MyMedR

Fulltext REMOVAL OF CADMIUM IONS FROM SYNTHETIC WASTEWATER BY USINGPennisetum purpureum(ELEPHANT GRASS) AS LOW COSTBIODEGRADABLE ADSORBENT (BIOSORBENT)

LING SHING YUN, ASMADI ALI

UMT Journal of Undergraduate Research, 2019;1(1):103-112.

MyJurnal

At present, heavy metal pollution is a major environmental concern and the adsorption technique is a potent method for removal of these heavy metals from wastewater. Activated carbon is one of the best adsorbents for metal ionsremoval but it is sometimes restricted due to high cost and problems with regeneration hamper large scale application. Low cost adsorbent is alternatively being introduced to replace activated carbon since it is available in large quantity, renewable and inexpensive. Hence, Pennisetum purpureum(elephant grass) was investigated for its potential in cadmium ions removal. The adsorbent was characterized by Fourier Transforms Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analyses.The effects of pH (1 to 5), initial metal ion concentration (5 to 25 mg/L), contact time (10 to 60 minutes) and adsorbent dosage (0.2 to 1.0 g) on cadmium ions removal were conducted by batch adsorption experiments. In this study, the FT-IR results demonstrated that the functional groups for untreated and nitric acid-treated P. purpureum mainly consisted of carbonyl, carboxyl, hydroxyl and amine groups which are able to bind with positively charged cadmium ions. SEM micrographs have proven that nitric acid modification would remove the surface impurities of P. purpureum, which increased the surface roughness, produced deep, open pores and better pore size distribution. From the BET and BJH analyses, the treated P. purpureum was mesoporous, had larger surface area and pore volume compared to untreated P. purpureum. The best pH, adsorbent dosage and contact time were pH 4, 0.6 g and 30 minutes, respectively. The highest removal percentage of cadmium ions for both untreated and treated P. purpureum were 92% and 98% correspondingly. The results shown strengthened the fact that both biosorbents have great potential in cadmium ions removal.

Matched MeSH terms: Electrons

Fulltext Isolation and Characterisation of a Molybdenum-reducing and Metanil Yellow Dye-decolourising Bacillus sp. strain Neni-10 in Soils from West Sumatera, Indonesia

Mansur R, Gusmanizar N, Roslan MA, Ahmad SA, Shukor MY

Trop Life Sci Res, 2017 Jan;28(1):69-90.

PMID: 28228917 MyJurnal DOI: 10.21315/tlsr2017.28.1.5

A molybdenum reducing bacterium with the novel ability to decolorise the azo dye Metanil Yellow is reported. Optimal conditions for molybdenum reduction were pH 6.3 and at 34°C. Glucose was the best electron donor. Another requirement includes a narrow phosphate concentration between 2.5 and 7.5 mM. A time profile of Mo-blue production shows a lag period of approximately 12 hours, a maximum amount of Mo-blue produced at a molybdate concentration of 20 mM, and a peak production at 52 h of incubation. The heavy metals mercury, silver, copper and chromium inhibited reduction by 91.9, 82.7, 45.5 and 17.4%, respectively. A complete decolourisation of the dye Metanil Yellow at 100 and 150 mg/L occurred at day three and day six of incubations, respectively. Higher concentrations show partial degradation, with an approximately 20% decolourisation observed at 400 mg/L. The bacterium is partially identified based on biochemical analysis as Bacillus sp. strain Neni-10. The absorption spectrum of the Mo-blue suggested the compound is a reduced phosphomolybdate. The isolation of this bacterium, which shows heavy metal reduction and dye-decolorising ability, is sought after, particularly for bioremediation.

Matched MeSH terms: Electrons

Reduced susceptibility of Burkholderia pseudomallei following exposure to carbapenem

Zamani A, Zueter AR, Muhd Besari A, Hasan H, Harun A, Deris ZZ

Trop Biomed, 2020 Sep 01;37(3):783-790.

