01683nas a2200205 4500008004100000022001400041245011400055210006900169260007100238300001400309490000800323520088500331100001801216700002001234700001601254700002701270700002201297700002601319856013201345 2012 eng d a0002-786300aMultiple topologies from glycopolypeptide-dendron conjugate self-assembly: nanorods, micelles, and organogels0 aMultiple topologies from glycopolypeptidedendron conjugate selfa a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAPR a7796-78020 v1343 a

Glycopolypeptides (GPs) were synthesized by ring-opening polymerization of glycosylated N-carboxyanhydride monomer and attached to hydrophobic dendrons at one chain end by ``click'' reaction to obtain amphiphilic anisotropic macromolecules. We show that by varying polypeptide chain length and dendron generation, an organogel was obtained in dimethylsulfoxide, while nanorods and micellar aggregates were observed in aqueous solutions. Assemblies in water were characterized by electron microscopy and dye encapsulation. Secondary structure of the GP chain was shown to affect the morphology, whereas the chain length of the poly(ethylene glycol) linker between the GP and dendron did not alter rod-like assemblies. Bioactive surface chemistry of these assemblies displaying carbohydrate groups was demonstrated by interaction of mannose-functionalized nanorods with ConA.

1 aPati, Debasis1 aKalva, Nagendra1 aDas, Soumen1 aKumaraswamy, Guruswamy1 aGupta, Sayam, Sen1 aAmbade, Ashootosh, V. uhttps://library.ncl.res.in/content/multiple-topologies-glycopolypeptide-dendron-conjugate-self-assembly-nanorods-micelles-and-001612nas a2200181 4500008004100000022001400041245006600055210006300121260007100184300001600255490000700271520097800278100001801256700002201274700002001296700002201316856009201338 2015 eng d a0020-166900aMechanism of alcohol oxidation by Fe-V(O) at room temperature0 aMechanism of alcohol oxidation by FeVO at room temperature a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcDEC a11792-117980 v543 a

{Selective oxidation of alcohol to its corresponding carbonyl compound is an important chemical process in biological as well as industrial reactions, The heme containing enzyme CytP450 has been known to selectively oxidize akohols to their corresponding carbonyl compounds. The mechanism of this reaction, which involves high-valent Fe-IV(O)-porphyrin(center dot+) intermediate with alcohol, has been well-studied extensively both with the native enzyme and with model complexes. In this paper, we report for the first time the mechanistic insight of, alcohol oxidation with Fe-V(O) complex of biuret TAML (bTAML), Which is isoelectronic with Fe-IV(O)-porphyrin(center dot+) intermediate form in CytP450. The oxidations displayed saturation kinetics, which allowed us to determine both the binding constants and first-order rate constants for the reaction. The K and k values observed for thel oxidation of benzyl alcohol by Fe-V(O) at room temperature (K = 300 M-1

1 aGhosh, Munmun1 aNikhil, Y., L. K.1 aDhar, Basab, B.1 aGupta, Sayam, Sen uhttps://library.ncl.res.in/content/mechanism-alcohol-oxidation-fe-vo-room-temperature-002238nas a2200193 4500008004100000022001400041245008200055210006900137260007100206300001400277490000700291520153500298100002201833700002701855700002001882700001701902700002201919856010301941 2015 eng d a0020-166900aMechanism of oxygen atom transfer from Fe-V(O) to olefins at room temperature0 aMechanism of oxygen atom transfer from FeVO to olefins at room t a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUL a6112-61210 v543 a

In biological oxidations, the intermediate Fe-V(0)(OH) has been proposed to be the active species for catalyzing the epoxidation of alkenes by nonheme iron complexes. However, no study has been reported yet that elucidates the mechanism of direct O-atom transfer during the reaction of Fe-V(0) with alkenes to form the corresponding epoxide. For the first time, we study the mechanism of O-atom transfer to alkenes using the Fe-V(0) complex of biuret-modified Fe-TAML at room temperature. The second-order rate constant (k(2)) for the reaction of different alkenes with Fe-V(0) was determined under single-turnover conditions. An 8000-fold rate difference was found between electron-rich (4-methoxystyrene; k(2) = 216 M-1 s(-1)) and electron-deficient (methyl transcinnamate; k(2) = 0.03 M-1 s(-1)) substrates. This rate difference indicates the electrophilic character of Fe-V(0). The use of cis-stilbene as a mechanistic probe leads to the formation of both cis- and trans-stilbene epoxides (73:27). This suggests the formation of a radical intermediate, which would allow C-C bond rotation to yield both stereoisomers of stilbene-epoxide. Additionally, a Hammett rho value of -0.56 was obtained for the para-substituted styrene derivatives. Detailed DFT calculations show that the reaction proceeds via a two-step process through a doublet spin surface. Finally, using biuret-modified Fe-TAML as the catalyst and NaOCl as the oxidant under catalytic conditions epoxide was formed with modest yields and turnover numbers.

1 aSingh, Kundan, K.1 aTiwari, Mrityunjay, K.1 aDhar, Basab, B.1 aVanka, Kumar1 aGupta, Sayam, Sen uhttps://library.ncl.res.in/content/mechanism-oxygen-atom-transfer-fe-vo-olefins-room-temperature-001112nas a2200181 4500008004100000022001400041245011000055210006900165260011000234300001600344490000700360520034800367100001900715700002100734700002500755700002200780856012800802 2015 eng d a1359-734500aMolecular Fe-complex as a catalyst probe for in-gel visual detection of proteins via signal amplification0 aMolecular Fecomplex as a catalyst probe for ingel visual detecti aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJUL a15257-152600 v513 a

We report the use of a molecular peroxidase mimic biuret-Fe-TAML for chemoselective labeling of proteins and the subsequent visual detection (<0.1 pmoles) of the conjugate in a polyacrylamide gel by catalytic signal amplification. Use of this probe in activity based protein profiling (ABPP) of serine proteases is also demonstrated.

1 aKumari, Sushma1 aPanda, Chakadola1 aMazumdar, Shyamalava1 aGupta, Sayam, Sen uhttps://library.ncl.res.in/content/molecular-fe-complex-catalyst-probe-gel-visual-detection-proteins-signal-amplification-0