The electronic spectra of nickel(II) bis(dithiocarbamate) chelates

1980 ◽  
Vol 45 (3) ◽  
pp. 791-799 ◽  
Author(s):  
Drahomír Oktavec ◽  
Bohumil Síleš ◽  
Jozef Štefanec ◽  
Elena Korgová ◽  
Ján Garaj
Keyword(s):  
Charge Transfer ◽  
Nitrogen Atom ◽  
Electronic Spectra ◽  
Alkyl Chain ◽  
Solvent Polarity ◽  
Blue Shift ◽  
Red Shift ◽  
Band Intensity ◽  
Absorption Bands

The synthesis and electronic spectra of the chelates of nickel(II) dithiocarbamates with ligands derived from dimethyl-, diethyl-, dipropyl-, dibutyl-, dipentyl-, dihexyl-, diheptyl-, dioctyl-, diisopropyl-, methylisopropylamine, piperidine, morpholine and piperazine are discussed. The absorption bands in the chelate spectra around 220 and 245 nm are assigned to absorption localized primarily in the S-C=S and N-C=S ligand groups. The analytically most important band with λmax around 330 nm assigned to M-L charge transfer is affected by alkyl substituents on the nitrogen atom and by the solvent polarity. The lengthening of the alkyl chain causes the increase in the intensity of the band and red-shift of its λmax; the increase of the polarity of the solvent leads to an increase in the band intensity and a blue shift.

The electronic spectra of the bis(dithiocarbamate) chelates of Cu(II) and Zn(II)

1982 ◽  
Vol 47 (11) ◽  
pp. 2867-2875 ◽  
Author(s):  
Drahomír Oktavec ◽  
Jozef Štefanec ◽  
Bohumil Síleš ◽  
Ernest Beinrohr ◽  
Václav Konečný ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Absorption Spectra ◽  
Electronic Spectra ◽  
Alkyl Chain ◽  
Solvent Polarity ◽  
Blue Shift ◽  
Red Shift

This work deals with the synthesis of dithiocarbamate chelates of Cu(II) and Zn(II) with ligands derived from dimethyl-, diethyl-, dipropyl-, dibutyl- and methylisopropylamine, piperidine and morpholine and the electronic spectra of these substances in the UV and visible regions. The absorption spectra of the cupric (and zinc(II)) chelates contain a single analytically important band around 270 (260) nm, assigned to the π-π* transition within the ligand, that is affected by the substituent on the nitrogen atom and the solvent polarity. Lengthening of the alkyl chain leads to increased intensity of the bands and a red shift of their λmax; increased solvent polarity leads to increased intensity of the bands and a blue shift.

Electronic spectra of salts of dithiocarbamic acids

1979 ◽  
Vol 44 (8) ◽  
pp. 2487-2493 ◽  
Author(s):  
Drahomír Oktavec ◽  
Jozef Štefanec ◽  
Bohumil Síleš ◽  
Václav Konečný ◽  
Ján Garaj
Keyword(s):  
Absorption Band ◽  
Electronic Spectra ◽  
Alkyl Chain ◽  
Carbon Disulphide ◽  
Blue Shift ◽  
Uv Spectra ◽  
Red Shift ◽  
Ammonium Salts ◽  
Absorption Bands

The report gives synthesis and UV spectra of a series of alkali and ammonium salts of the dithiocarbamic acids derived from dimethyl-, diethyl-, dipropyl-, dibutyl-, dipentyl-, dihexyl-, diheptyl-, dioctyl-, diisopropyl-, diisobutyl-, methylisopropylamine, piperidine, morpholine, piperazine and pyrrolidine. The absorption bands due to transitions localized in the groups CSS (λmax ~ 260 nm) and NCS (λmax ~ 280 nm) show a red shift with increasing length of the alkyl chain. Increasing polarity of solvent causes, with some of the compounds, a small red shift of λmax of the band due to CSS group, but it causes a considerable blue shift of λmax of the band due to NCS group in all the studied compounds. The absorption band near 207 nm is ascribed to the carbon disulphide produced by decomposition of the dithiocarbamates.

scholarly journals New Charge Transfer Complexes of K+-Channel-Blocker Drug (Amifampridine; AMFP) for Sensitive Detection: Solution Investigations and DFT Studies

