Antiradical Properties of trans-2-(4-substituted-styryl)-thiophene.

2-substituted thiophene compounds with electron donating and electron withdrawing p-phenyl substitution were synthesized and studied their radical scavenging properties using DPPH assay and DFT method. It is shown that p-hydroxy and p-amino phenyl substituted compound exhibit radical scavenging activity. From DFT and radical scavenging studies, a correlation between IC50 with the bond dissociation enthalpy, proton affinity, ground state dipole moment and optical band gap of compound is found. Compounds 1-3 with electron withdrawing substituent (NO2, CN, Cl) do not show any radical scavenging properties, whereas compounds 6-7 with electron donating substituent (OH, NH2) show antiradical properties. Further, the antiradical activity is reduced drastically by replacing the -OH and -NH2 with methoxy and -N-alkylating group respectively in 6 and 7. The compound with p-hydroxy phenyl substitution, exhibits stronger antiradical activity as compared to the p-amino phenyl substitution due to smaller O-H bond dissociation energy as compared to the N-H bond. From DPPH and DFT studies, it is suggested that the radical scavenging activity in 2-substituted thiophene is occurred through proton transfer mechanism. The other possible SET, SPLET mechanisms are also corroborated. Graphical Abstract Antiradical properties of trans-2-(4-substituted-styryl)-thiophene Anamika Gusain, Naresh Kumar, Jagdeep Kumar, Gunjan Pandey, Prasanta Kumar Hota.

Substituent Dependent Optical Properties of p-phenyl Substituted ethenyl-E-thiophenes.

Various electron donor and acceptor substituted (NO2, CN, Cl, H, OCH3, NH2) p-phenyl ethenyl-E- thiophenes (1-6) were synthesized and substituent dependent optical properties (dipole moment, transition dipole moment, oscillator strength, optical band gap, hyperpolarizability) were studied using Solvatochromism and Density functional theory. It is shown that thiophene acts as a weak electron donor in presence of an electron withdrawing p-phenyl substituent (NO2, CN, Cl), whereas thiophene acts as a weak electron acceptor in presence of an electron donating p-phenyl substituent (OCH3, NH2). In comparison to ethenyl thiophene 4, the HOMO-LUMO energy band gap is decreased upon increasing the electron donating or electron withdrawing capacity of p-phenyl substituent. From the excited state dipole moment calculation, it is shown that the excited state is highly dipolar for nitro and amino compounds 1 and 6, whereas compounds 2-5 show a non-polar excited state. As compared to the ethenyl thiophene 4, the first hyperpolarizability (ß) increases upon substitution either with a strong electron withdrawing or strong electron donating p-phenyl substituent. A large ß value is found for p-nitro phenyl ethenyl-E-thiophene and p-amino phenyl ethenyl-E- thiophene. Overall, these studies provide useful information in understanding the optical properties of phenyl and heterocyclic based ethenyl systems.

Substituent Dependence Charge Transfer and Photochemical Properties of Donor-Acceptor Substituted Ethenyl Thiophenes.

Donor-acceptor conjugated molecules with efficient light induced properties represent interesting material for electronic device application. In this context, we have calculated excited state dipole moment of three ethenyl thiophenes (1-3) bearing varied electron donor-acceptor substituent in p-phenyl unit using Lippert-Mataga, Bakhshiev and Kawski method. It is found that 1 with strong electron-withdrawing nitro substituent, is exhibiting charge transfer and highly dipolar excited state as compared to 2 and 3. Photochemical studies of 1-3, indicate towards the charge transfer dependence trans-cis photoisomerization under direct irradiation condition. Compound 1 exhibits charge transfer and less efficient towards photoisomerization, whereas 2 and 3 undergo efficient photoisomerization. Graphical Abstract Substituent dependence charge transfer and photochemical properties of donor-acceptor substituted ethenyl thiophenes.

Fluorescent carbon dots for sensing applications: a review.

Luminescent carbon dots (CDs) are important class of nanomaterials with fantastic photoluminescence (PL) properties, great biocompatibility, extraordinary solubility in water, minimal expense, and so on. There are many methods for their preparation and they are mainly classed into two groups, top-down and bottom-up approaches. In order to understand the origin of fluorescence in quantum CDs, three mechanisms have been proposed namely molecular state, surface state, and quantum confinement phenomenon. Fluorescent CDs have significant application in the fields of biochemical sensing, photocatalysis, bioimaging, delivery of drugs, and other related fields. In this review article the application of quantum dots as detecting component, for the sensing of different targets, has been summed up. In fact, the detection of several analytes including, anions, cations, small molecules, polymers, cells, and microscopic organisms has been discoursed. Moreover, the future aspects of CDs as detecting resources have been explored.

The Role of Vitamin C: From Prevention of Pneumonia to Treatment of Covid-19.

