General Spectroscopic Methods Research Articles

A fully conjugated imidazole-fused perylene phenantroline ruthenium(II) complex in photocatalytic oxidation

In this investigation, the suitability of a specially designed imidazole-fused perylene ruthenium(II) molecule, denoted as Ru-PhP, was explored by employing the photooxidation of 1,5-dihydroxynaphthalene (DHN) to produce Juglone as a model reaction. This distinctive, entirely conjugated compound was synthesized through the reaction between perylene imide anhydride dye (1) and a ruthenium(II) phenanthroline complex (2) in the presence of a Zn(OAc)2 catalyst. Structural analyses of the compound were performed by using general spectroscopic methods including FT-IR, 1H NMR, 13C- NMR, and MALDI-TOF analyses. Various photophysical properties, including the UV–Vis absorption spectrum, fluorescence emission spectrum, and fluorescence quantum yield, were examined. The photochemical studies via indirect method endorsed Ru-PhP as an efficient photosensitizer. Furthermore, Ru-PhP proved to be highly effective in facilitating the photooxidation of DHN to yield juglone. DFT-based natural bond orbital analysis revealed intramolecular charge transfer in Ru(II) coordination environment, with a strong total stabilization energy (25.31 eV) between the ruthenium acceptor and nitrogen donors in the bipyridine and phenanthroline units. The dispersion of HOMO electrons within the imidazole-bridged perylene moiety and the localization of LUMO electrons near Ru(II)-coordinated bipyridine units were observed through Frontier Molecular Orbital and molecular electrostatic potential analyses. Ru-PhP is proposed as photocatalyst for photo redox catalytic organic reactions.

Colorimetric and fluorimetric detection of CN– ion using a highly selective and sensitive chemosensor derived from coumarin-hydrazone

Novel chemosensors, including coumarin hydrazide, were designed and synthesized by a three-step synthesis sequence starting from 7-(diethylamino)-2-oxo-2H-chromene-3-carbohydrazide. General spectroscopic methods (FT-IR, 1H/13C NMR, and HRMS) were used to characterize all produced chemosensors. These chemosensors demonstrate the ability to detect cyanide (CN–) anion by shifting absorption and fluorescence turn-off response in DMSO. The reaction mechanism between the synthesized chemosensors and the CN– anion involves deprotonation and addition processes; as determined by dipole-dipole interactions, reversibility, 1H NMR experiments, and theoretical studies. With limit of detection (LOD) values of 0.25 μM and 0.15 μM for 3a and 3b, respectively, these chemosensors exhibit exceptional detection ability and demonstrate the high effectiveness of their use for CN– anion determination.

Non-Peripheral Octa- Zinc(II) Phthalocyanine: Synthesis and investigation of photosensitizer potential

New compounds 3,6-bis(2-azidoethoxy)phthalonitrile and 1,4,8,11,15,18,22,25-octakis-(2-azidoethoxy) phthalocyaninato zinc(II) were synthesized and characterized by general spectroscopic methods such as UV-Vis, FT-IR, 1H NMR and mass spectrometry. Moreover, photosensitizer ability for photodynamic therapy applications; singlet oxygen photosensitizer, photodegradation and fluorescence abilities of 14,8,11,15,18,22,25-octakis-(2-azidoethoxy) phthalocyaninato zinc(II) molecule were investigated and reported.

Exploring of antioxidant and antibacterial properties of novel 1,3,4-thiadiazole derivatives: Facile synthesis, structural elucidation and DFT approach to antioxidant characteristics

In recent years, compounds containing thiophene and 1,3,4-thiadiazole skeletons have become important cyclic compounds, especially in medicinal chemistry. In this manner, we synthesized and isolated seven 1,3,4-thiadiazole derivatives with thiophene groups and fully characterized by elemental analysis and general spectroscopic methods such as 1H NMR, 13C NMR, and FT-IR. Antibacterial activities of the title compounds were investigated by using TLC-Dot blot, macro dilution, well diffusion, and growth curve analysis methods. Compounds 1 and 6 showed inhibitory activities against all tested gram-negative and gram-positive bacteria. TLC-DPPH and DPPH assays, on the other hand, were performed to detect the antioxidant activities of the 1,3,4-thiadiazole derivatives and compound 1 exhibited the highest antioxidant activity at all tested concentrations. QTAIM and NCI calculations were performed as well as structural, electronic, and spectral analyzes using density functional theory (DFT). Calculations were carried out at the B3lyp/6–311 + +g(2d,2p) level of theory, and the data were used to examine the antioxidant activity of the compounds.

