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 …show more content…
Subsequently, 10mL of 3.5% H2O2 were added dropwise to the reaction mixture and was stirred for 20 minutes before heating to boiling at 80°C for 5 minutes. The reaction mixture was then taken off heat and allowed to cool undisturbed in an ice-bath for 30 minutes. Suction filtration was performed after to collect the crystals from the chilled solution The product was then washed with chilled 95% ethanol (2 x 15mL) and followed by diethyl ether (2 x 10mL). The crude product was then left to dry before recording the yield. 20mg of the crude product is then accurately weighed out and dissolved in deionized water in a 25mL volumetric flask. Deionized water was added to the volumetric flask to the mark and the UV-vis absorption spectrum of the crude product was recorded. Part 2: Resolution of Racemic Δ/Λ-[Co(en)3]Cl3 complexes 1.3g of crude product obtained from part 1, 0.81g of L-(+)-Tartaric acid and a magnetic stirrer bar were placed in a 50-mL beaker containing 2mL of deionized water. 5mL of 10% NaOH stock solution were then added dropwise to the reaction mixture. The mixture was gently stirred on a hotplate until the solids were observed to be completely dissolved. A piece of aluminum foil was then used to seal the beaker and kept in the fumehood for a week. After a week, the crystals of [Λ-Co(en)3][(+)-tart]Cl∙5H2O were collected by suction filtration using a Hirsch funnel. The crystals were subsequently washed with 3 ×
After 10 minutes the reaction liquid was separated from the solid using a vacuum filtration system and toluene. The product was stored and dried until week 2 of the experiment. The product was weighed to be 0.31 g. Percent yield was calculated to be 38.75%. IR spectra data was conducted for the two starting materials and of the product. Melting point determination was performed on the product and proton NMR spectrum was given. The IR spectrum revealed peaks at 1720 cm-1, which indicated the presence of a lactone group, and 1730 cm-1, representing a functional group of a carboxylic acid (C=O), and 3300cm-1, indicating the presence of an alcohol group (O-H). All three peaks correspond with the desired product. A second TLC using the same mobile and stationary phase as the first was performed and revealed Rf Values of 0.17 and 0.43for the product. The first value was unique to the product indicating that the Diels-Alder reaction was successful. The other Rf value of 0.43 matched that of maleic anhydride indicating some
Introduction: The purpose of this lab was to find the relative solubilities of some salts of the Alkaline Earths and use that information to find the order which they appear in the periodic table; also use that information to efficiently find an unknown alkaline earth halide. Also to find the relative oxidizing powers of the Halogens given and using that information finding the order of the Halogens in the periodic table; also use that information to efficiently find an unknown Halogen.
Likewise, the solution was placed in an hot water bath in order for the temperature to rise. Given the solution in the ice bath, it turned pink. Moreover, given the solution in the warm bath, it turned blue. At the wavelengths of 656nm and 519nm, the solutions absorbance’s were recorded at 4degrees Celsius and 40 degrees Celsius. Given the results, one can conclude that the reaction was exothermic. This is true because the reaction shifted to the left when heat was added which ultimately led to the production of more CoCl4
Zn-64,Zn-66,Zn-67 and Zn-70 is stable and Zn-62,Zn-63, Zn-65,Zn-68, Zn-69m and Zn-72 are unstable. The element subatomic
Identify two other triads which were identified during the early construction of the Periodic Table.
Abstract: Through a series of substitution reactions, different cobalt ammine complexes were created. These complexes were analyzed via, precipitation and gravimetric measures to determine that the substitution reactions that occurred.
The use of amino-polyalcohol ligands has been a particularly successful approach to synthesise such 3d-4f complexes, thanks to the degrees of freedom offered by the flexible ligand backbones.39 In previous work, we have shown how the ligand 1,3-bis(tris(hydroxymethyl)methylamino)propane (H6L, Fig. 1) can be used to build up polynuclear assemblies of 3d TM ions.40-43 Using H6L, both serendipitous assembly and directed synthesis were employed to synthesise novel compounds, with the most spectacular example being a [Mn18Cu6] complex built in a stepwise fashion starting from a monomeric precursor complex of Cu(II) with H6L.40 Whichever the approach, H6L has a tendency to encapsulate one 3d TM ion in the coordination pocket defined by the
The FTIR spectrum of CoCaOxM crystals were as shown in Fig 3. In FTIR spectrum, a strong band at 3434cm-1 and 3062cm-1 is due to asymmetric and symmetric OH stretching while an intense absorptions band at 3261cm-1 show inters molecular hydrogen bonded OH stretch. Intense absorption band at 1612cm-1 and 1318cm-1 can be assigned to asymmetric and symmetric C=O stretching bands specific to the Calcium Oxalate Monohydrate. The sharp band at 885cm-1 is due to C-C stretching vibrations which confirm the existence of oxalate group in Calcium Oxalate Monohydrate. The sharp peak at 781cm-1 is due to O-C=O and the wideband at 665cm-1 can be assigned to the bending modes of the water molecule. However, the peak at 518cm-1 is assigned to the presence of metal-oxygen bond (18-21). Thus FTIR reveals that the growth of COM crystals was due to the presence of O-H stretching, C=O, C-C, O-C=O and M=O bonds.
