Preparation and Characterization of 1,2,3,4- Butane four Carboxylate Transition Metal Complexes

1,2,3,4butane four carboxylic acidis(Na4C8H6O8)is mainly used to prepare photosensitive materials, medical polymer materials and functional polymer membrane materials.As a permanent finishing agent, 1,2,3,4butane four carboxylic acid plays an irreplaceable role.In this paper, the preparation of metal complexes by the reaction of 1,2,3,4-butane tetracarboxylic acid tetrasodium salt(Na4C8H6O8)with transition metals is described. The composition and structure of the prepared metal complexes were characterized by infrared spectroscopy, thermogravimetric analysis and elemental analysis. At the same time, through the analysis of thermogravimetric curves, the order of thermal stability of metal complexes is (from large to small): Co2C8H6O8·2H2O > Cd2C8H6O8 ·2H2O > Mn2C8H6O8·2H2O > Ni2C8H6O8·2H2O > Zn2C8H6O8·2H2O > Zn2C8H6O8·2H2O > Cu2C8H6O8 ·2H2O.

1,2,3,4-butane tetracarboxylic acid (Na4C8H6O8) is mainly used to prepare photosensitive materials, medical polymer materials and functional polymer membrane materials. As a permanent calendering agent, 1,2,3,4-butane tetracarboxylic acid has no formaldehyde in itself. Cotton and silk articles treated by it can obtain wrinkle resistance, solid shape and ironing-free properties. At present, the synthesis methods of 1,2,3,4-butane tetracarboxylic acid have been reported in China, but the literature on transition metal complexes of 1,2,3,4-butane tetracarboxylic acid is less. Therefore, this paper will further study and prepare metal complexes [1] Co, Cu, Ni, Mn, Zn, Cd and so on.

Preparation of transition metal complexes of 1,2,3,4-butane four carboxylic acid with Cu as an example
In the preparation of copper, the first step is to weigh the amount of H4C8H6O8 molten water, add 30% NaOH water solution while stirring, cool it, adjust the acidity and alkalinity to PH5-6, and concentrate the reaction solution. After cooling, the crystallization of 1,2,3,4-butane four carboxylic acid will be obtained. The white powder of Na4C8H6O8 was obtained by drying it at 90 C for 12 hours, and then it was put into a dryer for use. At this time, the quantitative Na4C8H6O8 is weighed and dissolved in water. After stirring and adding CuC12 to the aqueous solution, it should be noted that the mass ratio of CuC12 to Na4C8H6O8 is 2. It can be observed that a large number of blue precipitates are precipitated in the reaction solution, which is heated to 60-70 ℃ and stirred for 1 hour, and then cooled and filtered. Wash the precipitates with hot water for 3 times and remove the F in the precipitates. The blue precipitate Cu2C8H6O8·nH2O was then dried at 75 ℃ for 12 hour. The preparation of other metal complexes is basically the same as that of Cu complexes, but Cd complexes are made by Cd(NO3)2·4H2O and Na4C8H6O8 [2].

Using thermogravimetric analysis
In the analysis phase, the thermogravimetric analyzer (Pyris 1 TGA) produced by Perkin-Elmer is used. Use M2C8H6O8·nH2O, Co2C8H6O8·nH2O, Ni2C8H6O8·nH2O, Cu2C8H6O8·nH2O, Zn2C8H6O8·nH2O, Cd2C8H6O8·nH2O to analyze and analyze the data. It can be observed that when the heating rate reaches 20°C per minute and the number of samples is 6 mg, when the temperature is between 30°C and 850, the flow rate of dry air is 20 ml per minute as the atmosphere.

Elemental analysis by infrared spectroscopy
In element analysis, the Fourier transform infrared spectrometer (Spectrum GX) produced by Perkin-Elmer Company and the DITGS detector are still used. After preparing the relevant testing instruments, we use KBr pressing method to test. At the same time, he found that the resolution of the spectrum was 4cm -1 , and the range of this test was between 4000cm -1 and 400cm -1 . The cumulative number of signals in the test scan is 64 times, the gain is 1, and the speed of OPD is 0.2cm per second [3] .   (1) The sample quality was 6302 mg, the experimental temperature range was 30°C to 850°C.
(2) The sample quality was 2028 mg, the experimental temperature range was 30°C to 650°C.
Through the observation of the icon, it can be found that the weight loss rate of crystalline water is when the thermogravimetric curve rises to the first stage. At the same time, the value of N can be further obtained based on this data. Under general experimental conditions, the products of thermal decomposition of the transition metal complexes are Cdo, CuO, ZnO, NiO, Co3O4, Mn2O3 and so on, in the range of temperature between 30 C and 850 C. At the same time, by analyzing the thermogravimetric data in the experiment (as shown in Table 1), it can be found that the mass fraction values of various complexes after thermal decomposition are basically consistent with the theoretical values, which further illustrates the correctness of the original formulation. Therefore, we can get the theoretical values of H% and C% according to the formulated chemical formula. After calculating the values, we can put the corresponding data into Table 2. Through the analysis of Table 2, we can conclude that the composition of the two elements (C and H) is basically the same as the formulated data. From this, we can see that the chemical formula of the complex is M2C8H6O8·nH2O, and the analysis results can thus be determined. Molecular formula for over metal complexes.

