Microwave Irradiation

An efficient and direct procedure has been developed for the preparation of amidoalkyl naphthols by a one-pot condensation of aryl aldehydes, β-naphthol and urea or amides, in the presence of potassium dodecatungstocobaltate trihydrate [K5CoW12O40 · 3H2O, (1 mol%)] as a heterogeneous catalyst. The reactions were carried out in 1,2-dichloroethane at room temperature or under solvent-free media at elevated temperature. The present methodology offers several advantages such as excellent yields, simple procedure and the catalyst exhibited remarkable reusability.

In this work, we reported the synthesis and evaluation of the analgesic and anti-inflammatory properties of novel 3-or 4-substituted 5trifluoromethyl-5-hydroxy-4,5-dihydro-1H-1-carboxyamidepyrazoles (where 3-/4-substituent the exploration of the bioisosteric replacement of benzene present in salicylamide with a 5-trifluoromethyl-4,5-dihydro-1H-pyrazole scaffold. Target compounds were synthesized from the cyclocondensation of 4-alkoxy-1,1,1-trifluoromethyl-3alken-2-ones with semicarbazide hydrochloride through a rapid one-pot reaction via microwave irradiation. In addition to spectroscopic data, the structure of the compounds was supported by X-ray diffraction. Subcutaneous administration of the 5-trifluoromethyl-4,5-dihydro-1H-pyrazoles decreased pain-related behavior during neurogenic and inflammatory phases of the formalin test in mice. Moreover, the more active analgesic compounds (3-/4-¼ Et/H and H/Me) significantly decreased carrageenan-induced paw edema in mice. The data obtained in this work suggest that the synthesized compounds could be promising candidates for the future development of novel analgesic and anti-inflammatory agents.

Sodiumdependent high-aflinity choline uptake was measured in various regions of the brains of rats irradiated for 45 min with either pulsed or continuous-wave lowlevel microwaves (2,450 MHz; power density, 1 mW/cm2; average whole-body specific absorption rate, 0.6 W/kg). Pulsed microwave irradiation (2-ps pulses, 500 pulses/s) decreased choline uptake in the hippocampus and frontal cortex but had no significant effect on the hypothalamus, striatum, and inferior colliculus. Pretreatment with a narcotic antagonist (naloxone or naltrexone; 1 mg/kg i.p.) blocked the effect of pulsed microwaves on hippocampal choline u p take but did not significantly alter the effect on the frontal cortex. Irradiation with continuous-wave microwaves did not significantly affect choline uptake in the hippocampus, striatum, and hypothalamus but decreased the uptake in the frontal cortex. The effect on the frontal cortex was not altered by pretreatment with narcotic antagonist. These data suggest that exposure to low-level pulsed or continuouswave microwaves leads to changes in cholinergic functions in the brain. Key Words: Low-level microwaves-Pulsed microwaves-Continuous-wave microwaves-Acute microwave exposure-Sodium-dependent high-affinity choline uptake-Hippocampus-Frontal cortex-Narcotic antagonists. Lai H. et al. Low-level microwave irradiations affect central cholinergic activity in the rat. J. Neurochem.

An expeditious synthesis of 2-aryl-benzimidazoles by the condensation of o-phenylenediamine with various araldehydes is described. This greener protocol is catalyzed by Amberlite IR-120, and proceeds efficiently in the absence of any organic solvent under microwave irradiation within 3-5 min.

The synthesis of several chiral pyridinium salts via ZinckeÕs reaction can be easily accomplished by domestic microwave oven irradiation. Yield enhancements, reduction of reaction time, and less racemization were observed under microwave heating when compared to conventional heating in similar conditions.

A novel synthesis of silica-coated ZrO 2 nanoparticles is reported based on microwave irradiation (MW) method. The synthesis of silica-coated ZrO 2 nanoparticles was realized by a rapid uniform hydrolysis and subsequent copolymerization of the precursor tetraethoxysilane (TEOS) on ZrO 2 surface. One of the advantages of this MW irradiation method is the very short coating time and uniform heating in comparison to the conventional ones, allowing the synthesis of uniformly coated ZrO 2 nanoparticles with silica. The XPS analysis revealed the shifts in binding energies for Zr 3d5/2 and Zr 3d3/2 peaks after coating confirming the formation of silica layer on the surface of ZrO 2 nanoparticles. Characteristic silica peaks were observed in the FTIR spectra of coated nanoparticles. The shift in the isoelectric point measured by dynamic light scattering method was indicator of silica coverage of the ZrO 2 surface. The coatings formed at 70 8C were thin and uniform and extended up to 2 nm from the ZrO 2 surface as confirmed by the HR-TEM images.

