FORM 2
THE PATENTS ACT, 1970
(Act 39 of 1970)
COMPLETE SPECIFICATION
(See Section 10; Rule 13)
Title: "NOVEL CALIX[4]PYRROLE OCTAHYDRAZIDE, METAL
NANOPARTICLES DERIVED FROM IT AND USE OF THE NANOPARTICLES".
Applicants: 1. vinod kumar
2. Makwana Bharat Ambalal
3. Vyas Disha Jayantkumar
4. Bhatt Keyur Dineshchandra
3. Darji Savan Maheshbhai

5.Mishra Divya Ram
Address: Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad-380009, Gujarat, India.
Nationality: indian
The following specification describes the nature of the invention and the manner in which it is to be performed:

FIELD OF THE PRESENT INVENTION
The present invention relates to novel calix[4]pyrrole octahydrazide of formula (A) and process for the preparation thereof.

The present invention also relates to the use of calix[4]pyrrole octahydrazide (CPOH) of formula (A) in the preparation of water dispersible stable metal nano particles.
BACKGROUND OF THE PRESENT INVENTION
Calix[4]pyrrole belongs to the family of hetero-calixarene macrocycles, which has four pyrrole units instead of phenolic units have found applications as macrocyclic receptors, dendrimers in biological systems, nanoparticles, nano-capsule, supra-molecular tectons, optical chemosensors, host molecules or host-guest complexes, components in liquid crystals, pho-toresists, selective membranes, HPLC stationary phases, surface reforming agents, ion channel mimics, and metal-ion extraction agents.
Previously, Resorcinarene and other calixarene derivatives have been used to enhance the dispersion of colloidal metal particles in various organic solvents, as well as their self-assembly into well defined nanostructures with novel colligative properties.

A large number of methods have been developed for the synthesis of metal nanoparticles in last two decades, involving the use of different protecting reagents, such as alkylthiols, alkylamines, polymers and other ligands.
Recently, as per the disclosure in the references (i) "Langmuir 18 (2002) 3676" & (II) "Supramol. Chem. 17 (2005) 173", Balasubramanian and coworkers made a study of the dispersion and stability of resorcinarene-encapsulated gold nanoparticles through extracting gold particles from gold hydrosol into toluene or chloroform using resorcinarene surfactant as an extractant, and they revealed that the resorcinarene surfactants with sulphur functionalized head groups could make the mid nanometer sized gold particles stably dispersed in organic solvents.
In the reference "Angew. Chem. 117 (2005) 2973", Tshikhudo et al. has reported the preparation and chemical properties of water-soluble gold nanoparticles protected by sulfanylalkyl oligo (ethylene glycol) and sulfur-containing calix[4]arene ligands.
In another reference "Colloids Surf. A 181 (2001) 255", Sastry and coworkers prepared the hydrophobic gold nanoparticles capped by fatty amine with the simplified Brust "twophase" method and made a research into the interaction between the surface-bound alkylamines and gold nanoparticles.
There are several other methods available to reduce the metal ions to form nanoparticles.
One of the reference "J Nanopart Res (2011) 13:4997-5007" has disclosed a method wherein hydrazine hydrate is used as a reducing agent but the nanoparticles formed by this method lack stability.
The other reference "Journal of Physics and Chemistry of Solids 68 (2007) 2252-2261" has disclosed a process of preparing stable gold nanoparticles using aminoresoncinarene (TOMR) thus TOMR is used as

capping/stabilizing agent which can increase the stability of nanoparticles by preventing them to agglomerate.
Now, with this present invention, Inventors have tried to provide calix[4]pyrrole octahydrazide of formula (A) and have made use of the same in the preparation of water dispersible stable metal nano particles which may be efficiently used in the above said application.
SUMMARY OF THE PRESENT INVENTION
It is an object of the present invention to provide novel calix[4]pyrrole octahydrazide of formula (A).
It is further an object of the present invention to provide safe, industry viable process for the preparation of calix[4]pyrrole octahydrazide of formula (A).
It is yet another object of the present invention to provide metal nano particles derived from calix[4]pyrrole octahydrazide of formula (A),
It is also an object of the present invention to provide safe, industry viable process for the preparation of metal nanoparticles derived from calix[4] pyrrole octahydrazide of formula (A).
Yet another object of the present invention includes use of nanoparticles in nonvolatile random access memory device or resistive random-access memory device (RRAM).
It is an object of the present invention to provide the usage of nanoparticles as selective chemo sensors.
BRIEF DESCRIPTION OF DRAWINGS
FIG.l shows FT-IR of calix[4]pyrrole octahydrazide of formula (A)
FIG.2 shows 1H NMR of calix[4]pyrroIe octahydrazide of formula (A)
FIG.3 shows MASS Spectra of calix(4]pyrrole octahydrazide of formula (A)

