METAL COORDINATION COMPLEX FOR DETECTION OF VAPORS AND ANIONS AND PROCESS FOR THE PREPARATION THEREOF
20170284986 · 2017-10-05
Inventors
- Vedavati Gururaj Puranik (Pun, IN)
- Rajesh Ghanshyam Gonnade (Pune, IN)
- Rupesh Liladhar Gawade (Pune, IN)
Cpc classification
International classification
Abstract
The present invention discloses novel multi-action copper complexes which are used for reversible vapochromic detection of polar solvents as well as anion sensing in both aqueous and non-aqueous media.
##STR00001##
Claims
1. A complex of formula X ##STR00008## Wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is selected from H.sub.2O or NO.sub.3; Provided that when R.sub.1, and R.sub.3 is NO.sub.3 then R.sub.2 and R.sub.4 is absent.
2. The complex as claimed in claim 1, wherein representative compound of formula X are ##STR00009##
3. The complex as claimed in claim 1, wherein said complex shows vapochromic behavior for polar solvent within a minute.
4. The complex as claimed in claim 3, wherein the polar solvent is selected from the group consisting of methanol, ethanol, acetone, dimethylformamide, dimethyl sulfoxide and Tetrahydrofuran.
5. The complex as claimed in claim 1, wherein said complex showed colour change in the solid state.
6. A process for the synthesis of complex of formula X as claimed in claim 1 and the said process comprising the steps of: a. adding triethylamine (Et.sub.3N) to a stirred solution of isonicotinoylchloride in dichloromethane (DCM) followed by adding 2-phenethylamine with stirring for period in the range of 7 to 8 hrs at room temperature in the range of 20 to 30° C. to obtain N-phenethylisonicotinamide ligand; b. adding methanolic solution of N-phenethylisonicotinamide ligand of step (a) to Cu(NO.sub.3).sub.2. 3H.sub.2O with stirring followed by refluxing, filtering and separating the solution in two parts; c. crystallizing one part of the solution as obtained in step (b) in methanol to yield blue coloured needle shaped crystals of complex of formula (1) and crystallizing the second part of the solution as obtained in step (b) in a MeOH-water mixture to obtain green coloured plates of complex of formula (2); d. adding water to the blue crystals of formula 1 to obtain green crystal of formula 2 and suspending green crystals of formula 2 in methanol to yield blue crystals of formula 1.
7. A process for selective, naked eye detection of anions in aqueous and non-aqueous medium using complex of formula X comprising the steps of: i. suspending the powder of complex of formula X in aqueous solution of tetrabutylammonium (TBA) or ammonium salts, alkali metal salts of various anions in the ratio 20:1 followed by observing the change in colour of the solid sample.
8. The process as claimed in claim 7, wherein the anions are selected from the group consisting of chloride, bromide, nitro, thiocynate, formate and acetate.
9. The process as claimed in claim 7, wherein said process may comprises co-grinding the powder of complex of formula X with tetrabutylammonium (TBA) or ammonium salts, alkali metal salts of various anions for period in the range of 2 to 5 minutes followed by observing the change in colour of the solid sample.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Scheme 1 represents steps for the preparation of compound of formula X.
[0027]
[0028]
[0029]
[0030]
[0031]
[0032]
[0033]
[0034]
[0035]
[0036]
[0037]
[0038]
DETAILED DESCRIPTION OF THE INVENTION
[0039] The present invention provides multi-action copper complex of formula X and preparation thereof which are useful for reversible vapochromic detection of polar solvents as well as colorimetric detection of different anions in both aqueous and non-aqueous media.
##STR00005##
wherein,
R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is selected from H or R.sub.1 and R.sub.3 jointly represent NO group and R.sub.2 and R.sub.4 jointly represent NO group.
[0040] The present invention provides a multi-action vapochromic copper complexes wherein the representative compounds of Formula X are:
dinitratebis (N-phenethylisonicotinamide)copper(II) of formula (1);
##STR00006##
tetraaquabis(N-phenethylisonicotinamide)copper(II)nitrate of formula (2),
##STR00007##
[0041] The complex shows vapochromic behavior for polar solvents with colour change occurred within a minute and showed colour change in solid state.
[0042] The polar solvents are selected from methanol, ethanol, acetone, dimethylformamide, dimethyl sulfoxide and Tetrahydrofuran.
[0043] The complex shows anion sensing capability in the solid state.
[0044] The present invention provides novel multi-action metal coordination complexes which are useful for colorimetric detection of anions in both aqueous and non-aqueous media in few seconds.
