Water splitting, leading to hydrogen and oxygen in a process that mimics natural photosynthesis, is extremely important for devising sustainable solar energy conversion system. Development of earth-abundant, transition metal-based catalysts mimic the oxygen-evolving complex photosystem II, which involved oxidation water O2 during represents major challenge. Further, understanding exact mechanism, including elucidation role active metal-oxo intermediates (WO), critical development more...

An Fe(V)(O) complex has been synthesized from equimolar solutions of (Et4N)2[Fe(III)(Cl)(biuret-amide)] and mCPBA in CH3CN at room temperature. The characterized by UV-vis, EPR, Mössbauer, HRMS shown to be capable oxidizing a series alkanes having C-H bond dissociation energies ranging 99.3 kcal mol(-1) (cyclohexane) 84.5 (cumene). Linearity the Bell-Evans-Polayni graph finding large kinetic isotope effect suggest that hydrogen abstraction is engaged rate-determining step.

Biuret-modified tetraamidomacrocyclic cobalt complex [CoIII-bTAML]- is shown to catalyze electrochemical water oxidation at basic pH leading the formation of O2. Electrochemical and spectroscopic studies indicate a high valent oxo intermediate isoelectronic CoV(O) as active oxidant. The kinetic isotope effect 8.63 indicates an atom proton transfer mechanism.

Iron complex catalysed selective and efficient photocatalytic hydroxylation epoxidation reactions using water as the oxygen atom source has been reported.

In this report we compare the geometric and electronic structures reactivities of [FeV(O)]− [FeIV(O)]2– species supported by same ancillary nonheme biuret tetraamido macrocyclic ligand (bTAML). Resonance Raman studies show that Fe═O vibration complex 2 is at 798 cm–1, compared to 862 cm–1 for corresponding 3, a 64 frequency difference reasonably reproduced density functional theory calculations. These values are, respectively, lowest highest frequencies observed thus far high-valent...

A detailed electrochemical investigation of a series iron complexes (biuret-modified tetraamido macrocycles FeIII -bTAML), including the first generation FeV (O), and demonstration their efficacy as homogeneous catalysts for water oxidation (WO) in aqueous medium are reported. Spectroelectrochemical mass spectral studies indicated (O) active oxidant, formed due to two redox transitions, which were assigned FeIV (O)/FeIII (OH2 ) (O)/FeIV (O). The properties both these high-valent oxo species...

In biological oxidations, the intermediate FeV(O)(OH) has been proposed to be active species for catalyzing epoxidation of alkenes by nonheme iron complexes. However, no study reported yet that elucidates mechanism direct O-atom transfer during reaction FeV(O) with form corresponding epoxide. For first time, we using complex biuret-modified Fe–TAML at room temperature. The second-order rate constant (k2) different was determined under single-turnover conditions. An 8000-fold difference found...

We report the first example of a chiral mixed thiolate/stibine-protected gold cluster, formulated as Au18(S-Adm)8(SbPh3)4Br2 (where S-Adm = 1-adamantanethiolate). Single crystal X-ray crystallography reveals origin chirality in cluster to be introduction rotating arrangement Au2(S-Adm)3 and Au(S-Adm)2 staple motifs on an achiral Au13 core subsequent capping remaining atoms by SbPh3 Br- ligands. Interestingly, structure properties this new Au18 are found different from other reported clusters...

Nonheme iron complexes bearing tetradentate N-atom-donor ligands with cis labile sites show great promise for chemoselective aliphatic C–H hydroxylation. However, several challenges still limit their widespread application. We report a mechanism-guided development of peroxidase mimicking complex based on the bTAML macrocyclic ligand framework (Fe-bTAML: biuret-modified tetraamido ligand) as catalyst to perform selective oxidation unactivated 3° bonds unprecedented regioselectivity (3°:2°...

The presence of an FeV(O) species has been postulated as the active intermediate for oxidation both C–H and C═C bonds in Rieske dioxygenase family enzymes. Understanding reactivity these high valent iron–oxo intermediates, especially aqueous medium, would provide a better understanding enzymatic reaction mechanisms. formation complex at room temperature CH3CN mixture that contains up to 90% water using NaOCl oxidant is reported here. stability decreases with increasing concentration. We show...

Aerobic epoxidation of olefins catalyzed by iron complexes without the use a sacrificial coreductant is unknown. We report reductive activation O2 bioinspired [(bTAML)FeIII(H2O)]- (1) complex to catalyze alkenes with TONs up 80. Spectroscopic and kinetic evidence indicates involvement FeV(O) as active oxidant during reaction.

[Au 6 (SbP 3 ) 2 ][PF ] : the first gold nanocluster protected by multidentate coordination of stibine (Sb) and phosphine (P) moieties.

