Mixed Ligand Complexes Of Zinc Research Articles

Synthesis and Characterization of Some Hovel Pehta-Coordihated Mixed-Ligakd Derivatives of Zinc(II)-bis(Acetylacetone) and-bis(Acetoacetanilide) Chelates with 2/3-Pyrazoline-5-One Derivatives

A series of novel penta-coordinated mixed-ligand complexes of zinc(II) with the general formula, [zn(acac) 2 (L)](where acacH = acetylacetone and L = 3-methyl-l-phenyl-2-pyrazoline-5-one, 3-methyl-...

Synthesis and Physico-Chemical Studies of Some Novel Penta-Coordinated Derivatives of Zinc(II)-bis(acetylacetone) and -bis(acetoacetanilide) Chelates Containing Heterocyclic Nitrogen Donors

Abstract Some novel penta-coordinated, mixed-Ligand complexes of zinc(II), [zn(acac)2 (L)](where L 2-chloro-3-trifluoromethylpyridine, 2-(2′-pyridyl)benzimidazole, 2-(2′-pyridyl)-imidazoline, 2-amino-benzothiazole or 5,7-dlchloro-2-methyl-8-hydroxyquinoline, and [zn(aaa)2L](where L = 2-(2′-pyridyl)benzimidazole, 2-(2′-pyridyl)-iraidazoline or 5,7-dichloro-2-raethyl-8-hydroxyquinoline have been prepared. They have been prepared by refluxing the parent compounds [zn(acac)2(H20)] and [za (aaa)2(H20)] with the corresponding heterocyclic nitrogen donors in ethanol. The resulting derivatives have been characterized and suitable structures proposed on the basis of analytical data, electrical conductances, molecular weight determinations, magnetic measurements and infrared spectral studies.

Stability and structure of some binary and mixed-ligand complexes of zinc(II)

The stability and structure of ZnBH, ZnB, ZnB2H2, ZnB2H, or ZnB2 types of binary complexes in the ZnII–DL-2,3-diaminopropionic acid (dapa), –DL-2,4-diaminobutyric acid (daba), and –DL- ornithine (Orn)(B); and ZnABH2, ZnABH, or ZnAB types of mixed-ligand complexes in the ZnII–histamine/L-histidine (A)–dapa,–daba, and –Orn (B) systems are discussed from the computer based analysis of the pH titration data at 37 °C and I= 0.15 mol dm–3(NaClO4). In both the binary and mixed-ligand systems, dapa, daba, and Orn (B) appear to be tridentate. The results clearly demonstrate that in the ZnBH, ZnB2H2, and ZnB2H binary complexes and ZnABH mixed species the site of protonation is the terminal amino- group of ligand B. In the ZnABH2 complexes, one proton is attached to the ligand A and other to the ligand B. In the ZnII–histidine (A)–dapa,–daba, and –Orn (B) systems, the results suggest the histamine- like mode of binding for L-histidine (A). More than the statistical order of stabilities was observed for most of the mixed-ligand complex species detected in the present investigation.

Formation of mixed-ligand complexes of zinc(II) with chloride and substituted pyridines in 1,2-dichloroethane as solvent

The formation of mixed-ligand complexes of zinc(II) chloride with pyridine (py) and substituted pyridines R-py [R-py = 4-methyl-(4Me-py), 3-methyl-(3Me-py), 2-methyl-(2Me-py), 2-ethyl-(2Et-py), 4-acetyl-(4MeCO-py), and 4-cyano-pyridine (4CN-py)] in 1,2-dichloroethane has been investigated at 25.0 °C by means of solvent extraction. The extraction equilibrium of zinc(II) between the NaCl aqueous phase and the NBut4Cl–1,2-dichloroethane phase is given by equation (I), where the Zn2++ 2 Cl–+ 2 NBut4Cl (org) [graphic omitted] (NBut4)2ZnCI4(org)(i), thermodyanamic extraction constant log Kex,0= 5.61 ± 0.03 and ‘org’ denotes the species in the organic phase. The addition of substituted pyridines in this extraction system gives rise to the equilibria (ii) and (iii). (NBut4)2ZnCI4(org)+ R-py (org) [graphic omitted] (NBut4)ZnCl3(R-py)(org)+ NBut4Cl (org)(ii), (NBut4)ZnCl3(R-py)(org)+ R-py (org) [graphic omitted] ZnCl2(R-py)2(org)+ NBut4Cl (org)(iii), The successive formation constants, K1 and K2, were determined as log K1= 0.45, 0.25, –0.07, –0.47, 0.07, 0.13, and –0.48 ± 0.03, and log K2=–1.09, –1.34, –3.21, –3.33, –1.70, –3.56, and –4.86 ± 0.03 for the 4Me-py, 3Me-py, 2Me-py, 2Et-py, py, 4MeCO-py, and 4CN-py complexes, respectively. Except for the 2Me-py and 2Et-py complexes, the values of log K1 and log K2 show linear correlations with the pKa of the conjugate acid of the substituted pyridines.

