An analysis of the reactions of L-arginine with Cu(II), Co(II), Fe(III), Zn(II), and Cr(III).
Given that amino acids and their complexes are of high importance, the focus of the present study is on this chemical group as much as possible. C-NMR infrared and UV spectroscopy highly help to identify amino acids and their complexes. The purpose of the present study is to obtain some information about amino acids and their complexes with N (II) and Cr (III). In this study, acetyl acetone and potassium oxalate and their reactions with Ni (II) and Cr (III) only as complementary reactions. Also, using salt, it has been attempted to create amino acid complexes with the so called ions without associated ion.
Amino acids are of a high class of two-factor combinations. They are the constituents of proteins. Since two factor groups in amino acids include a basic and an acidic ones. These combinations are amphoterism and exist as two-ion or internal salts. Glycine is the simplest amino acid. It exists even in solid phase as two-ion state (one positive ion and one negative ion) but not in the form of amino acid .
[H.sub.3][N.sup.+]C[H.sub.2]CO[O.sup.-] [left arrow] [H.sub.2]NC[H.sub.2]COOH
Amino Acid Solubility in Water:
Since amino acids are soluble in water and the amount of their solubility in water is highly variable and such a fact has a significant role in amino acids reactions, solubility of various amino acids in water is discussed here. As shown in Table 1, next to solubility column, there is a column considering decomposition point of amino acids. Of course, the relation between amino acids' decomposition point and their solubility has not been considered but physical-chemical properties of these combinations have been considered .
In 1982, in Aust. J. Chem Magazine, Kim Colyvas, HansR.Tietze and S. K. J. Egri explained the structure of Dichloro (L-Histidine) Cu (II) and reported the length of bonds and angels in this complex . As they asserted, the complex of Cu and Histidine can be highly different and this difference is a function of pH [8-9]. Histidine can be as a neutral molecule or anion (pH dependent). In their article, they also reported the crystal structure of four cu combinations with Histidine [10-13].
In the magazine of Inorganic Chemistry, Patrick E.Hoggard studied L-Histidine complexes of Cr (III) to synthesize and identify base complexes (L-Histidinato), i.e. [[Cr[(I- His).sub.2]].sup.+] with nitrate anions and perchlorate as well as [(L-His).sub.2]Cr[(OH).sub.2]Cr[(L-His).sub.2]] complex . In the magazine of Acta Cryst., Tosio Sakurai and Hitoshi Iwasaki et al.  reported the structure of base (L-Histidananto) Ni (II0 monohydrate.
Berndt Evertsson (1969) also discussed the crystal structure of base (L- Histidine) Cu (II) dehydrate nitrate .
Kretsing and F.A. Cotton studied the crystal and molecular structure of Di-(L- Histidine)-Zn(II) Dehydrate. Regarding the structure of Zn [([C.sub.6][H.sub.8][N.sub.3][O.sub.2]).sub.2]2[H.sub.2]O complex, he asserted that the structure of this molecule is approximately four-dimensional and the atoms connected to Zn (II) are introduced as four nitrogen of Histidine molecule.
Kulkarni and Ginotra (2009), investigated the physiological structure of Cu [(His).sub.2] solution . They observed an inconsistency in the connection of Histidine to Cu and the structure of Cu [(His).sub.2] in the solution.
In an article entitled metal complexes and amino acids and derivatives, S. T. Chow and C. A. Mc. Auliffe investigated Ni complexes with Argenine.
Reaction of L-Argenine with Cu Nitrate (with the Ratio of 1:2):
The purpose of the present study is to investigate the reaction of L-Argenine with Copper (III) nitrate without using NaOH.
To this end, initially, 87 g (5 mmol) L-Arginine was totally solved in 10 ml distilled water so that a colorless solution was obtained. In another beaker, 6 g (2.5 mmol) copper nitrate with 3[H.sub.2]O was solved in 10 ml distilled water. Afterwards, copper nitrate was added to L-Arginine solution. The obtained pale turquoise blue Cu (III) nitrate was gradually added to the colorless L-Arginine solution. At the same initial seconds, the color of the solution was changed into dark blue and after some seconds, soft grains were started to appear which were rapidly deposited and covered the turquoise blue solution. After maintaining the experiment plate in refrigerator for one week, the ingredient of the plate had been frozen but the color of its sediment was still fixed (dark blue). After three weeks of maintaining the sample plate out of the refrigerator. It was observed that the sediment of the reaction of Cu (III) with L-Arginine without salt was very higher than other reactions. After one month and three weeks, to separate the sediment of the sample, the ingredients of the plate were put into a filter paper placed within a funnel and its sediment was remained in filter paper. In the following, turquoise blue liquid on the Zn sediment was placed in another plate and then, filter paper was packaged and it was maintained in a closet for one week to be dried. One week, with weighting the filter paper using digital weight scale, the amount of the sediment was reported 83 g which was the highest amount of the sediment weight during the experiment (M26 infrared spectroscopy). The obtained sediment was measured two times using CHN elemental analysis.