[0045] The present invention provides a process for selective, naked eye detection of anions in aqueous and non-aqueous medium using complex dinitratebis (N-phenethylisonicotinamide)copper(II) of formula (1) or tetraaquabis(N-phenethylisonicotinamide)copper(II)nitrate of formula (2), wherein said process comprises suspending the powder of (1) or (2) in aqueous solution of tetrabutylammonium (TBA) or ammonium salts, alkali metal salts of various anions followed by observing the change in colour of the solid sample within few seconds.
[0046] The anions are selected from of chloride, bromide, nitro, thiocynate, formate and acetate.
[0047] The present invention provides a process for the synthesis of multi-action copper complex of formula X comprising the steps of:
a. adding triethylamine (Et.sub.3N) to a stirred solution of isonicotinoylchloride in Dichloromethane (DCM) at 0° C. followed by addition of 2-phenethylamine and stirring the mixture for 8 hrs at room temperature to obtain N-phenethylisonicotinamide ligand;
b. adding methanolic solution of N-phenethylisonicotinamide ligand of step (a) to Cu(NO.sub.3).sub.2. 3H.sub.2O and stirring the reaction mixture followed by refluxing, filtration and then separating the product in two parts (i) and (ii);
c. crystallization of one part of the product of step (b) in methanol to yield blue coloured needle shaped crystals of formula (1) and crystallization of second part of the product of step (b) in a MeOH-water mixture to obtain green coloured plates of formula (2);
d. adding water to the blue crystals of formula 1 to obtain green colour Cu—H.sub.2O formula 2 compound or suspending green crystals of formula 2 in methanol to yield blue crystals of compound Cu-MeOH formula 1.
[0048] The present invention provides multi-action copper complex of formula X which shows colorimetric sensing of different geometry anions in aqueous and non-aqueous media within few seconds.
[0049] The invention provides products with various anions formed to illustrate the anion sensing properties of complex of formula 1 which are listed in Table 1.
TABLE-US-00001 TABLE 1 Complex of formula 3 (Complex monoaqua-trichloro-(.Math.2-chloro)-tetrakis of formula 1 and 2 + Cl anion (N-phenethylisonicotinamide)- source) dicopper(II) Complex of formula 4 (Complex monoaqua-tribromo-(.Math.2-bromo)-tetrakis of formula 1 and 2 + Br anion (N-phenethylisonicotinamide)- source) dicopper(II) Complex of formula 5 (Complex di-(N-thiocyanato)-bis(N- of formula 1 and 2 + SCN anion phenethylisonicotinamide)copper(II) source) Complex of formula 6 (Complex aqua-bis(formato)-bis(N- of formula 1 and 2 + Formate phenethylisonicotinamide)-copper(II) anion source) Complex of formula 7 (Complex diaqua-bis(acetato-)-bis(N- of formula 1 and 2 + Acetate phenethylisonicotinamide)-copper(II) anion source) Complex of formula 8 (Complex Single crystal could not be grown, of formula 1 and 2 + Nitrite however PXRD was recorded anion source)
EXAMPLES
[0050] Following examples are given by way of illustration and therefore should not be construed to limit the scope of the invention.
Example 1
Synthesis of N-Phenethylisonicotinamide Ligand
[0051] To the stirred solution of isonicotinoylchloride in dry DCM, dry Et.sub.3N (1.1 equivalent) was added drop wise at 0° C. To this reaction mixture, 2-phenethylamine (1.1 equivalents) was added slowly. The reaction mixture was kept stirring for ˜8 h at room temperature i.e. at 25° C. DCM was evaporated under reduced pressure to get crude residue to which ethyl acetate was added and sequentially washed with saturated solution of NaHCO.sub.3 and brine. The organic layer was dried over solid Na.sub.2SO.sub.4 and evaporated in vacuum to get crude product which after column chromatography yielded compound (I).
[0052] Complex of formula (1) was synthesized by adding dry methanolic solution of compound I (2.1 equivalent) to Cu(NO.sub.3).sub.2. 3H.sub.2O and stirred for 15 minutes. The reaction mixture was then refluxed for ˜8 h. The reaction mixture was then filtered to remove unwanted residue and then separated in two parts. The first part (A) was kept for crystallization in the vessel to allow slow evaporation of methanol at room temperature while in the other part (B) equal amount of water was added and kept for crystallization at room temperature i.e. at 25° C. for slow evaporation. Crystallization from part (A) yielded blue coloured needle shaped crystals whereas part (B) produced green coloured plates. The blue crystals (Cu_MeOH, 1) on addition of water turned green (Cu—H.sub.2O, 2) while suspension of green crystals in methanol yielded blue crystals within seconds.
