Much like the CO ligands, cyanide (CN-) ligands have IR stretching frequencies that are distinctive and...

Much like the CO ligands, cyanide (CN^-) ligands have IR stretching frequencies that are distinctive and therefore often particularly useful. Consult an appropriate character table, and give a reducible representation for the cyanide stretching vibrations in the square-planar tetracyanoplatinate(II) ion, Pt(CN)₄^2-.

Solutions

Expert Solution

Answer :

CN- is isoelectronic with CO and NO+. Both CO and CN- co-ordinate to the metal atom through carbon. The free CN- ion has a stretching frequency of 2080 cm-1, in complexes it generally has a higher value and a sharp absorption in the range 2000-2200 cm-1 is observed.

In the free state the contribution of II a is greater than I a towards the resonance hybrid.
In complexes the contribution of I b or II b depends on the metal atom to which it is coordinated. It has been found that CN stretching frequency in its complexes depends on electro negativity, oxidation state and co-ordination number of the metal atom.

Electro negativity of the metal The stretching frequency of the ligand CN increases with increase in electro negativity of the metal ion.

[ Ni (CN)4]2- < [ Pd (CN)4]2- < [ Pt (CN)4 ]2-

2135 cm-1 2143 cm-1 2150 cm-1

In the graph the CN- strching frequncy is in 2135 cm-1

queen_honey_blossom answered 5 months ago

Next > < Previous

Related Solutions

The relative donor effect of simple ligands can be determined by measuring the carbonyl stretching frequencies...

The relative donor effect of simple ligands can be determined by measuring the carbonyl stretching frequencies of their metal carbonyl coordination complexes. Imagine you have prepared a series of L2-Ir(CO)Cl complexes and measured the carbonyl stretches. Assign the stretches (2102, 2054, 2032, 2014, 1995 cm -1 ) to the complexes containing the following ligands (assume that all ligands are purely σ-donors): NPh3, PPh3, pyridine, 4-fluoropyridine, 4-bromopyridine. Explain your reasoning!

In IR spectroscopy, why do heavier atoms have IR absorptions at lower frequencies?

a) how many CO stretching absorption are in the IR spectrum of fac-(MeCN)3Cr (CO)3 b) Which...

a) how many CO stretching absorption are in the IR spectrum of fac-(MeCN)3Cr (CO)3 b) Which irreducible representations correspond to these absoprtions?

The CO ligands in the molecule Ni(CO)4 could have two possible geometries – a tetrahedral arrangement...

The CO ligands in the molecule Ni(CO)4 could have two possible geometries – a tetrahedral arrangement of carbon monoxides around the central nickel atom, or a square planar geometry in which all of the atoms are in the same plane and all of the C-Ni-C angles are 90º. For each geometry, determine the following: (a) What is its point group? (b) Write the reducible representation for the C-O stretching vibrational modes. (Hint: For the square planar form, C2' and sv...

The CO ligands in the molecule Ni(CO)4 could have two possible geometries - a tetrahedral arrangement...

The CO ligands in the molecule Ni(CO)4 could have two possible geometries - a tetrahedral arrangement of carbon monoxides around the central nickel atom, or a square planar geometry in which all the atoms are in the same plane and all of the C-Ni-C angles are 90 degrees. For each geometry, determine the following: (a) What is the point group? (b) Write the reducible representation for the C-O stretching vibrational modes. (c) Use the reduction formula to determine the irreducible...

Since the coronavirus has had a major effect on much life, we would like to have...

Since the coronavirus has had a major effect on much life, we would like to have some information on how many people have had it, have it or do not have it. How would you design a study? Would you use a variable measurement that is nominal, ordinal, interval, ratio or a combination of these? Would you obtain your random sample using an study based on an observational, experimental, simulation, published data or a survey using a stratified, clustered, systematic...

You would like to have $600,000 when you retire in 30 years. How much should you...

You would like to have $600,000 when you retire in 30 years. How much should you invest each quarter if you can earn a rate of 3% compounded quarterly? a) How much should you deposit each quarter? $ b) How much total money will you put into the account? $ c) How much total interest will you earn?

Your client would like to switch an 80% allocation in your portfolio to an 80% allocation in the stock market index. How much would your client have to earn in your portfolio to earn the same return?

You estimate that a passive portfolio invested to mimic the S&P 500 stock index yields an expected rate of return of 10% with a standard deviation of 19%. Assume you manage a risky portfolio with an expected rate of return of 12% and a standard deviation of 24%. The T-bill rate is 5%. Your client would like to switch an 80% allocation in your portfolio to an 80% allocation in the stock market index. How much would your client have...

Subjects