Photophysical and photochemical study on novel axially chalcone substituted silicon (IV) phthalocyanines

The novel axially chalcone bearing furan or thiphene groups substituted silicon (IV) phthalocyanine complexes were synthesized in this study. These novel phthalocyanines were characterized by general spectroscopic methods such as FT-IR, 1H NMR, UV–Vis, and MALDI-TOF. The aggregation behaviours of the synthesized phthalocyanines were investigated in different solvents and at different concentrations by UV–Vis spectroscopy. The aggregation behavior of the synthesized phthalocyanines were studied at different concentration and different solvents and it was observed chloroform and tetrahydrofuran solutions of furan substituted phthalocyanine (3a) show J-type aggregation as unusual. The photophysical and photochemical properties of the synthesized silicon(IV) phthalocyanine complexes were investigated in dimethylformamide (DMF). It was observed that although both of fluorescent and singlet oxygen quantum yields of the compounds were similar, thiophene substituted phthalocyanine Si(IV) complex show higher quantum yield (3b) than that of furan substituted (3a).

Synthesis, Optical, Electrochemical and Theoretical Studies of New Multicyclic Substituted Phthalocyanines.

Here novel phenanthrenoxy and pyrenoxy substituted phthalocyanines were synthesized and fully characterized by general spectroscopic methods such as elemental analysis, 1H NMR, MALDI-TOF, FT-IR, UV-Visible absorption. The aggregation property of these phthalocyanines was investigated in CHCl3 and Triton X. Furthermore, electrochemical and DFT calculations were performed for these molecules.

Synthesis, characterization, photophysicochemical properties and theoretical study of novel zinc phthalocyanine containing four tetrathia macrocycles

In this work, Zn(II) phthalocyanine derivative (TTU-Pc) bearing 13-membered tetrathia macrocycles was synthesized, and the novel Zn(II) phthalocyanine derivative was fully characterized by elemental analysis and general spectroscopic methods such as MALDI-TOF mass, FT-IR, UV-vis and [Formula: see text]H-NMR. The synthesized phthalocyanine derivative has quite limited solubility in most of the common organic solvents. Fluorescence measurement was conducted for this Zn(II)phthalocyanine to estimate its fluorescence quantum yields. The singlet oxygen generation ability was also examined to investigate its photosensitizer properties. General trends were described for quantum yields of fluorescence, photodegradation and singlet oxygen quantum yields of this compound. The electrochemical properties of the molecule were investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV). In addition, the lowest energy structure, the electronic structure and frontier molecular orbitals were calculated in DFT and the excitation spectrum was obtained by TDDFT calculations. We found that our computational and experimental results were in agreement.

Synthesis of novel dimeric subphthalocyanines via azide-alkyne Huisgen 1,3-dipolar cycloaddition and palladiumcatalyzed Glaser–Hay coupling reactions

In this study, the monomeric subphthalocyanines bearing azido (2) and terminal ethynyl (3) groups were synthesized. These subphthalocyanines were converted to their dimeric derivatives using azide-alkyne Huisgen cycloaddition and palladium-catalyzed Glaser–Hay coupling reactions subphthalocyanine (4) and (5), respectively. The novel subphthalocyanines were fully characterized by elemental analysis and general spectroscopic methods such as MALDI-TOF mass, FT-IR, UV-vis and [Formula: see text]H-NMR. All synthesized subphthalocyanines showed quite good solubility in the most of common organic solvents. The fluorescence measurements were conducted for these subphthalocyanines to estimate their fluorescence quantum yields. The singlet oxygen generation abilities were also examined to investigate their photosensitizer properties.