Example 2
Vapochromic Behavior of 1 and 2: (FIGS. 1 and 3)
[0053] Compound 2 was grinded to generate the fine polycrystalline sample that was then spread onto the glass plate. The plate was then placed in crystallization chambers containing solvent. The position of the glass plate in the chamber was much above the solvent upper layer. This crystallization assembly was then covered with glass plate in order to avoid the evaporation of the solvent vapours outside the chamber. After the exposure of the solvent vapours, the green fine crystalline powder of 2 turned blue (1) in methanol, ethanol, acetone, DMF, DMSO and THF vapours. The rate of the change of colour of the crystals was different for different solvents. For example, in methanol solvent, the colour change occurred in few seconds, while in less volatile solvents such as DMSO and DMF, the time taken for naked eye colorimetric change was up to 8-10 h because these solvent are high boiling and less volatile. This vapochromic behaviour is attributed to the electronic state changes and geometrical distortion of Cu(II) coordination sphere. Reversibility of the process was also monitored by keeping blue powder (1) in closed chamber containing water. The colorimetric changes from blue to green (2) revealed the reversible nature of vapochromic phenomenon. No colorimetric change was observed in solvent such as chloroform, dichloromethane, ethylacetate and benzene.
Example 3
Methodology for Anion Sensing Properties of Blue Crystals: (FIGS. 2 and 4)
[0054] Cu(II) complex of formula (1) and (2) both revealed anion sensing behavior exhibiting colorimetric change detected by naked eye in few seconds. In comparison to complex of formula (2), complex of formula (1) shows rapid colorimetric detection of anions attributed to faster anion-anion exchange (NO.sub.3.sup.− to X where X: Cl.sup.−, Br.sup.−, NO.sub.2.sup.−, SCN.sup.−, HCOO.sup.−, CH.sub.3COO.sup.−) than H.sub.2O-anion exchange (H.sub.2O to X where X: Cl.sup.−, Br.sup.−, NO.sub.2.sup.−, SCN.sup.−, HCOO.sup.−, CH.sub.3COO.sup.−). Based on this observation and reversible switching ability of complex of formula (1) and (2), the following protocol was developed for aqueous detection of anions. The green crystals of (2) was grinded first to generate fine polycrystalline sample which is then suspended in methanol to obtain blue crystallites of Cu(II) complex of formula (1) and subjected to sonication to form fine blue powder. The dry powder of (1) was then pressed to form circular disc which is then suspended in aqueous solution of tetrabutylammonium (TBA) or ammonium salts, alkali metal salts of various anions. The change in colour of the solid sample within a minute from blue to light blue to dark yellowish green was observed depending on the anion sensed by the complex of formula 1. The anion sensing behaviour of complex of formula 1 was confirmed by determining the crystal structure of these complexes (except NO.sub.2.sup.− (8) anions, single crystal of this complex could not be grown). The observed change in the chromogenic properties of complexes is attributed to change in the charge transfer LMCT (Ligand to metal charge transfer), MMCT (metal to metal charge transfer) or d-d transition. Measurement of the PXRD profiles of these complexes and their comparison with simulated PXRD graphs obtained from single crystals XRD showed good match revealing homogeneity of the sample. UV-vis reflectance spectra in solid state were obtained. The solid state UV spectra revealed noticeable λ.sub.max shift of the UV-vis reflectance spectrum, upon exposure to an analyte.
Example 4
[0055] Comparative Analysis of Experimental and Simulated PXRD Pattern Obtained from Single Crystal: (
[0056] To understand the mechanism of sensing and associated chromogenic change, the aqueous anionic solution of TBAX salts (X:Cl.sup.−, Br.sup.−, NO.sub.2.sup.−, SCN.sup.−, HCOO.sup.−, CH.sub.3COO.sup.−) one equivalent of insoluble blue powder of complex of formula 1 was suspended. After chromogenic change was observed the obtained powder was repeatedly washed with water and powder X-ray diffraction patterns were recorded on Rigaku instrument at continuous scanning rate of 2° 2θ/min using Cu Kα radiation (40 kV, 30 mA) with the intensity of the diffracted X-ray being collected at intervals of 0.1° 2θ. A nickel filter was used to remove Cu K.sub.β radiation.
[0057] Crystals were grown by suspending the powder into aqueous media from anion sensing experiment as mentioned above and heated till 70° C. in water bath. Sparingly solubilized supernatant was collected and kept for crystallization by slow-cooling method. Simulated powder pattern of single crystal structure analysis matched with collected experimental powder pattern after sensing experiment at room temperature and thus validated illustrated mechanism of anion detection.
