Anilate Tethered Neutral Tetrahedral Pd(II) Cages Exhibiting Selective Encapsulation of Xylenes and Mesitylene

The design of porous materials for the recognition of multiple hydrocarbons is highly desirable for the energy-efficient separation and recognition of chemical feedstock. Herein, three new iso-structural porous discrete metal–organic cages of formula {[Pd₃(NiPr)₃PO]₄(R-AN)₆} (R-AN=anilate linkers) for the selective recognition of substituted aromatic hydrocarbons are reported. The tetrahedral cages 1 , 2 , and 3 containing anilate, chloranilate, and bromanilate linkers exhibited selective encapsulation of mesitylene, o-xylene, and p-xylene, respectively, over other analogous aromatic hydrocarbons. These selective encapsulations were driven by the variations in the portal diameters present at each of these cages and their interactions with the hydrocarbon guests. These observations are supported by mass spectrometry, NMR studies, and theoretical binding-energy calculations.     

Montmorillonite KSF,a Mild and Efficient Catalyst for Benzodithiepination of Carbonyl Compounds

A mild and efficient procedure for the protection of carbonyl compounds as 1,5-dihydro-3H-2,4-benzodithiepines in high yields is described by using a readily available and inexpensive KSF clay catalyst.     

Sulfonated Charcoal,a Mild and Efficient Reagent for the Tetrahydropyranylation of Alcohols and Phenols

Sulfonated charcoal has been demonstradted to be very effective and mild catalyst for the tetrahydropyranylation of alcohols and phenols.     

Synthesis of melicodenines C,D and E

A synthesis of the unusual cyclobutane-quinolinone alkaloids melicodenines C, D and E by intermolecular [2+2] cycloaddition is described.     

Synthesis and Coordination Behavior of a New Hybrid Bidentate Ligand with Phosphine and Silylene Donors

This work describes the synthesis and coordination behavior of a new mixed-donor ligand PhC(NtBu)₂SiC₆H₄PPh₂ ( 1 ) containing both silylene and phosphine donor sites. Ligand 1 was synthesized from a reaction of ortho-lithiated diphenylphosphinobenzene (LiC₆H₄PPh₂) with chlorosilylene (PhC(NtBu)₂SiCl). Treatment of 1 with Se and GeCl₂ resulted in Si^IV compounds 2 and 3 by selective oxidation of the silylene donor. This strong σ-donor ligand induces dissociation of CuCl and PhBCl₂ leading to formation of ionic complexes 4 and 5 respectively. The reaction of 1 with ZnCl₂ and AlCl₃ resulted in the formation of chelate complexes 5 and 7 , respectively, while treatment with EtAlCl₂ and GaCl₃ forms monodentate complexes 8 and 9 . X-ray analysis of 4 showed that the copper is in the spiro center of the two five-membered rings. Moreover, the copper(I)chloride has not been oxidized but dissociates to Cu⁺ and [CuCl₂]⁻. All the compounds are well characterized by mass spectrometry, elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction studies.     

S-Substituted-2-mercaptobenzthiazolium-based chiral ionic liquids: efficient organocatalysts for enantioselective sodium borohydride reductions of prochiral ketones

Novel chiral ionic liquids having chirality in their cationic part have been synthesized for evaluation of their catalytic potential as organocatalysts in sodium borohydride reduction of prochiral ketones to yield optically active secondary alcohols. The chiral ionic liquids have been synthesized from the reaction of (?)-menthol or (?)-borneol, chloroacetic acid and S-methyl/benzyl-2-mercaptobenzthiazole. The synthesized chiral ionic liquids have been characterized by ¹H, ¹³C NMR and Mass spectrometry. Moderate to excellent enantiomeric excess (ee > 99%) has been obtained in asymmetric sodium borohydride reduction of prochiral ketones using these salts as chiral catalysts.     

Study of indoor radon and thoron progeny levels in surrounding areas of Nalbari, Assam, India

With the growing understanding of the role of radon and its daughter products as major sources of radiation exposure, the importance of large number of estimation of radon concentration in various parts of the country is realized. Inhalation of radon, thoron and their decay products is the major source of the total radioactive dose received by the human population from natural radiation. The indoor radon and thoron progeny levels in Nalbari area of Assam are studied by using the LR-115 (type II) Solid State Nuclear Track Detector in Plastic Twin Chamber dosimeter. Radon and thoron progeny levels in different types of dwellings for one full calendar year are presented in this paper. For Assam Type (A.T.) houses, indoor radon progeny concentrations vary from 0.17 to 0.64 mWL with an annual geometric mean of 0.27 mWL and that for Reinforced Cement Concrete (R.C.C.) houses vary from 0.22 mWL to 0.60 mWL with the annual geometric mean of 0.37 mWL. The thoron progeny levels in A.T. houses also vary from 0.01 to of 0.05 mWL with an annual geometric mean of 0.02 mWL and that for R.C.C. houses vary from 0.02 to 0.08 mWL with the annual geometric mean of 0.04 mWL.      

A Facile One‐Pot Route for the General Synthesis of Triazole Linked Chiral 2‐Substituted Benzimidazoles

One‐pot protocol for the synthesis of novel class of triazole linked 2‐sugar and 2‐aryl substituted benzimidazoles has been developed. The rapid and simple method involves copper (I) catalyzed simultaneous formation of benzimidazole and triazole rings at room temperature and in high yield.