Structural and Optical Properties of New Naphthalene and Perylene Imide Imidazoles

ABSTRACTNew unsymmetrically substituted naphthalene and perylene imide imidazoles, N-(2-ethylhexyl)-naphthalene-3,4-(4,5-dicyano-1,2-benzimidazole)-9,10-dicarboxyimide and N-(1-heptyloctyl)-perilene-3,4-(4,5-dicyano-1,2-benzimid-azole)-9,10-dicarboxyimide, were synthesized via condensation reactions of diaminophthalonitrile and aromatic monoimide monoanhydride derivatives. Their structural analyses have been conducted by using general spectroscopic methods including FT-IR, 1H- and 13C-NMR, mass and elemental analysis. The molecular structure of naphthalene derivative was also determined by single crystal x-ray diffraction. Electronic absorption and emission properties were investigated on comparison. For studied compounds, both DFT and TDDFT calculations were carried out with the 6-311G(d,p) basis set, taking into account solvation effects by means of polarizable continuum model as implemented in the Gaussian 09 package.

Synthesis and properties of octa-distyryl-BODIPY substituted zinc(II) phthalocyanines

A novel type octa-distyryl-BODIPY substituted zinc(II) phthalocyanines 9 and 10 were prepared by the copper-free Sonogashira coupling and “Click” reactions, respectively. The terminal ethynyl functionalized BODIPY (4,4’-difluoro-8-(4-propynyloxy)-phenyl-1,7-dimethyl-3,5-bis(4-4″-diethylaminophenyl)ethenyl)-4-bora-3a,4a-diaza-s-indacene, 8) compound was reacted with octakis (iodo) zinc(II) phthalocyanine (2) for the synthesis of BODIPY substituted zinc(II) phthalocyanine 9. On the other hand, the same BODIPY compound (8) was used to the synthesis of BODIPY substituted zinc(II) phthalocyanine 10 by the reaction of this BODIPY with octakis-(2-azidoethoxy) zinc(II) phthalocyanine (7). While eight distyryl-BODIPY groups were linked to the phthalocyanine core through ethynyl bonds for phthalocyanine 9, these BODIPY groups were connected to the phthalocyanine core via triazole ring for phthalocyanine 10. All newly synthesized compounds were characterized by elemental analysis and general spectroscopic methods such as 1H NMR, mass, FT-IR, UV–Vis and fluorescence. Moreover, the photophysical and photochemical properties of these conjugates were investigated for determination of their photosensitizer and fluorescence abilities for photodynamic therapy.

Synthesis, characterisation, photophysical and photochemical properties of free-base tetra-(5-chloro-2-(2,4-dichlorophenoxy)phenoxy)phthalocyanine and respective zinc(II) and lead(II) complexes

In this study, novel peripherally tetra-(5-chloro-2-(2,4-dichlorophenoxy)phenol) substituted metal-free (4), zinc(II) (5) and lead(II) (6) phthalocyanine derivatives were synthesised. The novel phthalocyanines (4–6) were characterised by general spectroscopic methods such as IR, 1H NMR, UV–vis, mass spectrometry and elemental analysis. Once the solubilities of the compounds were investigated, it was noticed that they have excellent solubility and did not tend to aggregation behaviour in common solvents. The photophysical and photochemical properties of novel phthalocyanines (4–6) were investigated in dimethysulfoxide. The effects of substituted 5-chloro-2-(2,4-dichlorophenoxy)phenoxy group and central metal ion [zinc(II)/lead(II)] on photophysical and photochemical properties of the novel phthalocyanines have also been examined, and the results were compared with unsubstituted zinc(II) phthalocyanine. According to photophysical and photochemical investigation results, it was observed that the novel phthalocyanines (4–6) have a potential for PDT application.