PMID: 33612791 DOI: 10.47665/tb.37.3.783

Reduced susceptibility in Burkholderia pseudomallei during carbapenem therapy may lead to treatment failure. We isolated a clinical strain that had developed reduced susceptibility to carbapenems while on treatment. After reviewing the patient's clinical notes, the initial isolate (BUPS01/14) was exposed to carbapenem in vitro to mimic the clinical scenario. The stability of susceptibility of the carbapenem-exposed strain (BUPS01/14R) was examined by serial subculture in antibiotic-free broth. Biochemical and morphological comparison was performed by the VITEK® system and electron microscopy. MICs increased 32-fold following carbapenem exposure and became stable in the antibiotic-free environment. On electron microscopic examination, the BUPS01/14R cells were smoother and less wrinkled compared to BUPS01/14 cells. This report highlights a potential anti-melioidosis treatment failure due to the emergence of resistance while on carbapenem monotherapy. Further study of this strain is necessary to understand the mechanism of resistance at a molecular level.

Matched MeSH terms: Electrons

Ultrastructural studies of developing goat oocytes in vitro

Rajikin MH, Yusoff M, Abdullah RB

Theriogenology, 1994 Nov 01;42(6):1003-16.

PMID: 16727604

The structure and distribution of organelles within developing goat oocytes at various stages of incubation were studied. In oocytes with 5 or more layers of cumulus cells, at 0 h of incubation, the zona pellucida had developed although zonation was not evident. Lipid bodies were present but no mitochondria were observed. At 20 h, the zona pellucida had differentiated into thicker and thinner regions. Clusters of membrane-bound electron-transparent bodies were present in the perivitelline space. The mitochondria were fully developed, distributed evenly and usually in close proximity with dilated endoplasmic reticula. Cortical granules were distributed at the periphery. At 40 h of incubation, a number of mitochondria was hooded. In oocytes of 2 to 4 layers of cumulus cells at 0 h, the zona pellucida was penetrated by cumulus cell processes, and the mitochondria were not well developed. However, in 20-h incubated oocytes, fully developed mitochondria, many of which were hooded, could be observed. Clusters of membrane-bound electron-transparent bodies were also observed, while cortical granules were at the periphery. In cumulus-free oocytes, zonation within the zona pellucida was indistinct. Very few vesicles and lipid bodies were observed. At 20 h, mitochondria were sparsely distributed and were not well developed and lacked cristae. At 40 h, the zona pellucida was less compact, and the membrane-bound electron-transparent bodies were less numerous compared with those of the other groups. Endoplasmic reticula were not dilated, and cortical granules were few and had no definite pattern of distribution.

Matched MeSH terms: Electrons

Fulltext Low-energy plasma focus device as an electron beam source

Khan MZ, Ling YS, Yaqoob I, Kumar NN, Kuang LL, San WC

ScientificWorldJournal, 2014;2014:240729.

PMID: 25544952 DOI: 10.1155/2014/240729

A low-energy plasma focus device was used as an electron beam source. A technique was developed to simultaneously measure the electron beam intensity and energy. The system was operated in Argon filling at an optimum pressure of 1.7 mbar. A Faraday cup was used together with an array of filtered PIN diodes. The beam-target X-rays were registered through X-ray spectrometry. Copper and lead line radiations were registered upon usage as targets. The maximum electron beam charge and density were estimated to be 0.31 μC and 13.5 × 10(16)/m(3), respectively. The average energy of the electron beam was 500 keV. The high flux of the electron beam can be potentially applicable in material sciences.

Matched MeSH terms: Electrons*

Fulltext Vacuum ultraviolet field emission lamp consisting of neodymium ion doped lutetium fluoride thin film as phosphor

Yanagihara M, Tsuji T, Yusop MZ, Tanemura M, Ono S, Nagami T, et al.

ScientificWorldJournal, 2014;2014:309091.

