Exercises I
1.) Name the following complexes according to the IUPAC nomenclature:
[Co(CO3)(NH3)4]NO3
K[MnO4]
[CrCl(H2O)5]Cl2
[CrCl2(H2O)4]Cl
Ba[FeO4]
Na2[TiO3]
[Pt(NH3)6]Cl4
K2[PtCl6]
2.) Write the formula for the following complexes:
Trisodium-hexafluoroaluminate
Pentacarbonyliron
Tetrapotassium-hexacyanoferrat(II)
Tripotassium-hexacyanoferrat(III)
Potassium-tetrafluorooxochromat(V)
Bisdiethylentriamincobalt(III)chlorid
Tris-2,2’-bipyridylchromium(I)iodide
3.) Ethylendiamine (abbreviated as “en”) formes with Cobaltchloride a complex [Co(en)2Cl2]Cl. Draw the possible structures of the complex in an octahedral and a hexagonal planar arrangement of the ligands. 4.) Give a reasoning for the finding that the OH- ion can function as a bridging ligand while this is never found with NH3?
Exercises II
1. Which structures do you expect for a complex with the formula [ZL4]? How could you distinguish between the different possibilities?
2. The molecules BCl3 and ICl3 have totally different structures though they both are element trihalogenides. Explain te difference.
3. From an aqueous solution of a complex with the composition CoClSO4(NH3)5 a precipitate is obtained with BaCl2 but not with AgNO3. Which structure has the complex?
4. Show the structures of a tetrahedron, a square, an octahedron and a trigonal prism by the method which uses points on the surface of a globe.
Exercises III
1. Which of the complexes [Cr(edta)]-, [Ru(bipy)3]2+, and [PtCl(dien)]+ are chiral?
2. Draw all the possible isomers of octahedral [Ru(NH3)4Cl2], square planar [Ir(PR3)2H(CO)], octahedral [CoCl3(OH2)3], and octahedral [CoCl2(en)(NH3)2]+.
3. Why is it not possible to separate and isolate the isomers cis-[CuCl2(NH3)4] and trans-[CuCl2(NH3)4]? Is it likely to be possible to separate and isolate the isomers cis-[IrCl2(NH3)4] and trans-[IrCl2(NH3)4]?
4. The commercially available chromium chloride has the composition CrCl3·6H2O. It is blue and produces a solution with a molar electrical conductivity similar to that of [Co(NH3)6]Cl3. In contrast CrCl3·5H2O is green and has a lower molar conductivity in solution. An acidified dilute solution of the green salt turns blue within some hours. Interpret these observations.
Exercises IV
1.) In a [CoF6]3--Complex the pairing energy of the electrons is 21000 cm-1 and the ligand field splitting is 13000 cm-1. Which type of a complex do you expect?
2.) Discuss the electronic structure and the magnetism of a d8 and a d10 ion in an octahedral and a tetrahedral field.
3.) How does the absorption band in the electronic spectra of complexes shift when the ligands I- is replaced by Cl-, Br- or CN-?
4.) Calculate the ligand field stabilization energy for a d1 and a d4system in an octahedral and a tetrahedral field.
5.) Which of the following complexes obey the 18 electron rule? [Cu(NH3)4]2+, [Fe(CN)6]4-, [Fe(CN)6]3-, [Cr(NH3)6]3+, [Cr(CO)6], [Fe(CO)5]?
Exercises to Coordination Chemistry
1. Give the formula of the following complexes according to the IUPAC rules:
a) Zinc hexachloroplatinate(IV)
b) Tetrammineplatin(II) amminetrichloroplatinate(II)
c) Potassium aquapentachlororhodate(III)
2. There are 5 diastereoisomers of a complex [PtCl2(NH3)2(NO2)2], one of them having an enantiomer. For each of the achiral isomers, locate the Sn axis to prove that it is not chiral.
3. How many coordination isomers could be formed starting with [Cu(NH3)4][PtCl4]. Write the formula for each isomer.
4.The addition of PEtPh2 to NiBr2 at -78°C in CS2 gives a red, diamagnetic complex with the formula (PEtPh2)2NiBr2 which is converted to a green, paramagnetic complex of the same formula on standing. Which of these complexes is square planar and which is tetrahedral?
5. The spinpairing energy P for Fe2+ is 210 kJ/mole. The ligand field splitting of [Fe(H2O)6]2+ and [Fe(CN)6]2+are 120 and 390 kJ/mole, respectively. Draw a diagram for the splitting of the d-Orbitals. Are these complexes in a high-spin or a low-spin state?
Klausurfragen
1. Make a sketch of an octahedral complex showing cis-/trans- isomerism and one showing fac-/mer-isomerism.
2. Write the formula of the following compounds:
Potassium-tetracyanoniccolate(0)
b) Potassium-tetracyanoniccolate(II)
c) Diaquabis(ethylendiamin)cobalt(III)-bromide
and the names of the following compounds:
d) [Co(en)2(SCN)Cl]Cl
e) cis[CrCl2(NH3)4]+
f) [Pt(NH3)4][PtCl6]
3. Make a sketch of the splitting of the d-orbitals in an octahedral ligand field. Name the different orbitals and show how the orbital energies are affected by an elongation of the octahedron along the c-axis.