Showing papers by "Dillip Kumar Chand published in 2020"

Self-assembled conjoined-cages.

Abstract: A self-assembled coordination cage usually possesses one well-defined three-dimensional (3D) cavity whereas infinite number of 3D-cavities are crafted in a designer metal-organic framework. Construction of a discrete coordination cage possessing multiple number of 3D-cavities is a challenging task. Here we report the peripheral decoration of a trinuclear [Pd3L6] core with one, two and three units of a [Pd2L4] entity for the preparation of multi-3D-cavity conjoined-cages of [Pd4(La)2(Lb)4], [Pd5(Lb)4(Lc)2] and [Pd6(Lc)6] formulations, respectively. Formation of the tetranuclear and pentanuclear complexes is attributed to the favorable integrative self-sorting of the participating components. Cage-fusion reactions and ligand-displacement-induced cage-to-cage transformation reactions are carried out using appropriately chosen ligand components and cages prepared in this work. The smaller [Pd2L4] cavity selectively binds one unit of NO3−, F−, Cl− or Br− while the larger [Pd3L6] cavity accommodates up to four DMSO molecules. Designing aspects of our conjoined-cages possess enough potential to inspire construction of exotic molecular architectures. Developing simple routes for construction of multi-compartmental cages is a compelling and challenging task. Here, the authors report modular construction of multi-3D-cavity cages featuring one, two or three units of a [Pd2L4] entity conjoined with a [Pd3L6] core.

Low-Symmetry Self-Assembled Coordination Complexes with Exclusive Diastereoselectivity: Experimental and Computational Studies

Abstract: A pyridine/aniline appended unsymmetrical bidentate ligand N-(4-(4-aminobenzyl)phenyl)nicotinamide, investigated in this work has two well-separated coordination sites. Combination of the ligand wi...

Multicomponent click reactions catalysed by copper(I) oxide nanoparticles (Cu2ONPs) derived using Oryza sativa

Abstract: A procedure for the expedient synthesis of well-characterized Cu(I) oxide nanoparticles (Cu2ONPs) from Cu(II) salts by employing Rice (Oryza sativa) as a cheap and ready source of reducing as well as stabilizing agent has been demonstrated. The judicious choice of rice as a catalyst has helped in the symbiotic combination of two events: viz., acidic hydrolysis of starch to form glucose and the subsequent formal reduction of Cu2+ by the in-situ generated monosaccharide reducing sugar (glucose) under the alkaline condition to produce Cu2O. Further, rice was also found to be effectively stabilizing the nanoparticles from agglomeration. Optical and microscopic techniques were suitably employed for the characterization of the nanoparticles of approximately 10 nm size. Furthermore, the specifically generated nanoparticles were found to be active catalysts in an aqueous medium for Azide-alkyne Huisgen cycloaddition (Click reaction) under base free condition via one-pot multi-component addition for the synthesis of mono-, bis- and tris-1,2,3-triazoles in good to excellent yields. Cu2ONPs synthesized using hydrolysed Rice, an active catalyst for synthesis of mono-, bis- and tris-1,4-disubstituted 1,2,3-triazoles via one pot multicomponent reactions in water.

Conformational Solvatomorphism in a [2]Catenane

Abstract: The combination of a flexible pyridine-appended ligand (L1) with 4,4′-bipyridine (L2) and cis-protected Pd(II) units, Pd(L′)(NO3)2 in water yielded a concentration-dependent equilibrium mixture of ...