Manish Bhattacharjee

Self-Healing and Moldable Metallogels as the Recyclable Materials for Selective Dye Adsorption and Separation

Four multiresponsive and self-sustaining metallogels were synthesized by the reaction of the disodium salt of the ligand carboxymethyl-(3,5-di-tert-butyl-2-hydroxy-benzyl)amino acetic acid with Cd(II) and Zn(II) halides, which were found to show excellent selectivity for dye adsorption and separation, and one of the gels shows a rare self-healing property.

Activation of bromide by vanadium pentoxide for the bromination of aromatic hydrocarbons : reaction mimic for the enzyme bromoperoxidase

Abstract Reaction of KBr with organic substrates in aqueous medium in the presence of V2O5 and H2O2 produces bromo organics in a reaction mimic of the enzyme bromoperoxidase.

Synthesis and structure of 1-D Na6 cluster chain with short Na-Na distance : Organic like aromaticity in inorganic metal cluster

A unique 1-D chain of sodium cluster containing (Na6) rings stabilized by a molybdenum containing metalloligand has been synthesized and characterized and the DFT calculations show striking resemblance in their aromatic behaviour with the corresponding hydrocarbon analogues.

A Moisture‐ and Air‐Stable Cationic Ruthenium Complex as Catalyst for Highly Atom‐Economical Stereo‐ and Regioselective Vinylation of Azoles

N-Vinyl amines are important starting materials for preparation of polymeric dyes and ion-exchange resins. For example, N-vinyl azoles have been shown to afford polymeric materials, which show catalytic properties and photorefractive properties. Moreover, some of the compounds have been shown to be active against fungal infections. In view of the importance of N-vinyl azoles, various synthetic methods have been developed. The most important method is the coupling of vinyl bromide to azoles mediated by metals, such as Hg or Pd. Both methods suffer from disadvantages. In recent years, there have been reports on Cu mediated C N bond formation via coupling of vinyl bromide/iodide with amines in the presence of various ligands and large amount of base, such as Cs2CO3. [5] The same method has been used for vinylation of azoles. 6] Most of these methods require either harsh conditions or longer reaction times and high catalyst loadings. One method has recently been reported, for which only 5 mol% catalyst and ligand is required, however, mainly vinyl iodide has been found to be effective. There are also reports on hydroamination of alkynes. However, most of the described methods afford the Markovnikov addition product. Anti-Markovnikov hydroamination of alkynes, catalyzed by actinides, Rh, and Ti, have been reported in the literature. Trisrutheniumdodecacarbonyl has been shown to catalyze vinylation of azoles by alkynes. However, mixtures of stereoisomers were obtained. Thus, the methods are not atom economical or suffer from other disadvantages. Recently it has been reported that, AgACHTUNGTRENNUNG(NO3)/Ag ACHTUNGTRENNUNG(OTf) can catalyze single and double addition of pyrazole to alkynes. However, for the single addition, the catalyst loading is high and the reaction conditions are harsh and mixtures of products were obtained. Note, in all the reactions, exclusion of air and moisture is essential. In addition, vinyl halides are expensive and all the methods of vinylation, described in the literature, are not environment friendly. We have been interested in the synthesis of cationic ruthenium complexes and studies of their catalytic properties and have reported the synthesis and structure of [RuACHTUNGTRENNUNG(PPh3)2ClACHTUNGTRENNUNG(CH3CN)3] ACHTUNGTRENNUNG[BPh4].[13] This complex has been shown to activate alkynes for the C O bond formation. Herein we report the synthesis, structure, and catalytic properties of [Ru ACHTUNGTRENNUNG(dppe) ACHTUNGTRENNUNG(PPh3) ACHTUNGTRENNUNG(CH3CN)2Cl] ACHTUNGTRENNUNG[BPh4] (1). The complex has been synthesized from the reaction of [RuCl2ACHTUNGTRENNUNG(PPh3)3] with diphenylphosphinoethane (dppe) in a 1:1 ratio in acetonitrile. The complex has been characterized by elemental analyses, IR, and H and P NMR spectroscopy. The H NMR spectrum (CDCl3) of 1 is in good agreement with other reported ruthenium dppe complexes. The P NMR spectrum (CDCl3) of 1 shows two sharp singlets at 74.2 ppm, due to dppe, and 34.3 ppm, due to coordinated PPh3. Note, at low temperature ( 20 8C and 50 8C), the H and P NMR spectra remain unaltered, thus ruling out the presence of fluxionality in solution. The complex crystallizes in triclinic space group P-1. The asymmetric unit contains one cationic ruthenium complex (Figure 1) and one tetraphenylborate anion. The ruthenium center is in a distorted octahedral coordination environment and is coordinated to two acetonitrile nitrogens, N1 and N2, one chloride, Cl1, and three phosphorus atoms, P1, P2, and P3. Appearance of two singlets in the P NMR spectrum shows that, in solution the structure of the complex is different from that at solid state. Based on the NMR studies we suggest that, in solution, the complex looses one acetonitrile ligand and the complex assumes a trigonal bipyramidal geometry (Figure S4 in the Supporting Information). Along with other signals, the H NMR spectrum of 1 shows a signal (singlet) at 2.00 ppm due to CH3 protons of the free acetonitrile ligand. We were interested in studying the catalytic properties of 1 towards activation of unactivated alkynes for addition reactions. We have shown that cationic ruthenium complexes are capable of activating alkynes towards addition reactions and we wanted to explore the efficacy of 1 as catalyst for the addition of alkynes to azoles. Thus, the addition of 3,5-dimethylpyrazole (2 a) to phenylacetylene (3 a) was chosen as a model reaction. As shown in Table 1, when the addition reaction of 2 a to 3 a was carried out in the presence of a catalytic amount of 1 in toluene at 50 8C, a 4:1 mixture [a] U. K. Das, Prof. Dr. M. Bhattacharjee Department of Chemistry Indian Institute of Technology Kharagpur 721 302 (India) Fax: (+91) 3222-282252 E-mail : mxb@iitkgp.ac.in Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201103424.