In order to obtain a good match to the data at low temperature, an intermolecular interaction, zJ, was included using the mean field approximation. The simulation shown in Fig. 5 has J = +0.255 cm−1 and zJ = −0.045 cm−1. Exchange between two transition metal ions as mediated by the closed-shell Ln(III) ions [La(III) at one end of the series, or Lu(III) at the other] has been found to be weak.29, 66, 67 A recent study used DFT calculations to show the exchange between Mn(III) ions across Y(III) in a Mn8Y8 disc to measure J = +0.43 cm−1,68 while antiferromagnetic coupling was observed in a linear Ni-La-Ni compound (J = −0.978 cm−1).69 An alternative to intermolecular antiferromagnetic interactions as an explanation for the decrease in χMT at low temperatures could be the ZFS associated with the Mn(III) ions. However, any attempt to include a contribution for the ZFS of the Mn(III) ion in the simulations was unsuccessful, because it overcompensated the weak intramolecular coupling interaction and negated the increase in χMT that is observed on lowering the temperature. To confirm the suitability of the simulated intra- and and intermolecular exchange interactions found for compound 1, and to investigate the possible ZFS associated with the Mn(III) ions, we used DFT and CASSCF calculations (vide infra).
The order stability of some divalent cations complexes with humic substances are as follows: Cu2+ > Ni2+
Organometallic are the most commonly compounds used in homogeneous catalysis. They usually contain various kinds of metals. Their reactivity, bonding (ionic and covalent or in-between) and stabilities are premised on 18 electrons rule. Organometallic compounds contain at least 1 carbon to metal bond. There are also organometallic complexes which have covalent bonds between organic ligands and a metal. The metal binds to ligands through an atom e.g. O2 or N; such compounds are referred to as coordination compounds. The complexes are basic in nature, also as reducing agents act as superoxide anion scavengers which help in catalyzing polymerization reactions and thus used clinically to treat tissues and cell injuries be it lymphomas or carcinomas. Rhodium compounds is analogues to the corresponding Platinum and Ruthenium compounds serve as effective anticancer agents due to significant antitumor properties. Effective advanced technologies such as nuclear magnetic resonance (NMR) and infrared spectroscopy (IR) are used to determine the dynamic properties, structures and industrial uses of organometallic compounds and complexes due to the ability to absorb the available proton occupied each site of a metal atom in the solution.
As shown in figure 3, C-C bond lengths for the tris(trimethylsilyl)cyclopropenylium cation are not equal. The ring is significantly distorted from its ideal D_3h symmetry since one of the carbon atoms in the ring system is close to the chlorine atoms in the hexachloroantimonate. This distortion shows that it is caused by the counterion and lattice effects.^4 Using the isodesmic hydride transfer reaction, the effect of trisilyl and trismethyl substitution was calculated. Three sillyl groups stabilize 1 by 22.4 kcal/mol while three methyl groups has a larger effect and more stable than 1 by 31.4 kcal/mol. Thus, Me > Si >>H was found as the order of the
Chemical structures of the ligands i) asperyellone [CID101600052]; ii) asperenone [CID5368642]; iii) hydroasperyellone [CID561143]; iv) CHEMBL1715716 [CID49859207] and v) CHEMBL2152350 [CID71458428] were downloaded PubMed (www. pubmed.com) database. The ligands were drawn in ChemBioDraw Ultra 12.0 (www.cambridgesoft.com) and subsequently molecular mechanics (MM2)
Since Alfred Werner proposed the concept of coordination chemistry at the beginning of 20th century, this field has developed very fast and led to the development of many interdisciplinary areas [1]. This has led to the emergence of allied fields like transition metal organometallic chemistry, homogeneous catalysis and bio-inorganic chemistry. Coordination chemistry is a fundamental to other pioneering fields like solid state chemistry, extended and mesoscopic materials, photonic materials, models for solid surfaces, separation sciences and molecular electronics. Together with supramolecular chemistry, coordination chemistry has developed new, sophisticated ways to synthesize novel materials for catalysis, gas storage and magnetic data storage [2-9].
Moreover we have found that the sol-gel chemistry which is dividing into two categories aqueous and non-aqueous; has many benefits likely easily produce metastable materials, homogeneity in structure with high purity at different temperatures with simple laboratory equipment. Also its gives various morphologies at synthesis stage (chemical transformation of the molecular precursor to the oxidic network). The aqueous sol-gel chemistry has vastly popular to fabricate bulk metal oxides; they have few limitations, when it works at their nanoscale counterparts. It is more complex because metal oxide precursors are high reactive in water based solvents.