Studies On The Syntheses And Crystal Structures Of The Complexes Of Metal Ions With Amino Acid

Amino acids possess biological activity in the body of the animal and plant. They are the basic unit of the protein. The studies of the complexes of the metal ions with amino acids are very important to understanding the biological effect of metal ions and the structure function reJationship of the protein. In this work,several metal ions complexes of amino acids have been synthesized and their structures have been studied. At the same time,complexes (1-5) have also been characterized by elemental analysis,1R and so on.The complex,{[La2( P -ala)s(H20)i] (ClOi)6 H20}n (1) ,was synthesized in an aqueous solution with a pll value of 3.5. Its crystal structure was determined by X-ray diffraction method . The crystal is triclinic with space group of Pi. The cell parameters are a=0. 9460(1)nm,b=l. 2917(1)nm,c=2. 1726(3)nm,a =76. 79(1)",P =80. 85(0",y =83. 35(1)",V=2. 5429(5)nm:',Z=2,Dc=l. 958g cm3. The structure of the complex can be viewed as an one-dimensional infinite chain. The lanthanum ion is nine-coordinate with a geometry of distorted tricapped trigonal prism.The complex,cis-[Cu(L-Arg)2] (NOsKWzO (2),was synthesized in aqueous solution under physiological pH-conditions. The crystal structure of the complex was determined by a single crystal X-ray diffraction analysis. The complex crystallized in monoclinic with space group Cz .The cell parameters are :a-2. 6705(4)nm h=0. 73190(10)rim c=l. 2788(2)nm. P =92. 09(10). In the crystal,there are two di f Cerent kinds of coordination modes for Argnine. One is tridentate mode and the other is bidentate mode. The coordination number of copper ion is five. The copper ions are connected by the carboxyl group bridging ligand of L'-Argnine,construct ing an infinite chain,then 2-D network and even 3-D network are formed by hydrogen bonding among different molecules. At the same time,the complex,trans-[Cu(L-Arg)2] (NOs)23H20(3),was synthesized in IW-CHsCOCHa solution.,The crystal is monoclinic with space group P2(1). The cell parameters are :a1.03857(15)nm,h=l. 6885(3)nm,c=l. 59856(19)nm,P 108. 485(10)",V=2. 6542(6)nm:',Z=4,Uc=l. 477 Mg. m In (3),both of the Argnine are bidentate. The coordination number of copper ions is four. The unit of the complex is held together by hydrogen bonds,which forms a structure of three-dimensional network.The ternary complex of [Cu?(L-Asp) (phen);1] (N0.i)2 4H20(4) was obtained for the first time in the mixed solvents of tkO-CaHsOH and under the condition of the pH value of the reaction solution equalling 3. Complex (4) crystallized in monoclinic with space group P2(1) c,a = 1.2613(2)nm,b= 1.5008(4)nm,c=2.2307.(4)nm,p = 99. 55(1)",V=4. 1641 (15)nm!,Z=4,Dc=l. 587 mg.m:'o The two copper ions in the complex (4) are connected by L-Asp. There are two kinds of copper ions with different coordination environment. One is four-coordinate and the other is five-coordinate. The phen ligand is normally bidentate providing two N atoms to coordinate with metal ions. The crystal exits hydrogen bonds and very strong it - n stacking i nteract. ions.The ternary complex of [Ni:,(l,-Asp) (phen)s(ll20):] (ClOih 4. 75 H20 (5) ,was obtained for the first time in a solution of HzO-CallsOH mixed solvent with a pH value of 3.5. Complex (5) crystallized in triclinic with space group Pi and the cell parametres are:a = 1. 1861(2)?b=l. 8384(4)nm,c=1.9746(3)nm,a =107. 68 (1) ,P= 105.94(1)",y =103. 41 (2)",V=3. 7036(15)nm3,1=2,Dc=l. 565Mg.m"'. There are two co-ordinated cations in the complex (5) ,namely binuclear [Niz(L-Asp) (phen):i(ILO)]2 and monoriuc 1 ear [Ni (phen)2(H20)]2. All the nickel ions are six-coordinate with a distored octahedral geometry,but have different environment .In complex (5),no hydrogen bonds were observed between the cation and the ClOi anion. They are held together just through static electricity interaction .