PMID: 25302320 DOI: 10.1155/2014/309091

A vacuum ultraviolet (VUV) field emission lamp was developed by using a neodymium ion doped lutetium fluoride (Nd(3+) : LuF3) thin film as solid-state phosphor and carbon nanofiber field electron emitters. The thin film was synthesized by pulsed laser deposition and incorporated into the lamp. The cathodoluminescence spectra of the lamp showed multiple emission peaks at 180, 225, and 255 nm. These emission spectra were in good agreement with the spectra reported for the Nd(3+) : LuF3 crystal. Moreover, application of an acceleration voltage effectively increased the emission intensity. These results contribute to the performance enhancement of the lamp operating in the VUV region.

Matched MeSH terms: Electrons*

Facile synthesis of CaFe2O4 for visible light driven treatment of polluting palm oil mill effluent: Photokinetic and scavenging study

Charles A, Khan MR, Ng KH, Wu TY, Lim JW, Wongsakulphasatch S, et al.

Sci Total Environ, 2019 Apr 15;661:522-530.

PMID: 30682605 DOI: 10.1016/j.scitotenv.2019.01.195

In this paper, a facile synthesis method for CaFe2O4 is introduced that produces a catalyst capable of significant photocatalytic degradation of POME under visible light irradiation. The co-precipitation method was used to produce two catalysts at calcination temperatures of 550 °C and 700 °C dubbed CP550 and CP700. CP550 demonstrated the maximum COD removal of 69.0% at 0.75 g/L catalyst loading after 8 h of visible light irradiation which dropped to 61.0% after three consecutive cycles. SEM images indicated that the higher calcination temperature of CP700 led to annealing which reduced the pore volume (0.025 cm3/g) and pore diameter (10.3 nm) while simultaneously creating a smoother and more spherical surface with lower SBET (9.73 m2/g). In comparison, CP550 had a rough hair-like surface with higher SBET (27.28 m2/g) and pore volume (0.077 cm3/g) as evidenced by BET analysis. XRD data indicated the presence of CaFe5O7 in the CP550 composition which was not present in CP700. The presence of Wustite-like FeO structures in CaFe5O7 are likely the cause for lower photoluminescence intensity profile and hence better charge separation of CP550 as these structures in CaFe2O4 have been known to increase resistivity and electron localization. The COD removal of CP550 dropped from 69.0% to just 7.0% upon adding a small quantity of isopropanol into the reaction mixture indicating hydroxyl radicals as the primary reactive oxidative species.

Matched MeSH terms: Electrons

Constructed wetland-microbial fuel cell for azo dyes degradation and energy recovery: Influence of molecular structure, kinetics, mechanisms and degradation pathways

Oon YL, Ong SA, Ho LN, Wong YS, Dahalan FA, Oon YS, et al.

Sci Total Environ, 2020 Jun 10;720:137370.

PMID: 32325554 DOI: 10.1016/j.scitotenv.2020.137370

Complete degradation of azo dye has always been a challenge due to the refractory nature of azo dye. An innovative hybrid system, constructed wetland-microbial fuel cell (CW-MFC) was developed for simultaneous azo dye remediation and energy recovery. This study investigated the effect of circuit connection and the influence of azo dye molecular structures on the degradation rate of azo dye and bioelectricity generation. The closed circuit system exhibited higher chemical oxygen demand (COD) removal and decolourisation efficiencies compared to the open circuit system. The wastewater treatment performances of different operating systems were ranked in the decreasing order of CW-MFC (R1 planted-closed circuit) > MFC (R2 plant-free-closed circuit) > CW (R1 planted-open circuit) > bioreactor (R2 plant-free-open circuit). The highest decolourisation rate was achieved by Acid Red 18 (AR18), 96%, followed by Acid Orange 7 (AO7), 67% and Congo Red (CR), 60%. The voltage outputs of the three azo dyes were ranked in the decreasing order of AR18 > AO7 > CR. The results disclosed that the decolourisation performance was significantly influenced by the azo dye structure and the moieties at the proximity of azo bond; the naphthol type azo dye with a lower number of azo bond and more electron-withdrawing groups could cause azo bond to be more electrophilic and more reductive for decolourisation. Moreover, the degradation pathway of AR18, AO7 and CR were elucidated based on the respective dye intermediate products identified through UV-Vis spectrophotometry, high-performance liquid chromatography (HPLC), and gas chromatograph-mass spectrometer (GC-MS) analyses. The CW-MFC system demonstrated high capability of decolouring azo dyes at the anaerobic anodic region and further mineralising dye intermediates at the aerobic cathodic region to less harmful or non-toxic products.

