Question

Exercise 1: 1. What kind(s) of interaction between the ligand and the metal ion is(are) considered in the crystal field approach? 2. Give and justify the degeneracy lifting for a tetrahedral complex. Would it be the same for an octahedral complex? 3. Let us consider hexaaquacopper(II) ion. Justify the elongation of two opposite Cu-O bonds (along z for example) compared to the other four Cu-O bonds using crystal field theory 4. Can tetrahedral Fe(II) complex exhibit low spin (LS) and high spin form (HS)? If yes, give example of ligand favoring LS state and HS state respectively. 5. Can octahedral Fe(III) complex exhibit low spin (LS) and high spin form (HS)? If yes, give example of ligand favoring LS state and HS state respectively. 6. Can octahedral Pt(IV) complex exhibit low spin (LS) and high spin form (HS)? If yes, give example of ligand favoring LS state and HS state respecyively 7. Calculate the Crystal Field Stabilisation Energy (CFSE) for the hexaaquairon(II). Exercise 2: Molecular orbitals diagram of hexafluorurocobaltate (II) ion 1. What is the electronic structure of 7Co? 2. What are the valence orbitals of this atom? Indicate on the diagram below to which irreducible representations (IR) of the Oh point group they belong. 3. Show that the fluoride ligand can play the role of both o-donor and x-donor ligand. r. decomposes as for purely o-donor ligands, e.g. . -aigtegtti0, leading to the same MO than for purely o-donor ligands (see diagram below). We are now going to look at the effect of the r-donor ability of the ligand. 4. Give the decomposition of r., the representation of the 12 m orbitals of the 6 fluorine ligands into IR of the Oh point group. 5. Schematize the linear combinations (LCs) of the n-symmetry orbitals of the fluorides enabling a z overlap with cobalt valency AOs. 6. Complete the diagram below taking into account the -donating ability of the ligands. 7. What is the qualitative influence of this overlap on the MO diagram of the complex? Accordingly, where fluorine will stand in the spectochemical series compared to a purely o-donating ligand? 8. Represent the MOs whose energy has changed significantly compared to the hexaamminecobalt (III) ion case.

i can't solve this question of coordination chemistry, could someone hlep me please

Answer 1

I 141 leg 14 de In Crystal field interaction electrostatic 3) Hexaaqua copper (II)ion forces of interaction takes place between [Cu(H2O) 2 (Ar]3d9 positively charged metal ion and ligand 1 day? containing e-hair. Nucleus of metalion altract &-fair of approaching ligand 7 Degreneracy is defined as the existence 2147 tag of same energy for orbitals. Egi In absence of ligand all d-orbitals | Cult ion is a symmetrically filled in have equal energy they are degenerate eg-state. So it undergo some sort Tetrahedral cause when ligand approaches of distortion (Jahn Teller distortion) to (4 in tetrahedral) then doskital of lower asymmetry and gain stability by metal gets splitted into 2 sets of splitting eg oobitals into dz² and datyt. Orbitals (e and tz) . This is called duty osbitals face ligands from splitting or lifting of degeneracy. 4 sides while dz² only from 1 side. Octahedral: th Octahedral casel 6 ligads) Due to presence of dz²+2 é more splitting also take filace but CFSE refeulsion takes place and hence bood is high becaux extent of repulsion becomes weak and elongated is more because of 6 ligands and This Colt hos 4 shooter and 2 loger bonds. legands approach along directly at the 3 [fe (420) 73 [FelloN)6] 3- Fe3+: [Ar]3d5 F²t: Part 3d 5 asis of d- orbitals. AZ as High Do as low Do ez 24/1417 lowshin Octahedral splitting Tetrahedral Splitting high shin shin depends on maximum number of unfaired e which intern depends on energy gap between 2 sets of orbitals. When weak legand At u yo

such as H₂O is used, Do is less and hence fairing does not occur resulting in high shin compound. On the contrary, when strong legand like CN is used, Do is too high to fill the ē in eg and hence fairing occurs to give low shin comfiles. Conclusion: Thus, Octahedral Fello) complexe can form low shin high spin complex defending on the ligand strength 9 Tetrahedral complexes already have . Very less energy gap. Therefore, always & jumps to higher energy level and forms high spis complex. {Fe (Holy 13tfe: [Ar] 3ds Ankita conclusion: Felt) tetrahedral ds/ lot complesses always form The high Shin and not low (High spin) Spein irrespective of legand used becaud It is very small.