Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Sol–gel process wikipedia , lookup
Jahn–Teller effect wikipedia , lookup
Metalloprotein wikipedia , lookup
Hydroformylation wikipedia , lookup
Metal carbonyl wikipedia , lookup
Spin crossover wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Int. J. Engg. Res. & Sci. & Tech. 2014 Ekakitie A O and Osakwe A A, 2014 ISSN 2319-5991 www.ijerst.com Vol. 3, No. 3, August 2014 © 2014 IJERST. All Rights Reserved Review Article ISOLATION OF COBALT (II) AND COPPER (II) MIXED LIGANDS COMPLEXES OF ACETAMIDE AND THIOUREA Ekakitie A O1* and Osakwe A A1 *Corresponding Author: Ekakitie A O [email protected] The complexes of CuSO4, Cu (NO3)2, CuCl2, (CH3COO) Cu, CoCl2, Co (NO3) 2 were isolated from mixed ligands of acetamide and thiourea, stoichiometrically using the molar ratio of 1:1,1:2,2:1. Metal analysis, melting point and decomposition temperature determination, solubility in various solvent (Ethanol, Methanol, Chloroform, Water, Toluene and Diethylether). Infra-red Spectroscopy were used for characterization. The percentage yields were about 49.62. CuSO4 Complexes were light green in color, Cu(NO3)2 complexes are green also the CuCl2 complexes. (CH3COO)Cu are blue while CoCl2 and Co (NO3) 2 complexes are red. The infra-red showed that the co-ordination to the metal is through the amidenitrogen of actamide and thiourea. Keywords: Isolation, Cobalt (II), Copper (II), Ligands, Acetamide INTRODUCTION ligand complexes in solution. Most authors recognized the importance of statistical factors in determining the stability of mixed complexes, although other factors such as repulsion between unlike ligand, geometric f actors, dipole interactions with the solvent, the type of binds formed and outer versus the inner orbital coordination have also been looked into (Jacobs, N E and Margrurn, 1967). A number of investigators have discovered that the formation of ternary complexes from two binary complexes is more favorable than a stabistical distribution of ligand. This has been explained by phenomena such as polarization, charges neutralization with decreased solution and symmetry of ligand field. Mixed ligands complexes are widely encountered and are of interest to the wide range of research workers. The development of computing techniques has facilitated considerably the description of the equilibrium in the complex system formed by a solution of mixed ligand complexes (I). It is now generally agreed that in solution containing metal ions and two suitable ligands, mixed ligand complexes are formed. Note the word “suitable”, since instances have been found where mixed ligand complexes cannot be formed, because of certain properties of the ligands. Many studies have been directed towards a better understanding c3f the formation of mixed 1 Department of Chemical Sciences, Novena University Ogume, Delta State, Nigeria. This article can be downloaded from http://www.ijerst.com/currentissue.php 138 Int. J. Engg. Res. & Sci. & Tech. 2014 Ekakitie A O and Osakwe A A, 2014 formation of stable and solid complexes confirmed that elemental analysis have been isolated (Maraus Y and Eliezer, 1969). Conclusively, research work was carried out on the synthesis and structural studies of mixed ligand (8-guinolinalato) (acetylacetanato) complexes of Vo (IV) Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) (Mesubi M A and Omotonea B A, 1990). In this research work, the ternary complexes Co(q) (acac) 2H2O, Ni(q) (acac) 2H2O and Cu(q) (acac) H2O were prepared by mixing aqueous solution of 8-quinolinol and acetylacetone in 1:1:1 molar ratio followed by the addition of 2 equivalent of KOH in ethanol. The Zn (q) (acac) 2H2O, Mn(q)(acac) 2H2O and Vo(q) (acac). 2H2O were obtained by reacting together ethanol solution of the metal aceta acetonate and hydroxyquinoline in equimolar ratio and stirring for a few Ni, Cu and Zn) salts have been carried out in the recent years. Resulting to the formation of a ternary complexes of the stoichiometry (m(q)Cl) where q = 8 - quinolinolato and L=acetyacetone. Although there is an extensive literature on addition compound of mg 2 with mono and bidentate molecules, however, only three papers concerning synthesis and structural studies are available on ternary complexes mql. These include studies on cuql. Ni(q)(acac) and Mn(q) (dtc) where 1= aminophenyl amine, typtophen tyrosine or ethylbenzoyl cyanoacetate, acac=acetylacetonate and dtc= diethyldithiocarbamate. Conditions that are necessary for the mixed ligands formation have been suggested and with potentials. In some of these works, the changes in free energy of coordination bonds as a result of mixed ligand complex formation has been considered. Studies have been carried out on mixed complexes of nickel (II) with only amino, carboxylate and water as the coordinate groups. The ligands were chosen in order to determine the effect of change, the effect of a number and types of groups bounded to the metal before and after mixed complex forrobon, and the effect of chelation. This work was used to treat a restricted system but consider more parameters which might influence the stability constant than has been the case in previous studies of mixed ligand complexes. The parameters are evaluated in terms of their contribution to the free energy conformation of the mixed ligand complexes [I]. It has also been discovered that copper (II) readily forms mixed complexes with various nitrogen-oxygen co-coordinating ligands but is reluctant to bind more than two bidentate ligands. (3) Similar studies have also been carried out on cobalt (II) in which the reaction acetate, Me — AA and Et—AA derivatives of Co(II) was carried out with triamines and hydroxyquinoline resulting to the isolation of hexacoordinated complexes of stoichiometry Co(L) 2 (L) 2 (L), where L is a CaC (AA). Methylacetoacetate (4Ne—AA) or ethylacetoacetate (Et—AA) and L1 is ethylenediamine (EA) propylenediamine (Pn) or 8-hydroxy guinoline (3). METHODS OF PREPARATION OF COMPLEXES The ternary complexes (Co(q) (acac). 2H2O’ Ni(q) (acac) 2 H 2 O and Cu(q) (acac). 2 H 2 O were prepared by mixing aqueous solution of 8quinolinol and acetylacetone in 1 : 1: 1: molar ratio followed by the addition of 2 equivalent of KOH in ethanol. The Zn(q) (acac). 2H2O, Mn(q) (acac). Further work has been carried on the synthesis and structural studies of Cobalt (II) and nickel (II) mixed ligand complexes with 2, 2-bis (1-pyrazoyl) propane (me2 (bpl) or 2, 2-bis(3) (5) - pyrazoyl) propane (Me 2 Cb-Mpz) and Bdeketonate ion (dike) was prepared. The This article can be downloaded from http://www.ijerst.com/currentissue.php 139 Int. J. Engg. Res. & Sci. & Tech. 2014 Ekakitie A O and Osakwe A A, 2014 H2O and Vo (q) (acac). 2H2O were obtained by reacting ethanolic solution of the metal acetylacetonate and Hq in Equimolar and stirring for a f ew minutes. All complexes which precipitated immediately were suction filtered and washed successively with 50% ethanol and ether and finally dried in a vacuum. The complexes were then analyzed for metal employing standard procedures (Sharman et al., 1981). Methanol USES OF MIXED LIGANDS Copper II Sulphate pentahydrate They are essential as true elements for most of the biological system. The 8-quinolinolate is extensively used in drug synthesis. It is well known for its anti-malaria and general antimicrobial properties and also widely employed in analytical chemistry for the separation and determination of metals. Copper II Nitrate trihydrate 2 Toluene Chloroform Diethyl ether Distilled water Disodium EDTA Copper II chloride dihydrate Copper acetate Cobalt II Nitrate Cobalt II chloride Universal indicator Solochrome black THE SCOPE AND OBJECTIVE OF THIS WORK Sodium acetate Murexide