Matched MeSH terms: Electrons

Ultrastructural aspects of sylvatic dengue virus infection in Vero cell

Fish-Low CY, Abubakar S, Othman F, Chee HY

Malays J Pathol, 2019 Apr;41(1):41-46.

PMID: 31025636

INTRODUCTION: Dengue virus (DENV), the causative agent of dengue disease exists in sylvatic and endemic ecotypes. The cell morphological changes and viral morphogenesis of two dengue ecotypes were examined at the ultrastructural level to identify potential similarities and differences in the surrogate model of enzootic host.

MATERIALS AND METHODS: Vero cells were inoculated with virus at a multiplicity of infection (MOI) of 0.1. Cell cultures were harvested over a time course and processed for transmission electron microscopic imaging.

RESULTS: The filopodia protrusions on cell periphery preceded virus entry. Additionally, sylvatic DENV infection was found spreading slower than the endemic DENV. Morphogenesis of both dengue ecotypes was alike but at different level of efficiency in the permissive cells.

CONCLUSIONS: This is the first ultrastructural study on sylvatic DENV and this comparative study revealed the similarities and differences of cellular responses and morphogenesis of two dengue ecotypes in vitro. The study revealed the weaker infectivity of sylvatic DENV in the surrogate model of enzootic host, which supposed to support better replication of enzootic DENV than endemic DENV.

Matched MeSH terms: Electrons

Electrochemically Mediated Oxidative Transformations of Substituted 4-Methoxystilbenes: Effect of Ortho-Substituted Nucleophilic Groups

Chong KW, Hong FJ, Thomas NF, Low YY, Kam TS

J Org Chem, 2017 06 16;82(12):6172-6191.

PMID: 28552001 DOI: 10.1021/acs.joc.7b00753

A systematic study was undertaken to determine the influence of ortho'-substituted nucleophilic groups (OH, NH2, or NHR) on the reactivity of anodically generated 4-methoxy- and 3,4-dimethoxystilbene cation radicals. The results showed that when ortho-substituted nucleophilic groups such as OH and NHR are present in the other ring, both direct and crossover intramolecular cation-nucleophile reactions occur to give bisbenzofurans/bisindoles or fused bisbenzopyrans/bisquinolines, respectively. Where an additional 3-methoxy substituent is present, bridged oxocine/azocine products are formed in addition to the bisbenzopyrans/bisquinolines and bisbenzofurans/bisindoles. Mechanistic rationalization of the observed behavior is presented based on a generalized pathway involving fast cation radical dimerization following electron transfer, followed by direct and crossover trapping of the benzylic cations by the ortho-substituted oxygen and nitrogen nucleophilic groups. In the instances where an additional 3-methoxy group is present, the bridged oxocine/azocine products are also formed as a result of competing aromatic substitution (Friedel-Crafts reaction). The results have shed further light and provided additional clarification on the reactivity of anodically generated stilbene cation radicals.

Matched MeSH terms: Electrons

Differential cross sections for intermediate-energy electron scattering from α-tetrahydrofurfuryl alcohol: excitation of electronic-states

Chiari L, Duque HV, Jones DB, Thorn PA, Pettifer Z, da Silva GB, et al.

J Chem Phys, 2014 Jul 14;141(2):024301.