The first elemental analysis:
C: 24.75%, H: 5.42%, N: 35.10%
The second elemental analysis:
C: 25.00%, H: 5.42%, N: 27.40%
Reaction of L-Argenine and Na with Cu Nitrate (with the Ratio of 1:2:2):
The purpose of this experiment was to investigate the reaction of L-Argenine with copper (III) nitrate with using NaOH.
To this end, initially, 2 g (5 mmol) NaOH was totally solved in 10 ml distilled water. To this solution, then, 87 g (5 mmol) L-Arginine was added. L-Arginine was totally solved in this basic solution. In another beaker, 6 g (2.5 mmol) copper (III) nitrate was solved in 10 ml distilled water. Afterwards, copper nitrate was added to L-Arginine solution. The obtained pale turquoise blue Cu (III) nitrate was gradually added to the colorless L-Arginine solution. At the same initial seconds, the color of the solution was changed into dark blue. After one day, the color of the solution was paled and changed into indigo color. Then, the plate of the solution was maintained in the refrigerator for one week. After taking it out, no change was observed in the color of the solution and the solution had not been frozen during one week. Afterwards, the plate was maintained out of the refrigerator for three weeks and it was observed that after one week, the color of the sediment and solution was almost identical. Of course, some black sediment was formed in the plate and the solution on the sediment was clearer. In the following, after one month and three weeks, the ingredients of the plate were put into two separate pipes in a centrifuge device. After 5 minutes, it was observed that an average amount of brown to black sediment was formed on the bottom of the pipe and a colorless liquid on the top of the solution. After one week (after passing two months from the experiment), to separate impurities from the sediment, the solution on the pipe was put into a separate plate and maintained as sediment at the bottom of the pipe. Then, 10 ml distilled water was added and the pipes were put in centrifuge for 15 minutes to let the sediment was totally deposited and separated. Next, the liquid on the pipe was added into the previous plate. Accordingly, it was observed that black sediment was formed at the bottom of the pipe and a colorless liquid was formed on the top of the solution in the pipe. After one week, to better purify the sediment, the liquid existing in the pipes was put in separate plate. 10 ml distilled water was added to the sediment in the pipe and the pipes were again put in the centrifuge for 15 minutes. After taking the pipes out, the liquid on the pipe surface was added to the previous plate. As observed, an average amount of brown to black sediment was formed at the bottom of the pipe as well as on the top of the pipe. Then, the ingredients of the pipe were discharged through aspatul on watch glass. Some distilled water was added to the remaining amount in the bottom of the pipe and it was again added on the watch glass. After that, a filter paper was put on the watch glass and for one week, it was maintained in a closet. As observed, some black sediment was formed over the watch glass which can be easily separated. After weighting, the weight of the sediment was reported 0.12 g (L26 infrared spectrum). The obtained sediment was measured two times using CHN elemental analysis.
The first elemental analysis:
C: 1.19%, H: 0.86%, N: 3.61%
The second elemental analysis:
C: 1.69%, H: 0.86%, N: 1.53%
Infrared Spectrometry of L-Arginine and Cu (III) Salts Reactions:
Infrared Spectrometry of L-Arginine and Cu (III) nitrate Reactions (with the ratio of 1:2):
Infrared spectrum shows the amount of water in products. Due to the peak pertained to tensional fluctuation of O-H (about 3420 [cm.sup.-1]), water can be considered out of complex. Tensional fluctuations of N-H cannot be seen so clearly due to network water. However, three existing peaks in 3365 [cm.sup.-1], 3260 [cm.sup.-1] and 3160 [cm.sup.-1] can be accepted for N-H tensional fluctuations. C-H tensional fluctuations can be observed with existing peaks in 2958 [cm.sup.-1], 2928 [cm.sup.-1] and 2887 [cm.sup.-1] in infrared spectrum of the product. Of courses, in this spectrum, peaks pertained to C-H tensional fluctuations have less intensity relative to H-O and N-H tensional fluctuations. The existing peak of 1690 [cm.sup.-1] can be considered for C=N tensional tension. Existing peak of 1635 [cm.sup.-1] can be also considered for N-H bending fluctuation. Existing peak of about 1585 [cm.sup.-1] is considered for asymmetric tensional fluctuation of carboxylate group. Existing peak of 1390 [cm.sup.-1] is considered for symmetric tensional fluctuation of carboxylate group. Of course, the two peaks are close to each other here, the peak pertained to NO tensional fluctuation belonged to N[O.sub.3.sup.-] is also observed here. For N[O.sup.3.sup.-], a peak of about 1380 [cm.sup.-1] is considered. The existing peaks in the region between 653 [cm.sup.-1] and 493 [cm.sup.-1] are considered for Cu-O and Cu-N tensional fluctuations.