indicator It can be deduced from experimental work that the percentage yield of the salt of the complexes is about 37.82 averagely of the acetamide and thiourea of this mixed ligand is small and that the isolation of this cobalt (II) and copper (II) is small also due to their high solubility of the salt. In this case weak paramagnetism results. This Temperature Independent Paramagnetism (TIP) thus resembles diamagnetism in that it is not due to any magnetic dipole existing in the molecule, but it is induced when the substance is placed in the magnetic field (Das R C Behera B, 1983). Concentrated tetraoxosulphate VI acid Concentrated trioxonitrate V acid Ammonia solution PREPARATION AND ISOLATION OF METAL COMPLEXES The complexes of Cu(ll) and cobalt (H) were isolated. Similar methods of preparation were used in all cases with Iittle modification when necessary. Stoichiometric amounts of 1: 1 and 2:1 of mixed ligands to metal salts were used. The metal salts were all hydrated. MATERIALS AND METHODS Reagent A minimum amount of water was used in dissolving the metal (II) salt of copper and cobalt. The solution of thiourea was made up with a Acetamide Thiourea Ethanol This article can be downloaded from http://www.ijerst.com/currentissue.php 140 Int. J. Engg. Res. & Sci. & Tech. 2014 Ekakitie A O and Osakwe A A, 2014 minimum amount of methanol while the acetamide was dissolved with minimum amount of methanol. complexes such as the copper (II) Chloride, copper (II) nitrate, copper (II) acetate, cobalt (II) nitrate. In the isolation of the metal complexes of 1:1, 1:2 and 2:1 the aqueous solution of the metal salt was treated with the mixture of stoichiometric amount of acetamide and thiourea and solution was buffered with ammonia solution to raise the pH from acidic to basic medium and stirred for sometime to allow it crystallize. SAMPLE CALCULATION METHOD FOR PERCENTAGE YIELD OF LIGAND (FORMED) 1:1 COMPLEXES The crystals were filtered and washed with water and dried over silica gel in a dessicator. Molar mass of the complexes = 385 g Molar of salt used = 0.010 METAL ANALYSIS: DIGESTION OF METAL COMPLEXES Experimental yield = 0.99 g Theoretical yield = molar mass x moles 385 x 0.010 = 3.85 CuSO4.5H20 + Cs(NH2) 2 Cu(CH3CoNH2)(CS (NH2) )SO4) 5H2O The metal complexes were digested by heating 0.03 g of the complexes with a 1: 1 ratio of concentrated trioxonitrate (v) acid and tetramonosulphate (VI) acid mixtures. There were heated but not to dryness and diluted with distilled water and made up to 100 cm in a standard flask. % of yield Experimental yield 100 Theoretical = 0.99 x 100S = 3.85 = 2571% PROCEDURE FOR TITRATIONS: CU (II) SULPHATE COMPLEXES (1:) Sample calculation of percentage of metal in the complexes. Cu(acetamide) (thiou)SO4) 5H2O = molarity of EDTA X Volume of EDTA X Atomic mass of metal x 100 20 cm3 of the digested solution was pipetted into a 250 cm conical flask buffered with NH3/NH4CI solution to raise the pH of the solution to pH 10. A speck of murexide indicator rnixture was added. The solution was titrated with EDTA. Co(lI) chloride complexes (1:) 200 cm3 of the digested solution was pipetted into a 250 cm3 comical flask, two or three drops of buffer solution (NH3H4CI) was added to raise the pH to 10. A speck of murexide indicator mixture was added. The solution was titrated with EDTA. Similar processes were used for the remaining metal salt Volume of complex pipetted x factor to make 100 x of Sample digested x 1 Average volume of EDTA used = 0.65 Atomic mass of Cu metal = 63.5 Wt of Cu (11) complex digested = 0.03 g Volume of complex pipetted = 25 cm Factor = 4 This article can be downloaded from http://www.ijerst.com/currentissue.php 141 Int. J. Engg. Res. & Sci. & Tech. 2014 % Cu = = Ekakitie A O and Osakwe A A, 2014 Percentage of Carbon 0.01 x 0.65 x 63.5 x 100 25 x 4 x 0.03 x 1 Cu(CH3 CONH2) CS(NH2) 2SO24H2O 