PMID: 25028013 DOI: 10.1063/1.4885856

We report on measurements of differential cross sections (DCSs) for electron impact excitation of a series of Rydberg electronic-states in α-tetrahydrofurfuryl alcohol (THFA). The energy range of these experiments was 20-50 eV, while the scattered electron was detected in the 10°-90° angular range. There are currently no other experimental data or theoretical computations against which we can directly compare the present measured results. Nonetheless, we are able to compare our THFA DCSs with earlier cross section measurements for Rydberg-state electronic excitation for tetrahydrofuran, a similar cyclic ether, from Do et al. [J. Chem. Phys. 134, 144302 (2011)]. In addition, "rotationally averaged" elastic DCSs, calculated using our independent atom model with screened additivity rule correction approach are also reported. Those latter results give integral cross sections consistent with the optical theorem, and supercede those from the only previous study of Milosavljević et al. [Eur. Phys. J. D 40, 107 (2006)].

Matched MeSH terms: Electrons

Integral cross sections for electron impact excitation of vibrational and electronic states in phenol

Neves RF, Jones DB, Lopes MC, Blanco F, García G, Ratnavelu K, et al.

J Chem Phys, 2015 May 21;142(19):194305.

PMID: 26001459 DOI: 10.1063/1.4921313

We report on measurements of integral cross sections (ICSs) for electron impact excitation of a series of composite vibrational modes and electronic-states in phenol, where the energy range of those experiments was 15-250 eV. There are currently no other results against which we can directly compare those measured data. We also report results from our independent atom model with screened additivity rule correction computations, namely, for the inelastic ICS (all discrete electronic states and neutral dissociation) and the total ionisation ICS. In addition, for the relevant dipole-allowed excited electronic states, we also report f-scaled Born-level and energy-corrected and f-scaled Born-level (BEf-scaled) ICS. Where possible, our measured and calculated ICSs are compared against one another with the general level of accord between them being satisfactory to within the measurement uncertainties.

Matched MeSH terms: Electrons*

Search for single production of vector-like quarks decaying to a top quark and a W boson in proton-proton collisions at s = 13 TeV

Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.

Eur Phys J C Part Fields, 2019;79(2):90.

PMID: 30814908 DOI: 10.1140/epjc/s10052-019-6556-3

A search is presented for the single production of vector-like quarks in proton-proton collisions at

s

=
13

TeV

. The data, corresponding to an integrated luminosity of 35.9

fb

-
1

, were recorded with the CMS experiment at the LHC. The analysis focuses on the vector-like quark decay into a top quark and a
W
boson, with one muon or electron in the final state. The mass of the vector-like quark candidate is reconstructed from hadronic jets, the lepton, and the missing transverse momentum. Methods for the identification of
b
quarks and of highly Lorentz boosted hadronically decaying top quarks and
W
bosons are exploited in this search. No significant deviation from the standard model background expectation is observed. Exclusion limits at 95% confidence level are set on the product of the production cross section and branching fraction as a function of the vector-like quark mass, which range from 0.3 to 0.03

pb

for vector-like quark masses of 700 to 2000

GeV

. Mass exclusion limits up to 1660

GeV

are obtained, depending on the vector-like quark type, coupling, and decay width. These represent the most stringent exclusion limits for the single production of vector-like quarks in this channel.

Matched MeSH terms: Electrons

Molecular structure, FT-IR, vibrational assignments, HOMO-LUMO analysis and molecular docking study of 1-[5-(4-Bromophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]ethanone

Mary YS, Panicker CY, Sapnakumari M, Narayana B, Sarojini BK, Al-Saadi AA, et al.

Spectrochim Acta A Mol Biomol Spectrosc, 2015 Feb 5;136 Pt B:473-82.

PMID: 25448948 DOI: 10.1016/j.saa.2014.09.060

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 1-[5-(4-bromophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]ethanone have been investigated experimentally and theoretically using Gaussian09 software package. The title compound was optimized using the HF/6-31G(d) (6D, 7F), B3LYP/6-31G (6D, 7F) and B3LYP/6-311++G(d,p) (5D, 7F) calculations. The B3LYP/6-311++G(d,p) (5D, 7F) results and in agreement with experimental infrared bands. The geometrical parameters are in agreement with XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular electrostatic potential was also performed. From the MEP it is evident that the negative charge covers the C=O group and the positive region is over the rings. First hyperpolarizability is calculated in order to find its role in nonlinear optics. Molecular docking studies suggest that the compound might exhibit inhibitory activity against TPII and may act as anti-neoplastic agent.