FIG.4 shows a transmission electron micrograph (TEM) of the gold
nanoparticles produced in accordance with Example- A.
Fig. 5 shows a graphical view on particle size of the gold nanoparticles
produced in accordance with Example-A.
FIG.6 shows an energy dispersive graph (EDS) of the gold nanoparticles
produced in accordance with Example-A.
FIG.7 shows stability analyzed through Surface Plasmon Resonance
(SPR) of the gold nanoparticles produced in accordance with Example-A.
FIG.8 shows stability for 150 days, analyzed through Surface Plasmon
Resonance (SPR) of the gold nanoparticles produced in accordance with
Example-A.
FIG.9 shows a transmission electron micrograph (TEM) of the silver
nanoparticles produced in accordance with Example-B.
Fig. 10 shows a graphical view on particle size of the silver nanoparticles
produced in accordance with Example-B.
FIG. 11 shows an energy dispersive graph (EDS) of the silver
nanoparticles produced in accordance with Example-B.
FIG. 12 shows stability analyzed through Surface Plasmon Resonance
(SPR) of the silver nanoparticles produced in accordance with Example-
B.
FIG. 13 shows stability for 120 days, analyzed through Surface Plasmon
Resonance (SPR) of the silver nanoparticles produced in accordance with
Example-B.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Inventors have thought of designing a novel compound which has all the chemical and physical properties of hydrazine hydrate to act as reducing agent and a web type of structure with inherent hollow cavity to encapsulate/cap/engulf/stabilize the reduced nanoparticles.
For this purpose calix(4)pyrroles have been chosen. Calix(4)pyrroles are the cyclic condensation product of pyrrole and ketone. Several references have disclosed that caIix(4)pyrroles have inherent anion binding cavity in the form of cyclic array of pyrrolic (NH) and have vast possibility of using

ketones having functional group of our choice at meso position of Calix(4)pyrroles.
Thus, the first aspect of the present invention is to provide a novel calix[4]pyrrole octahydrazide of formula (A).

In a second aspect, the present invention is directed to a process for the preparation of novel calix[4]pyrrole octahydrazide of formula (A).
Further, in accordance with the scheme-1, inventors have also develop a process for the preparation of calix[4]pyrrole octahydrazide of formula (A).
According to the present invention, a process for the preparation of calix[4]pyrrole octahydrazide of formula (Aj comprises the steps of:
(i) reacting pyrrole of formula (a) and 3,4-di-hydroxyacetophenone of formula (b) in presence of BF3(OEt)2 to give compound of formula
(i);
(ii) reacting compound of formula (1) with ethyl bromoacetate in
presence of base and catalytic amount of potassium iodide (KI) to
give compound of formula (2); (iii) carrying out reaction of compound of formula (2) using hydrazine
hydrate in a solvent to give calix[4]pyrrole octahydrazide of
formula (A).

Though, compounds of formula (1) & 2 of the scheme-1 are known and
may be prepared with the help of any reference available in the public
domain, the inventors have followed following references for the
preparation of compounds of formula (1) & (2):
Compound of formula (1) is prepared as per the process given in the
JACS: 2007, V-129, p-3820-3821.
Compound of formula (2) is prepared as Chem. Comm.: 2000, 1129-
1130.
Schematic diagram of the process for the preparation of novel calix[4]pyrole octahydrazide of formula (A) is given as follows.

Inventors have found novel compound of formula (A) by reacting the compound of formula (2) with hydrazine hydrate in a solvent, the obtained compound (A) is known as calix[4]pyrrole octahydrazide (CPOH).

Reaction is carried out at a reflux temperature of a solvent used in the reaction. The preferred reaction temperature is comprised between 60°C and 80° G more preferably between 70°C and 80° C.
Solvent used in the reaction is selected from the solvents like methanol, toluene or mixtures thereof. Quantity of the solvent used in the reaction is as per the reaction requirement which may vary between 10 to 120 times volume that depend on the starting materials used in the reaction, preferably reaction proceeds faster if 40 to 120 times volume of solvent is used in the reaction. Further, in case if mixture of toIuene:methoanol is used in the reaction, the ratio of mixture may vary between 20:80v/v to 80:20v/v of toluene:methanol.
Hydrazine/hydrate used in the reaction is added in a molar ratio selected from 5 to 20 compared to the molar ratio of the compound of formula (2). Preferably hydrazine hydrate is added in a molar ratio selected from 10 to 15 compared to the molar ratio of the compound of formula (2).
The process is typically carried out at atmospheric pressure. Of course, pressures below or above atmospheric pressure are not excluded by the present invention.
Reaction mixture is stirred for a period of 50-80 hrs to get the compound of formula (2). Once the reaction is completed, the reaction mass is taken for solvent removal using distillation method under vacuum.
If desired, calix[4]pyrrole octahydrazide (CPOH) of formula (A) may be taken for purification. Purification stage is performed by recrystallization in water. Calix[4]pyrrole octahydrazide of formula (A) is dissolved in hot water, stirred it for 15-30 minutes, cooled to room temperature and then to 0-5°C. Reaction mass is then stirred to 0-5°C for 30 minutes, filtered to give pure calix[4]pyrrole octahydrazide of formula (A). It is also possible to use other solvent for the purification purpose, the only condition, to carry out purification stage is that the calix[4]pyrrole