Using visible UV spectrums, some information regarding reactions can be obtained. Here, visible UV spectrums based on employed ions have been investigated.
Visible UV Spectrums Investigation:
Investigating Visible UV Spectrums of L-Arginine Reactions with Cu (II):
Investigating Visible UV Spectrums of L-Arginine Reactions with Cu (II) (with the ratio of 1:2:2):
This infrared spectrum shows the presence of Cu (II) in this complex. Of course, the spectrum measured in the above figure would be between 190-900 nm. Additionally, the blue solution of this product was colorless.
Investigating Visible UV Spectrums of L-Arginine Reactions with Cu (II) Acetate (with the ratio of 1:2):
In the two following figures, the mutation of [sup.2]Eg to [sup.2][T.sub.2]g in 618 nm can be well observed. The existing peaks between 190-340 nm can be considered for intra-legand mutations.
Due to changing the coordinates of x and y axis, absorption has been decreased from 618 nm to 614.4 nm while an identical solution was used to measure both spectrums.
Investigating UV Spectrum of the Reaction between L-Arginine, Na and Cu (II) Acetate (with the Ratio of 1:2:2):
The following spectrum was obtained from filtering the reaction of L-Rgenine with Na and Cu (II) acetate with the ratio of 1:2:2. Comparing this spectrum with the above spectrum revealed that in this spectrum, there is no of 2Eg to 2T2g mutation and intra-legand mutations in this spectrum are different from the above spectrum's ones.
The purpose of the present study was to provide a better understanding about the reactions of L-Arginine with Cu (II), Co (II), Zn (II), Fe (III), and Cr (III). In this study, the reactions were performed without using heat. The reactions were performed once using Na and once without Na. Nitrate salts and acetate ions of Cu (II), Co (II) and Zn (II) were employed. The salts of Fe (III) nitrate, Cr (III) nitrate and Cr (III) chloride were also used. In those reactions in which Na was not used, the ratio of L-Arginine to salt was 1:2. In those reactions in which Na was used, the ratio of L-Arginine to Na to salt was 1:2:2. Totally, 15 experiments were performed; 14 infrared spectrums were measured and 8 CHN elemental analyses were measured. Since it seemed the values of N were incorrect, each measurement was repeated one time. Totally, 11 visible UV spectrums were measured.
This study did not tend to obtain desirable efficiency level, but it attempted to investigate the reactions without heating and with the use of Na for comparison. The color of the sediment was different from the color of the solution under the filter in many cases, indicating two different products, (one with relatively low level (se1diment) and the other with relatively high level (the matter solved in the solution) and the color of the solution.
In the first experiment, the reaction between L-Arginine and Cu nitrate was investigated, the obtained sediment was in blue. In this experiment, the sediment was created without heating. The obtained combination was stable. Given to elemental analysis and infrared spectrum between the two following combinations, combination one can be accepted:
1) [Cu[([C.sub.6]HM[N.sub.4][O.sub.2]).sub.2]][(N[O.sub.3]).sub.2].2[H.sub.2]O2) [[Cu([C.sub.6][H.sub.13][N.sub.4][0.sub.2])].sub.2][(N[0.sub.3]).sub.2]
In the second experiment, the reaction (1) was initially performed but [Cu.sup.2+] were gradually separated from complex through O[H.sup.-], leading to the formation of Cu [(OH).sub.2]. Creating Cu [(OH).sub.2] caused the decrease of the intensity of blue color and the creation of black sediment.
Cu[(N[O.sub.3]).sub.2] + 2L-[C.sub.6][H.sub.14][N.sub.4][O.sub.2] [Cu[(L-2L-[C.sub.6][H.sub.14][N.sub.4][O.sub.2]).sub.2]][(N[O.sub.3]).sub.2] (1)
[Cu[(L-2L-[C.sub.6][H.sub.14][N.sub.4][O.sub.2]).sup.2]][(N[O.sub.3]).sub.2] + 2NaOH [right arrow] [right arrow] Cu[(OH).sub.2] + 2NaN[O.sub.3] (2)
In the third experiment, the reaction of copper acetate and L-Arginine was investigated. After adding L-Arginie solution to copper acetate, the color of the solution was changed but no sediment was observed until three months. Investigating visible UV spectrum indicated the connection of Histidine to copper. The existing peak in 618 nm (16181 [cm.sup.-1]) the connection of Histidine to copper (II). This peak in this region was observed in the reaction between amino acids and Cu (II). Since no sediment was created, elemental analysis and infrared spectrum of this combination's product was not measured.