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6037
Author(s):  
Reem M. Alghanmi ◽  
Maram T. Basha ◽  
Saied M. Soliman ◽  
Razan K. Alsaeedi
Keyword(s):  
Charge Transfer ◽  
Dft Calculations ◽  
Electronic Spectra ◽  
Channel Blocker ◽  
Molecular Structures ◽  
K Channel ◽  
Physical Parameters ◽  
Absorption Bands ◽  
Vis Spectroscopy ◽  
Ct Complexes

UV–Vis spectroscopy was used to investigate two new charge transfer (CT) complexes formed between the K+-channel-blocker amifampridine (AMFP) drug and the two π-acceptors 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetracyanoethylene (TCNE) in different solvents. The molecular composition of the new CT complexes was estimated using the continuous variations method and found to be 1:1 for both complexes. The formed CT complexes’ electronic spectra data were further employed for calculating the formation constants (KCT), molar extinction coefficients (εCT), and physical parameters at various temperatures, and the results demonstrated the high stability of both complexes. In addition, sensitive spectrophotometric methods for quantifying AMFP in its pure form were proposed and statistically validated. Furthermore, DFT calculations were used to predict the molecular structures of AMFP–DDQ and AMFP–TCNE complexes in CHCl3. TD-DFT calculations were also used to predict the electronic spectra of both complexes. A CT-based transition band (exp. 399 and 417 nm) for the AMFP–TCNE complex was calculated at 411.5 nm (f = 0.105, HOMO-1 → LUMO). The two absorption bands at 459 nm (calc. 426.9 nm, f = 0.054) and 584 nm (calc. 628.1 nm, f = 0.111) of the AMFP–DDQ complex were theoretically assigned to HOMO-1 → LUMO and HOMO → LUMO excitations, respectively.

scholarly journals Effects of Pyrazine Derivatives and Substituted Positions on the Photoelectric Properties and Electromemory Performance of D–A–D Series Compounds

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2063 ◽  
Author(s):  
Xuejing Song ◽  
Lingqian Kong ◽  
Hongmei Du ◽  
Xiangyu Li ◽  
Hanlin Feng ◽  
...  
Keyword(s):  
Flash Memory ◽  
Intramolecular Charge Transfer ◽  
Emission Spectra ◽  
Solvent Polarity ◽  
Band Gap Energy ◽  
Red Shift ◽  
Absorption Bands ◽  
Photoelectric Properties ◽  
Threshold Voltages ◽  
Very High

Pyrazine derivatives quinoxaline and pyridopyrazine were selected as the acceptors, and benzocarbazole was used as the donor to synthesize four different D–A–D compounds. The results showed that 2,3-bis(decyloxy)pyridine[3,4-b]pyrazine (DPP) exhibited stronger electron-withdrawing ability than that of 2,3-bis(decyloxy)quinoxaline (DPx), because DPP possesses one more nitrogen (N) atom, resulting in a red-shift of the intramolecular charge transfer (ICT) absorption bands and fluorescent emission spectra for compounds with DPP as the acceptor compared with those that use DPx as the acceptor. The band-gap energy (Eg) of the four D–A–D compounds were 2.82 eV, 2.70 eV, 2.48 eV, and 2.62 eV, respectively, for BPC-2DPx, BPC-3DPx, BPC-2DPP, and BPC-3DPP. The solvatochromic effect was insignificant when the four compounds were in the ground state, which became significant in an excited state. With increasing solvent polarity, a 30–43 nm red shift was observed in the emissive spectra of the compounds. The thermal decomposition temperatures of the four compounds between 436 and 453 °C had very high thermal stability. Resistor-type memory devices based on BPC-2DPx and BPC-2DPP were fabricated in a simple sandwich configuration, Al/BPC-2DPx/ITO or Al/BPC-2DPP/ITO. The two devices showed a binary non-volatile flash memory, with lower threshold voltages and better repeatability.

scholarly journals Synthesis and Photophysical Properties of a Series of Dimeric Indium Quinolinates

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 34
Author(s):  
Sang Woo Kwak ◽  
Ju Hyun Hong ◽  
Sang Hoon Lee ◽  
Min Kim ◽  
Yongseog Chung ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Nmr Spectroscopy ◽  
1H Nmr Spectroscopy ◽  
Photophysical Properties ◽  
Emission Spectra ◽  
Solvent Polarity ◽  
Low Energy ◽  
Quantum Yields ◽  
Absorption Bands ◽  
Indium Complexes