ocatahydrazide of formula (A) must be soluble and it gets reprecipitated once appropriate conditions applied.
In the third aspect, the present invention has disclosed water dispersible stable metal nanoparticles and process for the preparation thereof.
Inventors have found that most of the earlier reported methods have used reducing agent and capping agent separately to prepare reasonably stable metal nanoparticles. Few reports are also available where only one compound has acted as reducing as well as stabilizing agent but the nanoparticles obtained by such agents lack stability. Table-1 shows these references wherein the comparison of stability of the formed metal nano particles is provided.
Table-1: Comparison of stability of the formed metal nanoparticles:

Reference Compound name Reducing agent Synthesized Nanoparticles Stability
Journal of Inclusion Tetrathiol Sodium AuNPs 8 days
Phenomena and Resorcinarenes borohydride
Macrocyclic Chemistry 41:
83-86, (2001)
Journal of Colloid and C- Trisodium AuNPs Good
Interface Science:297, 584- undecylcalix[4]- citrate
588 (2006) resorcinarene
J. Dispersion Science and Tetrabenzylthiol Trisodium AuNPs 8 days
Tech.: 22(5), 485-489 Resorcinarenes citrate
(2001)
ACS Nano. Vol: 4(4), 2129- Polyamine Sodium AuNPs, 1 month
2141 (2010) Resorcinarenes borohydride AgNPs, PtNPs, PdNPs
Whereas inventors in the present invention, have developed an efficient, eco-friendly and simple method for the preparation of metal nano particles (Metal Nps) in which calix[4]pyrrole octahydrazide (CPOH) of formula (A) acted as both reducing as well as stabilizing agent and no need to use reducing agent or stabilizing agent separately.

Now, a process for the preparation of calix[4]pyrrole octahydrazide metal nanoparticles comprises the steps of:
(a) mixing aqueous solution of calix[4]pyrrole octahydrazide of formula (A) with aqueous solution of metal salt to get the reaction mass;
(b) stirring it to obtain metal colloids in the reaction mass;
(c) carrying out centrifugation of the colloidal reaction mass to get metal nano particles derived from calix[4]pyrrole octahydrazide.
Accordingly, in step (a), mixing is done at a temperature between 20°C to 35°C. At the time of mixing the solutions, vigorous stirring is required. In case, if vigorous stirring is not applied then the metal nano particles with the desired particle size will not be obtained.
The aqueous solution of calix[4]pyrrole octahydrazide of formula (A) and aqueous solution of metal salt is mixed in a ratio of 1:1 for ex: Under vigorous /stirring, ImMol aqueous solution of calix[4]pyrrole octahydrazide (CPOH) of formula (A) is mixed with ImMol solution of metal salt at a boiling temperature and stirred for half an hour to give metal colloids which is further taken for centrifugation atleast for three times to give desired metal nano particles.
With the help of the above said method, Silver (Ag) and Gold (Au) nano particles of calix[4]pyrrole octahydrazide may be obtained. To get the silver nanoparticles, silver nitrate (AgNO3) is used as the metal salt while to get the gold nanoparticles, HAuCU is used as the metal salt. The Gold nanoparticles of calix[4]pyrrole octahydrazide is known as CPOH-AuNps while silver nanoparticles of calix[4)pyrrole octahydrazide is known as CPOH-AgNps.
Silver and Gold Nanoparticles of calix[4]pyrrole octahydrazide (CPOH) of formula (A) were found to be stable at room temperature, at different pH and also over a long period of time. It was also found that CPOH-AuNps and CPOH-AgNps are selective and sensitive fluorescent chemo sensors.