13.75% (found). % Cn= CALCULATED PERCENTAGE METAL 12 x 3 100 9.35% 385 % of Hydrogen= For Cu(aceta) (thiou) SO4 5HO (1:1) Compound % Cu= Atomic mass of Cu x 100 63.5 16.6% molar mass of compound 385 % of Nitrogen= 19 100 4.93% 385 14 3 100 10.90% 385 This article can be downloaded from http://www.ijerst.com/currentissue.php 142 Int. J. Engg. Res. & Sci. & Tech. 2014 Ekakitie A O and Osakwe A A, 2014 Table 2: Solubility Test for Complexes This article can be downloaded from http://www.ijerst.com/currentissue.php 143 Int. J. Engg. Res. & Sci. & Tech. 2014 Ekakitie A O and Osakwe A A, 2014 Table 3: Using Shimadzu Infra Red The melting point and decomposition temperature of the complexes is shown in table. PHYSICAL MEASUREMENT Determination of Melting Point and Decomposition Temperature SOLUBILITY OF THE METAL COMPLEXES Ligand paraffin, thermometer and melting point tube were employed in the determination of the point and the decomposition temperature of the complexes. The solubility test results for the metal complexes in solvent such as water, toluene, methanol, chloroform, ethanol, diethyl ether is given in Table 2. Table 4: Using Shimadzu Infra Red (Infra-red Vibrational Frequencies 1:1) (In cm-1) Cu Complexes Ranges From 4000 - 650cm-1 C uCI2 Cu(NO3) 2 Acetat CuSO4 Tentative Assignment A(3450) A(3650) A(3600) A(3500) hydrogen bonded N H group A1(1655) A1(1675) A2(1670) A1(1650) W (2400-20) For Cobalt complexes ranges from 4000-650cm-1 >CO B-A(2400-2200) 1.1 Cobalt nitrate A (3550) hydrogen bonded N H group Al (2800) Thio group stretching This article can be downloaded from http://www.ijerst.com/currentissue.php 144 Int. J. Engg. Res. & Sci. & Tech. 2014 Ekakitie A O and Osakwe A A, 2014 RESULTS AND DISCUSSION - 2700 cm–1 in the spectra of the complexes is not much affected by complexation M - L. The finger - print region clearly shows that the metal salt complexes are sensitive to changes in their functional group. The absence of similar bands in the correlation chart is an evidence that this assignment is in order. The complexes were formed almost immediately in all cases. The yields are 49.62 in some cases and 32.45% in others. The low yield of 32.69% corresponding to Cu (aceta) (Thiou) NO3)3H3O and others below the above stated value might be possibly due to high solubility of Cu (aceta) (thiou) NO3) 3H2O in water. The yields of cobalt (II) nitrate complexes were moderate of 49.72. CONCLUSION There is no significant difference between the copper (II), Co (II) salt complexes prepared from acetamide and thiourea in the ratio 1:1. This is true because of the similarities in physicochemical properties of the complexes, for instance, all the complexes are insoluble in most of the solvents used for solubility test except for Cu (II) CI, complex which is soluble in water and sparingly soluble in ethanol and methanol. Some of the complexes prepared were red, and green due to the configuration of the metal except for the acetates. From infrared result, it is obvious that the same atoms were involved in the formation of the M - ligand bands for the complexes. The broadness of the bands around 3400 cm-1 is due to water interference still present in the molecules. COLOR OF THE COMPLEXES The color of the complexes is shown on Table 1. Generally, the intensity of the color of the complexes are higher then the starting materials. The color of the complexes formed were expected to be all green for copper except that of the Cu (aceta) (thiou) (CH3COO) H2O which was blue. The expected color for the cobalt complexes were red respectively. INFRARED SPECTRA OF LIGANDS AND COMPLEXES The shimadzu infrared absorption bands of ligands are given in Table 3 and those of the metal complexes are given in Table 4. Their assignment were made by comparing the correlation chart of shimadzu infra red group frequencies with those of the complexes and by reference