A novel class of quinolinol-based dimeric indium complexes (1–6) was synthesized and characterized using 1H and 13C(1H) NMR spectroscopy and elemental analysis. Compounds 1–6 exhibited typical low-energy absorption bands assignable to quinolinol-centered π–π* charge transfer (CT) transition. The emission spectra of 1–6 exhibited slight bathochromic shifts with increasing solvent polarity (p-xylene < tetrahydrofuran (THF) < dichloromethane (DCM)). The emission bands also showed a gradual redshift, with an increase in the electron-donating effect of substituents at the C5 position of the quinoline groups. The absolute emission quantum yields (ΦPL) of compounds 1 (11.2% in THF and 17.2% in film) and 4 (17.8% in THF and 36.2% in film) with methyl substituents at the C5 position of the quinoline moieties were higher than those of the indium complexes with other substituents.

Correlation of optical and electron spin resonance spectra for metal–electron species in alkali metal solutions

1977 ◽  
Vol 55 (11) ◽  
pp. 2017-2021 ◽  
Author(s):  
William Arthur Seddon ◽  
John Wallace Fletcher ◽  
Ron Catterall
Keyword(s):  
Electron Spin Resonance ◽  
Alkali Metal ◽  
Electron Spin ◽  
Ion Pairs ◽  
Solvent Polarity ◽  
Blue Shift ◽  
Esr Spectra ◽  
Absorption Bands ◽  
Continuous Transition ◽  
Spin Resonance

Pulse radiolysis of alkali metal cations (M+) in amines and tetrahydrofuran has demonstrated the formation of transient optical absorption bands attributed to a species of stoichiometry M. Such bands exhibit a distinct blue shift from that of es− observed in the same solvent. Comparisons with electron spin resonance (esr) spectra obtained in alkali metal solutions demonstrate that the blue shift can be correlated with the percent atomic character deduced for the species of the same stoichiometry. This correlation indicates that both the optical and esr spectra arise from the same species which, with decreasing solvent polarity, exhibits a continuous transition from well solvated ion-pairs to something approaching solvated atoms or tight ion-pairs.

scholarly journals A SERS Study of Charge Transfer Process in Au Nanorod–MBA@Cu2O Assemblies: Effect of Length to Diameter Ratio of Au Nanorods

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 867
Author(s):  
Lin Guo ◽  
Zhu Mao ◽  
Sila Jin ◽  
Lin Zhu ◽  
Junqi Zhao ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Shell Structure ◽  
Shell Structures ◽  
Core Shell ◽  
Absorption Bands ◽  
Au Nanorods ◽  
The Core ◽  
Band Position ◽  
Surface Enhanced Raman ◽  
Core Shell Structure

Surface-enhanced Raman scattering (SERS) is a powerful tool in charge transfer (CT) process research. By analyzing the relative intensity of the characteristic bands in the bridging molecules, one can obtain detailed information about the CT between two materials. Herein, we synthesized a series of Au nanorods (NRs) with different length-to-diameter ratios (L/Ds) and used these Au NRs to prepare a series of core–shell structures with the same Cu2O thicknesses to form Au NR–4-mercaptobenzoic acid (MBA)@Cu2O core–shell structures. Surface plasmon resonance (SPR) absorption bands were adjusted by tuning the L/Ds of Au NR cores in these assemblies. SERS spectra of the core-shell structure were obtained under 633 and 785 nm laser excitations, and on the basis of the differences in the relative band strengths of these SERS spectra detected with the as-synthesized assemblies, we calculated the CT degree of the core–shell structure. We explored whether the Cu2O conduction band and valence band position and the SPR absorption band position together affect the CT process in the core–shell structure. In this work, we found that the specific surface area of the Au NRs could influence the CT process in Au NR–MBA@Cu2O core–shell structures, which has rarely been discussed before.

scholarly journals Correction: Photophysical properties of the intramolecular excited charge-transfer states of π-expanded styryl phenanthrimidazoles – effect of solvent polarity

RSC Advances ◽  
2016 ◽  
Vol 6 (87) ◽  
pp. 83709-83709
Author(s):  
V. Thanikachalam ◽  
A. Arunpandiyan ◽  
J. Jayabharathi ◽  
P. Ramanathan
Keyword(s):  
Charge Transfer ◽  
Photophysical Properties ◽  
Solvent Polarity ◽  
Effect Of Solvent

Correction for ‘Photophysical properties of the intramolecular excited charge-transfer states of π-expanded styryl phenanthrimidazoles – effect of solvent polarity’ by V. Thanikachalam et al., RSC Adv., 2014, 4, 6790–6806.

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