Fluorescent chromic material, preparation method and use thereof

Abstract

The present invention discloses a fluorescent chromic material having a chemical formula of [PPy.sub.3Cu.sub.2I.sub.2].sub.n, wherein PPy.sub.3 is tripyridylphosphine. The present invention also provides a method for preparing the fluorescent chromic material, and the use of the fluorescent chromic material in the detection of dichloromethane vapor. The fluorescent chromic material of the present invention has simple synthesis steps, high yield, and capability of large production; and can be used as a fluorescent probe for detecting dichloromethane vapor. It has the advantages of simple operation, high selectivity, high sensitivity, good cycle performance and good stability.

Claims

1. A fluorescent chromic material, having a chemical formula of [PPy.sub.3Cu.sub.2I.sub.2].sub.n, wherein PPy.sub.3 is tripyridylphosphine, and wherein the fluorescent chromic material is a crystal having the following unit cell parameters: a=b=30.672 , c=11.631 , ==90, =120, and space group R-3.

2. A method for preparing the fluorescent chromic material according to claim 1, comprising steps of: adding cuprous iodide and tripyridylphosphine to a mixed solution of acetonitrile and water, and reacting by heating; and filtering the resulting solution after the reaction is completed, to obtain crystals that are the fluorescent chromic material.

3. The method for preparing a fluorescent chromic material according to claim 2, wherein the molar ratio of cuprous iodide to tripyridinyl phosphine is 2:1-3:1, and the volume ratio of acetonitrile to water is 1:1-2:1.

4. The method for preparing a fluorescent chromic material according to claim 2, wherein the heating temperature is 80-130 C., and the heating time is 24-48 h.

5. The method for preparing a fluorescent chromic material according to claim 2, wherein after filtration the crystals are washed with ether, and dried.

6. A method for the detection of dichloromethane vapor: providing the fluorescent chromic material according to claim 1; and detecting the dichloromethane vapor by using the fluorescent chromic material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order to more clearly explain the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. Obviously, the drawings depicted below are merely embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative efforts.

(2) FIG. 1 is a diagram showing the structural unit [Cu.sub.4I.sub.4] in the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n.

(3) FIG. 2 is a three-dimensional structural diagram of [PPy.sub.3Cu.sub.2I.sub.2].sub.n.

(4) FIG. 3 is a diagram showing fluorescence emission of the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n in response to various solvent vapors.

(5) FIG. 4 is a histogram of the fluorescence intensity at 580 nm of the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n in various solvent vapors.

(6) FIG. 5 shows the change in color of the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n in response to dichloromethane vapor.

(7) FIG. 6 shows a device showing the response of the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n to dichloromethane vapor.

(8) FIG. 7 is a diagram showing the reaction time and recovery time of the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n in response to dichloromethane vapor.

(9) FIG. 8 shows the response of the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n to dichloromethane vapor in 20 cycles.

(10) FIG. 9 is a statistical graph of the reaction time and recovery time of the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n in response to dichloromethane vapor in 20 cycles.

(11) FIG. 10 is a statistical graph showing the sensitivity and relative intensity of the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n in response to dichloromethane vapor in a 14-day period.

(12) FIG. 11 shows the PXRD patterns of the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n under different conditions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(13) The technical solutions in the embodiments of the present invention will be described clearly and fully with reference to the accompanied drawings in the embodiments of the present invention. Apparently, the embodiments described are merely some, rather than all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art without creative efforts based on the embodiments of the present invention shall fall within the protection scope of the present invention.

Example 1: Preparation of Cluster-Based MOF Material Based on [Cu.SUB.4.I.SUB.4.] Units

(14) At room temperature, CuI (0.0382 g, 0.2 mmol) and tripyridylphosphine (0.0532 g, 0.1 mmol) at a molar ratio of 2:1 were added to a mixed solvent of acetonitrile and water (1:1, 2 mL). The mixed solution was subjected to a solvothermal reaction at a temperature of 80 to 130 C. for 24 to 48 h, to obtain orange-yellow bulky crystals. The crystals were collected by filtration, then washed thoroughly with ether, and finally dried in a vacuum oven at 30 C. 0.0829 g (Yield: 90.7%, calculated based on copper).

(15) In the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n, the mode of connection between the basic unit that is the connection node Cu.sub.4I.sub.4 and the bridging ligand PPy.sub.3 is shown in FIG. 1. Cu.sub.4I.sub.4 shows a rare knot-like coordination structure. As a four-connection node, it is coordination bridged by PPy.sub.3 in four directions, to connect to other four equivalent Cu.sub.4I.sub.4 structures, thereby continuously extending to form a cluster-based three-dimensional MOF structure. To better show the structure, the stacked structure is illustrated in detail in FIG. 4. The structure shows an extended one-dimensional channel along the c-axis, with a channel diameter of about 8 . Six pyridine rings are hanged on the inner wall of the channel, which provides the possibility for subsequent interaction of small molecules therewith.

