Electron Acceptor Groups Research Articles

Recent Advances on Nitrofluorene Derivatives: Versatile Electron Acceptors to Create Dyes Absorbing from the Visible to the Near and Far Infrared Region.

Push–pull dyes absorbing in the visible range have been extensively studied so that a variety of structures have already been synthesized and reported in the literature. Conversely, dyes absorbing in the near and far infrared region are more scarce and this particularity relies on the following points: difficulty of purification, presence of side-reaction during synthesis, low availability of starting materials, and low reaction yields. Over the years, several strategies such as the elongation of the π-conjugated spacer or the improvement of the electron-donating and accepting ability of both donors and acceptors connected via a conjugated or an aliphatic spacer have been examined to red-shift the absorption spectra of well-established visible dyes. However, this strategy is not sufficient, and the shift often remains limited. A promising alternative consists in identifying a molecule further used as an electron-accepting group and already presenting an absorption band in the near infrared region and to capitalize on its absorption to design near and far infrared absorbing dyes. This is the case with poly(nitro)fluorenes that already exhibit such a contribution in the near infrared region. In this review, an overview of the different dyes elaborated with poly(nitro)fluorenes is presented. The different applications where these different dyes have been used are also detailed.

DFT and TD-DFT calculations on thieno[2,3-b]indole-based compounds for application in organic bulk heterojunction (BHJ) solar cells

Eight novel organic compounds with donor–π–acceptor (D–π–A) structure were designed for use as donors in organic bulk heterojunction (BHJ) solar cells. The molecules have thieno[2,3-b]indole as donor, methylene malononitrile as electron acceptor group, and a π-spacer bridge based on thiophene and benzene or its derivatives. The designed compounds were studied using density functional theory (DFT) and time-dependent DFT approaches, to shed light on how the π-conjugation order influences the performance of corresponding photovoltaic solar cells. The study includes prediction of the energy of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels, the energy gap, Voc (the open-circuit voltage), the λmax of absorption, and other quantum-chemical parameters. The results show that, the greater the number of thiophenes present in the bridge, the better the compound as a donor for BHJ solar cells. The theoretical power conversion efficiency calculated for the designed products reaches 6%.

Synthesis of Pyridazine Derivatives by Suzuki-Miyaura Cross-Coupling Reaction and Evaluation of Their Optical and Electronic Properties through Experimental and Theoretical Studies.

A series of π-conjugated molecules, based on pyridazine and thiophene heterocycles 3a–e, were synthesized using commercially, or readily available, coupling components, through a palladium catalyzed Suzuki-Miyaura cross-coupling reaction. The electron-deficient pyridazine heterocycle was functionalized by a thiophene electron-rich heterocycle at position six, and different (hetero)aromatic moieties (phenyl, thienyl, furanyl) were functionalized with electron acceptor groups at position three. Density Functional Theory (DFT) calculations were carried out to obtain information on the conformation, electronic structure, electron distribution, dipolar moment, and molecular nonlinear response of the synthesized push-pull pyridazine derivatives. Hyper-Rayleigh scattering in 1,4-dioxane solutions, using a fundamental wavelength of 1064 nm, was used to evaluate their second-order nonlinear optical properties. The thienylpyridazine functionalized with the cyano-phenyl moiety exhibited the largest first hyperpolarizability (β = 175 × 10−30 esu, using the T convention) indicating its potential as a second harmonic generation (SHG) chromophore.

Facile CO2 Cycloaddition to Epoxides by Using a Tetracarbonyl Metal Selenotungstate Derivate [{Mn(CO)3}4(Se2W11O43)]8.

A novel polyoxometalate cluster, i.e., Na1.5H4.5[(CH3)4N]2{[Mn(CO)3]4(Se2W11O43)}·9H2O (1), has been successfully synthesized under moderately acidic conditions. Compound 1 contains four electron-donating {Mn(CO)3}+ organometallic entities, which are grafted over an unprecedented heteropolytungstate electron-acceptor group. Compound 1 was further structurally characterized by various physicochemical techniques like elemental analyses, inductively coupled plasma (ICP) analyses, IR and UV-vis spectroscopy, electrochemistry, and single-crystal X-ray diffraction, and so on. The polyoxoanion of 1 comprises a novel {Se2W11} fragment, which is obtained from molecular assembly of rare {SeW3} and {SeW8} species. Evaluation of the data from solution-state IR spectrum showed excellent agreement with the solid state IR spectrum, indicating the intact clusters in the CH3CN/Na2SO4 solvent. Also, negative electrospray ionization mass spectrometry (ESI-MS) was an alternative tool to verify the stability of 1 in the mixed solvent. Additionally, the resulting hybrid can act as a catalyst for cyclic carbonate formation from the reactants epoxides and CO2 under modest reaction conditions in conjunction with a 1-ethyl-1-methylpyrrolidinium bromide (2). The good activity can be substantiated due to the cooperative influence of polyoxoanion and Br- ions. Complex 1 can also be easily recycled and reused three times without obvious decrease of catalytic activity.

Photoactuated Properties of Acetylene-Congeners Non-Metallic Dyes and Molecular Design for Solar Cells.

This paper theoretically simulated (using DFT and TD-DFT in N,N-dimethylformamide (DMF) solvent) the photodynamic properties of three non-metallic dye molecules with D-π-A1-π-A2 structure. The total photoelectric conversion efficiency (PCE) could be evaluated by the following parameters: the geometric structures, the electronic structures, and the absorption spectra, the analyses of charge difference density (CDD) and natural bond orbitals (NBO), the analyses of ionization potential (IP) and electron affinity (EA) from electronic contribution capacity, the reorganization energies (, , and ), and the chemical reaction parameter (h, ω, , and ) for intramolecular charge transfer (ICT) processing, the excited lifetime (τ) and the vertical dipole moment (). The , the , the light harvesting efficiencies (LHE) and the excited lifetime (τ) were used to explain experimental . The experimental trend of was explained by the calculation of and . Moreover, the 15 dyes were designed by adding the electron-donor groups (–OH, –NH2, and –OCH3) and the electron-acceptor groups (–CF3, –F, and –CN) to the LS-387 molecular skeleton, which improved electronic contribution, intramolecular charge transfer (ICT), and optoelectronic performance.

A sensitive pyridine-containing turn-off fluorescent probe for pH detection

A new pH fluorescent probe 2,8-(6H,12H-5,11-methanodibenzo[b,f]diazocineylene)-di(o-ethenyl-pyridine) (TBOP), which attaches electron-accepting pyridine groups into Tröger’s Base skeleton, was designed and synthesized. Compound TBOP exhibits excellent pH-dependent performance that its blue fluorescence emission can be quenched upon protonation and the fluorescence can be lighted by deprotonation. Accordingly, the color of the solution switched between colorless and yellow. Moreover, TBOP has high sensitivity, good selectivity and large Stokes’ shift (121 nm). Such property enables it to work as a fluorescent acidic pH sensor in solution state.

Tuning optical and electronic properties in novel carbazole photosensitizers for p-type dye-sensitized solar cells

This work reports the synthesis and characterization of three novel carbazole-based push-pull dyes that have been purposely designed to be applied in p-type dye-sensitized solar cells (DSSCs). By using the same electron-donor moiety (the carbazole group) and three different electron acceptor groups, we explore how these new substituents affect the optical and electrochemical properties of the dye. State-of-the-art theoretical characterization at the DFT and TD-DFT levels of theory provides the means to understand and elucidate the connection between the chemical composition, the structure and the electronic features of these dyes. The interface between the dyes and the prototypical p-DSSC electrode (i.e. NiO) is also investigated by first-principles calculations, highlighting the importance of taking into account the dye/electrode mutual polarization for a correct alignment of the relevant electronic states (e.g., dye HOMO and NiO valence band edge). Following these characterizations, preliminary studies on the photoelectrochemical performances of the new dyes in p-DSSCs provide promising results and motivate future investigations on these new systems.

Effects of the Methyl Group on the Emission Efficiency of the Red Phosphorescent Iridium(III) Complexes for OLEDs

Novel red phosphorescent iridium(III) complexes, namely (MN-Q)2Ir(tmd), (MN-MQ)2Ir(tmd), (PT-P)2Ir(tmd) and (PT-MP)2Ir(tmd) were synthesized for the red phosphorescent organic lightemitting diodes (phOLEDs). The ligands have sites of both the electron donor and acceptor in a molecule. The main ligands were synthesized by the Suzuki coupling reaction, and comprised an electron donor and an electron acceptor group. Subsequently, the iridium(III) complexes were synthesized by the Nonoyama reaction and their photochemical luminescence properties were investigated by ultraviolet-visible and photoluminescence spectroscopy. The manufactured devices were characterized by current density-voltage-luminance, power efficiency, external quantum efficiency, as well as their electroluminescence spectra. Finally, the effects of the trifluoromethyl group on the emission efficiency of the organic light-emitting diodes were investigated by comparing the energy levels and luminescence efficiency of the three iridium complexes.

