Semi‐classical formulation of time‐dependent discrete variable representation method

In this article, we apply a novel time‐dependent discrete variable representation (TDDVR) method proposed by Barkakaty and Adhikari to investigate tunneling through an Eckart barrier. This semi‐classical method is theoretically rigorous and straightforward to implement. Among the TDDVR formulations, this report presents the first derivation of a rigorous form of quantum force (QF) for the present perspective. The validity of this semi‐classical approach is demanded based on the excellent agreement of the tunneling probability with the corresponding quantum results. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004     

A convenient stereoselective synthesis of (R)-(−)-denopamine and (R)-(−)-salmeterol

β-Adrenoreceptor agonists (R)-(−)-denopamine (R)-1 and (R)-(−)-salmeterol (R)-2 have been prepared in good overall yield and high enantioselectivity through a biotransformative pathway.     

Role of non-conventional hydrogen bonding in controlling regioselectivity for nucleophilic aromatic substitution of 4,6-dinitroisoindoline-1,3-dione with 1,2,3-triazole isomers: a computational studies

Structural Chemistry - The nucleophilic aromatic substitution reactions of 4,6-dinitroisoindoline-1,3-dione with 1,2,3-triazole isomers, i.e., 1H-1,2,3-triazole and 2H-1,2,3-triazole, have been...     

A facile microwave assisted synthesis of spiro-1,3-oxazines from N-(2-(cyclohex-1-en-1-yl)ethyl)amides

A mild and efficient methodology has been developed for the synthesis of spiro-1,3-oxazine derivatives by the microwave assisted cyclization of N-2-(1′-cyclohexenyl)ethyl-acetamides/benzamides. The reaction was catalyzed by in situ generated trimethylsilyl iodide and featured by its very short reaction time. The starting materials were easily obtained by the condensation of substituted acetic/benzoic acids with 2-(1′-cyclohexenyl)ethyl amine.     

Synthesis and inverse virtual screening of new bi-cyclic structures towards cancer-relevant cellular targets

Structural Chemistry - We report here synthetic approaches to access new classes of small molecules based on three heterocyclic scaffolds, i.e. 3,7-dihydropyrimido[4,5-d]pyridazine-4,8-dione,...     

Copper(II)-catalyzed reactions of activated aromatics

The catalytic reaction of cis-bisglycinato copper(II) monohydrate in the presence of hydrogen peroxide leads to hydroxylation of phenol to give catechol and hydroquinone (1:1.2 ratio) in good yield. 2,6-Dimethylphenol can be hydroxylated by hydrogen peroxide and a catalytic amount of cis-bisglycinato copper(II) monohydrate to give an aggregate of 1,4-dihydroxy-2,6-dimethylbenzene and 2,6-dimethylphenol. A similar reaction of o-cresol gives 2,5-dihydroxytoluene. The reactivity of cis-bisglycinato copper(II) monohydrate in hydrogen peroxide with o-cresol is 4.5 times faster than that of a similar reaction by trans-bisglycinato copper(II) monohydrate. A catalytic reaction of cis-bisglycinato copper(II) monohydrate with aniline in aqueous hydrogen peroxide gives polyanilines in the form of pernigraniline with different amounts of Cu(OH)2 attached to them. The two major components of polyanilines obtained have Mn values of 1040 and 1500, respectively. Resistance of films of these polyanilines increases with temperatures from 40 degrees C to a maximum value at 103 degrees C and then decreases in the region of 103-150 degrees C, showing the property of a thermolectric switch. The aggregate prepared from hydroxylation of 2,6-dimethylphenol shows a similar property in the region of 30-180 degrees C.     

Determination of PuO2% in power reactor mixed oxide fuel blends (0.4–44% PuO2) by neutron well co-incidence counting technique

Neutron Well Coincidence Counting has been explored as a non destructive assay technique for determining the percentage of PuO₂ in blended mixture of UO₂ and PuO₂ powders. The method has been applied to MOX blends having PuO₂ content varying from 0.4 to 44% for both thermal and fast reactors. The use of Neutron Well Coincidence Counting technique is validated as a process control step for determining PuO₂ content in the fabrication of MOX fuel by comparing it with chemical analysis of sintered pellets. It has been used at Advanced Fuel fabrication Facility, Bhabha Atomic Research Centre, Tarapur during the manufacture of MOX fuel of various types for thermal and fast reactors.     

Polyazamacrocycles VI. Homo-trimetallic copper(II) and nickel(II) complexes with a new tri-cavity macrocycle

Summary A new tri-cavity decaaza macrocycle (TCM) has been synthesised by the condensation of tetra(aminopropyl)-cyclam with diethanolamine. The new macrocyclic ligand forms tri-nuclear complexes, [Cu₃(TCM)(H₂O)₂]-(ClO₄)₆ and [Ni₃(TCM)(H₂O)₂](ClO₄)₆.     

Tuning the Gate‐Opening Pressure in a Switching pcu Coordination Network,X‐pcu‐5‐Zn,by Pillar‐Ligand Substitution

Coordination networks that reversibly switch between closed and open phases are of topical interest since their stepped isotherms can offer higher working capacities for gas‐storage applications than the related rigid porous coordination networks. To be of practical utility, the pressures at which switching occurs, the gate‐opening and gate‐closing pressures, must lie between the storage and delivery pressures. Here we study the effect of linker substitution to fine‐tune gate‐opening and gate‐closing pressure. Specifically, three variants of a previously reported pcu ‐topology MOF, X‐pcu‐5‐Zn , have been prepared: X‐pcu‐6‐Zn , 6 =1,2‐bis(4‐pyridyl)ethane (bpe), X‐pcu‐7‐Zn , 7 =1,2‐bis(4‐pyridyl)acetylene (bpa), and X‐pcu‐8‐Zn , 8 =4,4′‐azopyridine (apy). Each exhibited switching isotherms but at different gate‐opening pressures. The N₂, CO₂, C₂H₂, and C₂H₄ adsorption isotherms consistently indicated that the most flexible dipyridyl organic linker, 6 , afforded lower gate‐opening and gate‐closing pressures. This simple design principle enables a rational control of the switching behavior in adsorbent materials.     

Efficient CO2 Removal for Ultra‐Pure CO Production by Two Hybrid Ultramicroporous Materials

Removal of CO₂ from CO gas mixtures is a necessary but challenging step during production of ultra‐pure CO as processed from either steam reforming of hydrocarbons or CO₂ reduction. Herein, two hybrid ultramicroporous materials (HUMs), SIFSIX‐3‐Ni and TIFSIX‐2‐Cu‐i , which are known to exhibit strong affinity for CO₂, were examined with respect to their performance for this separation. The single‐gas CO sorption isotherms of these HUMs were measured for the first time and are indicative of weak affinity for CO and benchmark CO₂/CO selectivity (>4000 for SIFSIX‐3‐Ni ). This prompted us to conduct dynamic breakthrough experiments and compare performance with other porous materials. Ultra‐pure CO (99.99 %) was thereby obtained from CO gas mixtures containing both trace (1 %) and bulk (50 %) levels of CO₂ in a one‐step physisorption‐based separation process.