عنوان المقالة:أنظمة جديدة لليكاندات ثنائي داي ثايو كارباميت في تكوين المعقدات, تحضير وتشخيص طيفي والفعالية البكتيرية New Bis(dithiocarbamate) Ligand Systems for Complex Formation; Synthesis, Spectral Characterisation and Bacterial Activity
Summary
This thesis is based on the synthesis and characterisation of a number of dithiocarbamate (dtc) ligands and their binuclear metal(II) dithiocarbamate macrocyclic complexes. In these complexes, metal ion assisted the assembly of the complex formation. ligands were prepared from the reaction of precursors with CS2, Preparation of the precursors was based on using of secondary diamines, which were synthesised in two steps; first step includes preparation of acetamide precursors from the reaction of benzidine with chloroacetyl chloride or dichloroacetyl chloride in the presence of alkali base (KOH), while second step based on preparation of secondary amines from the reaction of acetamide with primary amines.The ligands were prepared from the reaction of carbon disulfide and secondary amines in the presence of alkali base (KOH) that gave the free ligands (L1, L2, L3, L4).
Where:
L1= (potassium 2,2'-(biphenyl-4,4'-diylbis(azanediyl))bis(2-oxoethane- 2,1-diyl)bis(propylcarbamodithioate)
L2=(potassium2,2'-(biphenyl-4,4'-diylbis(azanediyl))bis(2-oxoethane-2,1-diyl) bis(benzylcarbamodithioate)
L3= (potassium2,2'-(biphenyl-4,4'- diylbis(azanediyl))bis(1-chloro-2 -oxoethane-2,1-diyl)bis(cyclohexylcarbamodithioate))
L4=(potassium2,2'-(biphenyl-4,4'-diylbis(azanediyl))bis(2-oxoethane-2,1-diyl) bis(isopropylcarbamodithioate))
The aim of preparation of the free ligands was to allow us conducting full characterisation on the ligands. The free dithiocarbamate ligands; L1 , L2, L3 and L4 (see Scheme).
Scheme: Synthetic route for ligands L1 , L2, L3 and L4
The bimetallic complexes were synthesised using two approaches; (i) from the reaction of free ligand with metal ion, and (ii) via a one pot reaction. In free ligand approach; complexes were prepared from the reaction of equivalent potassium dithiocarbamate salt with equivalent of the metal salt; MnII, CoII, NiII, CuII, ZnII and CdII. In the second approach; the complexes were prepared in one pot reaction by mixing carbon disulfide, with the appropriate secondary amine and metal salt in the presence of (KOH) using mixture of MeCN:H2O. Ligands and complexes were fully characterised by elemental analysis for selected complexes, melting points, magnetic susceptibility for complexes, conductance, bacterial activity, FTIR, UV-Vis, mass spectroscopy L1 , L2, L3 and L4 and 1H-, 13C-, 13C-DEPT at 135º and COSY NMR spectroscopy. FTIR and NMR studies revealed a bidentate coordination mode of the CS2 moiety to the central metal ion. Furthermore, FTIR studies showed asymmetric (anisobidentate) and symmetric bidentate coordination mode. Physico-chemical analysis revealed that the bisthiocarbamate macrocyclic complexes exhibited four coordinate structures in the solid and solution state with the general formula:
[M(Ln)]2
(where M = Mn II, CoII, NiII, CuII, ZnII and CdII; Ln = L1-L4)
Ligand
R Metal ion(II)
L1
Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)
L2
Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)
L3
Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)
L4
Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)
ا.د. انعام اسماعيل يوسف | Enaam Ismail Yousif | 22725