Efficient donor-acceptor-donor borylated compounds with extremely small ΔEST for thermally activated delayed fluorescence OLEDs

Borane-based complexes have attracted considerable attention as thermally activated delayed fluorescence (TADF) emitters because of their thermal stability, high fluorescence efficiency, and favourable carrier mobility. In this work, we provide a facile way for borylated compounds to enable the spatially adjacent electron donor and acceptor groups to form a near-orthogonal configuration, generating an extremely small energy gap between triplet and singlet excited states (ΔEST, ∼30 meV). We demonstrate here a new series of donor-acceptor-donor borylated compounds using functional acridan derivatives as the electron donors and dimesitylborane as the acceptor moieties, which easily generates an intramolecular charge transfer upon excitation. All compounds achieved strong TADF emission and were used as dopants to fabricate TADF OLEDs. Yellow-emitting devices A and B yielded maximum efficiencies of 7.6% (22.2 cd/A) and 10.1% (32.2 cd/A), respectively. Moreover, the green-emitting device C achieved a maximum efficiency of 19.3% (56.8 cd/A) and subsequently dropped to 18.2% (53.6 cd/A) at luminance levels of 102 cd/m2. Overall, the high electroluminescent (EL) efficiencies, together with mitigated efficiency roll-off, illustrate that these compounds have a high potential for EL applications.

Complexes between H2 and neutral oxyacid beryllium derivatives. The role of angular strain

ABSTRACTThe complexes between 14 different Be-salts of oxyacids from groups 13 to 16 with one and two molecules of H2 have been investigated by means of the MP2/aug-cc-pVTZ ab initio molecular orbital theory method, which was found to be reliable for the treatment of these weakly bound species. The main conclusion is that these Be-salts yield rather stable complexes with dihydrogen, with binding energies one order of magnitude larger than other typical H2 complexes reported in the literature. This strong binding is shown to be due to an enhancement of the electron-deficient nature of Be when attached to an oxyacid moiety, which depends more on the type of coordination of the central atom of the oxyacid moiety. The formation of these complexes is followed by a significant lengthening of the H2 internuclear distance and a concomitant red-shift of the H–H stretching frequency, which becomes a good indicator of the strength of the interaction. The charge shifting from the bonding region of the H2 molecule to the interboundary Be···H2 region is the physical phenomenon behind the stability of these complexes. Accordingly, the most important contributor to this stability is the inductive term, followed by the electrostatic interactions. The ability of Be to bind H2 is enhanced by the angular arrangement of the O–Be–O electron-acceptor group.

Synthesis and catalytic property of inorganic-organic hybrid copper vanadate Cu<sub>2</sub>(eIM)<sub>6</sub>[V<sub>4</sub>O<sub>12</sub>] in selective oxidation of sulfides