Data analysis using infrared spectroscopy
Infrared spectra of 1,2,3,4-butane tetracarboxylic acid, 1,2,3,4-butane tetracarboxylic acid tetrasodium salt and their transition metal complexes were determined by infrared spectroscopy. The spectra of these three elements are shown in Table 2 (for transition metals, manganese is taken as an example, and the main characteristic peaks of A infrared spectra are shown in Table 3).  In the infrared spectra of 1,2,3,4-butane tetracarboxylic acid (Na4C8H6O8), the C=O bond strong absorption peaks of -COOH are at 1701cm -1 , and a pair of vibration coupling absorption peaks are at 1296cm -1 and 1416cm -1 , respectively. At the same time, it can be further found that the out-of-plane angular variation of dimer carboxylic acid OH group caused wide peaks at 920cm -1 due to vibration. However, in the infrared spectra of 1,2,3,4-butanetetracarboxylic acid (Na4C8H6O8) and M2C8H6O8·nH2O, the bond strength absorption peaks at 1701cm -1 disappeared completely, and the broad peaks of the out-of-plane angular vibration of the dimer carboxylic acid OH group also disappeared. Based on these data, it can be further concluded that the metal ions in the experimental reactions are fully compatible with -COOH, which leads to the disappearance of the C = O bond strong absorption peak of -COOH. This indicates that -COOH does not exist in M2C8H6O8·nH2O, which is also consistent with the previous results of thermogravimetric analysis and elemental analysis [4]. You can see in Table  3, there is a strong absorption peak at 3447cm -1 to 3379cm -1 wide, this broad absorption peak is due to changes in peak water of crystallization -OH stretching vibration caused by the certain. The characteristics of carboxylate bands by metal ions and the carboxyl oxygen coordination mode play a great role, with ion carboxylate in metal according to figure four (coordination) three ways of coordination of [5]. It can be found that the size of ∆vcoois the same as that of ions and ionic compounds in the three coordination modes. For example, in the single-tooth coordination mode, the ∆vcooof compound itself is much larger than that of free ions; in the chelating coordination mode, the ∆vcooof compound is much smaller than that of ionic compounds in the chelating coordination mode [6]. At the same time, we can see the values of vas(coo -) and vs(coo -) corresponding to M2C8H6O8·nH2O in the experiment. In order to further facilitate the experimental analysis of coordination methods, the table lists the effective data related to 1,2,3,4-butane tetracarboxylic acid (Na4C8H6O8), which serves as the basis for judging ∆v. Taking 200cm -1 as the critical point for judging, a single-tooth coordination is greater than this value, and a double-tooth coordination is less than this value. At the same time, we can use ∆vcooof sodium carboxylate and ∆vcooof metal complex to judge and compare, so as to determine the form of coordination. According to the above experimental judgment basis, we can make further judgement. In the Na4C8H6O8 experiment of 1,2,3,4-butane tetracarboxylic acid, Co, Cu and Ni metal complexes were used as single-tooth coordination, Zn and Cd metal complexes were used as chelating coordination, and Mn metal complexes were used as bridge coordination. However, in the actual experiment, which of the three coordination modes should be used, we should also analyze and prove [7].

Data analysis using thermogravimetric analysis
Through the experimental thermogravimetric analysis, it can be concluded that the complexes of transition metals in 1,2,3,4-butane tetracarboxylic acid (Na4C8H6O8) experiment are different in the thermal decomposition process, which is caused by different transition metals. At the same time, we can further observe that there are two stages in the diagram of copper, Cd, Mn, Ni and Zn metal complexes: 1,2,3,4-butane tetracarboxylic acid (Na4C8H6O8). During the weightlessness stage, Co metal complexes began to gain weight in the third stage. Through experiments, we can know that CoO is produced during the thermal decomposition of CO2C8H6O8·2H2O at a specific temperature, and CoO is oxidized to form Co3O4. At the same time, we can further find that there is a big difference between the predicted and measured values of CoO, which is due to the partial overlap between CoO and Co2O3 or Co3O4. From this we can speculate that in the whole thermal decomposition reaction, the changes experienced by the experimental substance are: At the same time, through the analysis of thermogravimetric curves, the order of thermal stability of metal complexes from large to small is obtained as follows:

Concluding remarks
In the experimental process, 1,2,3,4-butane tetracarboxylic acid tetrasodium salt (Na4C8H6O8) was prepared by reaction with excess metal salts. The composition and structure of the prepared metal complexes were characterized by infrared spectroscopy, thermogravimetric analysis and elemental analysis. At the same time, the thermal stability of the complex was studied by thermogravimetric analysis, and the order of thermal stability was obtained as follows: