A probe based on 2-(2'-hydroxyphenyl) benzothiazole (HBT) has been synthesized and used for the ratiometric detection of hydrazine. The probe is designed in such a way that the excited state intramolecular proton transfer (ESIPT) of the HBT moiety gets blocked. The chemodosimetric approach of hydrazine to the probe results in the recovery of the ESIPT by removal of a free HBT moiety through subsequent substitution, cyclization, and elimination processes. The probe is successfully demonstrated to enable the detection of hydrazine in live cells.

Reduced graphene oxide (rGO) generates reactive oxygen species (ROS) under visible light in air via a singlet oxygen–superoxide anion radical pathway that readily kills Enterobacter sp.

The complex [Ph4P]2[Cu(bdt)2] (1(red)) was synthesized by the reaction of [Ph4P]2[S2MoS2CuCl] with H2bdt (bdt = benzene-1,2-dithiolate) in basic medium. 1(red) is highly susceptible toward dioxygen, affording the one electron oxidized diamagnetic compound [Ph4P][Cu(bdt)2] (1(ox)). The interconversion between these two oxidation states can be switched by addition of O2 or base (Et4NOH = tetraethylammonium hydroxide), as demonstrated by cyclic voltammetry and UV-visible and EPR spectroscopies. Thiomolybdates, in free or complex forms with copper ions, play an important role in the stability of 1(red) during its synthesis, since in its absence, 1(ox) is isolated. Both 1(red) and 1(ox) were structurally characterized by X-ray crystallography. EPR experiments showed that 1(red) is a Cu(II)-sulfur complex and revealed strong covalency on the copper-sulfur bonds. DFT calculations confirmed the spin density delocalization over the four sulfur atoms (76%) and copper (24%) atom, suggesting that 1(red) has a "thiyl radical character". Time dependent DFT calculations identified such ligand to ligand charge transfer transitions. Accordingly, 1(red) is better described by the two isoelectronic structures [Cu(I)(bdt2, 4S(3-,)*)](2-) ↔ [Cu(II)(bdt2, 4S(4-))](2-). On thermodynamic grounds, oxidation of 1(red) (doublet state) leads to 1(ox) singlet state, [Cu(III)(bdt2, 4S(4-))](1-).

Water soluble fluorescent carbon nano onions (wsCNO) cross the blood brain barrier (BBB) in the CADASIL murine model as well as in GBM induced mice.

Keyword: GO, Open and close form of GO, Alzheimer drug entrap and release, TPP, Drug delivery. nm nmGraphene oxide, (GO) in the size range of 40 -200 nm, has been extracted from low grade coal or wood charcoal by leaching with dil nitric acid then neutralize with aqueous sodium hydroxide. We show that tetraphenylporphyrin (TPP ) type large molecule got entrapped inside GO in its closed form. Such GO -TPP composite retains the property of pure GO with respect to its solubility in ethanol in which free TPP is insoluble. Further we show that in phosphate buffered saline (PBS) this composite is soluble to retain the TPP inside displaying the combined spectral signatures of GO and TPP at pH, 6.8. The water insoluble TPP inside the composite cannot be extracted by dichloromethane where free TPP is highly soluble. On raising the pH of PBS buffer to 7.4, it releases all entrapped TPP by opening the clenched fist form. We further show that donepezil, a drug, used in Alzheimer treatment gets entrapped by GO to remain inside in PBS which is released at higher pH . The clenched and open fist forms of GO are related to pH dependent epoxide -diols inter-conversion that uniquely provide GO to act as Trojan horse in carrying a drug molecule and its delivery under physio-compatible environment.Abstract : Graphene oxide, (GO), present in the low grade coal, formed under natural coalifcation of plants is extracted by leaching with cold nitric acid. Similar easy extraction of GO is followed from wood charcoal. Such GO sheets are thermally not very stable and on aging is fragmented into small spherical shape . These can be solubilized in 10% NaOH and reprecipitating these by adjusting the pH around 7. Further purification could be achieved by extracting with ethanol where this is highly soluble . This GO is larger than graphene quantum dot and get folded to close like fisted form and it is shown to entrap tetraphenylporphyrin (TPP). The TPP in the composite is not soluble in dichloromethane where free TPP is highly soluble. Such GO -TPP composite retains the property of pure GO as it is soluble in ethanol in which free TPP is insoluble. It is shown that in phosphate buffered saline (PBS, pH , 6.8) this composite is soluble and remained intact . At higher pH of PBS buffer it releases all entrapped TPP by opening the clenched fist form. Similarly the drug Donepezil, used in Alzheimer treatment gets entrapped by GO which is also released at higher pH, 7.4. The clenched fist form of corrugated GO is related to the pH dependent epoxide dominated structure as proposed by Hofmann and Holst's model and the open structure may be dominated by hydroxyl groups ( enol ) following Ruess's model . Such pH dependent inter-conversion uniquely provide GO to act as Trojan horse in carrying a drug molecule andits release under physio-compatible environment.

Facile synthesis of water soluble fluorescent N-doped graphene nanosheets for multifunctional applications in photocatalysis and sensing.

Modeling of molybdoenzymes began even before the knowledge of the three-dimensional structure of these enzymes. The theoretical and experimental knowledge on these enzymes is vast and newer investigation is regularly pursued to understand the electronic aspect of these proteins using computational means. The present review deals with some unique observation regarding the structure, function and reactivity of some models and native proteins in rationalizing the choice of diverse substrates in seemingly similar enzymes such as Nap (nitrate reductase) and Fdh (formate dehydrogenase) and the dual form of a specific substrate of an enzyme like trimethylamine N-oxide reductase (TAMOR) and providing the electronic reason for the inhibition in the oxypurinol-inhibited xanthine oxidase (XO).

A fluorescein based reactive probe has been designed and synthesized to detect hydrazine selectively over other common analytes. We used here 4-bromobutyrate as a masking unit of fluorescein dye. Hydrazine plays here the role of a de-masking agent to set free the fluorescein dye through a simultaneous substitution-cyclisation-elimination process. This leads to 'turn on' fluorescence with easily discernible color change with a fast response time (<15 minutes).Scheme 1 Synthetic scheme of the probe (FLB).