to literatures. The region of interest in both the ligands and complexes is the region 3500-1600. The important vibration of these regions are the NH, >CO, thio group stretching. The presence of the NH vibration around the region of 1580 - 1490 (W) often too weak to be noticed and that the vibration at high frequency is due to NH instead of OH group. The shift to lower frequency upon coordination is the indication that NH group of the acetamide is involved in the formation of C - H. The vibrational frequency occurs between 2980 REFERENCES 1. Aggarwal R C, Rai R A and Rao T R (1981), “Synthesis and structural studies of mixed ligand (8 - quinolinolato) (acetylacetonato) Complexes of VOL (IV), Mn (II), Ni (II), Cc (II) and Zn (II)”, Journal of Inorganic Nuclear Chemistry, Vol. 43, pp. 1927 -29. 2. Borisovg A P (1983), “Simple and Coordination Compounds”, Russian journal of Inorganic Chemistry, Vol. 28, No. 10, pp. 1393-1395. 3. Buihausen C J and liehr A D (1958), This article can be downloaded from http://www.ijerst.com/currentissue.php 145 Int. J. Engg. Res. & Sci. & Tech. 2014 Ekakitie A O and Osakwe A A, 2014 “Intensities of inorganic complexes”, Journal of Molecular Spectroscopy, Vol. 2, No. 4. 11. 4. Das R C and Behera B (1983), Experimental Physical Chemistry, Tata McGraw -Hill Publishing Co. Ltd, New Delhi, pp. 315 - 32. 5. Degischer G and Nancollas G H (1969), “Thermodynamics of ion Association XXI. Mixed Complexes of transition metal ions with Aminopoly carboxylate and Amines Ligands”, Inorganic Chemistry, Vol. 9, pp. 1259 - 62. 12. Mesubi M A and Omotonea B A (1990), “Synthesis and structural studies of cobalt (II) and Nickel (II) Mixed ligand complexes with BIS (1 Cr15) Polypyrazoy1) propane and B - Diketone”, Books of Abstract of Chemistry Society of Nigeria, p. 42. 6. T W Gilbert Jr and Newman L (1970), “Mixed Ligand complexes of Nickel (II) with Bromide and chloride in Acetonitrile”, Inorganic Chemistry, Vol. 9, No. 7, pp. 1705 - 1710. 8. Jacobs N E and Margrurn (1967), “Stability constants of Nickel Aminocarboxylate, Amine, Polyamine Mixed Ligands Complexes”, Journal of Inorganic Chemistry, Vol. 6, No. 11, pp. 2038-2042. 9. 13. Panda P K, Mishera S B and Mohagatra B K (1979), “Complexes of Cobalt (II), Nickel (II), Copper (II), Copper (II) and Zinc (II) with Dicyanadiamide”, Journal of Inorganic Chemistry, Vol. 42, pp. 497 - 498. Furnis B S, Hannoford A J, Roggers V, Smott P N G and Tatchell A R (1973), Vogell textbook of Practical Organic Chemistry, 3rd Edition, Longman Group Limited, London, pp. 341 - 722. 7. Mayo Pikwe Butcher, Microscale Organic Laboratory, pp. 396 - 400. 14. Pauling L and Witso E B (1935), Introduction to Quantum Mechanics, McGraw - Hill, New York, pp. 450 - 59. 15. Ramanujam V V and Kriham U (1987), “Synthesis of mixed Ligand complexes of copper (II), - (II), copper diamine - amino carboxylate complexes”, Journal of Inorganic Nuclear chemistry, Vol. 43, No. 12, pp. 3407 - 08. 16. Sankhla DS, Mathur R C and Sudhindra N M (1979), “Synthesis Spectral and Magnetic Studies of some Mixed ligand complexes of Spin free cobalt (II)”, Journal of Inorganic Chemistry, Vol. 42, pp. 489 - 491. Laurie S H (1967), “Coordination complexes of amino acids, preparation and properties of some copper (II) complexes Containing mixed bidentate ligands”, Australian Journal of Chemistry, Vol. 20, pp. 2597 - 2608. 17. Sharman C H, De T K and Jain P K (1981), “Characterization of mixed ligand complexes of some bivalant transition metal imides with Polyamides”, Journal Inorganic Nuclear Chemistry, Vol. 43, pp. 1811 – 15. 10. Maraus Y and Eliezer (1969), “Stability of mixed ligand complexes in solution”, Journal of Coordination Chemistry Review, Vol. 4, No. 3, pp. 273-322. 18. Whiffen D H (1971), Spectroscopy, Second Edition, pp. 92 - 108. This article can be downloaded from http://www.ijerst.com/currentissue.php 146