A highly selective and sensitive chemosensor derived coumarin–thiazole for colorimetric and fluorimetric detection of CN− ion in DMSO and aqueous solution: synthesis, sensing ability, Pd(II)/Pt(II) complexes and theoretical studies

A colorimetric and fluorescence turn-on cyanide probe, including coumarin–thiazole and imine (azomethine) group, has been designed and synthesized. It showed an immediate visible color change from yellow to deep red only in DMSO, and an appearance of strong yellow and green fluorescence when CN− was added to DMSO, and a mixture of DMSO:H2O (9:1), respectively. Thus, the sensor can be used to detect CN− in aqueous solution. The sensing mechanism of chemosensor 4 reactions with CN− ion was observed with the deprotonation and addition mechanisms at the same time. The mechanisms of reactions of chemosensor 4 with; CN−, F−, and AcO− were examined using 1H NMR spectroscopy, and were also theoretically supported by DFT and TD-DFT calculations. In addition, the metal complexes of chemosensor 4 with Pd(II) and Pt(II) were also synthesized and all the synthesized compounds were characterized using general spectroscopic methods (FTIR, 1H/13C NMR, and mass spectrometry), magnetic susceptibilities, and conductivity measurements. Also, the molecular structure of 4 was determined using single crystal X-ray analysis.

Rapid, sensitive, and reproducible screening of liquid milk for adulterants using a portable Raman spectrometer and a simple, optimized sample well.

We have developed a powerful general spectroscopic method for rapidly screening liquid milk for adulterants by combining reflective focusing wells simply fabricated in aluminum with a small, portable Raman spectrometer with a focusing fiber optic probe. Hemispherical aluminum sample wells were specially designed to optimize internal reflection and sampling volume by matching the focal length of the mirror to the depth of focus of the laser probe. The technique was tested on milk adulterated with 4 different nitrogen-rich compounds (melamine, urea, dicyandiamide, and ammonium sulfate) and sucrose. No sample preparation of the milk was needed, and the total analysis time was 4min. Reliable sample presentation enabled average reproducibility of 8% residual standard deviation. The limit of detection interval measured from partial least squares calibrations ranged between 140 and 520mg/L for the 4 N-rich compounds and between 7,000 and 36,000mg/L (0.7-3.6%) for sucrose. The portability of the system and the reliability and reproducibility of this technique open opportunities for general, reagentless screening of milk for adulterants at the point of collection.

Metal-free, zinc(II) and lead(II) phthalocyanines functioning with 3-(2H-benzo[d][1,2,3]triazol-2-yl)-4-hydroxyphenethyl methacrylate groups: Synthesis and investigation of photophysical and photochemical properties

In this study, the synthesis and characterization of 3-(2H-benzo[d][1,2,3]triazol-2-yl)-4-hydroxyphenethyl methacrylate substituted novel phthalonitrile compound and its peripherally substituted zinc(II) lead(II) and metal-free phthalocyanine derivatives were performed for the first time. This novel compounds were characterized by obtained data from general spectroscopic methods such as FT-IR, 1H NMR, 13C NMR and mass. The photophysical and photochemical properties of these phthalocyanines were investigated in N,N-dimethylformamide solutions for determination of their photosensitizing abilities in photocatalytic applications such as photodynamic therapy. The lead(II) phthalocyanine complex did not produce any fluorescent in N,N-dimethylformamide because of the heavy atom effect of bigger lead atom. The fluorescence quantum yields of studied zinc(II) and metal-free phthalocyanines were found to quite higher than unsubstituted zinc(II) phthalocyanine due to substitution of the phthalocyanine skeleton. The influence of substituent and variety of the central metal ions on spectroscopic, photophysical and photochemical properties were also determined and compared.

Novel phthalocyanine–BODIPY conjugates and their photophysical and photochemical properties

Novel zinc(II) phthalocyanines bearing boron dipyrromethene (BODIPY) (8) and its mono-styryl (9) and di-styryl (10) derivatives containing p-(N,N-diethylamino)benzaldehyde moieties were designed and synthesized for the first time. These phthalocyanines (8–10) were prepared by the copper-free Sonogashira coupling reaction of terminal ethynyl functionalized BODIPYs [4,4′-difluoro-8-(4-propynyloxy)-phenyl-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (2), 4,4′-difluoro-8-(4-propynyloxy)-phenyl-3,5,7-trimethyl-1-((4-diethylaminophenyl)ethenyl)-4-bora-3a,4a-diaza-s-indacene (5), or 4,4′-difluoro-8-(4-propynyloxy)-phenyl-3,5-dimethyl-1,7-bis((4-4″-diethylaminophenyl)ethenyl)-4-bora-3a,4a-diaza-s-indacene (6)] with tetrakis(iodo) zinc(II) phthalocyanine (7). All newly synthesized compounds were fully characterized by elemental analysis and general spectroscopic methods such as 1H NMR, FT-IR, mass, UV–Vis, and fluorescence. The photophysical (fluorescence quantum yields and lifetimes), photochemical (singlet oxygen generation capability and photodegradation behaviors) properties of these phthalocyanines were also investigated for determination of their photodynamic therapy (PDT). The results obtained indicated that these conjugates could be promising photosensitizers for PDT applications.