Polyoxometallates (POMs) a re familiar inorganic building blocks for their rich structural diversities and potential applications in many fields, such as catalysis, magnetism, and energy, etc. As an important subclass of POMs, vanadates are a promising candidate to construct POMs-based hybrid materials due to their unprecedented structural diversity, mixed valency, and variable coordination geometries. Inorganic-organic hybrid vanadates with first-row transition metals show very rich structural diversities. Further, the hybrid vanadates are expected to exhibit improved properties by the synergetic interaction between the metal-organic subunits and the vanadium oxide. Thus, it is essential but remains challenging to control the synthesis of inorganic-organic hybrid vanadates rationally. Recently, our group reported several examples of inorganic-organic hybrid vanadates by controlling the synthetic reaction conditions and further explored their catalytic properties in the oxidation of sulfides, alcohols and olefin, etc. In order to continue our research in the controlling synthesis and catalytic properties of inorganic-organic hybrid vanadates, here we synthesized a hybrid copper vanadate Cu2(eIM)6[V4O12] ( 1 ). In the synthetic procesure, a neutral V6 cluster VIV2VV4O14(eIM)8 (eIM=1-ethylimidazole) which was reported in our earlier research, was selected as vanadium source and reacted with Cu(OAc)2·H2O in the presence of triethylamine by rationally controlling the reaction conditions. Compound 1 was fully characterzized by single-crystal X-ray diffraction (SXRD) and powder X-ray diffraction (PXRD) analyses, FT-IR spectroscopy and element analyses, etc. SXRD analyse shows that the molecular struture of 1 contains a [V4O12]4- anion cluster and two types of copper complex cation, Cu[(eIM)2]2+ and Cu[(eIM)4]2+. All the [V4O12]4- anion clusters were further connected to a two- dimensional (2D) plane network supramolecular structure by four- and six-coordinated copper complexes cations with the eIM ligands. Two types of coordination modes existing in the same tructure is rare in complexes of inorganic-organic hybrid vanadates. Selective oxidation of organic compounds, such as sulfides, alcoholes, aromatic and aliphatic hydrocarbons, etc., is one of the most vital transformations for upgrading raw starting materials into high value added products. Vanadium-containing materials show excellent catalytic performance in selective oxidation of these compounds. Given the importance of sulfoxides and sulfones as intermediates of biologic molecules, chiral auxiliaries and oxo-transfer reagents, the high selective oxidation of sulfides to obtain these compounds is more desirable. As a green oxidant, H2O2 offers significant enviromental and economic benefits over traditional stoichiometric oxidants. First, we selected the oxidation of methyl phenyl sulfide as a model reaction to evaluate the catalytic activities of compound 1 . We evaluated the influencing factors of the ammount of catalyst and oxidant, the reaction temperature and time. Under the optimized conditions, the conversion of methyl phenyl sulfide and the selectivity to corresponding sulfoxide up to 98.5% and 97.5%, respectively. Other aromatic sulfides were also examined and no obvious decrease of the catalytic activity was observed when electron donor or acceptor groups with less steric hindrance were introduced in the monophenyl sulfides (conversion from 87.4% to 96.5%; selectivity toward corresponding sulfoxides from 97.5% to 98.5%). When the reaction conditions were applied to aliphatic sulfides including n -butyl sulfide, 2-chloroethyl ethyl sulfide and dimethyl sulfide, the high conversion (from 92.2% to 98.7%) and selectivity toward corresponding sulfoxides (from 83.5% to 95.5%) were also abtained. We also probed the role of each active center of compound 1 and found that the cooperation between copper complex cations and vanadate anions played some synergistic role in the sulfonation process, which can improve the catalytic performance. As a heterogeneous catalyst, 1 was also selected to examine the long-term stability and after at least 3 runs still maintained its activity without significant changes in its structure which characterized by FT-IR spectra and PXRD analyses, respectively. It is worth pointing out that by controlling the catalytic reaction conditions and using the same oxidant, we can prepare sulfones by various sulfides oxidation with excellent conversion and selectivity up to >99% and 97.5%, respectively.

Helicenes Grafted with 1,1,4,4-Tetracyanobutadiene Moieties: π-Helical Push-Pull Systems with Strong Electronic Circular Dichroism and Two-Photon Absorption.

Enantiopure P- and M-carbo[6]helicenes substituted with one or two tetracyanobutadiene moieties at positions 2 and 15 have been prepared. Grafting of these electron-accepting groups onto the π-helical core resulted in strong charge-transfer effects, which greatly affected the UV/Vis, electronic circular dichroism (ECD), and two-photon absorption (TPA) responses. The ECD signal was found to be reversibly switched by applying a redox stimulus.

On the structural and spectroscopic properties of the thienyl chalcone derivative: 3-(5-Bromo-2-thienyl)-1-(4-nitrophenyl)-prop-2-en-1-one