The very high stability of silver nanoparticles is due to the web type architecture of CPOH, which has eight hydrazide groups on its periphery and the inherent hollow cavity. Hydrazide group on periphery reduces the metal ions to metallic silver which further nucleates to form the nanoparticles which are engulfed in the inherent hollow cavity of CPOH to give more or less uniform spherical size. The web type structure of CPOH shields the nanoparticles so effectively that they do not aggregate and retain their size for months together.
The nanoparticles have shown good antimicrobial activity as well as interaction with DNA. Nanoparticles being stable in the aqueous system provides ample opportunity of their application in various biological systems.
EXAMPLES
Materials and methods:
All reagents were of analytical reagent grade and were used without further purification. Solvents employed were purified by standard procedure before use.
For the purpose of preparation of the compounds of formula (A), the starting materials, reactants, catalyst, solvents are commercially available in the market. Starting materials i.e. compounds of formula (1) and compounds of formula (2) may also be prepared using any process which is reported in the prior art.
Melting points were determined in open capillary on Veego (Model: VMP-D) electronic apparatus and are uncorrected.
FTIR spectra (4000-400cm-1) recorded on Simadzu 8400-S spectrophotometer using KBr disk.
Nuclear magnetic resonance (1H NMR) spectra were recorded on Bruker 500 MHz model spectrometer using CDCl3 as a solvent and TMS as internal reference (Chemical shifts in δ ppm).

Preparation of calix[4]pyrrole octahydrazide of formula (A): Ex-1: Preparation of compound of formula (1):
An equimolar mixture of pyrrole of formula (a) (0.5 mL, 0.007 mol), 3, 5-dihydroxy acetophenone of formula (b) (1.14 g, 0.007 mol) and boron trifluoroetharate (0.5 mL) were placed in a conical flask with 15 ml of methanol. The reaction mixture was subjected to microwave irradiation for 10 min at 0% output with a slight pause after every 2 min. After completion of the reaction, a brown reaction mixture was quenched in a mixture of 50 mL of cold water and 0.5 mL of tri-ethylamine (for neutralization). The brown coloured residue was dissolved in diethyl ether (25 mL), dried over MgSCH, filtered and concentrated until light brown colored isomers were obtained with the yield 85%. The product was recrystallised in acetonitrile to get the enriched fraction by column chromatography using silica gel (160-200 mesh size) with methanol: chloroform (8:2) as an eluent. Colour: Brownish solid Melting point: 225°C.
Ex-2: Preparation of compound of formula (2):

Compound of formula (1) (lg, 2.5 mmol) and K2CO3 (2.7g, 19.8 mmol) were suspended in acetone (100ml dry) and stirred for 4 hours. BrCl-teCOOEt (3.2g, 19.8 mmol) was added and the suspension was refluxed for 5 days. After cooling the solution was filtered off to remove K2CO3, and the solvent removed under a vacuum. Brown oil was obtained that was dissolved in dichloromethane (40ml) and washed with water (4 x 15ml). The organic phase was separated and then dried with MgS04. The solvent was removed in vacuum affording an oil which was triturated with EtOH (50ml) affording the product as a light brownish powder which was collected by filtration and dried under a high vacuum. The product was recrystallised in chloroform to get the enriched fraction by column chromatography using silica gel (160-200 mesh size) with methanol: chloroform: Acetonitrile (2:4:4) as an eluent. The fraction was

recrystallised from chloroform to give light brownish crystal of 2 (0.80 g, 66%) with a melting point of 85°C.
Ex-3: Preparation of calix[4]pyrrole octahydrazide of formula (A):
Compound of formula (2) (lg, 0.76 mmol) and Hydrazine hydrate (0.43g, 8.6 mmol) were suspended in a mixture of 120ml of methanol: toluene (50:50) and stirred at reflux temperature for 72 hours. The solvent was removed in vacuo, and the white solid was suspended in dichloromethane (50ml). The suspension was filtered and washed with dichloromethane (3x20ml). The product was then recrystallized in hot water to'give light white crystal of calix[4]pyrrole octahydrazide of formula (A). Yield: 0.62 g, 46% Melting point: 155°C. IR as per Fig. 1.
(Fig. 2): 1H NMR (500 MHz in d6-DMSO, δ ppm): 1.90 (12H, t, J = 7.0Hz, CH3), 4.32 (16H, t, OCH2), 4.38(16H, q, NH2), 6.06 (8H, s, pyrr. CH), 6.36 (8H, d, J =8.5Hz, ArH), 8.49-8.99 (4H, s, NH). 9.37 (8H, s, CONH), (Fig. 3): MASS: 1378.7 (M+).
Preparation of metal nanoparticles:
Ex-A: Synthesis of CPOH-AuNps (Gold nanoparticles):
25 mL (ImM) solution of HAuCl4 was added to a 30 mL of conical flask and then 25 mL (1 mM) aqueous solution of calix[4]pyrrole octahydrazide of formula (A) (CPOH) was added rapidly under vigorous stirring. Calix[4jpyrrole octahydrazide stabilized gold colloids (AuNps) were obtained immediately but vigorous stirring was continued for 15 minutes to ensure complete homogenization. The transparent colourless solution was converted to the characteristic ruby red colour, indicating the formation' of Gold nanoparticles (CPOH-AuNps). This CPOH-AuNps solution was then subjected to repeated centrifugation (3 times) at 5000 RPM, washed with a copious amount of deionized water to remove uncoordinated molecules and again redispersed in deionized water for