Direct oxidation of benzene to phenol over Fe-ZSM-5 catalyst was chosen as a model reaction to characterize the influence of microwave irradiation on ad-/desorption processes during heterogeneously catalyzed reactions. The direct oxidation of benzene was investigated under different reaction conditions (temperature, residence time, reactant-concentrations) and microwave power in a specially designed reactor. The results obtained by additional microwave radiation were compared to those obtained by conventional heating under similar reaction conditions. In addition, ex situ TG-MS analyses were also conducted to study the sorption behaviour. Extensive investigations were carried out to determine adsorption-desorption effects (benzene, phenol and a mixture of both) and the coking behaviour under microwave conditions. Microwave induces a trend towards increased phenol selectivity and relative deactivation during the reaction. However, there was no conclusive improvement in the performance was obtained by means of microwave heating.

A convenient and efficient method for the synthesis of triphenodioxazines [TPDOs] 1 by oxidative cyclisation of 2,5-bis-(arylamino)-3,6-dichlorocyclohexa-2,5-diene-1,4-diones 6 using potassium persulfate as the oxidising agent in 95-97% sulfuric acid triggered by microwave irradiation is described.

Efficient synthesis of 7-aminocoumarins was performed via the Pechmann reaction by microwave irradiation of the reactants on solid support (graphite/montmorillonite K10). In this convenient new methodology, the strong thermal effect due to graphite/microwaves interaction is associated with the acidic catalyst role of the clay.

A new class of modified C-nucleosides has been synthesized according to the 1,3-dipolar cycloaddition methodology. The obtained compounds are structurally related to natural pseudouridine, where the sugar moiety is replaced by an isoxazolidine ring. Different experimental conditions, and the effect of additives on the cycloaddition process, have been examined; the best results were obtained when the cycloaddition reaction was performed

An efficient, practical, and eco-friendly method of preparation of 9-chloro-6,13-dihydro-7-phenyl-5H-indolo[3,2-c]-acridines (3a-c) is reported by Friedlander condensation of 2-amino-5-chlorobenzophenone 1 and active methylene compound 3,4-dihydro-2H-carbazol-1(9H)-ones (2a-c) in the presence of SnO 2 nanoparticles under microwave irradiation. Indoloacridines, 3a-c, were screened for their in vitro hemolytic activity, on human erythrocytes and cytotoxicity, on HeLa and Vero cells.

Guar gum was grafted with polymethylmethacrylate (PMMA) by microwave initiated method. The synthesis was optimized for highest percentage grafting, by varying the microwave irradiation time and monomer (methyl methacrylate) concentration. The various grades of grafted product (GG-g-PMMA) were characterized through standard physicochemical characterization techniques (intrinsic viscosity measurement, elemental analysis, FTIR spectroscopy & SEM morphology study). Further, flocculation efficacy of this grafted polysaccharide was studied by standard 'Jar test' procedure in 0.5% kaolin suspension, to assess its application as flocculating agent for wastewater treatment and mineral ore beneficiation. Correlation between percentage grafting and intrinsic viscosity was also studied for the possibility of using it as a tool to control the intrinsic viscosity in the final product. This leads to the possibility of application of the grafted product as superior viscosifier than guar gum.

The aromatization of 1,4-dihydropyridines (1,4-DHPs) employing group 4 (Zr and Hf) and 5 (V, Nb, Ta) elements of periodic system has been studied. The reaction with VOCl 3 in dichloromethane at room temperature afforded products, substituted pyridines, in high-to-excellent yield. For the first time, the formation of charge-transfer complexes (CTCs) has been evidenced in preorganization step between 1,4-DHP and oxidant before electron transfer. The CTC has been formed only in neutral solvents such as dichloromethane and is characterized by intensive coloration. The aromatization of 1,4-DHP with V 2 O 5 in refluxing acetic acid has found to be superior over microwave promoted reaction in solventless media. The only reasonable explanation was found in polymeric structure of V 2 O 5 , which slowly transfer energy of microwaves needed for the activation of the reactants. The solvent polarity dependent oxidative dealkylation of 4-n-propyl-1,4-DHP has been discovered. Unexpectedly, the reaction in acetic acid afforded only 33% of dealkylated product compared to 91% obtained in dichloromethane under the same reaction conditions.