Matched MeSH terms: Electrons*

Synthesis, molecular structure, FT-IR, Raman, XRD and theoretical investigations of (2E)-1-(5-chlorothiophen-2-yl)-3-(naphthalen-2-yl)prop-2-en-1-one

Chidan Kumar CS, Fun HK, Parlak C, Rhyman L, Ramasami P, Tursun M, et al.

Spectrochim Acta A Mol Biomol Spectrosc, 2014 Nov 11;132:174-82.

PMID: 24858359 DOI: 10.1016/j.saa.2014.04.155

A novel (2E)-1-(5-chlorothiophen-2-yl)-3-(naphthalen-2-yl)prop-2-en-1-one [C17H11ClOS] compound has been synthesized and its structure has been characterized by FT-IR, Raman and single-crystal X-ray diffraction techniques. The isomers, optimized geometrical parameters, normal mode frequencies and corresponding vibrational assignments of the compound have been examined by means of the density functional theory method, employing, the Becke-3-Lee-Yang-Parr functional and the 6-311+G(3df,p) basis set. Reliable vibrational assignments and molecular orbitals have been investigated by the potential energy distribution and natural bonding orbital analyses, respectively. The compound crystallizes in the monoclinic space group P2₁/c with the unit cell parameters a=5.7827(8)Å, b=14.590(2)Å, c=16.138(2)Å and β=89.987 (°). The CC bond of the central enone group adopts an E configuration. There is a good agreement between the theoretically predicted structural parameters and vibrational frequencies and those obtained experimentally.

Matched MeSH terms: Electrons

A DFT analyses for molecular structure, electronic state and spectroscopic property of a dithiolene tungsten carbonyl complex

Arifin K, Daud WR, Kassim MB

Spectrochim Acta A Mol Biomol Spectrosc, 2014 Apr 24;124:375-82.

PMID: 24508875 DOI: 10.1016/j.saa.2013.12.107

Bis(dithiolene) tungsten carbonyl complex, W(S2C2Ph2)2(CO)2 was successfully synthesized and the structure, frontier molecular orbital and optical properties of the complex were investigated theoretically using density functional theory calculations. The investigation started with a molecular structure construction, followed by an optimization of the structural geometry using generalized-gradient approximation (GGA) in a double numeric plus polarization (DNP) basis set at three different functional calculation approaches. Vibrational frequency analysis was used to confirm the optimized geometry of two possible conformations of [W(S2C2Ph2)2(CO)2], which showed distorted octahedral geometry. Electronic structure and optical characterization were done on the ground states. Metal to ligand and ligand to metal charge transfer were dominant in this system.

Matched MeSH terms: Electrons*

Zinc (II) complex with a cationic Schiff base ligand: synthesis, characterization, and biological studies

Lee SK, Tan KW, Ng SW, Ooi KK, Ang KP, Abdah MA

Spectrochim Acta A Mol Biomol Spectrosc, 2014;121:101-8.

PMID: 24231745 DOI: 10.1016/j.saa.2013.10.084

A cationic Schiff base ligand, TSB (L) and its Zn (II) complex (1) were synthesized and characterized by using CHN, (1)H-NMR, FT-IR, UV, LC-MS, and X-ray methods. Their ability to inhibit topoisomerase I, DNA cleavage activities, and cytotoxicity were studied. X-ray diffraction study shows that the mononuclear complex 1 is four coordinated with distorted tetrahedral geometry. The singly deprotonated Schiff base ligand L acts as a bidentate ON-donor ligand. Complexation of L increases the inhibitory strength on topoisomerase I activity. Complex 1 could fully inhibit topoisomerase I activity at 250 μM, while L did not show any inhibitory effect on topoisomerase I activity. In addition, L and complex 1 could cleave pBR322 DNA in a concentration and time dependent profile. Surprisingly, L has better DNA cleavage activity than complex 1. The cleavage of DNA by complex 1 is altered in the presence of hydrogen peroxide. Furthermore, L and complex 1 are mildly cytotoxic towards human ovarian cancer A2780 and hepatocellular carcinoma HepG2.