further studies. The stability of the solution at room temperature was observed to be more than three months.
Ex-B: Synthesis of CPOH-AgNps (Silver nanoparticles):
25 mL (1 mM) aqueous solution of calix[4]pyrrole octahydrazide of formula (A) (CPOH) was added rapidly into 25 mL (ImM) boiling solution of AgNO3 in a 30 mL of conical flask under vigorous stirring. Calix[4]pyrrole octahydrazide stabilized silver colloids (AgNps) were obtained immediately but vigorous stirring was continued for 30 minutes to ensure complete homogenization. The transparent colourless solution was converted to the characteristic pale yellow colour, indicating the formationvof silver nanoparticles (CPOH-AgNps). This CPOH-AgNps solution was then subjected to repeated centrifugation (3 times) at 5000 RPM, washed with a copious amount of deionized water to remove uncoordinated molecules and again redispersed in deionized water for further studies. The stability of the solution at room temperature was observed to be more than one month.
While the invention has been described and exemplified in sufficient detail for those skilled in this art to make and use it, various alternatives, modifications, and improvements should be apparent without departing from the spirit and scope of the invention. .
CHARACTERIZATION AND APPLICABILITY OF NANOPARTICLES
(A) For CPOHAugNps (Gold nanoparticles):
Characterization of CPOH-AuNps by particle size analyzer, Transmission Electron Microscope (TEM) and Energy Dispersive X-Ray (EDX):
A drop of dilute solution of aqueous nanoparticles was placed on carbon coated copper grids and was dried in vacuum and directly observed in the TEM. The morphology and particles size of CPOH-AuNps as shown in figure 4 revealed that the particles are roughly spher^al in shape and uniform in size, as well as, well dispersed

with a narrow size distribution with an average particles size of 8±2 nm (Figure 5) which is less than 50nm.

The size distribution of the CPOH-AuNps was also determined using particle size analyzer where the average hydrodynamic diameter was found to be 16±3 nm. These higher values were due to the light scattered by the core particle and the layers formed on the surface of the particles.
Energy-dispersive X-ray (EDX) analysis spectrum recorded in the spot-profile mode from one of the densely populated CPOH-AuNps regions on the surface of film. Strong signals from Au atoms while weaker signals from C, O, Si, Cu and Ca atoms were observed (Figure 6). Th^ overall particles charge in a particular medium is denoted as their zeta potential value which is also responsible for deciding the fate of stability. Here, synthesized gold nanoparticles (CPOH-AuNps) had a 15 ± 2 MeV zeta potential values, which is sufficient to keep the particles away from aggregation and maintained the stability, moreover positive value also suggests that hydrazide groups were successfully introduced onto the surface of nanoparticles.
CPOH-AuNps which are water dispersible, highly stable for more than 150 days at neutral pH with a size of less than 10 nm and zeta potential of 15 ± 2 MeV makes these nanoparticles very potential candidate for various biological/biomedical applications.
Stability Study: Effect of pH and time on stability of CPOH-AuNps:
Stability of gold nanoparticles (CPOH-AuNps) has been investigated by change in their surface plasmon resonance (SPR) band and fluorescence intensity at different pH (3.0 to 11.0).
SPR band of CPOH-AuNps shows slight change at pH other than 7.0 and tend to agglomerate. It is noteworthy that when their agglomerated form is sonicated for 10-15 minutes they retain their