The present work was aimed on utilizing the solid state microwave synthetic method for the growth of molybdenum disulphide (MoS 2 ) and tungsten disulphide (WS 2 ) in powder as well as in the form of thin films. It was observed that the microwave exposure of simple powder mixture of Mo (or W) and S could not lead to the formation of MoS 2 (or WS 2 ). Therefore the work was pursued by the study of the possibility to use this technique to grow thin films. Either Mo or W in the form of thin foils or Mo layers deposited by sputtering onto glass substrates was used as metal source. These metal samples were introduced with some sulphur into a Pyrex tube and sealed under vacuum. After microwave oven exposure the formation of polycrystalline 2H-WS 2 with well-defined grains was confirmed by X-ray diffraction and scanning electron microscopy, respectively. Mo foil as well as Mo layers deposited on glass showed formation of MoS 2 under the limit of our experimental conditions that is to say homogeneous thin films can be achieved only as small surface films.

The effects of 2.45-GHz microwave radiation on the Raman-active lattice phonons of two selected (Wako) anatase and rutile specimens and on Degussa P-25 TiO 2 nanoparticles were probed by in situ microscopic Raman spectroscopy in the solid phase with samples subjected to microwave irradiation (MW) or in combination with UV illumination (UV/MW). Significant changes were seen in the Raman band intensities for the pure anatase E g mode at 143 cm −1 and for the rutile vibration at 446 cm −1 , whereas only negligible changes in intensity were observed for the 144 cm −1 band of P-25 nanoparticles exposed to MW and UV/MW radiation. It is deduced that microwaves have a negligible impact on the lattice vibrational modes (phonons) of P-25 titania, even though this specimen was thermally heated by the microwaves. The photodegradation of phenol was re-visited to examine the photoactivity of the TiO 2 specimens selected for the in situ Raman study, as attested by the number of • OH radicals produced (DMPO spin trap ESR) under UV versus UV/MW irradiations, and by the related enhanced dynamics under UV/MW irradiation relative to UV alone or UV/CH.

An efficient, microwave irradiated synthesis of novel chromeno[2,3-b]-pyrimidine derivatives was carried out. 2-Amino-3,4-dihydro-2H-chromene-3-carbonitrile was converted into imine using N,N-Dimethylacetaldehyde dimethylacetal to give the core intermediate, which was used for the preparation of chromenopyrimidine library, using acetic acid and different amine in microwave irradiation for 5 min. Structures of newly synthesized compounds were confirmed by spectral studies. Compound 6g was characterized by single crystal X-ray analysis. All the compounds were also screened for their antimicrobial activity. Few of the compounds are found to be potential antimicrobials.

Crystallization of amorphous silicon (a-Si:H) film is extremely important in many aspects of electronic devices and has been heavily explored. We demonstrate that microwave irradiation, 200 W, is able to fast-crystallize a-Si:H film using as susceptor carbon-overcoat which contains graphite and carbon nano-tube. X-ray diffraction and Raman spectra reveal that nearly full crystallization is reached within 90 s. Microwave absorption by the carbon-overcoat generates thermal energy which heats up a-Si:H film to a threshold temperature 440 ± 10°C required for initiation of microwave crystallization. Dielectric properties of a-Si:H film facilitate its self-heating and nucleation of Si crystallites at above the threshold temperature. This method is extendable to fast-crystallize a-Si:H film on a remote and large-area basis.

Microwave-initiated synthesis of polyacrylamide-grafted sodium alginate, a graft copolymer with wide variety of applications has been reported in this study. The effect of reaction parameters (i.e., irradiation time and monomer concentration) onto the percentage grafting has been investigated. The resulting polymer has been characterized by a variety of characterization techniques such as intrinsic viscosity measurement, Fourier transform infrared spectra, 13C NMR spectra, elemental analysis, thermogravimetric analysis, molecular weight determination using static light scattering analysis, and scanning electron micrographs. Further, the flocculation efficiency of this graft copolymer has been investigated in coal suspension. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Mg doped ZnO nanoparticles were prepared by chemical synthesis associated with microwave
irradiation method. The prepared samples were characterised by XRD, FT-IR, SEM, EDAX, UV and PL methods. The X-ray diffraction pattern revealed the prepared sample was crystalline in nature. FT-IR results help to identify the presence of functional groups in the prepared samples. The morphology and purity of samples were analysed by
Scanning Electron Microscopy (SEM) and Energy dispersion X-ray Diffraction (EDAX) analysis. The optical
properties were studied using ultra-violet spectroscopy (UV) and Photo Luminance spectroscopy (PL). The
synthesized materials will be used as catalysis for the degradation of various pollutants, gas sensors, solar cells and LED devices.