In the fourth experiment, the sediment was identical with the sediment obtained in the second experiment. In both experiments, the product within the solution was colorless and the sediment was in black. By the way, elemental analysis and infrared spectrum of both sediments were black and almost identical. The black sediment was analyzed twice using elemental analysis.
The first measured elemental analysis:
C: 1.02%, H: 0.66%, N: 9.65%
The second measured elemental analysis:
C: 0.79%, H: 0.65%, N: 3.59%
The obtained sediment was violet. In this experiment, the sediment was obtained without heating and the resulted combination was stable. Given to elemental analysis and infrared spectrum, the formula of the violet sediment is Co[([C.sub.6][H.sub.14][N.sub.4][O.sub.2]).sub.2][([H.sub.2]O).sub.2]][(N[O.sub. 3]).sub.2]. This sediment has the closed formula of [C.sub.12][H.sub.32]Co[N.sub.10][O.sub.12] and molecular mass of 567.72 g/mol. The computed elemental analysis is as follows:
C: 25.39%, H: 5.68%, N: 24.67%
With respect to the empirical results and high color changes during the experiment, it can be stated that instable products were created during the study; these products reacted two times and created other products. As we found, Na cannot separate proton from Argenine since Arginine is a basic amino acid. Initially, Arginine reacted with cobalt nitrate and produced the complex of cobalt with Arginine. Then, Na reacted with the created complex and produced new product or products. Considering low the amount of sediment and different color of sediment and the under filter solution, there is the possibility of the formation of several products with cobalt.
In the fifth experiment, the reaction between Arginine and cobalt acetate was investigated. Considering the fact that no sediment was created after two months, the solution was measured using visible UV spectrum. The change of color in the solution initially indicates the reaction. In visible UV spectrum, three peaks of 262 nm (38167 [cm.sup.-1]), 370 nm (27027 [cm.sup.-1]) and 538 nm (18587 [cm.sup.-1]) were observed. Given that the peak existing in 38167 [cm.sup.-1] had the more intensity compared to other peaks, this peak was not considered for the mutation of d [right arrow] d and only two peaks existing in 27027 [cm.sup.-1] and 18587 [cm.sup.-1] were considered for d [right arrow] d mutations. These two peaks were seen in [[Co[([H.sub.2]O).sub.6]].sup.2+] in 16000 [cm.sup.-1] and 19400 [cm.sup.-1]. Then, with respect to visible UV spectrum, it can be concluded that in the complex around Co (II), there is no water molecule. In the following complexes, Co (III) had two peaks for [sup.1][A.sub.1g] [right arrow] [sup.1][T.sub.1g] and [sup.1][A.sub.1g] [right arrow] [sup.1][T.sub.2g] mutations.
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In the sixth experiment, the reaction between cobalt acetate with Arginine-Na solution was investigated. Various color change during the reaction initially indicated the reaction of Arginine and cobalt acetate and the formation of cobalt-Arginine complex. This complex was then attacked by Na and the complex was decomposed. The resulted infrared spectrum well showed acetate within the sediment. By the way, given to infrared spectrum, there is the possibility of the connection between hydroxide groups and cobalt. The obtained sediment was measured twice through CHN elemental analysis. The difference in nitrogen amount in the two measurements indicated wrong values for nitrogen.
C: 6.87%, H: 2.23%, N: 8.52%
C: 7.12%, H: 3.23%, N: 3.49%
In the seventh experiment, the reaction between Arginine and Zn nitrate was investigated. Just like other experiment, this experiment was performed at the temperature of laboratory and heater was not used. Also, in this experiment, the ratio of Arginine to salt was 1:2. The amount of the sediment in this experiment was measured 0.48 g. infrared spectrum of the sediment had the peaks belonged to Arginine and nitrate. Given to the empirical results, it was revealed that the best method of synthesizing Zn- Arginine complexes was to use very low water amount; a little heat can be also useful.