First electrosynthesis of transition metal peroxo complexes. Synthesis, characterization and reactivity of molybdenum and tungsten heteroligand peroxo complexes

Abstract Molecular peroxo complexes of molybdenum and tungsten, viz. [MO(O2)2L] (M = Mo or W; L = 2,2′-bipyridine, 1,10-phenanthroline or 2,2′-bipyridine-N,N′-dioxide), in the presence of hydrogen peroxide and then precipitating with the corresponding heteroligands. These complexes have also been prepared by the dissolution of metal powders in hydrogen peroxide. They have been characterized by elemental analysis and vibrational spectra. The complexes oxidize triphenylphosphine and triphenylarsine to triphenylphosphine oxide and triphenylarsine oxide, respectively.

Aromaticity in cyclic alkali clusters

Density functional calculations on a hexagonal 1D sodium cluster and a 2D potassium cluster show that the M6 (M = Na, K) rings in the chain present in 3D [Na2MoO3L(H2O)2]n (1) and 2D [K2MoO3L(H2O)3]n (2) are aromatic in character according to the nucleus independent chemical shift (NICS) and multicenter bond indices (MCI) values. The NICS values at the center of the Na6 rings and at the cage center of the K6 rings are comparable to the corresponding values of their polyacene analogues in most cases. The stability and reactivity patterns of the M6 rings also follow a similar trend as their organic analogues.

SYNTHESIS OF A NEW MACROCYCLIC LIGAND WITH SIX AMIDE RECEPTOR SITES

Abstract The macrobicyclic hexaamide ligand LH 6 has been synthesized from double condensation of triethyl ester of nitrilotriacetic acid and 1,2 - diaminobenzene in 60% yield.

Synthesis and structure of a 3D porous network containing aromatic 1D chains of Li(6) rings: experimental and computational studies.

A bimetallic 3D network containing 1D chains of Li(6) unit rings has been synthesized by using a molybdenum containing metalloligand and the DFT calculations reveal that the rings are aromatic in behavior and resemble the corresponding hydrocarbon analogues.

Synthesis, structure and catalytic properties of [Ru(dppp)2(CH3CN)Cl][BPh4] and isolation of catalytically active [Ru(dppp)2Cl][BPh4]: ruthenium catalysed alkyne homocoupling and tandem alkyne–azide cycloaddition

The compound, [Ru(dppp)2(CH3CN)Cl][BPh4] (1) has been synthesised from the precursor complex, [Ru(PPh3)3Cl2]. The complex has been structurally characterised. The complex has been found to be an efficient catalyst for the homocoupling of alkynes in the presence of silver salts. The complex can also catalyse homocoupling of alkynes and subsequent alkyne–azide cycloaddition. The catalytically active species, [Ru(dppp)2Cl][BPh4] (2) and one of the intermediate complexes, [Ru(dppp)2(CCPh)2] (6), have been isolated and structurally characterised.

First electrosynthesis of transition metal peroxofluoro complexes. Synthesis, characterization and reactivity of some peroxofluoro complexes

Abstract Peroxofluoro complexes of the transition metals, viz. V, Nb, Ta, Mo and W, have been synthesized electrochemically using the sacrificial metal anodes in the presence of hydrogen peroxide (15%) and hydrofluoric acid (10%). These complexes have also been prepared by the dissolution of the metal powders in a mixture of hydrogen peroxide and hydrofluoric acid. While the monoperoxo complexes are formed at lower pH, higher pH is conducive to the formation of diperoxo complexes. The compounds have been characterized by elemental analysis and vibrational spectral studies. K2[MoO(O2)F4]·H2O and K2[WO(O2)F4]·H2O can oxidize triphenylphosphine to triphenylphosphine oxide in high yield.