Tiny Peaks vs Mega Backgrounds: A General Spectroscopic Method with Applications in Resonant Raman Scattering and Atmospheric Absorptions

A simple method using standard spectrometers with charge-coupled device (CCD) detectors is described to routinely measure background-corrected spectra in situations where the signal is composed of weak spectral features (such as Raman peaks or absorption lines) engulfed in a much stronger (by as much as ∼10(5)) broad background. The principle of the method is to subtract the dominant fixed-structure noise and obtain a shot-noise limited spectrum. The final noise level can therefore be reduced as desired by sufficient integration time. The method requires multiple shifts of the diffraction gratings to extract the pixel-dependent noise structure, which is then used as a flat-field correction. An original peak-retrieval procedure is proposed, demonstrating accurate determination of peak lineshapes and linewidths and robustness on practical examples where conventional methods would not be applicable. Examples are discussed to illustrate the potential of the technique to perform routine resonant Raman measurements of fluorescent dyes with high quantum yield, using conventional Raman systems. The method can equally be applied to other situations where small features are masked by a broad overwhelming background. An explicit example is given with the measurement of weak absorption lines in atmospheric gases.

Spectroscopic Characterization of Supersonic Molecular Beams

AbstractA general spectroscopic method is described by which samples prepared in supersonic molecular beams can be characterized independently in their ground and excited electronic states. The centerpiece of this experiment is a Fourier transform spectrometer operating at high resolution in the infrared, visible, and ultraviolet. This method is illustrated with studies of the NO2 and OClO radicals prepared in supersonic molecular beams at temperatures and pressures characteristic of the Earth's atmosphere.This general spectroscopic method is discussed by analogy with low‐ and high‐resolution studies of electronic states which in limited cases have been used to characterize sample conditions in supersonic molecular beam experiments.

96/03786 Fischer-Tropsch and methanol synthesis

In this study, novel peripherally tetra-(5-chloro-2-(2,4-dichlorophenoxy)phenol) substituted metal-free (4), zinc(II) (5) and lead(II) (6) phthalocyanine derivatives were synthesised. The novel phthalocyanines (4–6) were characterised by general spectroscopic methods such as IR, 1H NMR, UV–vis, mass spectrometry and elemental analysis. Once the solubilities of the compounds were investigated, it was noticed that they have excellent solubility and did not tend to aggregation behaviour in common solvents. The photophysical and photochemical properties of novel phthalocyanines (4–6) were investigated in dimethysulfoxide. The effects of substituted 5-chloro-2-(2,4-dichlorophenoxy)phenoxy group and central metal ion [zinc(II)/lead(II)] on photophysical and photochemical properties of the novel phthalocyanines have also been examined, and the results were compared with unsubstituted zinc(II) phthalocyanine. According to photophysical and photochemical investigation results, it was observed that the novel phthalocyanines (4–6) have a potential for PDT application.

Quantitative Analysis of Binary Mixtures. I. General Method

A general spectroscopic method for the analysis of binary mixtures which does not require external calibration has been developed. Spectra of the original mixture and of the mixture following some fractionation procedure are obtained. The method is based on the scaling factors required to null the components, one at a time, in successive absorbance subtractions of the two spectra. The accuracy is improved by a factor of approximately ten more than that of an earlier method. The effect of errors in the scaling factors on the analytical results is considered.

Quantitative Infrared Spectroscopic Measurements of Mixtures without External Calibration

A general spectroscopic method for the analysis of mixtures that does not require external calibration has been developed. The method is based on the obtaining of absorbance ratio spectra and the determination of a concentration ratio at frequencies unique to each component. The method is applied to mixtures hexane and cyclohexane.