In the eighth experiment, the reaction between Arginine and Zn nitrate with Na was investigated without using heat. After two months, only 0.05 g sediment was obtained. Infrared spectrum of this sediment has not the peaks pertained to Arginine. It seemed that the created sediment on the hydroxide has a great deal of water. Interesting point in infrared spectrum of this slight sediment is two peaks existing in 1089 [cm.sup.-1] and 1036 [cm.sup.-1]. After two months, the main part of the material was still as solved material in the solution. Accordingly, the diluted solution of visible UV spectrum was measured. Visible UV spectrum of the solution has two peaks of 223 nm and 290 nm. The intensity of these two peaks is highly different.
In the nineth experiment, Zn (III) acetate and Arginine was used. The amount of sediment was very low (0.01 g). Infrared spectrum of the sediment was measured. The peaks pertained to Arginine was not clearly seen in infrared spectrum; however, there was the possibility of the presence of Arginine in the sediment with respect to infrared spectrum. In infrared spectrum, the peaks pertained to acetate were ob served. Visible UV spectrum of the under filter solution was also measured. In visible UV spectrum, one peak of 213 nm (46948 [cm.sup.-1]) was only observed. This peak should belong to Arginine.
Zn (II) acetate and Arginine with Na was used. The amount of sediment was low (0.157 g). the sediment was measured twice using CHN elemental analysis.
C: 0.73%, H: 0.66%, N: 10.14%
C: 1.97%, H: 0.61%, N: 2.09%
In the tenth experiment, the reaction between Arginine and Na with Fe (III) nitrate was investigated. After two months, no sediment was isolated; however, it seemed that suspended particles were formed in the solution. The color of the solution seemed dark red at the end of the experiment. After diluting, visible UV spectrum of the solution was measured.
In the eleventh to fifteenth experiments, the reactions of L-Arginine with nitrate salts and Cr (III) chloride were analyzed. Totally, to evaluate the reactions of three visible UV spectrum and one infrared spectrum were measured. Out of four reactions, three reactions were resulted in no sediment. The way of noting and the amount of notes during performing reactions and precise reports of observations is of high importance in such research works.
The purpose of the present study was not to obtain desirable efficiency level, but it attempted to investigate the reactions without heating and with the use of Na for comparison. The color of the sediment was different from the color of the solution under the filter in many cases, indicating two different products, (one with relatively low level (sediment) and the other with relatively high level (the matter solved in the solution) and the color of the solution. In most of the reactions, no sediment was obtained or its amount was highly slight. In case of using Cu (II) or Co (II) and salt, the amount of sediment was very slight and the obtained sediment was metal hydroxide. Additionally, the under filter solution was colorless.
Received 25 September 2014
Received in revised form 26 October 2014
Accepted 25 November 2014
Available online 15 January 2015
 Rasekh, H.A. and Y. Nasiri, 2008. MA thesis, Firouz Kouh Islamic Azad University.
 Rasekh, H.A. and S. Mokhtari, 2009. MA thesis, Firouz Kouh Islamic Azad University.
 Rasekh, H.A. and Ghadami M. Meymandi, 2012. MA thesis, Firouz Kouh Islamic Azad University.
 Rasekh, H.A. and M.H. Beheshti, 2010. MA thesis, Firouz Kouh Islamic Azad University.
 Rasekh, H.A. and S. Hasan Beygi, 2011. MA thesis, Firouz Kouh Islamic Azad University.
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(1) Seyed Majid Hosseininezhad and (2) Hosseinali Rasekh
(1) M.A.Departeman of chemistry, Islamic Azad University, Firuzabad Branch, Firuzabad Iran.
(2) Factulty Member of Academic Board of University, Firuzabad Branch, Firuzabad, Iran.
Corresponding Author: Seyed Majid Hosseininezhad, M.A. Department of chemistry, Islamic Azad University, Firuzabad Branch, Firuzabd, Iran.
Table 1: Various amino acids' solubility in 100 ml water and their decomposition point. Solubility in 100 ml Decomposition Amino acid water at 25[degrees]C point ([degrees]C) 25 233 Glycine 16/7 297 Alanine 8/9 315 Valine 2/4 293 Lucien Va 284 Isoleucine 3/4 280 Methionine 162 220 Proline 3/0 283 Phenylalanine 1/1 289 Tryptophan 5/9 228 Gluteus Very high 225 Thr -- -- Cysteine 0/04 342 Tyrosine 3/5 234 Asparagines 3/7 185 Glutamine 0/54 270 Sparatyk acid 0/86 247 Glutamic acid Very high 225 Lysine 15 244 Argentine 4/2 287 Histidine
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|Author:||Hosseininezhad, Seyed Majid; Rasekh, Hosseinali|
|Publication:||Advances in Environmental Biology|
|Date:||Dec 1, 2014|
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