Matched MeSH terms: Electrons

Time-dependent density functional theory study of UV/vis spectra of natural styrylpyrones

Anouar el H, Weber JF

Spectrochim Acta A Mol Biomol Spectrosc, 2013 Nov;115:675-82.

PMID: 23880409 DOI: 10.1016/j.saa.2013.06.114

Natural styrylpyrones isolated from fungi are known for various biological activities including antioxidant activity by scavenging free radicals. UV/vis spectra play an important role in elucidating chemical structures of these compounds via identification of chromophore units. With the aim of predicting the UV/vis spectra of a series of natural styrylpyrones, we tested TD-DFT, CIS and ZINDO methods in gas and in PCM solvent. The results showed that the individual or combined B3P86 and B3LYP hybrid functionals are suitable to predict the maximum wavelength absorption bands (λmax) for styrylpyrones. The structure property relationship (SPR) study emphasized the role of (i) structural parameters (e.g., hydrogen bond and the length of conjugated double bonds) and (ii) electronic descriptors (e.g., ionization potential, electronic affinity, hardness and electrophilicity) in bathochromic and hypsochromic shifts of maximum wavelength absorption bands (λmax) of styrylpyrone derivatives.

Matched MeSH terms: Electrons

One pot synthesis, molecular structure and spectroscopic studies (X-ray, IR, NMR, UV-Vis) of novel 2-(4,6-dimethoxy-1,3,5-triazin-2-yl) amino acid ester derivatives

El-Faham A, Soliman SM, Osman SM, Ghabbour HA, Siddiqui MR, Fun HK, et al.

Spectrochim Acta A Mol Biomol Spectrosc, 2016 Apr 15;159:184-98.

PMID: 26845586 DOI: 10.1016/j.saa.2016.01.051

Novel series of 2-(4,6-dimethoxy,1,3,5-triazin-2-yl) amino acid ester derivatives were synthesized using simple one pot method in methanol. The products were obtained in high yields and purities as observed from their spectral data, elemental analyses, GC-MS and X-ray crystallographic analysis. The B3LYP/6-311G(d,p) calculated molecular structures are well correlated with the geometrical parameters obtained from the X-ray analyses. The spectroscopic properties such as IR vibrational modes, NMR chemical shifts and UV-Vis electronic transitions were discussed both experimentally and theoretically. The IR vibrational frequencies showed good correlations with the experimental data (R(2)=0.9961-0.9995). The electronic spectra were assigned based on the TD-DFT results. Intense electronic transition band is calculated at 198.1nm (f=0.1389), 204.2nm (f=0.2053), 205.0 (f=0.1704) and 205.7 (0.2971) for compounds 6a-i, respectively. The molecular orbital energy levels contributed in the longest wavelength transition band were explained. For all compounds, the experimental wavelengths showed red shifts compared to the calculations due to the solvent effect. The NMR chemical shifts were calculated using GIAO method. The NBO analyses were performed to predict the stabilization energies due to the electron delocalization processes occur in the studied systems.

Matched MeSH terms: Electrons

The study of dipole moment of some substituted acetic acids in an electronically excited state

Murthy MB, Daya Sagar BS, Patil RL

Spectrochim Acta A Mol Biomol Spectrosc, 2003 Apr;59(6):1277-80.

PMID: 12659896

The electronic absorption spectra of eight substituted acetic acids have been measured at room temperature in several solvents. The ground state dipole moments are evaluated experimentally for these molecules. These ground state values are used in conjunction with the spectral results to evaluate their first electronically excited state dipole moments. For all the molecules investigated here the dipole moments in the excited state are higher than their ground state values.

Matched MeSH terms: Electrons

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