CM2191 A0111185R Expt3
Name: Chen Yao Le Lab Group: Tues
Email: A0111185@nus.edu.sg
Matriculation Number: A0111185R Date of Experiment: 17 February 2015
Experiment 6: Synthesis, Electronic Spectra, Structural Isomerism: Octahedral Co(III) complexes with Chloride and Ethylenediamine Ligands
Abstract:
In this experiment, Δ/Λ-[Co(en)3]Cl3∙4H2O was synthesized and the absorbance in UV-vis spectrum was recorded. Δ/Λ-[Co(en)3]Cl3∙4H2O has an εmax of 197.33 mol–1dm3cm at 466.00nm and 210.39mol–1dm3cm-1 at 338.00nm. and the colour of the crystals obtained were orange. The crude product was then reacted with L-(+)-tartaric acid and 0.59g of the enantiomer [Λ-Co(en)3][(+)-tart]Cl∙5H2O was obtained. FT-IR spectroscopy was performed and the spectrum was analyzed. Green crystals of trans-[Co(en)2Cl2]Cl∙HCl∙2H2O was also synthesized and the cis-isomer was subsequently isolated by heating the aqueous solution in a steam bath. The UV-vis spectrum of trans-[Co(en)2Cl2]Cl∙HCl∙2H2O and cis-[Co(en)2Cl2]Cl∙HCl∙2H2O were recorded. The trans isomer has εmax values of 30.24, 24.55 and 32.03 mol–1dm3cm-1 at 609.00, 449.00 and 400.00nm respectively, while the εmax values of cis-[Co(en)2Cl2]Cl are 51.03 mol–1dm3cm-1 and 451.2 mol–1dm3cm-1 and the corresponding λmax are 504.00nm and 451.2 mol–1dm3cm-1 respectively. Cis-[Co(en)2Cl2]Cl∙HCl∙2H2O was observed to be pink in solution form.
Aims:
The aims of the experiment were to:
(1) Synthesize Δ/Λ-[Co(en)3]Cl3∙4H2O, [Λ-Co(en)3][(+)-tart]Cl∙5H2O, and the cis and trans isomers of [Co(en)2Cl2]Cl∙HCl∙2H2O.
(2) Perform UV-vis spectroscopy on Δ/Λ-[Co(en)3]Cl3∙4H2O, cis-[Co(en)2Cl2]Cl∙HCl∙2H2O and trans-[Co(en)2Cl2]Cl∙HCl∙2H2O, and report the λmax and εmaz of the complexes.
(3) Obtain and analyze the FT-IR spectrum of [Λ-Co(en)3][(+)-tart]Cl∙5H2O.
Introduction:
Molecules with identical chemical formula but different structures are known as isomers. There
Email: A0111185@nus.edu.sg
Matriculation Number: A0111185R Date of Experiment: 17 February 2015
Experiment 6: Synthesis, Electronic Spectra, Structural Isomerism: Octahedral Co(III) complexes with Chloride and Ethylenediamine Ligands
Abstract:
In this experiment, Δ/Λ-[Co(en)3]Cl3∙4H2O was synthesized and the absorbance in UV-vis spectrum was recorded. Δ/Λ-[Co(en)3]Cl3∙4H2O has an εmax of 197.33 mol–1dm3cm at 466.00nm and 210.39mol–1dm3cm-1 at 338.00nm. and the colour of the crystals obtained were orange. The crude product was then reacted with L-(+)-tartaric acid and 0.59g of the enantiomer [Λ-Co(en)3][(+)-tart]Cl∙5H2O was obtained. FT-IR spectroscopy was performed and the spectrum was analyzed. Green crystals of trans-[Co(en)2Cl2]Cl∙HCl∙2H2O was also synthesized and the cis-isomer was subsequently isolated by heating the aqueous solution in a steam bath. The UV-vis spectrum of trans-[Co(en)2Cl2]Cl∙HCl∙2H2O and cis-[Co(en)2Cl2]Cl∙HCl∙2H2O were recorded. The trans isomer has εmax values of 30.24, 24.55 and 32.03 mol–1dm3cm-1 at 609.00, 449.00 and 400.00nm respectively, while the εmax values of cis-[Co(en)2Cl2]Cl are 51.03 mol–1dm3cm-1 and 451.2 mol–1dm3cm-1 and the corresponding λmax are 504.00nm and 451.2 mol–1dm3cm-1 respectively. Cis-[Co(en)2Cl2]Cl∙HCl∙2H2O was observed to be pink in solution form.
Aims:
The aims of the experiment were to:
(1) Synthesize Δ/Λ-[Co(en)3]Cl3∙4H2O, [Λ-Co(en)3][(+)-tart]Cl∙5H2O, and the cis and trans isomers of [Co(en)2Cl2]Cl∙HCl∙2H2O.
(2) Perform UV-vis spectroscopy on Δ/Λ-[Co(en)3]Cl3∙4H2O, cis-[Co(en)2Cl2]Cl∙HCl∙2H2O and trans-[Co(en)2Cl2]Cl∙HCl∙2H2O, and report the λmax and εmaz of the complexes.
(3) Obtain and analyze the FT-IR spectrum of [Λ-Co(en)3][(+)-tart]Cl∙5H2O.
Introduction:
Molecules with identical chemical formula but different structures are known as isomers. There
References: 1Irving, H and Williams, R. J. P, The Stability of Transition-metal Complexes. 1952, J. Chem. Soc., 1953, 3192-3210 DOI: 10.1039/JR9530003192 http://www.ciens.ucv.ve/eqsol/Inorganica%20II/articulo2.pdf (assessed 20 Oct 2014) 2IR Applied to Isomer Analysis. http://www.spectra-analysis.com/documents/AppNote025IRAppliedToIsomers.pdf (accessed 20 Oct 2014,). 3Experiment 6. Alfred Werner, Early Insights on the Composition and Structure of Transition Metal Coordination Complexes. http://www.colorado.edu/chemistry/chem4021/Experiment%206.pdf (accessed 20 Oct 2014). 4The Kinetics of Aquation of the Trans-dichlorobis (ethylenediamine)-Cobalt(III) ion. http://www.colby.edu/chemistry/PChem/lab/KineticsAquation.pdf (assessed 20 Oct 2014)