In this study, we investigate the structural and spectroscopic properties of the thienyl chalcone derivative 3-(5-Bromo-2-thienyl)-1-(4-nitrophenyl)-prop-2-en-1-one, C13H8BrNO3S, using nuclear magnetic resonance (1H and 13C NMR), UV–vis and Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy at room conditions combined with density functional theory (DFT) and time-dependent DFT (TD-DFT) augmented with B3LYP/6-311G(d,p) and CAM-B3LYP/6-311G(d,p) basis sets, yielding valuable information on the molecular conformational preferences, vibrational assignments, optical properties and electronic transitions. The vibrational mode assignments of the most stable conformer of C13H8BrNO3S are discussed based on potential energy distribution (PED) analysis and establishing a comparison with a similar chemical structure. The temperature dependence on the Raman spectra of the C13H8BrNO3S shows a reversible phase transition in the range 443–443 K pointed out by the discontinuity in the dω/dT of bands in the external and internal modes region. The UV–vis spectrum of the C13H8BrNO3S indicates a semiconductor behavior with an optical band gap of 2.6 eV, corresponding to the predicted value of 3.42 eV assigned as the electronic transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO). TD-DFT calculations reveal that the electron donor and acceptor group substitution on the 1-phenyl-3-(thiophen-2-yl)prop-2-en-1-one affects its absorption and nonlinear activity.

Laser ablation of block copolymers with hydrogen-bonded azobenzene derivatives

Supramolecular assemblies (PS-b-P4VP (AzoR)) are fabricated by hydrogen-bonding azobenzene derivatives (AzoR) to poly(4-vinyl pyridine) blocks of polystyrene-block-poly(4-vinyl pyridine) (PS-b-P4VP). PS-b-P4VP(AzoR) forms phase separated nanostructures with a period of ∼75–105 nm. A second length scale structure with a period of 2 μm is fabricated on phase separated PS-b-P4VP(AzoR) by laser interference ablation. Both the concentration and the substituent of AzoR in PS-b-P4VP(AzoR) affect the laser ablation process. The laser ablation threshold of PS-b-P4VP(AzoR) decreases as the concentration of AzoR increases. In PS-b-P4VP(AzoR) with different substituents (R = CN, H, and CH3), ablation thresholds follow the trend: PS-b-P4VP(AzoCN)<PS-b-P4VP(AzoCH3)<PS-b-P4VP(AzoH). This result indicates that the electron donor group (CH3) and the electron acceptor group (CN) can lower the ablation threshold of PS-b-P4VP(AzoR).

Improving the optical properties of [14] and [18] annulenes sandwiched between electron donor-acceptor groups

In the present research, an electron donor-acceptor compound (called push-pull systems) were studied using DFT methods in the vacuum space. We used [14] annulene and [18] annulene as π conjugated system and connected methoxy diphenylamine group as an electron donor and cyanoacrylic acid as an electron acceptor group. It was shown that the donor and acceptor groups narrowed the Eg of structure which is the result of hyperconjugation. Pristine annulenes had intensive light absorption in the ultraviolet region in electromagnetic radiation. After both molecules sandwiched between electron donor-acceptor groups, a significant redshift from the UV region to the visible and IR region was observed. Also in NMR calculation, it was observed the amount of aromaticity has increased after sandwiching. In all IR and Raman spectrum, it was shown the amount and intensity of light absorption increased after placing annulenes in electron donor-acceptor groups. The results of this research may be useful in designing new materials applicable as photosensitizers and photodynamic therapy.

Chlorination and chloramination of benzophenone-3 and benzophenone-4 UV filters

The objective of this research was to explore the fundamental reactions between chlorine/chloramine and 2-hydroxyl-4-methoxyl benzophenone (BP3)/2-hydroxyl-4-methoxyl benzophenone-sulfonic acid (BP4), which were the most common reactions in benzophenone-type UV filters during drinking water treatment processes. Both BP3 and BP4 could react with free chlorine and chloramine, with reactions following pseudo-first-order kinetics in excess of chlorine (HClO) and chloramine (NH2Cl). Generally, chlorination was more rapid than chloramination. BP4 was less reactive than BP3 toward both chlorine and chloramine, due to the presence of an electron-accepting sulfonate group. Therefore, BP3 had a significantly higher disinfection by-products (DBP) formation potential than BP4. Chlorination of BP3 and BP4 generated remarkably higher levels of DBPs than chloramination, with high pH conditions facilitating the formation of chloroform but inhibiting the formation of haloacetic acid (HAAs). Comparison of the reaction behavior of two different BP-type UV filters, i.e., BP3 and BP4, revealed that certain functional groups significantly affected the reactivity of BP-type UV filters in chlorination and chloramination processes. This contribution may provide new insights into the reaction behavior of UV filters during drinking water disinfection process using chlorine and/or chloramine as disinfectant, and provide guidelines for drinking water safety management.

