ChemInform Abstract: Thermo- and Photochromic Dyes: Indolino-benzospiropyrans. Part 1. UV- VIS Spectroscopic Studies of 1,3,3-Spiro(2H-1-benzopyran-2,2′- indolines) and the Open-Chain Merocyanine Forms; Solvatochromism and Medium Effects on Spiro Ring For

ChemInform ◽  
2010 ◽  
Vol 23 (27) ◽  
pp. no-no
Author(s):  
S.-R. KEUM ◽  
M.-S. HUR ◽  
P. M. KAZMAIER ◽  
E. BUNCEL
Keyword(s):  
Spectroscopic Studies ◽  
Medium Effects ◽  
Open Chain

Thermo- and photochromic dyes: indolino-benzospiropyrans. Part 1. UV–VIS spectroscopic studies of 1,3,3-spiro(2H-1-benzopyran-2,2′-indolines) and the open-chain merocyanine forms; solvatochromism and medium effects on spiro ring formation

1991 ◽  
Vol 69 (12) ◽  
pp. 1940-1947 ◽  
Author(s):  
Sam-Rok Keum ◽  
Mun-Suk Hur ◽  
Peter M. Kazmaier ◽  
Erwin Buncel
Keyword(s):  
Transition State ◽  
Ultraviolet Irradiation ◽  
Ground State ◽  
Phenyl Group ◽  
Spectroscopic Studies ◽  
Ring Closure ◽  
Medium Effects ◽  
Open Chain ◽  
Semi Empirical ◽  
Electronic Character

A kinetic and ultraviolet–visible study of a series of thermo- and photochromic dyes is reported. Ultraviolet irradiation of the indolino-benzospiropyran derivatives 1′–4′ leads to their transformation to the open-chain, colored merocyanine forms, which undergo thermal ring closure into the colorless spiro forms. The rate of this ring closure has been determined in different solvents. Plots of log (rate) vs. the solvent parameter ET are linear but are dependent on the nature of the substituent in the phenyl moiety, which yields information on the electronic character of the ground state (IIa↔IIb) and the transition state. The ring-closure process is characterized by a zwitterionic type transition state, TS3. The merocyanine dyes exhibit a significant solvatochromic effect, which unexpectedly shows sensitivity to substituents on the phenyl group. This observation finds explanation through semi-empirical molecular orbital (MOPAC) calculations. The MOPAC calculations also predict that the most stable configurational isomer of the merocyanines is the CTTC form. Key words: indolino-benzospiropyran–merocyanine interconversion, photochromic–solvatochromic dyes.

scholarly journals Synthesis and characterization of substituted acetophenone-4, 4-dimethyl-3-thiosemicarbazone derivatives with an evaluation of antimicrobial and antioxidant activities

2020 ◽  
Vol 11 (4) ◽  
pp. 7192-7197
Author(s):  
Nagoor Meeran M ◽  
Narayanan Ravisankar
Keyword(s):  
Antioxidant Activity ◽  
Metal Complexes ◽  
Antioxidant Activities ◽  
Spectroscopic Studies ◽  
Biological Properties ◽  
Butylated Hydroxytoluene ◽  
Significant Activity ◽  
Pharmaceutical Drugs ◽  
Open Chain ◽  
Antimicrobial And Antioxidant Activity

Thiosemicarbazones are organic compounds; these are widely used in the medical field. It is primarily in the manufacture of pharmaceutical drugs and bio molecules. These compounds have the azomethine functional group (-N=CH-) used to derive organic open chain and heterocyclic compounds. Thiosemicarbazones are similar to semicarbazones, and carbonyl group oxygen is replaced by sulphur. Thiosemicarbazone contains nitrogen and sulfur atoms, so they are used as ligands in coordination chemistry and form metal complexes. Thiosemicarbazone and its metal complexes are used in a variety of ways. It is especially widely used in the preparation of polymers and biochemicals products. Thiosemicarbazone and its metal complexes are closely correlated with biological properties and act as antioxidants, antifungals, antimicrobials and anticancer. Subsequently, in the current study, substituted thiosemicarbazones were synthesized and examined for their antimicrobial and antioxidant activity. Newly substituted thiosemicarbazones were obtained from the respective acetophenones and thiosemicarbazides. The structure of the newly prepared compounds was confirmed by spectroscopic studies such as IR, 1H, 13C NMR, Mass and elemental analysis. The antimicrobial activity of all the new compounds showed significant activity against the selected bacteria and fungi in the studies. The compound TZ04 exhibited good antioxidant activity compared with standard ascorbic acid and butylated hydroxytoluene.

Gender Differences in the Mental Rotations Test (MRT) Are Not Due to Task Complexity

2008 ◽  
Vol 29 (3) ◽  
pp. 130-133 ◽  
Author(s):  
Corinna Titze ◽  
Martin Heil ◽  
Petra Jansen
Keyword(s):  
Gender Differences ◽  
Mental Rotation ◽  
Task Complexity ◽  
Time Constraints ◽  
Medium Effects ◽  
Performance Factors ◽  
Mental Rotations ◽  
Sufficient Power ◽  
Forced Choice Tasks ◽  
Choice Tasks

Gender differences are one of the main topics in mental rotation research. This paper focuses on the influence of the performance factor task complexity by using two versions of the Mental Rotations Test (MRT). Some 300 participants completed the test without time constraints, either in the regular version or with a complexity reducing template creating successive two-alternative forced-choice tasks. Results showed that the complexity manipulation did not affect the gender differences at all. These results were supported by a sufficient power to detect medium effects. Although performance factors seem to play a role in solving mental rotation problems, we conclude that the variation of task complexity as realized in the present study did not.

Spectroscopic studies of Pd (II) complexes with cysteine and its di- and tripeptides

1987 ◽  
Vol 84 ◽  
pp. 443-448 ◽  
Author(s):  
Teresa Kowalik ◽  
Brigitte Decock-Le Reverend ◽  
Claude Loucheux ◽  
Damien Ficheux ◽  
Henryk Kozlowski
Keyword(s):  
Spectroscopic Studies
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