The determination of the total content and the leachable aliquot by aqua regia dissolution of eight heavy metals (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) in soils and sediments was developed by microwave digestion technique combined with inductively coupled plasma atomic emission spectrometry. A complete digestion of soils and sediments was achieved by using an acid mixture of HF-HCl-HNO 3 (1:3:1); the microwave-irradiated closed vessel system used for the determination of aqua regia leachable quota, proved to be a viable alternative to the traditional reflux system. The experimental study was conducted using five BCR standard reference materials (CRM 141R 'Calcareous Loam Soil', CRM 142 'Light Sandy Soil', CRM 143 'Sewage Sludge Amended Soil', CRM 277 'Estuarine Sediment' and CRM 320 'River Sediment') in two laboratories with different microwave ovens and ICP-OES. Calculated recovery, repeatability, and reproducibility confirm the good performance of the procedures adopted. A Nested Design statistical analysis was carried out for both procedures and showed that the major source of variability in the analysis was due to ICP-OES measurements rather than microwave-assisted dissolution.

A rapid and easy route to formamides by microwave assisted N-formylation of primary and secondary amines is described. Using an insoluble polymer or an inorganic solid-supported reagent as a formylating agent, microwave irradiation furnished the corresponding formamides in high yields, with reduced reaction time and solvent volume over the conventional approach.

This work presents a complete method for the screening and confirmation analysis of diuretics in human urine by gas chromatography–mass spectrometry (GC–MS). The method comprises a pretreatment stage (extraction, preconcentration and derivatization to form the corresponding methyl derivatives) and the subsequent analysis of the derivatized extracts by GC–MS. Particularly, the derivatization stage, necessary to form the methyl derivatives of the compounds detectable by the GC–MS technique, is carried out under microwave irradiation rather than with direct thermal heating, thus reducing the incubation time from 3 h to 10 min. Microwave assisted derivatization also allowed an improvement of the limits of detection (LODs) for all the compounds here considered. The technique is particularly suitable for the rapid analysis of huge population of samples, as it is the case of urine analysis by the antidoping laboratories, and especially in all those occasions where rapid response times are requested.

In this study, essential oils from pomegranate seeds of the Malas variety from Shahreza, Iran, were extracted using hexane and petroleum benzene applying four extraction methods: normal stirring, soxhlet, microwave irradiation, and ultrasonic irradiation. Also, supercritical fluid extraction (SFE) using CO 2 under different conditions was used for comparison. Different methods of extraction with organic solvents (normal stirring, soxhlet, microwave irradiation, and ultrasonic irradiation) showed significant differences in the extraction yields. However, no differences were found when a given method (e.g., microwave irradiation) was applied using different organic solvents. On the other hand, different extraction conditions from the various runs of SFE resulted in different extraction yields, all of which were lower than those of the other extraction methods using organic solvents. No significant differences were observed in the fatty acid compositions of the extracted oils using organic solvents. However, the fatty acid compositions of the oils extracted under different conditions of the SFE system indicated significant differences among several fatty acids including unsaturated fatty acids.

This paper details the study of applicability of microwave initiated synthesized polyacrylamide grafted guar gum (GG-g-PAM) as matrix for controlled release of 5-amino salicylic acid (a drug used for the treatment of ulcerative colitis). In vitro release of this drug from various grades of GG-g-PAM has been studied by USP dissolution method (paddle type). The effect of percentage grafting on the rate of drug release has been investigated. The power of the microwave oven and other factors being kept constant, the percentage grafting in turn is dependent on the net time of exposure to microwave irradiation; thus a correlation can be drawn between net time of irradiation and rate of drug release (from the matrix). This holds the promise of a tailor-made matrix, with the rate of drug release being precisely programmed at the molecular level. Further, the drug release study was carried out in different pH medium, to investigate the possibility of pH triggered release for colon targeted drug delivery (where the pH is alkaline).

