Views
3 years ago

Wzor A,B-tekst

Wzor A,B-tekst

Wzor

Techno Science Africana Journal, Volume 3 Number 1, June, 2009N4O3 SCHFF BASE LIGAND IN THE SYNTHESIS OFMULTIMETALLIC ZINC LANTHANUM COMPLEXAbdullahi MustaphaDepartment of Chemistry, Kano University of Science and Technology, Wudil. PMB 3244 Kano State ,Nigeria, Email: abmustapha2004@yahoo.comABSTRACTThe synthesis and characterisation of schiff base has been carried out. The metal to ligand ratiowas found to be 3:2, while zinc metal was found to sit deep inside the pocket of the tripodalligand, the lanthanum ion bridge between the peripheral oxygen of the tripod to form atrimetallic metal complex.Key words: zinc, lanthanum, heptadentate, trimetallic.INTRODUCTIONRecently we have develop interest in designing amultidentate ligand, which is capable ofencapsulating metal ion into its pocket, and allowthe complexation of second metal at theperipheral of the complex. Through this system abi and trimetallic complexes have been generated(Abdullahi et al 2008). The potentiallyheptadentate ligand with N4O3 potential donorswas synthesised, while the metal complexes of Niand Zn were reported, with the ligandcoordinated to the metals in octahedral fashion.The homotrinuclear metal complexes wereisostructural (figure 1) with the linear anglebetween the three metals found to be 175 o .Figure 1: The diagram representation of [(TtrenSalNi)2Ni] complexOver the years there has been a developinginterest in the preparation of mixed d/f metalcomplexes, due to their relevance in singlemolecule magnet (SMM), and as contrast agentsfor magnetic resonance imaging (MRI) (Bayly etal., 2003 ). Due to hydrolysis problem (Malek etal 1979) there has been a limited report on theschiff base chemistry of lanthanides and mixedmetallic system. However, until recently whenkobayashi (2006) reported the sythesis of mixedmetal system with schiff base containing Ni/Feand Ni/Mn.Our aim is to design a system thatcoagregate 3f 0 and 3d 10 metal ions (lanthanumand zinc). This will allow us to study theircoordination chemistry and to look in to theirpotential application in chemoluminiscene.MATERIALS AND METHODSAll chemicals were used as purchased withoutfurther purification. The microanalysis, massspectra and infrared spectroscopy were run atuniversity of Strathclyde (UK). Briefly, the ligandwas prepared by refluxing one mole oftriethylamine with three mole of salicylaldehydein methanol for one hour. The resulting yellowpowder was obtained, filtered and dried.48Complex preparation: 1mole of theligand (TrenSal = Tris (2-hydroxybenzylaminoethyl)amine) was dissolve in50ml absolute ethanol, followed by the additionof 1mole equivalent of ZnCl 2. To the mixture wasadded slowly 0.5mole equivalent La(NO 3) 3.6H 2O.The resulting cloudy mixture was brought toreflux for 0.5 hours, after which the solution wasallowed to cool and the light yellow solid filteredand dried under vacuum. Yield 65%.Infra red spectrum FTIR [/cm -1 (KBr)]:3426 (broad,OH); 1639 (strong, -C=N); 768 (aromatic); 1152(C-O); 1460 (NO 3). Mass Spectral analysis (ESI)m/z, 1174 (20%, [(LZn) 2La] + , 1045 (15%, [(LZn) 2] 2- ,521 (90% [LZn] + ). Elemental analysis, % calculatedfor C 55H 58N 9O 10Zn 2La: C; 51.33, H; 5.48, N; 9.79. %found, C; 51.99, H; 5.06, N; 10.12.RESULTS AND DISCUSSIONIn our recent report (Abdullahi et al., 2009), wehave highlighted the use of hydrogenatedschiffbase in the synthesis of d and f metalcomplexes. The system reported there is simpleand rely on the stepwise coagregation of the twometals in a systematic way.

Vrouwen en freefight - MCM tekst
download PDF (820 Kb) - mike tekst & beeld
326x Romi - engleski tekst - slog - za site.indd - Rosa Luxemburg ...
120106 A cover 1 laag met tekst 2 - VHM
Titel-slide (44 pt groene tekst op groene lijn; 2e regel eronder)
Titel-slide (44 pt groene tekst op groene lijn; 2e regel ... - Efmo.org
Titel-slide (44 pt groene tekst op groene lijn; 2e regel eronder)
Titel-slide (44 pt groene tekst op groene lijn; 2e regel eronder)
Titel-slide (44 pt groene tekst op groene lijn; 2e regel eronder)
B