Crystal Structure Investigation: (FIGS. 5, 6, 7 and 8)
[0058] Single crystal X-ray analysis of compounds 1, 2, 3, 4, 5, 6 and 7 were carried out on a Bruker SMART APEX II single crystal X-ray CCD diffractometer, with graphite-monochromatised (Mo—K.sub.α=0.71073 Å) radiation. Crystal structure of 8 (Cu-Nitrite) could not be determined due to poor quality of the crystals. The X-ray generator was operated at 50 kV and 30 mA. Diffraction data were collected with a ω scan width of 0.5° and at different settings of φ and 2θ. The sample-to-detector distance was fixed at 5.00 cm. The X-ray data acquisition was monitored by APEX2 program package. All the data were corrected for Lorentz-polarization and absorption effects using SAINT and SADABS programs integrated in APEX2 package. The structures were solved by direct methods and refined by full matrix least squares, based on F.sup.2, using SHELX-97. The crystallography data of all the samples is summarized in Table 2.
TABLE-US-00002 TABLE 2 α γ Space a (Å) b (Å) c (Å) (°) β (°) (°) V (Å.sup.3) group Ligand 8.312(1) 5.189(1) 28.456(1) 90 96.440(1) 90 1219.46 P2.sub.1/n Cu_MeOH 5.109(1) 16.644(1) 16.645(1) 90 98.30(1) 90 1400.61 P2.sub.1 (1), nitrate complex Cu_H.sub.2O 8.106(1) 19.032(1) 10.426(1) 90 104.109(1) 90 1559.87 P2.sub.1/n (2), water complex Cu(II)- 8.304(1) 32.290(2) 10.127(1) 90 90.00 90 2715.14 P2.sub.1/m Chloride (3) Cu(II)- 8.277(1) 32.574(4) 10.174(2) 90 90.001(8) 90 2743.02 P2.sub.1/m Bromide (4) Cu(II)- 5.113(1) 16.664(2) 17.680(1) 90 103.78(1) 90 1462.88 P2.sub.1/c Thiocyanate (5) Cu(II)- 5.131(1) 16.312(3) 33.050(4) 90 98.931(2) 90 2732.64 P2.sub.1/c Formate (6) Cu(II)- 8.62(1) 18.36(2) 10.59(2) 90 108.52(2) 90 1588.23 P2.sub.1/n Acetate (7)
Comparative Analysis of Solid State UV Reflectance Spectra of Starting Cu_MeOH (1) and Final Experimental Solid Material of Vapochromism or Anion Sensing Experiment: (FIG. 9)
[0059] The reflectance spectra of the samples were measured by using Jasco UV-Vis spectrophotometer (V570 UV-VIS-NIR. The reflectance λ.sub.max are mentioned in Table 3.
TABLE-US-00003 TABLE 3 Reflectance Compound .Math..sub.max(nm) Complex of formula 1 (Cu_MeOH) 450 Complex of formula 2 (Cu_H.sub.2O) 390 Complex of formula 3 (1 + Cl) 485 Complex of formula 4 (1 + Br) 532 Complex of formula 5 (1 + SCN) 522 Complex of formula 6 (1 + Formate) 442 Complex of formula 7 (1 + Acetate) 425 Complex of formula 8 (1 + Nitrite) 538
Example 5
Naked Eye Detection of Anions Via Grinding
[0060] So far the use the complex of formula 2 for sensing polar solvent vapors and anions in competent aqueous media was explored but peculiar features is its ability to differentiate between various salts by simple grinding. Although many methods are available in the market for removal or discrimination of various salts such as anion exchange chromatography but they are laborious and expensive.
[0061] Co-grinding of particular potassium/sodium salts of Cl.sup.−, Br.sup.−, NO.sub.2.sup.−, SCN.sup.−, HCOO.sup.−, CH.sub.3COO.sup.− with 20:1 ratio for 2-5 minutes imparts corresponding colour to the solid material as shown in table 3. We have demonstrated use of complex of formula 2 for differentiating between potassium salt of chloride and bromide by grinding method (
Advantages of Invention
[0062] Solid state detection and can be used in the form of film or tablet. [0063] Detection in aqueous as well as non-aqueous media. [0064] Fast detection of anions, Cost-effective. [0065] Highly sensitive and ability to detect low concentration of anions. [0066] Covers broad spectrum of anions from monovalent halides to larger anions such as acetate. [0067] Detection via visible colour changes.