A catalyst-free highly efficient synthesis of 3(5)-amino-5(3)-(het)aryl-1,2,4-triazoles in aqueous medium was performed using conventional heating and microwave irradiation. The tautomerism in the products was investigated using NMR spectroscopy and X-ray crystallography. The effects of the substitution, temperature, solvents, and concentration on the tautomerism were studied. The triazoles were found to exist in 1H-forms, the 4H-form was not observed either in solid state or in solution. In general, 5-amino-1,2,4-triazoles were electronically preferred in the tautomeric equilibrium, but some exceptions from the established relationship were also identified.

The salient features of clays, their modified forms (pillared and 'doped' with reagents) and their application in organic synthesis are described. A wide variety of chemical reactions such as addition, isomerization, rearrangement, electrophilic substitution etc. are presented ...

The tetrasulfophthalocyanine complexes of Ni, Cu, Co, Pd, Pt, and tetranitrophthalocyanine complexes of Ni, Cu, Co, Mn, Fe, Pd are prepared in high purity upon exposure to microwave irradiation under solvent-free and reflux conditions and reaction times are considerably reduced.

Assessment of the viability for different types of solar PV tracking technologies rely on the assessment of whether the annual production of the different tracking technologies is increased enough relative to a benchmark Fixed Tilt system to compensate for the higher installation and operational costs incurred by the tracking systems. To investigate this issue, we use the PVsyst software to simulate electricity production from three representative solar PV systems at Karnataka. In these simulations we use hourly solar irradiance, weather and surface albedo data, technical data relating to both module and inverter characteristics and impacts associated with module soiling and shading.

The synthesis of a number of benzimidazole Schiff bases 3 and 3-oxo-pyrimido[1,2-a]benzimidazoles 4 in excellent yields by a one-step sequence from the reaction of 2-aminobenzimidazole under green chemistry conditions is described. Structural assignments of the new compounds as well as complete assignment of 1 H and 13 C NMR signals have been unambiguously achieved based on the analysis of their 1 H and 13 C NMR (1D and 2D), IR, MS and elemental analysis data. To the synthesized Schiff bases the E-configuration was assigned on the basis of comparison of experimental and calculated (DFT) 13 C NMR chemical shifts. Compounds 3 and 4 were evaluated as inhibitors of lipoxygenase (LOX) and of lipid peroxidation (LPO). All the tested derivatives showed inhibition of lipid peroxidation, whereas most of them were found to have higher activation than the reference compound trolox; The Schiff bases 3e, 3h, and 3i, and the pyrimidobenzimidazoles 4a, 4e and 4f were found to be the most potent. The most potent LOX inhibitor within the subset of Schiff bases was found compound 3i, followed by 3f, whereas compounds 4a and 4g were found the most potent of the 3-oxo-pyrimido[1,2-a]benzimidazole group. Moreover, some cytotoxicity assessments were undertaken, whereupon it was found that Schiff base 3i and pyrimidobenzimidazoles 4e and 4f did not exhibit cytotoxicity at similar concentrations resembling thus the inhibitory activity of lipid peroxidation. The most cytotoxic Schiff base and pyrimidobenzimidazole were found to be 3d and 4c, respectively.

1-Methylimidazolium hydrogensulfate, [Hmim] [HSO 4 ], a Brønsted acidic room temperature ionic liquid, is used as a catalyst and reaction medium for facile and ecofriendly deprotection of methoxymethyl (MOM) and ethoxymethyl (EOM) ethers to their corresponding alcohols under thermal conditions (D) and microwave irradiation (MW). Furthermore, one-pot interconversion to the respective acetates and trimethylsilyl (TMS) ethers was also achieved.

N,N′-Pyromelliticdiimido-di-l-methionine (3) was prepared from the reaction of pyromellitic dianhydride (1) with l-methionine (2) in glacial acetic acid and pyridine solution at refluxing temperature. The direct polycondensation reaction of the monomer diimide–diacid (3) with 1,3-phenylenediamine (4a), 1,4-phenylenediamine (4b), 2,6-diaminopyridine (4c), 3,5-diaminopyridine (4d), 4,4′-diaminodiphenylether (4e) and 4,4′-diaminodiphenylsulfone (4f) was carried out in a medium consisting of triphenyl phosphate, N-methyl-2-pyrolidone, pyridine and

A potassium iodide catalysed method for the selective N-monoalkylation anilines with alkylhalides and alkyltosylates under microwave irradiation is described. The corresponding N-alkylanilines are obtained in good yields with only minor quantities of dialkylation by-products.