originality with a negligible compromise in their SPR band and thereby size (Figure 7). No change in SPR band of the CPOH-AuNps at pH 7.0 was recorded up to 150 days (Figure 8). Likewise, fluorescence intensity of gold nanoparticles CPOH-AuNps decreases slightly at pH other than 7.0 (Figure 2c). Therefore, pH 7.0 was selected to carry out all experiments on CPOH-AuNps and concluded that CPOH-AuNps shows maximum stability and fluorescence intensity at pH 7.0.
Colorimetric detection of Co(II) using CPOH-AuNps and its applicability:
The metal nanoparticles are considered as important type of colorimetric reporters because of their large extinction coefficients and tendency to agglomerate in the presence of analyte. Agglomeration leads to distinct colour and thereby making them very useful colorimetric sensing platforms.
To investigate the colorimetric response of CPOH-AuNps, various metal ions i.e. Pb(II), Cd(II), Mn(II), Fe(III), Ni(II), Zn(II), Hg(II), Co(II) and Cu(II) in μM concentration were added to these nanoparticles. No visible colour change was observed with any of the metal ions except Co(II), which exhibits a sharp change in colour from ruby red to purple, and finally to blue which can be easily judged by the naked eye. The colour change with Co(II) ions can be easily noticed even at nano molar (nM) concentration in aqueous samples. It may be concluded that CPOH-AuNps can be used a remarkable selective colorimetric sensor for Co(II) ions.
Interaction of various cations with CPOH-AuNPs by spectrophotometry and spectrofluorimetry measurements:
The absorption spectra of CPOH-AuNps with various metal ions i.e. Pb(II), Cd(II), Mn(II), Fe(III), Ni(II), Zn(II), Hg(II), Co(II) and Cu(II) were recorded (Figure 4). No change in the absorption spectra was observed with all the metal ions except Co(II) ions which shows red

shift of 55 nm. The red shift is dependent on the number of particles and their spatial arrangement within an aggregate. The red shift and significant broadening of the absorption bands is also due to overlapping of shifted modes of vibration. Because of these reasons, - gold nanoparticles offer significant potential for detection applications due to (i) their high sensitivity to perturbations in the local dielectric constant (or refractive index) of the surrounding media and (ii) aggregation-induced colour changes, which result from the plasmon peak shift and broadening. It is concluded that the shift to higher wavelength (red shift) is related to a change in the particles size.
The emission spectra of the CPOH-AuNps were recorded at 698 nm. The fluorescence emission of CPOH-AuNPs was studied over a wide range of pH (3.0 to 11.0). The maximum emission intensity was observed at pH 7.0. The selectivity of CPOH-AuNPs for Co(II) ions was also examined in the presence of various metal ions i.e. Pb(II), Cd(II), Mn(II), Fe(III), Ni(II), Zn(II), Hg(II) and Cu(II) at 7 pH. The linear range of minimum and maximum detection of Co(II) ions was determined by means of fluorescence titration of CPOH-AuNPs (0.0084%) with increasing concentration of Co(II) ions. It was noted that fluorescence intensity, at 698 nm, gradually decreases with an increase in the concentration of Co(II) ions. The minimum and maximum fluorescence quenching (90%) was observed at 1 nM and 1 μM concentration of Co(II) ions, respectively, which is considered as the minimum and maximum detection limit CPOH-AuNps. Therefore these nanoparticles can be used as a highly sensitive and selective fluorescence "turn-off sensor for Co(II) ions without further modification. This highly sensitive and selective sensoring properties may result from the aggregation of CPOH-AuNps induced by the cross-link complexation between and Co(II) ions.

(6) For CPOH-AgNps (Silver nanoparticles):
Characterization of CPOH-AgNps by particle size analyzer, TEM and EDX:
A drop of dilute solution of aqueous nanoparticles was placed on carbon coated copper grids and was dried in vacuum and directly observed in the TEM. The morphology and particles size of CPOH-AgNps as shown in figure 9 revealed that the particles are roughly spherical in shape and uniform in size, as well as, well dispersed with a narrow size distribution with an average particles size of 18±2 nm (Figure 10) which can considered as less than 50nm.
The size distribution of the CPOH-AgNps was also determined using particle size analyzer where the average hydrodynamic diameter was found to be 26±3 nm. These higher values were due to the light scattered by the core particle and the layers formed on the surface of the particles.
Energy-dispersive X-ray (EDX) analysis spectrum recorded in the spot-profile mode from one of the densely populated CPOH-AgNps regions on the surface of film. Strong signals from Ag atoms while weaker signals from C, O, Si, Cu and Ca atoms were observed (Figure
11).
The overall particles charge in a particular medium is denoted as their zeta potential value which is also responsible for deciding the fate of stability. Here, synthesized silver nanoparticles (CPOH-AgNps) had a 13 ± 2 MeV zeta potential value, which is sufficient to keep the particles away from aggregation and maintained the stability, moreover positive value also suggests that hydrazide groups were successfully introduced onto the surface of nanoparticles.