<ns4:p><ns4:bold>Background:</ns4:bold>At KIST Medical College, Lalitpur, Nepal, a Humanities module for first year medical students has been conducted. Role plays are used to explore social, and sexual issues in the Nepalese context. The present study obtained student feedback about role module, difficulties faced, suggestions further improvement.</ns4:p><ns4:p><ns4:bold>Method:</ns4:bold>The was conducted from January August 2011 using total of 15 plays. Student semi-structured...

Concern has been raised about inadequate pharmacology teaching in medical schools and the high incidence of prescribing errors by doctors training. Modifications have carried out many countries. The present study was using a semi-structured questionnaire to obtain students' perceptions their knowledge, attitudes, skills with regard different subject areas related rational at end two-year activity-based practical learning sessions private school Nepal. effectiveness strengths suggestions...

Pharmaceutical promotion is widespread and can impact prescribing by health professionals. Little research has been conducted on interactions between medical students the pharmaceutical industry. Teaching about inadequate. A survey showed that many schools spend only two hours teaching this important topic while others around six hours. Recently a manual understanding responding to published Health Action International (HAI) World Organization (WHO). From April August 2011 department of...

Herein, we report the synthesis and characterization of two manganese tricarbonyl complexes, MnI (HL)(CO)3 Br (1 a-Br) (MeL)(CO)3 b-Br) (where HL=2-(2'-pyridyl)benzimidazole; MeL=1-methyl-2-(2'-pyridy)benzimidazole) assayed their electrocatalytic properties for CO2 reduction. A redox-active pyridine benzimidazole ancillary ligand in complex 1 a-Br displayed unique hydrogen atom transfer ability to facilitate conversion at a markedly lower reduction potential than that observed b-Br. Notably,...

Manganese tricarbonyl complexes have attracted considerable attention as competent electrocatalysts for CO2 reduction owing to their unique chemistry and the natural abundance of Mn. While analogous Re are well-known activate under anhydrous conditions, most reported Mn catalysts require exogenous protons. In an effort understand reason different mechanisms, we investigate reactivity Mn(pbt)(CO)3Br, (1, where pbt = 2-(2-pyridyl)-benzothiazole) with CO2. Our combined electrochemical...

The present study examined to investigate the influence of self-efficacy on student engagement Senior Secondary School students. respondents were students from senior secondary school Jammu and Kashmir. A Sample 400 Students (200 boys 200 girls) selected Kashmir by employing simple random sampling. T-test, correlations regression employed analyze data. indicated that (a) there exists significant difference between girls with their (b) Significant Difference Between Private Government (c)...

Background: At KIST Medical College, Lalitpur, Nepal, a Humanities module for first year medical students has been conducted. Role plays are used to explore social, and sexual issues in the Nepalese context. The present study obtained student feedback about role module, difficulties faced, suggestions further improvement. Method: was conducted from January August 2011 using total of 15 plays. Student semi-structured questionnaire. Informal discussions were held questionnaire circulated among...

Pharmaceutical promotion is an integral part of modern medical practice. Surveys show that students have a positive attitude towards promotion. not adequately taught in schools. A module based on the manual produced by Health Action International was conducted for second year at KIST Medical College, Lalitpur, Nepal. Student feedback various aspects obtained using semi-structured questionnaire. Eighty-six 100 (86%) provided about module. Forty-five (52.3%) were female and 39 (45.3%) male....

A medical humanities (MH) module has been conducted for first year students at KIST Medical College, Lalitpur, Nepal the last four years. The are divided into small groups and case scenarios, role-plays, paintings, activities used to explore MH. fourth batch of was from December 2011 March 2012. In this article authors provide a brief overview MH module, Sparshanam learning objectives different sessions. They transcripts some role plays done during module. were in Nepali with help guidance...

Molecular cavities that mimic natural metalloenzymes have shown the potential to trap elusive reaction intermediates. Here, we demonstrate formation of a rare yet stable Fe(IV)-superoxo intermediate at room temperature subsequent dioxygen binding Fe(III) site (Et4N)2[FeIII(Cl)(bTAML)] complex confined inside hydrophobic interior water-soluble Pd6L412+ nanocage. Using combination electron paramagnetic resonance, Mössbauer, Raman/IR vibrational, X-ray absorption, and emission spectroscopies,...

A medical humanities (MH) module has been conducted at KIST Medical College, Lalitpur, Nepal for the last four years. The students are divided into small groups and case scenarios, role-plays, paintings activities used to explore MH. fourth batch was from December 2011 March 2012. In this article authors provide a brief overview of MH module, Sparshanam learning objectives different sessions. They transcripts certain role plays during fourth, fifth sixth sessions module. were in Nepali with...