Laila H. Abdel-Rahman

SYNTHESIS, X-RAY CRYSTAL STRUCTURES AND CHARACTERIZATION OF COPPER(II)-2,2'-BIPYRIDYL DERIVATIVES OF (4-AMINO)-HIPPURIC ACID AND OF L-PROLINE

Abstract In this paper the synthesis and the characterization of two complexes of copper and 2,2′-bipyridyl with amino acids 4-aminohippuric acid and l -proline are reported. The X-ray structure reveals for the first complex, [Cu2(OH)(OH2)(bipy)2(Am-hip)](NO3)2·4H2O, dinuclear copper(II) cations with nitrate counterions and lattice water molecules. The two metal centres are linked together by a water molecule, a hydroxyl group and the carboxylic moiety of the 4-amino-hippuric acid, the remaining two positions on both metal centres are occupied by bipyridyl molecules. The second compound consists of monomeric [Cu(OH2)(bipy)( l -pro)]+ cations and perchlorate anions. Also in this case copper is five-coordinated in a distorted square pyramidal geometry with the bipyridine nitrogens, one carboxylate oxygen atom and the amino nitrogen of the l -proline ion on the basal plane.

N-Phthaloylglycinate ternary complexes with cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) metal ions and aromatic mono, bi and tridentate amines

Complexes of N-phthaloylglycinate (N-phthgly) and CoII, NiII, CuII, ZnII and CdII containing imidazole (imi), N-methylimidazole (mimi), 2,2′-bipyridyl (bipy) and 1,10-phenanthroline (phen), and tridentate amines such as 2,2′,2′′-terpyridine (terpy) and 2,4,6-(2-pyridyl)s-triazine (tptz), were prepared and characterized by conventional methods, i.r. spectra and by thermogravimetric analysis. For imi and mimi ternary complexes, the general formula [M(imi/mimi)2(N-phthgly)2]·nH2O, where M = CoII, NiII, CuII and ZnII applies. For CdII ternary complexes with imi, [Cd(imi)3(N-phthgly)2]·2H2O applies. For the bi and tridentate ligands, ternary complexes of the formula [M(L)(N-phthgly)2]·nH2O were obtained, where M = CoII, NiII, CuII and ZnII; L = bipy, phen, tptz and terpy. In all complexes, N-phthgly acts as a monodentate ligand, coordinating metal ions through the carboxylate oxygen, except for the ternary complexes of CoII, NiII and CuII with mimi and CuII and ZnII with imi, where the N-phthgly acts as a bidentate ligand, coordinating the metal ions through both carboxylate oxygen atoms.

Ruthenium carbonyl derivatives of N-salicylidene-2-hydroxyaniline

The ruthenium tricarbonyl derivative [Ru(CO)3(sha)] (1), was synthesized from reaction of [Ru3(CO)12] with N-salicylidene-2-hydroxyaniline (shaH2) Schiff base. The corresponding reactions of the ruthenium cluster with shaH2 in presence of a secondary ligand L,Lu2009=u2009pyridine and triphenyl phosphine resulted in the formation of the dicarbonyl derivatives [Ru(CO)2(shaH2)(L)] (2, 3). In the presence of Lu2009=u20092-aminobenzimidazole or thiourea, two complexes [Ru(CO)2(sha)(L)] (4, 5) were formed and the shaH2 ligand bonded to ruthenium oxidatively. The bipyridine(bpy) derivative had the molecular formula [Ru(CO)2(shaH)(bpy)] (6), with shaH coordinated bidentate. All complexes were characterized by elemental analysis and mass, IR, 1H NMR and UV–Vis spectroscopy. The spectroscopic studies of these complexes revealed several structural arrangements and different tautomeric forms.

Synthesis and spectroscopic properties of N-acetyl-DL-phenyl-glycinato complexes of cobalt(II), nickel(II) and copper(II). Crystal structures of bis(N-acetyl-DL-phenyl-glycinato)diaquobis-(N-methylimidazole)cobalt(II), bis(N-acetyl-DL-phenylglycinato)diaquobis (imidazole)cobalt(II) and nickel(II)

Abstract A series of complexes of N-acetyl-DL-phenylglycine and Co II , Ni II and Cu II containing heterocyclic bases as imidazoles, phen, bipy and terpy were prepared and characterized by conventional methods, IR spectra and, for [Co(OH 2 ) 2 (mimi) 2 (Ac-phgly) 2 ] ( 1 ), [Co(OH 2 ) 2 (imi) 2 (Ac-phgly) 2 ] ( 2 ) and [Ni(OH 2 ) 2 (imi) 2 (Ac-phgly) 2 ( 3 ), by X-ray crystal structure. The structure of these complexes consists of discrete [M(OH 2 ) 2 (mimi/imi) 2 (Acphyly) 2 ] units in which the metal shows nearly ideal centrosymmetrical trans -octahedral geometry bonding two imidazole nitrogens, two carboxylic oxygens and two water molecules. In all cases the amino acid behaves as monodentate via carboxylic oxygen, the second carboxylic oxygen; the NH and CO peptide groups are involved in hydrogen bonds which are responsible for the packing in the crystal.