Stability Study: Effect of pH and time on stability of CPOH-
AgNps:
Stability of silver nanoparticles has been investigated by change in their SPR band and fluorescence intensity at different pH. SPR band of CPOH-AgNps shows negligible change at pH other than 7.0 for a day or two but CPOH-AgNps tend to agglomerate after that. It is noteworthy that when their agglomerated form is sonicated for 15-20 minuties they retain their originality with a negligible compromise in their SPR band and thereby size (Figure 12) [55, 56]. No change in SPR band of the CPOH-AgNps at pH 7.0 was recorded up to 120 days (Figure 13). Likewise, fluorescence intensity of silver nanoparticles CPOH-AgNps decreases slightly at pH other than 7.0. Therefore pH 7.0 was selected to carry out all experiments on CPOH-AgNps and was concluded that CPOH-AgNps shows maximum stability and fluorescence intensity at pH 7.0.
Colorimetric detection of Hg(II) ions and its applicability using CPOH-AgNps:
CPOH-AgNPs have been found to be unique in their performance for selective and sensitive naked eye detection of Hg(II) ions in aqueous samples for the following reasons, (i) Very low concentration of nanoparticles (0.0054 %) is needed for detection of Hg(II) ions (ii) High stability of water dispersible nanoparticles (iii) Selectivity among various metal ions. 2 mL of CPOH-AgNPs (0.0054 %) which is yellowish brown in colour was mixed with 2 mL (2 μM) of each metal ion (Pb(II), Cd(II), Mn(II), Fe(III), Ni(II), Zn(II), Co(II) and Cu(II)) separately. There was no visible change in colour with all the metal ions except Hg where the colour changed instantly from yellowish brown* to colourless. The repeated observation confirm that method is simple, sensitive and selective for colorimetric detection of Hg(II) in water media.

Interaction of various cations with CPOH-AgNps by spectrophotometry and spectrofluorimetry measurements:
Interaction of different cations with CPOH-AgNps concluded that except Hg(II), no other cations (Pb(II), Cd(II), Mn(II), Fe(III), Ni(II), Zn(II), Co(II) and Cu(II) showed any noticeable change in the SPR band of CPOH-AgNps.
To farther study the interaction behaviour of Hg(II) with CPOH-AgNps different concentrations of aqueous solutions of Hg(II) ranging from 1 nM to 1 μM were mixed with nanoparticles and absorption spectra were recorded. Interestingly, with the increasing concentration of Hg(II) ions SPR band shifted 21 nm towards the lower wavelength region (i.e. from 428 nm to 407 nm, blue shift). The authors believe that the shift to lower wavelength is related to a change in the polarization of the near surface region (Hg is known to lower the work function of Ag surfaces by 0.3 eV).
The emission spectra of the CPOH-AgNps were recorded at 580 nm. The fluorescence emission of CPOH-AgNPs was studied over a wide range of pH (3.0 to 11.0). The maximum emission intensity was observed at pH 7.0. The selectivity of CPOH-AgNPs for Hg(II) ions was also examined in the presence of various metal ions (Pb(II), Cd(II), Mn(II), Fe(III), Ni(II), Zn(II), Hg(II), Co(II) and Cu(II)) at 7 pH. The linear range of minimum and maximum detection of Hg(II) ions was determined by means of fluorescence titration of CPOH-AgNPs (0.0054%) with increasing concentration of Hg(II) ions. It was noted that fluorescence intensity, at 580 nm, gradually increases with an increase in the concentration of Hg[II] ions. The minimum and maximum fluorescence enhancement was observed at 1 nM and 1 μM concentration of Hg(II) ions respectively, which is considered as
the minimum and maximum detection limit CPOH-AgNps. As there is no aggregation of nanoparticles on addition of Hg(II) ions, SPR bands shows blue shift, the emission intensity is increased, therefore it is

deduced that CPOH-AgNps can be used as selective and sensitive sensor for Hg(II) ions.
One skilled in the art readily appreciates that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. The processes and methods for producing them are representative of preferred embodiments, are exemplary, and are not intended as limitations on the scope of the invention. Modifications therein and other uses will occur to those skilled in the art. These modifications are encompassed within the spirit of the invention and are defined by the scope of the claims.
It will be readily apparent to a person skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention.
All patents and publications mentioned in the specification are indicative of the levels of those of ordinary skill in the art to which the invention pertains.
The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations, which are not specifically disclosed herein. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. Other embodiments are set forth within the following claims.

ADVANTAGES OP THE PRESENT INVENTION
Now, without limiting the scope of the present invention, advantages of the present invention may be provided as follows:
Calix[4]pyrrole octahydrazide of formula (A) is used in the preparation of metal nanoparticles and the formed nanoparticles are having below mentioned applications:
1. Nanoparticles exhibits the electrical switching properties at a reasonably low voltage suggesting its potential application in nonvolatile random-access memory device or resistive random-access memory device (RRAM).
2. CPOH-AuNps and CPOH-AgNps have been found to be selective chemo sensors for cobalt and mercury ions, respectively.
3. Further work is required to show whether Nanoparticles shows their antimicrobial activity towards S. Aureus and B.Subtilis, P. Aeruginosa and S. Marcescens therefore have the great potential of their usage as antibacterial and antifungal agents in various pharmaceutical preparations.