ChemInform Abstract: EQUILIBRIUM STUDIES OF BINARY AND MIXED‐LIGAND COMPLEXES OF ZINC(II) INVOLVING IMIDAZOLE, HISTAMINE, AND L‐HISTIDINE AS LIGANDS

Chemischer InformationsdienstVolume 13, Issue 25 Article ChemInform Abstract: EQUILIBRIUM STUDIES OF BINARY AND MIXED-LIGAND COMPLEXES OF ZINC(II) INVOLVING IMIDAZOLE, HISTAMINE, AND L-HISTIDINE AS LIGANDS M. S. NAIR, M. S. NAIRSearch for more papers by this authorK. VENKATACHALAPATHI, K. VENKATACHALAPATHISearch for more papers by this authorM. SANTAPPA, M. SANTAPPASearch for more papers by this author M. S. NAIR, M. S. NAIRSearch for more papers by this authorK. VENKATACHALAPATHI, K. VENKATACHALAPATHISearch for more papers by this authorM. SANTAPPA, M. SANTAPPASearch for more papers by this author First published: June 22, 1982 https://doi.org/10.1002/chin.198225067AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume13, Issue25June 22, 1982 RelatedInformation

Equilibrium studies of binary and mixed-ligand complexes of zinc(II) involving imidazole, histamine, and L-histidine as ligands

Binary and mixed-ligand complexes formed by zinc(II) with imidazole, histamine, and L-histidine ligands (A) have been investigated by potentiometry in aqueous solution at 37 °C and I= 0.15 mol dm–3(Na[ClO4]) and the relevant stability constants are evaluated using advanced computer techniques. The results suggest that in the zinc(II)–imidazole, –histamine, and –L-histidine binary systems, the complex formation process is favoured by the π-electron system of the imidazole group in both the 1 :1 and 1 :2 complexes. It appears that the extra proton in the ZnAH histamine complex and ZnA2H2 and ZnA2H L-histidine complexes resides on the primary amino-group of the respective ligands. The mixed-ligand systems, (i) zinc(II)–imidazole (A)–histamine (B), (ii) zinc(II)–imidazole (A)–L-histidine (B), and (iii) zinc(II)–histamine (A)–L-histidine (B) respectively showed the presence of the mixed species, (i) ZnAB and ZnA2B, (ii) ZnAB, and (iii) ZnAB, ZnABH, and ZnABH2. Formation of ZnA2B in system (i) was found to be less favoured. All other mixed species do have marked stabilities. The probable site of protonation in ZnABH and ZnABH2 species in system (iii) is discussed in terms of their stability constant data.

Mixed ligand complexes of zinc(II) dibenzoyl methanate with nitrogen donor ligands—penta co-ordination

Mixed ligand complexes of zinc(II) dibenzoyl methanate with nitrogen donor ligands—penta co-ordination

Influence of feeding of mixed-ligande complexes of zinc, manganese and cobalt on cow productivity, feed digestibility and nitrogen metabolism in the last period of lactation

Purpose. To study of the effectiveness of feeding high-yielding cows in the last 100 days of lactation of different levels and sources of zinc, manganese and cobalt and establish their impact on milk productivity, feed digestibility and nitrogen balance. Methods. Five groups of highly productive cows (one control and four experimental) of Holstein, Ukrainian red-spotted and Ukrainian black-spotted dairy breeds were selected for the experiment at “Terezyne” farm, Bila Tserkva district, Kyiv region. Experimental cows were fed the same rations. The difference was in different doses of mixed ligand complexes of trace elements in the premix. The control was the optimal dose of mixed-ligand complexes of zinc, manganese and cobalt, which was established in a previous experiment with a concentration of 1 kg of dry matter (DM) of feed, mg: zinc – 50, manganese – 50 and cobalt – 0.78. Results. It was found that the use of different doses of mixed ligand complexes of zinc, manganese and cobalt using Suplex selenium and copper sulfate and potassium iodide in feeding cows in the last 100 days of lactation have differently affected their milk productivity. If 2320 kg of milk was milked from each cow of the control group during this period, then from cows of the 2nd-5th experimental groups – 40-220 kg more. The difference in the average daily milk yield of 4% fat was 0.5-2.67 kg and it was significant (P <0.001). The results of the balance experiment show that the animals of the experimental groups better digested feed nutrients and absorbed nitrogen. Thus, in cows of the 2nd, 3rd, 4th and 5th experimental groups nitrogen was deposited in the body respectively by 2.1, 4.1, 7.3 and 12.8 g more, and it was statistically significant (P <0,05) compared with animals of the control group. Conclusions. The use of mixed ligand complexes of zinc, manganese and cobalt helps to increase milk productivity of cows, reduce feed consumption per 1 kg of product and reduces the need of animals for these elements. The best performance results were obtained in the 4th experimental group, the animals of which were fed with a feed mixture containing 1 kg of DM, mg: zinc – 35; manganese – 35; cobalt – 0.4; selenium – 0.3; copper – 9 and iodine – 0.8.