(NO2)2)3(DMSO)2]n coordination polymers (Ln=Sm (6), Gd (7)) are formed even with a large excess of TMPD. In the case of Tb, the [Tb(O2CC6H3(NO2)2)3(DMSO)(H2O)]n·0.5nTMPD·1.5nDMSO·0.5nCH3CN polymer (13) was isolated in a small yield in the presence of excess TMPD. Due to charge transfer between TMPD molecules and [Ln2(O2CC6H3(NO2)2)6(DMSO)4] fragments, stacking interactions occur that determine the supramolecular structures of the compounds. Spectral studies of these compounds indicate that a charge transfer structure predominates over an ion radical structure; however, according to EPR studies, the charge transfer moieties in the compounds are significantly paramagnetic. The magnetic properties of 1, 2a, 3a and 4b complexes correspond to predominance of antiferromagnetic interactions in all cases. Complex 2a manifests SMM properties.

Interplay of Halogen and π-π Charge-Transfer Bondings in Intermolecular Associates of Bromo- or Iododinitrobenzene with Tetramethyl-p-phenylenediamine.

Two modes of intermolecular interactions (halogen and π-π charge-transfer bonding) between bromo- or iododinitrobenzene (XDNB) and tetramethyl-p-phenylenediamine (TMPD) are compared. X-ray crystallography revealed that TMPD·XDNB cocrystals comprise alternating donors/acceptors stacks formed by π-bonded (cofacial) TMPD and XDNB molecules. These structures also show two-point (C-X···O-N) halogen bonding between XDNB molecules resulting in formation of (XDNB)2 dimers. In solutions, XDNB and TMPD molecules formed 1:1 complexes showing strong absorption bands near 550 nm which followed the same Mulliken correlation as the associates of TMPD with the (halogen-free) nitro- and cyanobenzenes. In accord with the experimental data, density functional theory calculations with the M062X functional showed that TMPD·XDNB associates formed via π-π charge-transfer bonding are more stable (by 6-12 kcal/mol) than their halogen-bonded analogues. If XDNB is replaced with iodo- or bromoperfluorinated benzenes, or TMPD is replaced with pyridine, the energy gap between the π-π and halogen-bonded associates decreased. The analysis of the molecular-orbital interactions and surface electrostatic potentials of the interacting species indicated that charge-transfer contributions represent a critical component which determines variations of the strength of halogen bonding in these systems.

An all-organic solid-state electrochromic device containing poly(vinylidene fluoride-co-hexafluoropropylene), succinonitrile, and ionic liquid

A high contrast, self-standing, and thermoplastic solid polymer electrolyte (PE) with electrochromic property is fabricated by utilizing N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD), heptyl viologen (HV(BF4)2), succinonitrile (SN), and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP). Various amounts of the ionic liquid (IL, BMIMBF4) are added into the PE, and the amount of IL is found to play an important role in affecting the ionic conductivity, morphology, and thus electrochemical property of the obtained PE. The IL content in the PE is optimized in order to achieve a better electrochemical and electrochromic properties of the obtained electrochromic device (ECD). The effect of the IL content in PE on the electrochemical and electrochromic properties of the ECD is discussed in terms of the ionic conductivity and morphology of the PE. The optimized ECD, which uses the PE containing 5wt% IL, exhibits a reversible transmittance change of 60.1% at 615nm during the switching between 0 and 0.9V with a promising long-term stability; both the transmittance change and the long-term stability of the ECD using the PE containing 5wt% IL are much better than that using the PE without IL.

Fully printed flexible and disposable wireless cyclic voltammetry tag.

A disposable cyclic voltammetry (CV) tag is printed on a plastic film by integrating wireless power transmitter, polarized triangle wave generator, electrochemical cell and signage through a scalable gravure printing method. By proximity of 13.56 MHz RF reader, the printed CV tag generates 320 mHz of triangular sweep wave from +500 mV to −500 mV which enable to scan a printed electrochemical cell in the CV tag. By simply dropping any specimen solution on the electrochemical cell in the CV tag, the presence of solutes in the solution can be detected and shown on the signage of the CV tag in five sec. 10 mM of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) was used as a standard solute to prove the working concept of fully printed disposable wireless CV tag. Within five seconds, we can wirelessly diagnose the presence of TMPD in the solution using the CV tag in the proximity of the 13.56 MHz RF reader. This fully printed and wirelessly operated flexible CV tag is the first of its kind and marks the path for the utilization of inexpensive and disposable wireless electrochemical sensor systems for initial diagnose hazardous chemicals and biological molecules to improve public hygiene and health.