We Claim:
1. Calix[4]pyrrole octahydrazide of formula (A):
2. A process for the preparation of calix(4]pyrrole octahydrazide of
formula (A) comprises the steps of:
(i) reacting pyrrole and 3,4-di-hydroxyacetophenone in presence of
BF3(OEt)2 to give compound of formula (1); (ii) reacting compound of formula (1) with ethyl bromoacetate in
presence of base and catalytic amount of potassium iodide (KI) to
give compound of formula (2); (iii) carrying out reaction of compound of formula (2) using hydrazine
hydrate in a solvent to give calix[4]pyrrole octahydrazide of
formula (A).
3. The process for the preparation of calix[4]pyrrole octahydrazide of formula (A) of claim 2 wherein in step-(iii), solvent is selected from methanol, toluene or mixture thereof.
4. CPOH-AuNps (Gold nanoparticles) prepared using calix[4]pyrrole octahydrazide of formula (A).
5. CPOH-AgNps (Silver nanoparticles) prepared using calix[4]pyrrole octahydrazide of formula (A).

6. CPOH-AuNps (Gold nanoparticles) having particle size of of less than 50 nm.
7. CPOH-AgNps (Silver nanoparticles) having particle size of less than
50 nm.
8. A process for the preparation of calix[4]pyrrole octahydrazide metal
nanoparticles comprises;
(a) mixing aqueous solution of calix[4]pyrrole octahydrazide of formula (A) with aqueous solution of metal salt to get the reaction mass;
(b) stirring it to obtain metal colloids in the reaction mass;
(c) carrying out centrifugation of the colloidal reaction mass to get metal nano particles of calix[4]pyrrole octahydrazide.
V
9. The process for the preparation of calix[4]pyrrole octahydrazide
metal nanoparticles as claimed in claim 8 wherein in step (a), ratio of mixing of calix[4]pyrrole octahydrazide and metal salt is 1:1 wt/wt.
10. The process for the preparation of calix[4]pyrrole octahydrazide metal nanoparticles as claimed in claim 8 wherein in step (a) mixing is done at a temperature between 20°C to 35°C.
11. The process for the preparation of calix[4]pyrrole octahydrazide metal nanoparticles as claimed in claim 8 wherein metal salt in step (a) is selected from AgNO3 or HAuCk
12. The process for the preparation of calix[4]pyrrole octahydrazide metal nanoparticles as claimed in claim 8 wherein centrifugation at 5000 rpm is done for three times.
13. The process for the preparation of calix[4]pyrrole octahydrazide metal nanoparticles as claimed in step (c) of claim 8 wherein the metal nanoparticles of calix(4]pyrrole octahydrazide are either

CPOH-AuNps (Gold nanoparticles) or CPOH-AgNps (silver
nanoparticles) of calix[4]pyrrole octahydrazide.
14. A process for the preparation of CPOH-AuNps with the particle size
of les^than 50nm comprises:
(a) mixing aqueous solution of calix[4]pyrrole octahydrazide of formula (A) with aqueous solution of HAuCl4 to get the reaction mass;
(b) stirring it to obtain metal colloids in the reaction mass;
(c) carrying out centrifugation of the colloidal reaction mass to get CPOH-AuNps having particle size of 8±2 nm.
15. The process for the preparation of CPOH-AuNps as claimed in claim
8 wherein in step (a), ratio of mixing of calix[4]pyrrole octahydrazide
(CPOH) and HAuCUis 1:1 wt/wt.
s
16. The process for the preparation of CPOH-AuNps as claimed in claim 14 wherein in step (a) mixing is done at a temperature between 20°C to 35°C.
17. The process for the preparation of CPOH-AuNps as claimed in claim 14 wherein centrifugation at 5000 rpm is done for three times.
18. A process for the preparation of CPOH-AgNps with the particle size of less than 50 nm comprises:

(a) mixing aqueous solution of calix[4]pyrrole octahydrazide of formula (A) with aqueous solution of AgN03 to get the reaction mass;
(b) stirring it to obtain metal colloids in the reaction mass;
(c) carrying out centrifugation of the colloidal reaction mass to get CPOH-AgNps having particle size of 18±2 nm.
19. The process for the preparation of CPOH-AgNps as claimed in claim
18 wherein in step (a), ratio of mixing of calix[4]pyrrole
octahydrazide (CPOH) and AgN03is 1:1 wt/wt.

20. The process for the preparation of CPOH-AgNps as claimed in claim 18 wherein in step (a) mixing is done at a temperature between 20°C to 35°C.
21. The process for the preparation of CPOH-AgNps as claimed in claim 18 wherein centrifugation at 5000 rpm is done for three times.