Synthesis and characterization of ternary L-histidine complexes: crystal structure of (2,2'-dipyridyl)-(L-histidinato-N,N',O) copper(II) perchlorate 1.5 hydrate

A series of ternary complexes of copper(II), cobalt(II) and zinc(II) with L-histidine, 1,10-phenanthroline, 2,2′-dipyridyl or imidazole having perchlorate or acetate as counterions were synthesized and characterized by conventional methods and for [Cu(bipy)(L-hist)]ClO4·1.5H2O and X-ray crystal structure was determined. The crystals belong to the monoclinic space groupC2 witha=18.843(3),b=10.582(2),c=11.020(2)Å, β=115.20(10)°,Z=4,R=0.0535. The structure is consistent of [Cu(bipy)(L-hist)]+ cations, perchlorate ions and water molecules. The geometry around copper is trigonal bipyramidal with one N,N′,O tridentate L-histidine molecule and one 2,2′-dipyridyl ligand, the apical sites are occupied by the α-amino nitrogen [Cu−N(71) 1.995(8)Å] and by N(11) of 2,2′-dipyridyl [Cu−N(11) 1.983(7)Å], the equatorial plane is formed by the N(3) imidazole δ-nitrogen [Cu−N(3) 2.140(6)Å], O(82) carboxylic oxygen [Cu−O(82) 2.009(5)Å] and N(22) [Cu−N(22) 2.010(7)Å].

Complexes of zinc(II) and cadmium(II) with N-phthaloylglycinate, imidazole, 5-amino tetrazole and 2,4,6- tris (2-pyridyl)-1,3,5-triazine. X-ray crystal structure of [Cd(imi)3(N-phthgly)2]·2H2O

Complexes of Zn(II) and Cd(II) with N-phthaloylglycinate (N-phthgly), imidazole (imi), 5-amino tetrazole (Atz) and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) were synthesized and characterized by elemental analysis, IR and thermogravimetric analysis. The X-ray crystal structure of the cadmium complex [Cd(imi)3(N-phthgly)2]u2009·u20092H2O is also reported. It crystallizes in the space group P21/m. The metal centre is hepta coordinated as a distorted pentagonal bipyramid. The cadmium atom is surrounded by five equatorial atoms (four oxygen atoms of two bidentate N-phthaloylglycinate moieties and a nitrogen atom of an imidazole ligand) and two axial nitrogens of two imidazole rings. In the crystal, the molecules are connected by H-bonds involving water molecules, the carboxylic oxygens of the N-phthaloylglycinate molecules and the imidazole nitrogens.

Synthesis and spectroscopic properties of copper(II)-N- phthaloylglycinate derivatives of imidazole, methylimidazole, 1,10-phenanthroline and 2,2′,2′′-terpyridine. Crystal structure of [Cu(OH2)2(phen)(N-phthgly)] (NO3) · H2O and [Cu(terpy)(N-phthgly)2] · H2O

A new series of copper(II) ternary complexes of N-phthaloylglycinate (N-phthgly) with imidazole (imi), methylimidazole (mimi), 1,10-phenanthroline (phen) and 2,2′,2′′-terpyridine (terpy) have been synthesized and characterized. For two complexes [Cu(terpy)(N-phthgly)2]H2O (1) and [Cu(OH2)2(phen)(N-phthgly)] NO3u2009·u2009H2O (2), crystal structures have been determined by X-ray diffraction. In complex 1, the Cu(II) exhibits a distorted square-pyramidal geometry arising from coordination of three nitrogen atoms of 2,2′,2′′-terpyridine and one oxygen of N-phthaloylglycinate in the basal plane and an oxygen atom of the second N-phthgly in the apex. In compound 2, the copper(II) shows a distorted square-based pyramidal conformation with two nitrogens of the phenanthroline molecule, one water oxygen atom and a carboxylic oxygen of N-phthgly ligand forming the base; a second water is in the apex position. Water molecules and the carboxylate oxygens of the N-phthaloylglycinate molecules connect the molecules by H-bonds.

Complex formation equilibria for s‐amino acid amides with nickel(ii) in aqueous solution

Abstract Solution equilibria of Ni11 with S-amino acid amides (alaninamide, valinamide, phenylalaninamide, prolinamide, tryptophanamide, (L)) were studied by potentiometry and spectrophotometry at 25°C and I = 0.1 mol dm−3 (KCl). The main species detected were [NiL]2+, [NiL2]2+, and [NiL2H−2]. Simultaneous ionization of two amide protons from [NiL2]2+ yielded a square planar complex [NiL2H−2] showing very different complexing behaviour of Ni11 with respect to Cu11at high pH values (but not at low pH). These results are discussed with reference to literature data for other amino-amide ligands and oligopeptides.