Electronic and optical properties of edge modified peritetracene: a DFT study

Peritetracene (PTA) molecules have promising applications in organic electronics and organic light-emitting diodes, but the major constraints come from their poor stability with higher energy gap. We have investigated the stability, electronic, and optical properties of different electron-donating- and electron-withdrawing-substituted PTA molecule groups using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. On substituting suitable electron donor and acceptor groups, the energy gap of PTA molecules reduces up to 0.37 eV with an increase in their stability. The stabilities of considered PTA molecules have been investigated using the distribution pattern of frontier molecular orbital energies. The charge transfer properties with smaller ionization potential and larger electron affinity for PTA molecule have been evaluated using Koopmans’ theorem. Enhancement in dipole moment, polarizability, and hyperpolarizability of PTA substituted with electron-donating groups shows the presence of NLO properties. Also, we have investigated the spectroscopic properties of different electron-donating- and electron-withdrawing-substituted PTA molecule groups. Our spectroscopic properties show the bathochromic shift and small hypsochromic shifts in wavelengths of PTA with substituents groups. It is therefore concluded that the –NCH3 and –NO2 substituent groups on PTA are observed to have the strongest and highest stability than the other substituent groups considered.

DFT/TD-DFT study on halogen doping and solvent contributions to the structural and optoelectronic properties of poly[3,6-carbazole] and poly[indolo(3,2-b)-carbazole

The polycarbazoles have been proved to be a good organic semiconductor. These are investigated by quantum chemical studies using B3LYP density functional theory (DFT), and the studies have given a detailed understanding on the impact of carbazole units and an introduction to the electron donating on the optoelectronic properties. The electron withdrawing groups of halogen atoms (chlorine, bromine and iodine) have been substituted into the side chain of the poly[3,6-carbazoles] (PCs) and poly[indolo(3,2-b)-carbazoles] (PICs) and analysed. The band was assigned in the gas phase at 354.8 and 365.1 nm for PCs and PICs which are in good agreement with experimental values of 350 and 390 nm. The calculated results show that the selected three halogen derivatives exhibit a strong blue shift in the toluene solvent medium, with high electronic transition. It is found that PCs, PICs and their derivatives have a narrow band derived in the conduction band, and it is composed of 3p, 4p and 5p states; thus, the energy gap of PCs and PICs increased between the highest occupied molecular orbital and lowest unoccupied molecular orbital energy level by the addition of electron acceptor group atoms. The doped PC and PIC electronegativities are well plotted by an electrostatic potential map, and the plot reveals that chlorine-doped PCs and PICs have less electronegativity and bromine-doped polymer has high electronegativity than that of the chlorine-doped polymers. The results obtained from these studies will expose the affairs between the molecular geometry and electronic and optical properties of the investigated polymers.

Effects of the Trifluoromethyl Group on the Emission Efficiency of Red Phosphorescent Iridium(III) Complexes.

In this work, three novel phosphorescent iridium(III) complexes, namely (PT-TFP)2Ir(tmd), (PT-P)2Ir(tmd), and (MN-TFP)2Ir(tmd), were synthesized. All three complexes were phosphorescent red-emitting diode materials. The main ligands were synthesized by the Suzuki coupling reaction, and comprised an electron donor and an electron acceptor group. Subsequently, the iridium(III) complexes were synthesized by the Nonoyama reaction and their photochemical luminescence properties were investigated by ultraviolet-visible and photoluminescence spectroscopy. The manufactured devices were characterized by current density-voltage-luminance, power efficiency, external quantum efficiency, as well as their electroluminescence spectra. Finally, the effects of the trifluoromethyl group on the emission efficiency of the organic light-emitting diodes were investigated by comparing the energy levels and luminescence efficiency of the three iridium complexes.

Synthesis and Optical Properties of Dipolar Thiazole Derivatives Incorporating Nitro and Amino Substituents

We report the synthesis of two dipolar thiazole derivatives functionalized with nitro group as electron acceptor and amino group as electron donor, in order to study their optical properties in the UV-vis range. Their structures were verified by 1H NMR, 13C NMR, HRMS and FT-IR. The resulted thiazole derivatives have good thermal stability with decomposition temperature, Td of 320.20 °C and 284 °C for compounds 1 and 2 respectively. The absorbance bands of compound 2 in the UV-vis range are more red-shifted than that of compound 1 which made compound 2 could have high potential as a great organic NLO material.