Example 2: Characterization of Cluster-Based MOF Material Based on [Cu.SUB.4.I.SUB.4.]

(16) The fluorescent chromic material was characterized by IR spectroscopy, elemental analysis and single crystal X-ray diffraction. The specific results are shown below.

(17) Elemental analysis (%): C.sub.15H.sub.12Cu.sub.2I.sub.2N.sub.3P (M.W.=646.13), calculated: C, 27.86; H, 1.85; N, 6.50%; found: C, 27.97; H, 2.03; N, 6.57%.

(18) Infrared spectroscopy (potassium bromide pellet pressing method): 3440 (s), 1627 (m), 1593 (s), 1475 (s), 1436 (s), 1400 (m), 1218 (w), 1159 (w), 1098 (s), 1083 (s), 997 (m), 858 (s), 742 (m), 693 (m), 507 (m), 481 (w) cm.sup.1.

(19) The above data shows that a cluster-based MOF material based on [Cu.sub.4I.sub.4], that is [PPy.sub.3Cu.sub.2I.sub.2].sub.n is successfully obtained in this example.

(20) TABLE-US-00001 TABLE 1 Selected crystal data and structural refinement parameters of the compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n Compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n Molecular formula C.sub.15H.sub.12Cu.sub.2I.sub.2N.sub.3P Molecular weight 646.130 Crystal system Trigonal system Space group R-3 a/ 30.672 (10) b/ 30.672 (10) c/ 11.631 (4) / 90.000 / 90.000 / 120.000 V/.sup.3 9476.1 (70) D.sub.c/g cm.sup.3 2.038 Z 18 (Mo-K)/mm.sup.1 5.028 Total number of reflections 5244 Number of independent reflections 3278 F (000) 5436 R.sub.1.sup.a 0.0649 wR.sub.2.sup.b 0.1606 GOF.sup.c 1.073

Example 3: Test for Selectivity of the Fluorescence Response of Cluster-Based MOF Material Based on [Cu.SUB.4.I.SUB.4.] Units to Various Solvent Vapors

(21) The compound [PPy.sub.3Cu.sub.2I.sub.2].sub.n was placed respectively in cuvettes containing different solvent vapors, and the fluorescence response was tested after 30 min. The results are shown in FIG. 3. The compound shows a significantly enhanced fluorescence response to dichloromethane and chloroform, and shows a 15-fold increase in the fluorescence response to dichloromethane vapor. FIG. 4 shows that the compound has a better selectivity for dichloromethane. FIG. 5 shows the color change of the compound in dichloromethane vapor.

Example 4: Test for Response Sensitivity

(22) [PPy.sub.3Cu.sub.2I.sub.2].sub.n in the present invention was used as a fluorescent chromic material to detect its response sensitivity to dichloromethane vapor. Specific steps were shown in FIG. 6. The compound was made into a film and placed in a cuvette. Subsequently, a three-way valve was used to adjust the gas introduced into the cuvette, which is air or gas passing through the dichloromethane solvent and containing dichloromethane vapor, and the fluorescence intensity at 580 nm was tested. The results are shown in FIG. 7. The compound shows a fast and sensitive response to the dichloromethane vapor, where the response time is only no more than 1 s, and the recovery time is only about 45 s. It can be seen that the compound shows a better sensitivity in the detection of dichloromethane vapor.

Example 5: Cycle Test

(23) To test the cycle performance of the compound in the fluorescence detection of dichloromethane vapor, the related investigations were performed. The air and air with dichloromethane vapor were manually controlled to enter the cuvette by using the instrument shown in FIG. 6 to test the cycle performance, and the time interval between the two gases was 50 seconds. The test results are shown in FIG. 8. The compound shows an excellent cycle performance in response to dichloromethane vapor. After 20 rounds of cycle test, it still retains a high sensitivity, and the fluorescence intensity has no significant change before and after the response to dichloromethane vapor.

Example 6: Stability Test

(24) The compound was placed in air for a period of time to test its fluorescence response to dichloromethane vapor. As shown in FIG. 10, if the time is extended to two weeks, the response speed and response intensity to dichloromethane vapor are not significantly decreased. After the sample was placed in air for 6 months, its PXRD patterns (FIG. 11) show that its structure remains stable, proving that this compound has good stability.

(25) The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but falls within the widest scope consistent with the principles and novel features disclosed herein.