A series of 1,3,5-triazine derivatives that contain aniline, coumarins (4-hydroxy coumarin and 7-hydroxy-4-methyl coumarin) and different piperazine moieties as substituent on the carbon atoms of the triazine ring have been synthesized by a simple and efficient synthetic protocol. Comparative studies were performed on above series, which were synthesized with conventional and microwave heating methods. The microwave method was observed to be more beneficial as it provides an increase in yield and 90–95% reduction time. All the synthesized compounds were then examined for their efficacy against two Gram −ve bacteria (Escherichia coli and Pseudomonas aeruginosa), two Gram +ve bacteria (Staphylococcus aureus and Bacillus subtilis) and two fungal species (Candida albicans and Aspergillus niger) with an intent to overcome multiple drug resistance to the pathogenic strains. All the synthesized compounds were structurally elucidated by IR, 1H NMR, 13C NMR and elemental analysis.

This paper studies different organophosphorus extractants for the selective recovery of metal ions such as Cu (II), Co (II), Ni (II), Pb (II), Fe (III), Cd (II) from effluents resulting from the metal finishing at the time of industry process. In a first step, a commercial extractant such as di(2ethylhexyl)phosphoric acid (D2EHPA) was used as carrier for SLM extraction. Combining D2EHPA and TOPO (tri-octylphosphine oxide) leads to enhanced extraction of Cu (II), Ni (II) and Co (II). The influence of other critical parameters such as pH, ionic strength and mass transfer resistance of the feed was investigated as well as the diffusion of metal ions and membrane permeation. D2EHPA showed good extraction efficiency for Pb (II) (91%) in the mixture, whereas it is lower for Cu (II) (9%). When TOPO was added to D2EHPA, the extraction efficiency of copper increases up to 57%. In a second step, new organophosphorus extractants, synthesized by microwave irradiation, were tested in SLM extraction of metal ions. Di[p-(1,1 ,3,3 -tetramethylbutyl)phenyl] phosphoric acid (DOPPA) and 1,12-(4,9-dioxatrisdecanyl)diphosphonic acid (DOTDDA), selectively extracted Cu (II) and Co (II) (100%) from Fe (III), Cd (II), Pb (II) and Ni (II) in the mixture (0%), whereas methylenediphosphonic acid (MDPA) is a good carrier for Cd (II) (83%), Pb (II) (69%) and Ni (II) (63%) extraction. However 1,13-diamino-4,7,10-trioxatridecanyltetramethylene phosphonic acid (DATOMPA) is useful for extraction of trace metals (Fe (III); 72%). For a selective extraction of Co (II) and Cu (II) from other metals, DOPPA shows the highest extraction efficiency for these two cations, whereas the rest of heavy metals tested are not extracted. (J.Å. Jönsson).

A rapid, efficient, clean and environmentally benign exclusive synthesis of Schiff bases as new ligands and their complexes with Cu(II) have been developed using condensation of salicylaldehyde and amoxicillin (L 1 ), cephalexin (L 2 ), sulphamethoxazole (L 3 ) and trimethoprim (L 4 ) efficiently in analcoholic suspension medium using alkali catalyst with excellent yields under microwaves irradiation. This method provides several advantages such as environmental friendliness, simple work-up procedure, short reaction times, non-hazardous and excellent yield of products.The results are compared with conventional methods for their yield and reaction time. The Schiff base ligands and the complexes were characterized by micro-analytical, thermo-gravimetric, magnetic and spectroscopic studies.Allthe Schiff bases were bidentate (NO donor) ligands. Salicylidenesulphamethoxazole-Cu(II) monohydrate was five co-ordinate whereas all other complexes were found to be six co-ordinate dihydrates and ML 2 [1:2 (metal: ligand) ratio] type. The complexes are coloured and stable in air. All the complexes under investigation possess antibacterial activity. The antibacterial activity showed the following trend: Cu(II)-complexes ˃ Schiff base ligands ˃ parent drugs.

A zeolite catalyzed, single step and environmentally friendly process for synthesis of classical Biginelli reaction was investigated. For this reaction Transition metal/Y zeolites were prepared by microwave solid-state and aqueous solution ion-exchange methods.