Vitamins are the main components of our diet. In our nutrition 14 vitamins are present namely A, B1 (Thiamine), B6(Pyridoxine), B12(Cyanocobalamin), C, D, E, K, niacin, folacin, choline, pantothenic acid and biotin. The main role of it is in treating common diseases like cold. Vitamin C's role in treating pneumonia or Sepsis /Septicemia has been underway for many decades. A great benefit in decreasing the duration of cold is by injecting heavy dose of ascorbic acid. So, at high dose/ risk of injection like it may be obese, diabetes, and the elderly. Vitamin C always acts as an antioxidant that can help to prevent our cells from getting any harm. Recently injection of vitamin C was used in treatment of Covid-19 patients. In this review we have primarily discussed its effects on the immune system and the treatment of pneumonia disorders using vitamin C. At the beginning we have discussed the bio-avalibility of vitamin-C followed by the synthesis of it by plants and animals and then the dietary allowance to be followed for vitamin C regularly. The level of vitamin C is very low in people having pneumonia and those with low immunity are being effected by COVID-19 virus. Kiwi is the main source of vitamin C. Preliminary observational studies show that critically sick individuals use vitamin C for the prevention of the pneumonia to the treatment of the virus COVID-19 by increasing the vitamin C levels in the body.

Optical properties of 3-substituted indoles.

The optical properties of various donor or acceptor p-phenyl substituted ethenyl indoles were studied in solvents of varying polarity using absorption, fluorescence and TDDFT methods. Ethenyl indole exhibits non-linear optical properties (NLO) in a substituent dependent manner. Compound with a strong electron-attracting substituent, shows large NLO properties with charge transfer behavior, whereas ethenyls with moderate electron withdrawing or electron donating substituent exhibit lower NLO properties with non polar excited state. A highly dipolar excited state for p-nitro phenyl substituted ethenyl indoles (µ e: 18.2-27.1 debye; Δµ: 9.4-17.8 debye) is observed as compared to other ethenyls (µ e: 6.6-9.5 debye; Δµ: 4.2-6.2 debye). From TDDFT study, it is shown that the HOMO-LUMO energy of ethenyl is increased with increasing the electron donating ability of the p-phenyl substitution. The optical band gap of ethenyl 3 without substitution, is decreased upon p-phenyl substitution either with an electron withdrawing (Cl, NO2) or an electron donating (OCH3, OH, NH2) substituent. The compound with a strong electron accepting, p-nitrophenyl ethenyl indole 1 shows 12 times better NLO response as compared to the reference ethenyl indole 3 (ß: 1: 115 × 10-30 esu-1 cm5, 3: 9 × 10-30 esu-1 cm5). Ethenyls 2-6 bearing a weak or moderately electron withdrawing or electron accepting substituent, exhibit lower NLO response. The ß of ethenyl is increased with increasing the order of electron withdrawing nature of phenyl ring. Overall, a correlation of ß with the optical band gap, ground state dipole moment, % of charge transfer in the ground and excited state is found.

Tuning of optical properties of p-phenyl ethenyl-E-furans: A Solvatochromism and Density functional theory.

p-Phenyl ethenyl-E-furans (1-6) with varied electron donor and acceptor substituent (NO2, CN, Cl, H, OCH3, NH2) were synthesized and studied the substituent induced optical properties (dipole moment, transition dipole moment, oscillator strength, optical band gap, hyperpolarizability) using Solvatochromism and Density functional theory. It is shown that furan acts as a weak electron donor in presence of an electron withdrawing p­phenyl substituent (NO2, CN, Cl), whereas furan acts as a weak electron acceptor in presence of an electron donating p­phenyl substituent (OCH3, NH2). In comparison to ethenylfuran 4, the HOMO-LUMO energy band gap is decreased upon increasing the electron donating or electron withdrawing nature of the phenyl ring. Calculation of excited state dipole moment and polarizability of 1-6 in solvent of varying polarity suggest that the nitro and amino compounds (1, 6) exhibit charge transfer excited state, whereas excited state of compounds 3-5 is non-polar in nature. As compared to the ethenylfuran (4), the first hyperpolarizability (ß) is increased in presence of a strong electron withdrawing or strong electron donating p­phenyl substituent. The higher ß value is found for ethenylfuran with p­nitrophenyl and p­amino phenyl substitution. Overall, these studies provide useful information in tuning the optical properties of p­phenyl substituted heterocyclic ethenyl systems.

Genetic analysis of reproductive performance of Frieswal cattle at Military Farm, Ambala.

AIM: This study was carried out to investigate the genetic analysis of reproductive performance of Frieswal cattle at Military Farm, Ambala. MATERIALS AND METHODS: A total number of 3005 lactation records of 1147 Frieswal cows over a period of 15 years extending from 1993 to 2007 were used to study at Military Dairy Farm, Ambala. The study period was divided into 5 period of 3 years each. The average performances of reproduction traits, effect of genetic and non-genetic factors were analyzed, and estimation of genetic and phenotypic parameters of reproduction traits was undertaken. RESULTS: The age at first calving (AFC) differed significantly across the periods of calving. The AFC was lowest during the third period (1999-2001) and longest in the first period (1993-95). The effect of season and period of calving, lactation order and regression of AFC on dry period, calving interval and service period was highly significant. The effect of sire was non-significant. The heritability estimates were low for almost all the traits under study. The service period had a high genetic correlation with dry period and calving interval. The dry period also found to have a low genetic correlation with calving interval in Frieswal cows. Service period had a high phenotypic correlation with dry period and very high with a calving interval. The phenotypic correlation between the dry period and calving interval was recognized high. CONCLUSIONS: Low heritability estimate for the reproduction traits indicates that there is a very little additive genetic variance in these traits, and individual selection will not be helpful for improving them. Improvement may be brought through better feeding and management of cows by reducing the environmental variability.